Date: Wed, 06 Jan 1999 08:14:22 -0800 From: Eric Westland Subject: Re: COZY: Epolite 9935 substitute While hot glue is not a replacement for the 5 minute epoxy, I found that in many of the applications you are just using the 5 min. to tack parts together and the hot glue did just fine. Militch@aol.com wrote: > I am using MGS285 epoxy and like it a lot. It is easy to use, flows well, and > has no offensive odor. This is important because I am working in my basement. > Unfortunately the 5 minute epoxy (Epolite 9935) that I use to glue pieces of > foam together occasionally is not so nice. The hardener stinks terribly, and > the smell goes through the house in an instant. Senior management (my wife and > kids) have handed me a cease and desist notice. Can anyone suggest an > alternative that has no odor? Cost is no object since I only use the stuff in > small quantities. > > Thanks, > Peter Militch Chapter 4, bulkheads. From: Epplin John A Subject: RE: COZY: Epolite 9935 substitute Date: Wed, 6 Jan 1999 10:31:55 -0600 Try the System Three quick cure 5 minute epoxy. Almost no odor. Only drawback I have found is the B part will harden on its own in about a year, order the smaller kits, I believe they are one pint total. I am not sure, but maybe heating the stuff will get it back into usable form again, anybody out try that? John epplin Mk4 #467 > -----Original Message----- > From: Militch@aol.com [SMTP:Militch@aol.com] > I am using MGS285 epoxy and like it a lot. It is easy to use, flows well, > and > has no offensive odor. This is important because I am working in my > basement. > Unfortunately the 5 minute epoxy (Epolite 9935) that I use to glue pieces > of > foam together occasionally is not so nice. The hardener stinks terribly, > and > the smell goes through the house in an instant. Senior management (my wife > and > kids) have handed me a cease and desist notice. Can anyone suggest an > alternative that has no odor? Cost is no object since I only use the > stuff in > small quantities. > > > Thanks, > Peter Militch Chapter 4, bulkheads. Date: Wed, 06 Jan 1999 12:15:21 -0500 From: bil kleb Subject: Re: COZY: Epolite 9935 substitute Militch@aol.com wrote: > > I am using MGS285 epoxy [...] it has no offensive odor. how would you know? don't you wear a respirator?! i can't stand the thought of losing my ten-year-plus dream to an allergic reaction have way through building. carbon monoxide has no odor. please review the archives on epoxy, safety, etc. -- bil Date: Wed, 06 Jan 1999 12:41:32 -0500 From: Bulent Aliev Subject: Re: COZY: Epolite 9935 substitute "While hot glue is not a replacement for the 5 minute epoxy, I found that in many of the applications you are just using the 5 min. to tack parts together and the hot glue did just fine." I use that too and like it. Just that if you have to sand it later will gum up your sand paper Bulent Date: Wed, 06 Jan 1999 14:46:25 -0500 From: bil kleb Subject: Re: COZY: Epolite 9935 substitute someone responded (privately): > > I wore a respirator when I used Saf-t-poxy that stuff stinks my point was (supposed to be) that certain stuff kills without any detectable odor. what does the msds sheet say for MGS? > I too am using MGS and he is right there is No Odor odor isn't the only thing to consider. 2427 had low odor, but plenty of folks doing layups in their basements chose to wear respirators. > I too Dont use a respirator with the MGS that's fine by me, it's your choice. > But the hands.... I wear gloves to protect myself from buildup > from an allergic reaction. good plan, just remember that _latex_ gloves have been shown to pass components of our epoxy systems... > not Going to get into a pissing contest... But :) > If your Not using the MGS epoxy Dont make Comment on it.... i apologize, i was not intending to make a comment on MGS. i was just trying to point an apparently new builder to the archives to raise his awareness of safety considerations... and offering a brief glimpse of the rationale behind what i have chosen to do. (which is what this group is all about, no?) > this is my second cozy.. and I have helped a few Friends Build Longs.. > I have used RAE, Saf-t-poxy and this new MGS...and from personal > experience.. the MGS is the best i don't understand "best", best in what respect? pot-life, storage properties, humidity sensitivity, safety, odor, viscosity, etc.? > however personal saftey always comes first. my point exactly. > Maybe I,m lucky I have not had any allergic reactions to any > of the above. that is what they say: it is not a matter of "if", but when; and it depends on the person how soon "when" is. however, once you find out "when", it's too late. plenty of people have had to put their dream projects up for sale... > I have more Problems with fumes from the heaters in the shop > than I do with the Epoxy. to each his own. personally, i like the smell of kerosene... :) -- bil From: cdenk@ix.netcom.com Date: Wed, 6 Jan 1999 17:21:48 -0600 (CST) Subject: Re: COZY: Epolite 9935 substitute Someone said The epoxy most times functions as structural adhesive to transfer shear loads (parallel to the joint plane), I wouldn't want to trust hot glue for that! If you were to cut a section, say a 1 foot wide perpendicular to direction of travel, piece of wing forward of the spar. All the loads (lift) have to be transfered by foam and fiberglass skin to the spar. The skin takes the bending in compression (and partly by foam) and tension (all by skin). The vertical load is carried entirely (glass does so little, it is neglected) by the foam. This same principle carry through nearly everywhere, including the fuselage bulkheads and sides. Date: Wed, 06 Jan 1999 19:57:24 -0600 From: James Russell Subject: Re: COZY: Epolite 9935 substitute cdenk@ix.netcom.com wrote: > > Someone said > The epoxy most times functions as structural adhesive to transfer > shear loads (parallel to the.... Hi to all: In general, I just wanted to say thanks to all for making this list interesting reading! Having many views of a problem is certainly a help to me. I think people asking for input regarding changes is so much better than just substituting blindly. I work on corporate jets and the Structural Repair Manuals are very specific about approved materials, methods, etc. I certainly don't want all the paperwork, expense, and older technology of the certified aircraft world in homebuilding, however! Anyway, I once was using Hysol 934 EA to bond foam ribs to a spar (racing car wing). I realized since the allowable of the foam was only 40 psi I was spending alot ($90 kit) for 5-6 ksi epoxy bonds much stronger than the foam. However, I remember Rutan speaking to this issue in the Long-Eze plans saying that shear loads, although low, must be carried by the foam so no joining foam with spray adhesive, etc. I guess the old chain and its weakest link idea applies... Date: Wed, 6 Jan 1999 23:11:50 -0500 Subject: COZY: Safety and MGS From: dhill36@juno.com (Dana Hill) To any of the new Cozy Builders, Although I am only about a year into the project (and only on Ch 5), I have reviewed all the archives and other material on safety/exposure to epoxy and discussed this issue with other Cozy builders. There is much hard learned wisdom in those archives. I to quickly found out that MGS epoxies have little odor. However as Bill K. mentioned this really isn't a case of no odor therefore no concern. These faint fumes are dangerous in the long term and this is a multi-year project for most of us. During layups I have always worn a respirator and on the hands cotton liner gloves, then butyl gloves and then latex or vinyl gloves to maximize the life of the $ butyl gloves and also safety glasses. I feel its a small price to pay for such a huge return (your health). It is very likely that any experienced builder will give you the same story. Hope everyones staying warm and productive! ____________________________________________________ Dana Hill Cozy IV #676 ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] From: cozy623@juno.com Date: Sat, 9 Jan 1999 17:58:42 -0700 Subject: COZY: mgs I like the mgs alot but it wants to ingest tons of air with stippling and stirring and stuff. I bet you could make whipped cream out of it if you really tried. Any hints? Jeb Date: Sun, 10 Jan 1999 10:37:30 -0600 From: "Joseph H. Hart IV" Subject: Re: COZY: mgs Jeb: I've been using MGS 285 and am currently almost finished with Chapter 6 (currently waiting for more supplies -- I haven't been able to figure out how to get by with the minimal supplies suggested by the plans!). I have noticed that the MGS gets a lot of air in it when it is mixed; however, I haven't had a problem with air in my layups. I have used a hair dryer a lot and this may account for the fact that I haven't had an air bubble problem. Have you been using a hair dryer? If not, give it a try. I think the heat gets the viscosity low enough for the air to easily escape. I've also peel-plied just about everything. I can't say whether this has helped minimize entrapped air but it is possible that it has helped as well. Good luck with your project. -- Jody Hart New Orleans, LA Cozy Mark IV plans no. 648 Chapter 6, see latest progress at: home.gs.verio.net/~jodyhart/home.html N359JH (reserved) From: Militch@aol.com Date: Sun, 10 Jan 1999 14:21:42 EST Subject: Re: COZY: mgs In a message dated 1/9/99 8:58:36 PM, you wrote: >I like the mgs alot but it wants to ingest tons of air with stippling and >stirring and stuff. I bet you could make whipped cream out of it if you >really tried. Any hints? Jeb I am surprised. I use the MGS epoxy and am impressed at the lack of air bubbles when I mix it up. I keep it in a heated cabinet that stays around 85 to 88 degrees. Do you have it that warm when you mix it? Peter Militch Mark IV #740 Chapter 4 Bulkheads From: cozy623@juno.com Date: Sun, 10 Jan 1999 15:59:58 -0700 Subject: COZY: mgs Duh! It is the cold. I keep my garage at a little over 80 but the epoxy didn't act this way when it was hotter. Thanks. Jeb Date: Mon, 11 Jan 1999 09:40:28 -0800 From: Frank Johanson Subject: Re: COZY: mgs Hi Jeb I have the same problem, I have to heat the epoxy and work with the room 80 to 85. What part of the country are you in ? Auburn Me. here. cozy623@juno.com wrote: > Duh! It is the cold. I keep my garage at a little over 80 but the epoxy > didn't act this way when it was hotter. Thanks. Jeb From: "Hunter GA (Gary) at MSXSCC" Subject: COZY: "Overheating" epoxy Date: Thu, 14 Jan 1999 09:22:44 -0600 In a post with the SUBJECT: COZY:Canard Spar > Bill Kastenholz wrote: > How hot can the epoxy get before "overheating" it? > The boiling point of uncured liquid resin is over 400F and the curing agents are often less - 300F or so. Theoretically, the blended resin and curing agent will have an initial boiling point somewhere in the middle. Obviously, you don't ever want to boil the resin / curing agent combination. In working with a heat gun during laminating, the goal is to simply reduce the viscosity of the resin to help facilitate wet out, and to achieve the desired resin/glass ratio. The viscosity of epoxy resins drop quickly from room temperature to about 140F. Above that, it is pretty flat line. So, heating the resin above 140F has no significant benefit. So in my book - anything over 140F is - "overheating it" and 100F is plenty hot enough for our work. NOW - from a cured resin perspective..... Most cured epoxy resins can be exposed to temperatures as high as 450F for short periods of time (up to 12 hrs.) without serious damage to the polymer matrix. However, over extended periods of time, it will begin to slowly break down by thermal oxidative reduction and physical properties will diminish over time (2-10 weeks). At 650F, molecular cleavage begins, and it will decompose into volatiles like, carbon monoxide, carbon dioxide, water, cyclopentadiene, and methylcyclopentadiene. Above that temperature it simply happens faster and produces less water. To determine the glass content of a epoxy/fiberglass composite, the industry performs what we sometimes call a "burnout". A pre-weighed specimen of the composite is placed in a ceramic crucible and placed in a furnace that usually starts out at 600F and slowly increased to about 800F. In about 6 hrs., the epoxy resin surrounding the fiberglass is completely burned away - carbonized and then oxidized. What is left is nothing but the fiberglass. Re-weighing the crucible's contents yields the amount of glass that was in that specimen. Gary Hunter EAA Technical Counselor Shell Chemicals Epoxy Guy Date: Tue, 26 Jan 1999 12:37:38 -0500 From: "Johnson, Phillip" Subject: COZY: Transport of epoxy in cold weather I'm down to my last gallon kit of ez-poxy II and I guess that I need to order some more soon. I live in Canada where the temperature gets to -30C overnight on occasions and is more typically -20C. If I order new epoxy at this time of year there may be periods in which the temperature may get close to these extremes. What happens to the epoxy? I know that it may crystallize and that can be recovered by controlled heating but can permanent damage result if it gets too cold? Phillip Johnson Cozy MKIV RG #30 From: cdenk@ix.netcom.com Date: Tue, 26 Jan 1999 18:17:25 -0600 (CST) Subject: Re: COZY: Transport of epoxy in cold weather was said You might check with your carrier (UPS, FEDEX), the might be able to guarantee for a price the temperature, since they do lots of things where temp is critical, from food, and flowers to drugs. The order fastest way when warm front is moving through. Date: Tue, 26 Jan 1999 22:57:58 -0500 From: "Marc J. Zeitlin" Subject: Fwd: COZY: Transport of epoxy in cold weather Phillip Johnson wrote: >can permanent damage result if it gets too cold? Everything I've ever seen says no - heating it up gently (or not so gently) will un-crystallize the hardener (I don't think the resin will crystallize - at least I've never seen it do so, and I've had the hardener crystallize on me a couple of times). I hope Gary Hunter will weigh in here with confirmation. To tell you the truth, I think these epoxies (at least the EZ10/84 that I'm now using - I won't speak for the are pretty insensitive to most anything we can do to them with respect to temperatures, mix ratios, etc. Before anyone jumps down my throat, I'm in no way claiming that we should pay no attention to mix ratios, keeping temperatures in the proper range, mixing times, etc. I'll say is that in tests that I've done with purposefully wrong ratios (off by 20% or so), poor mixing (just barely visually mixed to a consistant color), and temperature extremes (warmed up hardener, or really thick goopy hardener), I've never NOT had the epoxy harden and pass the "scratch" test, as described in the plans. I will also state that I do, in fact, use an epoxy pump that is accurate to a couple of % at the worst, keep the epoxy at a constant 80 F, and mix like mad :-). -- Marc J. Zeitlin marcz@ultranet.com http://www.ultranet.com/~marcz/ From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: Transport of epoxy in cold weather Date: Wed, 27 Jan 1999 07:11:52 -0600 > Phillip Johnson wrote: > > >can permanent damage result if it gets too cold? > Marc J. Zeitlin wrote: > Everything I've ever seen says no - heating it up gently (or not so > gently) > will un-crystallize the hardener (I don't think the resin will crystallize > - at least I've never seen it do so, and I've had the hardener crystallize > on me a couple of times). I hope Gary Hunter will weigh in here with > confirmation. > Don't worry about frozen resin / curing agent and do not pay for temperature controlled shipping. They may (or may not) crystallize during cold shipping conditions. However, they will reconstitute with gentle warming and be as good as new. Never use a resin or curing agent that has any evidence of crystallization. If the container is tightly sealed, you can simply immerse the resin or curing agent container in a bucket of Hot tap water. Replenish the hot water as necessary to keep the temperature up. Occasionally, mildly shake or rotate the resin container to stir the contents. Mix ratios are very important. Do not compromise. If in doubt, throw it out. Gary Hunter Shell's Epoxy Guru From: "Chris Byrne" Subject: COZY: MGS Epoxy Date: Fri, 26 Feb 1999 14:21:17 +1100 Builders using MGS epoxy I have had a problem with cloudy resin (L335), and thought I would share the results with you. I know there is a lot in the archives about this problem (with other epoxies) but from what I can see it deals only with the hardeners, not resin. Below is the e-mail I sent to Johannes Meunier at MGS in Stuttgart and his reply as well as my findings. This is a bit long winded but some of you may find it useful and it comes straight from the horses mouth. The reply came from MGS within minutes of them opening for business and the offer of testing implies great customer support. Dear Johannes I have a quick question about the L335 resin. I have noticed that the last 1cm (3/8 inch) in the bottom of my epoxy pump is very milky/cloudy and is a lot thicker than the rest of the resin.(almost sludge) I have the same problem in a 2 L plastic container that has some resin in it. The resin has been in the pump and container for about 6 weeks. The container has been full and the cap on it for the entire time, so I do not think that it has been exposed to too much air or humidity, and the temp has been between 17 and 30 degrees C ever since I received the epoxy from you. What is causing this cloudiness and is it a normal occurrence? Is it any of the key components of the resin falling out of solution?(ie are all of the important bits of the resin ending up in the bottom) Should I discard the cloudy resin or mix it in with the rest? Has the strength of the epoxy been compromised? If this is happening in the bottom of these two containers it is probably also occurring in the bottom of my 30KG Hobbock. The hardener does not have this problem. I have no problem with discarding the cloudy/thick resin, but am worried that the strength is being compromised. Otherwise the epoxy is very good too use and I seem to be getting good results. Regards Chris Byrne Sydney Dear Chris, I can imagine two possible situations that would explain the cloudiness in your resin. The first and most likely one is, that the resin simply has crystallised. Epoxy resins, when exposed to temperatures lower than 15 degrees Celsius may start to do this. It is basically the same as water when it freezes. It may have started during transportation and continued during storage. The way to get out of this is simply to warm up the resin to approx 60-70 degrees Celsius. Keep the temperature for a couple of hours and stir or shake the contents a little This will dew up the resin - if it is crystallisation. You should have a clear resin afterwards. The second possibility would be a contamination of the material. For example a contamination with hardener that happened by mistake or that for whatever reason the resin started to dissolve the plastic container (although we´ve never experienced that before). The containers should be made of Polyethylene (HDPE), its the best material to resist most aggressive chemicals. If you can´t clarify the resin by heating it up, the best procedure would be to mix it with the equivalent amount of hardener, cure it and then put it in the garbage. Please do only scrap the resin as it has cured, the liquid resin and hardeners are considered to be environmental dangerous. Most likely it will only be crystallisation, this is normal. However, don´t use the white stuff. Clarify it before use. If you want to be 100% sure I can offer you the following. We can measure the quality of a cured resin sample and tell if it has been properly mixed, resp. if the resin or hardener quality has deteoriated. If a resin sample we obtain shows the normal quality, you can be sure that it has it full properties. I can offer you to send me a sample of the cured resin, for example cut offs from parts that you made. Some grams is enough. We both want you to have a high quality airplane! If I can be of any further assistance, please let me know. Regards, Johannes Armed with that info I sat the 1/2 gallon container of resin in a pot on the stove and within 30mins it was as clear as if looking into a glass of water. The resin had never been this clear, even the first time it was used. I then bought my epoxy pump upstairs and sat it on my oil filled electric heater, placed a couple of towels over it to keep the heat in, again it was crystal clear in about 30 mins. I can now see the outlet valve clearly, before it I could just make it out through the haze. I think the temp would have been about 55-60C (130F). The pump had previously been kept at 30C (85F) with a globe in a box (globe on a couple of hours before use). For those of you using this epoxy it may be worth warming up your resin and observing the difference in clarity. I intend to send a sample of cured resin (cloudy resin) to MGS and have it tested. And will let you know the out come. Chris Byrne Sydney From: "John Slade" Subject: Re: COZY: MGS Epoxy Date: Thu, 25 Feb 1999 23:57:30 -0500 Chris, Thanks for posting your experience with L335. I have my first delivery of the stuff coming in next week. Could you also post the email address of Johannes Meunier at MGS in case I, or others, want to contact him? John Slade From: "Hunter GA (Gary) at MSXSCC" Subject: COZY: MGS Epoxy / Crystallization Date: Fri, 26 Feb 1999 09:42:31 -0600 Chris Byrne wrote: > Builders using MGS epoxy > > I have had a problem with cloudy resin (L335), and thought I would share > the > results with you. > > I know there is a lot in the archives about this problem (with other > epoxies) but from what I can see it deals only with the hardeners, not > resin. > Only some hardeners crystallize (Safe-T-poxy / EZ-poxy type in particular) - but ALL liquid epoxy resins are susceptible to crystallization. The base component of all liquid epoxy resins are in fact - "meta-stable super cooled liquids" - with melting points between 110F and 140F. Which means at temperatures below their melting points, they are in a physical state unnatural to their molecular structure. And as such, they will try to revert to the crystallized state when conditions are correct. Generally, cool temperatures appears to be the most significant cause for crystallization. In actuality, it is cool temperatures combined with constant cycling that really accelerates the crystal growth process. Cool nights, warm days, etc. Therefore, to retard crystallization, it is best to keep the resin stored at as constant a temperature as practical - preferably 75F or better. Below are some of my earlier comments on shop temperatures. Crystallization occurs long before any VISUAL evidence (haziness) indicates so. The only way to detect it prior to appearance of visual indicators is to measure the resins viscosity. It will steadily increase over time, and will almost double before haziness starts to set in. SO, if you notice a marked increase in the resin's viscosity (assuming temperature is not a factor) then you have the beginnings of crystallization. Resin crystals are comprised of the purest molecules of resin (n=0 if your a chemist) in the container, and as such they are more dense and tend to settle to the bottom. The composition of remaining liquid on top is now different from what it was supposed to be. Primarily, it will be higher in viscosity and reactivity (shorter pot life). In haste, it may be tempting to use the (somewhat clear) resin on top in order to "get the job done" and reconstitute the remaining contents later. Although the part you made is probably OK, this is not a good deal overall. It is best to reconstitute the container by heating AND agitating the contents to redistribute the purest molecules throughout the resin. Every vendor (MGS, Aeropoxy, PTM&W, EZ-poxy, etc) of formulated epoxy resins like to believe their formulas are shelf stable and resist crystallization sufficiently enough to not be a concern for the end user. However, in my job, I speak with many surprised vendors on how to deal with their unexpected crystallization problems. When you receive a shipment of resin from Wick's Aircraft Supply, there is no way to tell how long it has been sitting around, what temperature is was stored at, or what state it is in. It may be clear, but the viscosity may be higher than it is supposed to be. Therefore, it would be a good practice to "reconstitute" or de-crystallize the unopened containers prior to using. Here are some excerpts from my replies to this issue on Canard-Aviators.com. It is long but worth reading. In my job, this is the time of the year (fall/winter) we start hearing people cry -"my epoxy won't pour out of the bottle any more", or "it won't harden", or "it turned to wax", or "can I exchange it for fresh". ...............Keeping the resin from crystallizing is only a small portion of the temperature control picture. The temperature of "ALL" the materials in your shop is just as important. The temperature of the reinforcement (fiberglass) and the foam directly effects the temperature of the resin. Even though the resin you just mixed may be 80F, as soon as it hits the fiberglass and foam, it immediately cools off to the temperature of the foam and fiberglass. The only effective way to manage the temperature of these materials is to control the temperature of the room. From a resin perspective, cool temperatures: 1) Increases viscosity that effects the resin/glass ratio - cooler temperatures tend to make heavier lay-ups 2) Lengthens pot life / cure times - reaction rate doubles every 10C (18F) - anything below 65F is taboo 3) increase surface tension (slows fiberglass fabric wet-out - tends to make heavier lay-ups) If you shop isn't temperature controlled, I would make it so. You will probably reduce the construction time on your airplane by a year or better as the shop will be more hospitable. Now that I have said that, let's talk about resin crystallization. Keeping the resin warm will only "retard" the crystallization of the epoxy resin. The only way to completely prevent crystallization is to keep the resin above 120F. Storing resins at this temperature will not harm them at all. In fact, we (Shell Chemical) store our liquid epoxy resins in bulk at 160F for months at a time. We do this to reduce the viscosity for pumpability. However, this is both impractical and way too warm for you to work with. Whether you have a heated shop or not, all you NEED to do for "retarding" crystallization is keep the resin in a "hot box" or constant temperature box at about 80-90F. You can keep it warmer if you want, but I would not go over 120F. To keep the resins warm I recommend building a hot box, or make one out of an old "Igloo" cooler by hanging a (small) light bulb inside with a small fan from a computer CPU (Radio Shack) to circulate the air. Depending on the size of the box and the actual temperature of your shop, you'll need a different wattage light bulb. Just start with a 25 watt bulb and work your way up until you get the temperature you desire. If your using the hot box for storage, or "de-crystallizing the resin" 120F is good. Otherwise, 80-90F is just fine. IF, you want, you can use this kind of hot box for your (ugh) epoxy pump too. Turn the "Igloo" on its side and mount it to the wall so the lid hinges upward. Put the pump inside with the hanging light bulb and the circulating fan. Open to pump resin, close it when your done. Below is the word advice we put on the shelf life statement for all our liquid epoxy resins: Refrigeration will not enhance the storage stability of this product. Furthermore, EPON 862 is a super-cooled liquid and is inherently susceptible to crystallization, particularly at temperatures below 50?F. Therefore, refrigerated storage is neither beneficial nor necessary for this product. Crystallized resin is evidenced by a product visual appearance that can range from a hazy liquid to a waxy semi-solid. Resin that has crystallized can be reconstituted by gentle warming of the entire container and it's contents to approximately 120-140?F until all visual evidence of crystallization has gone away. Upon cooling to normal ambient temperature conditions the product will regain its original liquid state physical properties. Perhaps I should present a forum at Sun-n-Fun or Oshkosh this year. Anybody interested ?? How about - Everything you wanted to know about epoxy resins - or maybe not. KINDEST REGARDS, Gary Hunter Technical Service Representative EPOXY RESINS TECHNICAL INQUIRY SHELL CHEMICALS, USA Toll Free in North America - 800-832-3766 (800-TEC-EPON) International - 713-246-8295 Facsimile - 713-241-1606 E-Mail - gahunter@shellus.com From: "Nat Puffer" Subject: Re: COZY: MGS Epoxy / Crystallization Date: Fri, 26 Feb 1999 11:05:39 -0600 Gary, We would like to invite you to speak at our Cozy Builders Forum in Oshkosh on Friday, July 30, 1pm, date and time to be confirmed. Best regards, Nat ---------- > From: Epplin John A > To: 'Cozy Mailing List' > Subject: RE: COZY: MGS Epoxy / Crystallization > Date: Friday, February 26, 1999 10:12 AM > > > Gary Hunter asks: > > > Perhaps I should present a forum at Sun-n-Fun or Oshkosh this year. > > Anybody interested ?? > > > > How about - Everything you wanted to know about epoxy resins - or maybe > > not. > > > > > [Epplin John A] > > Definitely, I will be there at OSH, not sure about Sun-n-Fun yet. > I am sure you will have a good crowd! From: "Todd B. Acheson" Date: Sun, 28 Feb 1999 08:28:29 -0500 Subject: Re: COZY: MGS Epoxy / Crystallization On Fri, 26 Feb 1999 09:42:31 -0600 "Hunter GA (Gary) at MSXSCC" wrote: > > Crystallization occurs long before any VISUAL evidence (haziness) indicates > so. The only way to detect it prior to appearance of visual indicators is > to measure the resins viscosity. It will steadily increase over time, and > will almost double before haziness starts to set in. SO, if you notice a > marked increase in the resin's viscosity (assuming temperature is not a > factor) then you have the beginnings of crystallization. > Are there any simple techniques to measure viscosisty that the home builder can use check whether cyrstallization has occurred? ---------------------- Todd Acheson 740 593-0034 acheson@ohiou.edu From: Jim Hocut Subject: RE: COZY: MGS Epoxy / Crystallization Date: Sun, 28 Feb 1999 10:24:07 -0500 > > Are there any simple techniques to measure viscosisty that the home > builder can use check whether cyrstallization has occurred? > Viscosity can be measured by timing how long it takes a given amount of liquid to flow through a calibrated orifice. As a comparison such as is being discussed here, you could use any container with a small hole and time how long it takes a given size sample to flow out. Then some months later use the same container and compare the results. Temperature of the sample would have to be exactly the same each time to be able to make a comparison. >From a practical standpoint my personal opinion is that it's better to avoid any problems in the first place. Keep your epoxy in a hot-box, around 80 - 85 deg F and it should be just fine. Heating (and stirring) the resin before first use is also a good idea. Jim Hocut jhocut@mindspring.com From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: MGS Epoxy / Crystallization Date: Mon, 1 Mar 1999 11:49:33 -0600 Todd inquired: > > Crystallization occurs long before any VISUAL evidence (haziness) > indicates > > Are there any simple techniques to measure viscosisty that the home > builder can use check whether cyrstallization has occurred? > Yes, you can use a painter's viscosity cup you can buy at the paint store. You measure the time it takes for the contents to drain through an orifice. But, to be honest with you, it isn't worth the trouble. It is VERY temperature dependant, and you have to clean up the cup each time with solvents and stuff. That process alone is just enough of a pain you probably won't do it again. Putting a sealed container of resin in a bucket of hot tap water is a lot less messy and virtually guarantee's you have crystal free resin. No muss, no fuss, no worries. Gary Hunter From: "kim lueck" Subject: COZY: RAE Replacement Date: Tue, 2 Mar 1999 06:36:35 -0600 Does anyone know where I can get 2 gallons of the RAE epoxy? Wicks and ASS are both listing it as no longer in production. What is an acceptable substitute (4 to 1ratio, I don't want to buy a new pump just to finish attaching the turtleback). thanks, Daryl Lueck N797DL Cozy IV From: "Bill Kastenholz" Subject: Re: COZY: RAE Replacement Date: Wed, 3 Mar 1999 03:47:30 -0500 >Does anyone know where I can get 2 gallons of the RAE epoxy? Wicks and ASS >are both listing it as no longer in production. What is an acceptable >substitute (4 to 1ratio, I don't want to buy a new pump just to finish >attaching the turtleback). > > >thanks, > Daryl Lueck > N797DL > Cozy IV > Hi Daryl, The Composite Polymer Design (CPD) epoxy is the same formula as the old RAE. As I understand it, just a different company producing the epoxy. I have used this product for the last half year at least, and it has all the same working properties of the RAE. I did call the company last year and talked to a tech rep who convinced me to continue using it. Bill Kastenholz wkasty@ix.netcom.com From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: RAE Replacement Date: Wed, 3 Mar 1999 09:56:47 -0600 Dave Hoefell - 800-755-8568 St. Paul, MN or Phil Cuthbert - 800-886-0429 Simi, CA > -----Original Message----- > From: Michael Amick [SMTP:mkamick@wans.net] > Sent: Wednesday, March 03, 1999 11:01 AM > To: Bill Kastenholz > Cc: kim lueck; cozy builders > Subject: Re: COZY: RAE Replacement > > Bill Kastenholz wrote: > > > The Composite Polymer Design (CPD) epoxy is the same formula as the old > > RAE. ....it has all the same working properties of the RAE. > > ....talked to a tech rep who convinced me to continue using it. > > > > > Address? > > Phone? > > Michael Amick From: "astrong" Subject: Re: COZY: RAE Replacement Date: Thu, 4 Mar 1999 08:04:08 -0800 Kent, My son-in-law and I are building a MkIV with the active help of our respective spouses. We are using the CPD, RAE equivalent from WICKS Epoxy # 4426 A. Slow Hardener# 9377 and using the original pump that I used building My COZY III ten years ago. Goodluck.WICKS contact ;Janet Stomacher -----Original Message----- From: Kent Ashton To: cozy_builders@canard.com Date: Thursday, March 04, 1999 7:52 AM Subject: Re: COZY: RAE Replacement >Bill Kastenholz wrote: >> >> The Composite Polymer Design (CPD) epoxy is the same formula as the old >> RAE. > >Very interesting. There are a lot of us who like the RAE and would like >to have a source for it. > >--Kent Ashton > From: "John Slade" Subject: COZY: Chap 4 - MGS epoxy won't harden Date: Sat, 6 Mar 1999 21:13:06 -0500 I'm using MGS 335 epoxy with the slow hardner. I tried a test layup 2 days ago and it's still not hard. Today I tried another test and left the remaining epoxy in the cup. 12 hours later the layup is still tacky and the epoxy in the cup is still mobile. ie I can still move the tongue depresser in it and depress the surface with my finger. Temperature has ranged between 62 and 75 during this period. The epoxy is kept in a HOT box. I measured the temp in there and found it was 106f. Tomorrow I'm going to try the "fast" hardner and lower the temp in the hot box to about 85. Anyone have any suggestions or ideas? Is the MGS rep who helped out a week or two ago reading this mail list? Anyone have his email address? I haven't done a "real" layup yet. If the epoxy doesnt cure the part is ruined. - right? John Slade (#757) From: "Neal Newman" Subject: Re: COZY: Chap 4 - MGS epoxy won't harden Date: Sun, 7 Mar 1999 05:31:35 -0500 Hi Chris it took 4 days for it to harden when I first started to use the Mgs epoxys.... I found the best is to mix 50/50 the fast and slow hardners.. when I first started using the stuff I didnt know there were 2 different hardners... because my First order came with the slow...... try the 50/50 fast/slow and you will be very happy...... Neal -----Original Message----- From: Chris Byrne To: Cozy Builders Date: Sunday, March 07, 1999 2:04 AM Subject: Re: COZY: Chap 4 - MGS epoxy won't harden >John Slade wrote > >I'm using MGS 335 epoxy with the slow hardner. >>I tried a test layup 2 days ago and it's still not hard. Today I tried >>another test and left the remaining epoxy in the cup. 12 hours later the >>layup is still tacky and the epoxy in the cup is still mobile > >I have not used just the 340 (slow) hardener but acording to the company you >will get a pot life of 6 hrs. >So still being able to move the stick after 12 hrs sounds may be about right >although it does sound a bit slow. >The temp of 62 is probably the culprit. >Try another test and take it to bed with you or somewhere equally as warm >and see how it goes. > >The fast (335) will give a pot life of 15 mins.(starts to thicken and cloth >will not wet out as easily) >All my layups (until my last one) have been with a 50/50 mixture of the fast >and slow hardener, because 15 mins is to fast and 6 hrs way to slow. >Being able to mix the hardeners is the great advantage that the MGS system >has. >I get a pot life of around 30 mins and is easily tack free in about 6 hours. >All my temps are around 80-85 F. >Last night I added some more 340 (slow) to my pump to give me a roughly >70/30 ratio because I was on a big layup and wanted a slightly longer >working time, this gave me about a 50 Min pot life and the layup was hard >this morning (about 12 hours) > >I mix a batch about 1/2 gal of 50/50 hardener every couple of months, the >factory says there is no change at all to the shelf life of the combined >hardener. > >This is from MGS and has been posted before so should be in the archives. > >Mixing ratio of resin: hardener for L335-system is >100:38 by weight, resp. >100:45 by volume > >Note that these are all related to a temp of 25C (77F) > >Hardener 335 and 340 can be mixed together, in order to get a suitable pot >life. Potlife of 100g mix L335/hardener335 at 25°C is approx 15min, 100g mix >L335/hardener340 at 25°C is more than 5h. Geltime in the laminate is even >longer. To give you a rough idea of potlifes among different hardener >mixtures > >Hardener335: Hardener340 Processing time >100 0 10-15min >50 50 60-90min >20 80 approx4h >0 100 approx6h > >With the above in mind it may be that your temps are a bit low. > >MGS web sight www.mgs-online.com > > >Chris Byrne > > > From: "John Slade" Subject: COZY: slow expoxy Date: Sun, 7 Mar 1999 09:29:28 -0500 I posted my message at 9pm on Saturday. By 9.am sunday morning I had seven replies all with very useful information. Some had even done tests of their own MGS epoxy. Incredible! >Are you using the correct ratio? Is it by volume or by weight? I'm using a brand new 45:100 stickystuff epoxy pump. I've been doing really small tests - less than a "full stoke". Perhaps a combination of this and the high hot box temp is a problem. I'll check the ratio by pumping into two cups. >Try another test and take it to bed with you or somewhere equally as warm and see how it goes. I love my plane, Chris - but, she's still very young! >You should be able to scrape the surface with a nail, and get a scrape with dusty debris (not a groove in a rubbery mass). After being in the hot box and the house my test pieces eventually reached this stage. >it took 4 days for it to harden when I first started to use the Mgs epoxys....I found the best is to mix 50/50 the fast and slow hardners.. I thought I'd start out slow, but perhaps 100% slow is overdoing it. I'll try to 50/50 approach. >They tend to say that below 65 it might not harden at all. >you need to keep the part at 72 + for the epoxy to cure any time soon Ah! That I didnt know. I think temperature is is my main problem. My workshop is a large covered patio which is open on one side. In a month or two temperatures here in S. Florida will be in the right range. In the meantime, I'll work during the 75f daytime. I'm left with one question. If the layup is done with "warm" epoxy at , say an ambiant 75f, then left to cure overnight when the temp goes down to, say 60f, will the resultant part be ok in all respects after it eventually cures? Thanks to all for the help, John Slade From: Militch@aol.com Date: Sun, 7 Mar 1999 16:00:03 EST Subject: Re: COZY: Chap 4 - MGS epoxy won't harden In a message dated 3/7/99 2:17:56 AM, jslade@adelphia.net wrote: >I'm using MGS 335 epoxy with the slow hardner. >I tried a test layup 2 days ago and it's still not hard. Today I tried >another test and left the remaining epoxy in the cup. 12 hours later the >layup is still tacky and the epoxy in the cup is still mobile. ie I can >still move the tongue depresser in it and depress the surface with my >finger. I use the 225 and the slow hardener. Generally I do my layup in the evening and then do the knife trim the next morning. That's 10 hours or so and it's still soft. It typically takes up to 24 hours to set like a rock in the cup. That is at temperatures around 70 degrees. I would be surprised to hear that 2 days is ok. Sounds like something isn't right. What ratio are you mixing the parts in? I use a scale, so have to do it by weight, and its 100:40. Peter Militch Cozy Mark IV #740 Chapter 4/5 Date: Sun, 07 Mar 1999 16:37:15 -0600 From: David Domeier Subject: Re: COZY: Chap 4 - MGS epoxy won't harden John, re "I tried a test layup 2 days ago and it's still not hard." Sounds to me like the resin/hardener ratio is off. You know the old cliché, this stuff goes together like 2 gears and if they don't match, it won't cure. I've had it happen with the original RAF ratio scale when I somehow moved the balance weight while pouring.... dd From: "Nat Puffer" Subject: Re: COZY: Chap 4 - MGS epoxy won't harden Date: Mon, 8 Mar 1999 13:43:30 -0600 John, I just finished a several hour layup with 335. I used half slow and half fast hardner, and it cured right on schedule in about 2.5 to 3 hours. Regards, Nat ---------- > From: John Slade > To: Cozy Builders > Subject: COZY: Chap 4 - MGS epoxy won't harden > Date: Saturday, March 06, 1999 8:13 PM > > I'm using MGS 335 epoxy with the slow hardner. > I tried a test layup 2 days ago and it's still not hard. Today I tried > another test and left the remaining epoxy in the cup. 12 hours later the > layup is still tacky and the epoxy in the cup is still mobile. ie I can > still move the tongue depresser in it and depress the surface with my > finger. Temperature has ranged between 62 and 75 during this period. The > epoxy is kept in a HOT box. I measured the temp in there and found it was > 106f. Tomorrow I'm going to try the "fast" hardner and lower the temp in the > hot box to about 85. > > Anyone have any suggestions or ideas? > Is the MGS rep who helped out a week or two ago reading this mail list? > Anyone have his email address? > > I haven't done a "real" layup yet. If the epoxy doesnt cure the part is > ruined. - right? > John Slade (#757) > From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: Chap 4 - MGS epoxy won't harden Date: Tue, 9 Mar 1999 07:43:08 -0600 John Slade wrote: > > I'm using MGS 335 epoxy with the slow hardner. > I tried a test layup 2 days ago and it's still not hard. Today I tried > another test and left the remaining epoxy in the cup. 12 hours later the > layup is still tacky and the epoxy in the cup is still mobile. ie I can > still move the tongue depresser in it and depress the surface with my > finger. Temperature has ranged between 62 and 75 during this period. The > epoxy is kept in a HOT box. I measured the temp in there and found it was > 106f. Tomorrow I'm going to try the "fast" hardner and lower the temp in > the > hot box to about 85. > > Anyone have any suggestions or ideas? > Is the MGS rep who helped out a week or two ago reading this mail list? > Anyone have his email address? > > I haven't done a "real" layup yet. If the epoxy doesnt cure the part is > ruined. - right? > John Slade (#757) > John: I'm sorry it took so long to respond. What you are experiencing is what I feared most when I found out MGS was being distributed to homebuilders. Although these are fine resin systems for which they were formulated for (factory built gliders - motor gliders, wind mill blades), they inherently exhibit this peculiarities from time to time that puzzle the un-knowing. Because these products are primarily cycloaliphatic amines and stericly hindered polyoxyalkyl amines accelerated with copious amounts of unreactive ingredients, they tend to be sensitive to temperature during cure. If it is too cool, (below 70F in my book) they will slow down dramatically of course, but they can "B-Stage" as well. This is a physical state where the resin is neither liquid or cross-linked sufficiently enough to be called a plastic. It is "vitrified" and depending on how much is has crosslinked, it can be a sticky taffy like substance to a brittle friable solid. Once it has achieved this vitrified state, it can take a considerable amount of time for it to continue curing past that vitrified state - if ever. Sometimes, it is quite easy to mistakenly identify the brittle friable solid as genuine cured plastic state. NOT GOOD. HOWEVER, in most cases, with the addition of heat you can "re-start" the curing process and drive it to completion. THIS IS WHY MGS recommends a post cure for their resin systems. If you must use the MGS systems, please be sure your room temperature is at least 70F. Especially if your going to use the slow curing agent. I have talked about the importance of temperature control many times before. It is always important to control the "room temperature" at which ALL your building materials are stored at prior to their use. I think it is well worth the money to buy a window air conditioner for your garage or shop area. It reduces the overall sweat factor. NAT, HUNTER - sign me up for your forum and dinner. I have compiled a nice little presentation on epoxies I think everyone can benefit from. Gary Hunter Shell Chemical Co. Epoxy Resin Technical Service EAA Technical Counselor From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: Chap 4 - MGS epoxy won't harden Date: Tue, 9 Mar 1999 10:20:49 -0600 > -----Original Message----- > From: John Slade [SMTP:jslade@adelphia.net] > Sent: Tuesday, March 09, 1999 9:09 AM > To: Hunter GA (Gary) at MSXSCC > Subject: Re: COZY: Chap 4 - MGS epoxy won't harden > ...they inherently exhibit this peculiarities from time to > >time that puzzle the un-knowing. > > The above sounds ominous. I realize that you have to be careful what you > say > in public. Are you saying between the lines that MGS is not really suited > for the Cozy? > Not at all. The MGS systems provide ample performance for the homebuilt. It is the end-user (you) that it may not be suited for. If you are not used to working with epoxies, you can (and have) experience things that will really confuse you. > >If you must use the MGS systems, please be sure your room temperature is > at > >least 70F. Especially if your going to use the slow curing agent. > > I'm building under a covered patio which open on one side. In S. Florida > temp isnt a problem provide I dont do layups at night during "winter". > > >I think it is well worth the money to buy a window air conditioner for > your > garage or shop > >area. It reduces the overall sweat factor. > I'd prefer not to delay my project (and divert finances) to closing in the > patio. > Granted, summer time temperature conditions are usually favorable in Florida for curing epoxies. However, there are many other things to consider. Humidity, morning dew, sudden afternoon thundershowers with blowing rain. Ugh.... If I were you, I would spend the money to close it in before you have to spend the money on rebuilding a part that was ruined inadvertent by un-expected weather conditions. > >NAT, HUNTER - sign me up for your forum and dinner. I have compiled a > >nice little presentation on epoxies I think everyone can benefit from. > > I'd like to go to this. WHen and where is it? > We'll let you know with an announcement later. > Thanks for the input. > John Slade > > PS - I've changed my hardner slow/fast ratio to 50/50 and am doing all > layups during the day when temps are 75f and above. Hardning is now to > spec > and the MGS is easy to work with. > I think that is a safer gamble than the pure slow. Gary Hunter From: cozy623@juno.com Date: Thu, 11 Mar 1999 21:16:33 -0700 Subject: Fw: RE: COZY: Chap 4 - MGS epoxy won't harden --------- Forwarded message ---------- From: "Hunter GA (Gary) at MSXSCC" > Jeb Butler wrote: > > I have had MGS over the winter and I keep my garage nice and > warm. No problems so far. My question is about heat. I live in PHX. > Is there a point where it is too hot and I should not work with epoxy? > I guess 105-110F in the shade is not to unrealistic for PHX. You should stop working with the epoxy when you pass out from heat exhaustion. :-) In all seriousness, there comes a time when the viscosity becomes too low for laminating vertical surfaces. "Drain-out" can occur as a result - leaving resin starved laminates. > > Is MGS different in how it reacts to heat also? > Yes, it won't pass out from heat exhaustion like you - ha ha. The MGS resin system likes heat. It will simply cure faster. The rate of reaction doubles every 10 degrees Celsius. So a 2 hr. gel time at 25C (77F) will become 1 hr at 35C (95F) and 30 minutes at 45C (113F). > I had thought that the long cure time of the MGS would be very handy when > the heat comes back > and accelerates the cure to mach speed. > You are absolutely correct. You can probably get away with the slow curing agent in the summer and a 50/50 blend of slow and fast in the winter. Gary Hunter ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866] From: "Will Chorley" Subject: COZY: MGS Epoxy - Can set up too fast!! Date: Tue, 16 Mar 1999 21:20:30 -0600 Reading the recent correspondence on MGS NOT setting I thought my recent (this evening) experience may be of interest. I just had a "small job" to do - you know one of those that should take 10-15 minutes but ends up taking half an hour - and decided to mix a couple of ounces of MGS 285 with the fast hardener. I had my shop at about 80 degrees, but the epoxy had been out on my bench before I turned up the heat and was probably closer to 70 degrees when I mixed it. After about 15 mins, I had used probably half the mix and it was beginning to get a little warm - actually this was good as the viscosity had become really low - and then, almost without warning it turned to jelly and then, within seconds, crackled and popped and smoked and set up hard - with my brush stuck firmly in it!! I have only recently started using this stuff - I've been a Safty-poxy user up to my last batch and have never had an exotherm with the Safety-poxy. I was surprised at the rapidity of the reaction, particularly as there was less than 1/4 inch in the bottom of the pot. I find that with the slow hardener I get about 45 mins working life at 80 degrees before it starts getting a bit jelly like and doesn't wet out very well - this is about the same working time as I got with the Safty-poxy. I do have one other problem with the MGS product - it seems to "foam" easily when wetting out, rather like the Epolite 2427 which I tried for a short while. Any thoughts on reducing/avoiding this problem, or similar experience to share? Will Chorley From: "John Slade" Subject: Re: COZY: MGS Epoxy - Can set up too fast!! Date: Wed, 17 Mar 1999 09:33:03 -0500 Will, >then, almost without warning it turned to jelly I had a similar experience with my MGS last night. I keep my epoxy in a hot box (90 or so). The workroom temp was about 78 and I'm using 50% fast / 50% slow. After about 30 mins I needed some epoxy to wet up a dry area and found I was painting jelly. I discarded the ply of bid, cut another piece and mixed new epoxy. This wasnt a dramaric exotherm, just jelly way before I expected it. First time it happened. >it seems to "foam" easily when wetting out I also get some foam if I stipple a lot, but it paints away with a gentle brush stroke. Nat said in a newsletter "If I were building another plane I'd use MGS". I spoke with him about it and he confirmed that he'd used it and liked it so I took his advise. MSG is the only epoxy I've used, so I can't offer a comparison. I like the stuff and I'm getting used to how it works. I'm getting good results (confirmed by EAA tech consultant) and my parts are light. John Slade (Cozy #757) Moving into Chap 5.... From: Epplin John A Subject: RE: COZY: MGS Epoxy - Can set up too fast!! Date: Wed, 17 Mar 1999 10:47:15 -0600 My experience has been very similar to what I have seen posted. I might add a couple of points. I prefer using a squeegee rather than a brush if possible. I think this reduces the foaming somewhat. Obviously it is not feasible to use the squeegee to apply the resin to vertical surfaces. Also, it seems the fast hardener is too fast for anything except very small jobs if the temp is above 75. I found a mix of 50-50 to be a good general purpose ratio. I used the slow straight for large lay-ups such as the strake outer skins where there is multiple layers over large surfaces. Get your glass prepared so as not to spend much time between layers. If you have help you may be able to take it right off the roll onto the surface, this works best IMHO. Otherwise have it cut to size and rolled neatly so you can get it in place with a minimum of fiddling around. My experience has been that the two hardeners full cure at about the same time, that is about 24 hours before you want to do any sanding at 75 to 80 deg. F. The fast hardener may be sanded 8 hours after mix in 90+ deg conditions usually. I have used 2427 and Aeropoxy also and at this stage I agree 100% with Nat, I would use the MGS for all laminating. I keep both the resin and hardener at 100 deg F in a temperature controlled box that I would recommend you fabricate somehow. Grainger sells a couple of thermostats that are capable of 115 volt operation at several amps, you can use light bulbs or strip heaters or whatever you can come up with, I use some large power resistors that I happened to have around. A small fan is needed, otherwise the top of your box will be hot and the material sitting on the bottom will not be heated as desired. Leave the fan run continuously. I found a small 115 volt muffin fan at Radio Shack that has run continuously for over three years now. It rattles a bit but keeps on running. I have it fused for 1 amp, just in case. My box is a compartment of a utility cabinet purchased from Loews, lined with fiberglass ceiling tile pieces with a foam gasket around the door. Hope this helps someone. John Epplin Mk4 #467, almost done with laminating epoxy, going to filler stuff next. From: "Steven Willhoite" Subject: RE: COZY: MGS Epoxy Date: Wed, 17 Mar 1999 12:57:17 -0700 Just wanted to put in my two cents that I too have turned into a fan of MGS L335 epoxy. I built my Mark IV up through chapter 13 using Safe-T-Poxy and am now using MGS. The smell of Safe-T-Poxy would spread from my garage through the house every day I did layups. It was especially bad in the winter. My family hardly knows I am doing layups with the MGS. I also find the viscosity of the MGS to be slightly lower which makes it much easier to wet out the cloth. I find a 50/50 mixture of the slow/fast hardener to be about right. I do get some crystallization in the hardener nozzle of my Sticky Stuff dispenser when I don't use it for a few weeks, but it is easily cleaned out prior to pumping a fresh batch. I always keep my epoxy pump closet thermostatically controlled to 80 degrees F using a light bulb for heat. Steven Willhoite Cozy Mark IV #006 P.S. You can get more info, including mixing ratios and curing times at... L285 spec. sheet: http://www.mgs-online.com/pdf/foreign/01mgs037.pdf L335 spec. sheet http://www.mgs-online.com/pdf/foreign/01mgs061.pdf From: "Hunter GA (Gary) at MSXSCC" Subject: COZY: More epoxy questions - Fuel Resistance Date: Fri, 19 Mar 1999 07:28:47 -0600 Ric Lee on Canard Aviators wrote: Gary, have some epoxies been found that are better suited for use in making fuel tanks than others? I believe I read about some epoxy flaking off in fuel and causing a Cozy to crash. All the suppliers claim their "structural resins" are suitable for fuel containment. And, they are - IF - the builder knows how to go about it and does everything correctly. I have always been adamant about "post curing" epoxies, especially the fuel tank. You can't buy cheaper insurance. Safe-T-Poxy I or now EZ-Poxy 87 is probably by far the best in this category, with or without a post cure. Chemical resistance is one of the prime attributes of epoxies beyond homebuilding airplanes. They are used for building fiberglass chemical storage tanks and piping and for lining of steel tanks to prevent corrosion. In that industry the curing agent "type" governs the degree of chemical resistance. Aromatic amines are by far the best know curing agent type for overall chemical resistance - particularly in fuels, solvents and strong acids. EZ-Poxy 87 is the only aromatic amine curing agent available to the homebuilt world. Next in line are "aliphatic amines". The original RAES & RAEF were "modified" aliphatic amines. However, according to my tests the RAES without a post cure was absolutely no good for fuel and marginal with. But, the RAEF without a post cure was marginal and did just fine with a post cure. Thus, the original Vari-Eze plans mandated RAEF for the fuel tanks. Next in line are "cycloaliphatic" amines. Aeropoxy, MGS, Proset, and EZ-Poxy 83 & 84 are "blends of modified aliphatic and cycloaliphatic amine adducts". Modified - because the straight stuff has bad cure behavior. Some modifications work out better than others. A prime example is the Aeropoxy's sensitivity to temperature and moisture. I call these "quirky cure characteristics". However, even the "quirkiest" of these curing agents will resist fuel - IF - they are properly applied and fully post cured. DO NOT simply brush the resin on the inside surface of the already cured fuel tank and expect it to cure like a 2 or 4 ply lay-up. This is were the screen plugging flakes of epoxy come from. Your original layups for all the inside tank components should be "wet" so to be certain there are no dry spots, pinholes or voids. This is no place to be too concerned about weight. Even the BID tapes in the corners should be nice and wet. Peel ply only were secondary bonds will be needed. For those of you than like the smooth surface of peel plying - add an extra final ply of a fine weave light weight fiberglass deck cloth. It will give you a similar smooth surface without introducing or hiding voids. Warm shop temperatures and low humidity will reduce the curing agents "quirk" factor. There are many ways to obtain a post cure on the tank. Before the tops are put on, you can use heat lamps to cure the inside surfaces. You can pre-post cure the inside surface of the top too. After the top is bonded in place you can post cure these bonds by heating the exterior surface with heat lamps. The heat will work its way to the bonds. OR, after the top of the tank is bonded on, you can circulate warm air through the tank for several hours. I did this with the outlet end of my vacuum cleaner inserted in to the fuel cap opening. About 140F is sufficient. RULE OF THUMB - If you can hold your hand on the surface to the count of 10 - the temperature is 140F or below. Hope this is helps. Gary Hunter EAA Technical Counselor Vari-Eze N235GH From: Chm12345@aol.com Date: Sun, 21 Mar 1999 21:30:08 EST Subject: COZY: Experience w/ MGS epoxy I'd like to share my experience with MGS epoxy. I'm currently using L285 and I'm extremelly happy with it. I initially used the H285 hardener but discontinued that practice since, here in Florida, the use of this hardener almost guaranties an exotherm reaction unless the quantities are very small (and I usually mix very small quantities) or the temperature is low. I now use H287 which is the slow hardener and it works great. I haven't experienced the problem another Cozy builder reported with the product not hardening but the temperature never really gets too low. I do inspect the contents of the pump for crystalization every time I use it and verify the ratio and document the results every month or every time I'm going to perform a critical layup (I'm using the AR100 pump). The only problem I experienced with the MGS hardener is that it tends to crystalize with relative ease when left on the pump's plastic container for an extended period of time. The problem is that this crystals will not return to the normal product after heating it. MGS explained to me that this is caused by the hardener reacting with CO2 and the crystals are urea crystals which will not revert to the original hardener after heating. After sealing the container's lid very well with the use of tape the problem re-occured. I noticed that the hardener in the original metal continer never cristalized so I drilled a hole on the bottom of the original hardener metal container and installed on the pump (The resin is OK in the plastic container). No crystals noticed again. Lastly, I always cap the nozzels of the pump with a bit of masking tape which I wrap arround the nozzle, letting some extend beyond the end of the tip, and I then pinch the end of the little tube that forms to seal the nozzles. The hardener does tend to crystalize very easely in this area and by keeping it away from the air it doesn't do it anymore. The reason I like MGS so much is that it is not only a very nice product but is is used on certified aircraft such as the Diamond Katana and other German gliders imported in the US (which I had the opportunity to own and can attest to the quality of this resins). By being certified (by german authorities) it gives me the assurance that the product will perform if used as specified. No risk of changed formulation or old components. This to me is worth any extra money the MGS epoxy cost. Chris From: Lee810@aol.com Date: Mon, 22 Mar 1999 00:24:18 EST Subject: Re: COZY: Experience w/ MGS epoxy In a message dated 3/21/99 7:34:54 PM Mountain Standard Time, Chm12345@aol.com writes: > Lastly, I always cap the nozzels of the pump with a bit of > masking tape which I wrap arround the nozzle, letting some extend beyond the > end of the tip, and I then pinch the end of the little tube that forms to > seal the nozzles. The hardener does tend to crystalize very easely in this area > and by keeping it away from the air it doesn't do it anymore. I use the finger of a latex glove held on with a rubber band to prevent crystallization of the MGS epoxy on my hardener nozzle. It always seems that I have about ten of those things available after a layup. Lee Devlin http://members.aol.com/lee810 Date: Sun, 11 Apr 1999 12:33:09 -0500 From: "Joseph H. Hart" Subject: COZY: Yet Another Epoxy Question Fellow Builders: I haven't worked on the project in few weeks and am ready to get back to it. One of the reasons (other than work!) for my hiatus is that the last gallon of MGS 285 resin that I purchased, coupled with the recent discussions on this forum, caused me some concern. I noticed when my old bottle of resin (with about 3/4" of resin in it) and my new bottle were next to one another, the new bottle does not seem as transparent. However, I don't really think that the new bottle is any less transparent than my earlier bottles appeared when I got them. Because of the recent discussions and because the bottle say "USE ONLY COMPLETELY TRANSPARENT RESIN", I started to question the condition of the new resin. Frankly, but for the discussions, I don't think that I ever would have questioned a thing. Anyway, I e-mailed MGS but never received a response. Thus, I turn to you (Gary, are you out there?). The resin is not what I would call "cloudy" as it is homogenous in the degree to which it is transparent. It looks more like tap water with a lot of minerals in it. I heated it up in a double boiler to about 155 - 160 degrees F for approx. 2 - 3 hours, shaking it up during the process. There was no change but for the labels coming off. What do you think? Is it OK to use? I've got one side glassed and one to go. I'd really like to get the other side done. Thanks in advance for you advice. -- Jody Hart Cozy Mark IV plans 648, Chap. 7, progress at: http://members.home.net/jodyhart/index.html From: "Chris Byrne" Subject: COZY: MGS Epoxy Date: Mon, 12 Apr 1999 14:22:56 +1000 Builders The email from Jody Hart jogged my memory. Again this is a bit long winded, but the archives will now contain all of the info I have recieved from MGS on their epoxies. About two months ago I had some problems with the crystalization of the L335 resin, which was easily fixed by warming the resin, however I had been using this cloudy resin for a good month or so and some of it was almost sludge like in the very bottom of the epoxy pump. I was concerned (so was MGS) about the strength of these layups, so I sent some offcuts to MGS to be tested at their suggestion. They were actually very quick in their response, its me who has been a bit slack in posting the results. Below is a copy of all the info I recieved from Johannes Meunier about my samples. "The way the crystallisation effects the epoxy resin. Both, resin and hardener are a formulation of different ingrediences. These different substances have different properties, one of them is a different affinity for crystallisation. Each of the ingrediences also have different mixing ratios. What may happen at a crystallisation is, that only a part of one component of the composition gets solid. If you take the remaining material, the mixing ratio has changed and you may mix resin and hardener in a non-optimum mixing ratio. This affects the amount of cross linking in the molecular structure, because you either have too much resin or too much hardener. This is measurable by determination of the Glass Transition Temperature. Each of our resin systems has a certain range of a maximum possible Tg. By comparing the maximum Tg of your sample to the "normal" value, I can tell whether the material is o.k. or not. The effect of crystallisation on the mixing ratio of the resin is way lower than on the hardeners. So I would not worry at this time about the quality of the laminates. I will, however measure the samples you´re sending over and let you know about the results". The results of the four samples that I sent all indicated the TG to be within 2C of the maximum that MGS expect from the L335 system (80-85C). They would have been concerned if they were down to (70-75C) The samples showed a TG of around 51-55C after the first run (indicates the room temp TG) and 82-84C after the rapid postcure. "We performed two runs on the samples. In the first run, the sample gets heated up to 200-250°C. After that run, we can determine the Tg as it was when we got the sample. After that run, we assume, that the sample is completely cured (some kind of a very fast post curing cycle). The secon run gives us the info of the maximum Tg, we get with the sample. As I wrote you, if a sample is not mixed properly, or the mixing ratio would be wrong for whatever reason (such as chrystallisation), it would be significantly lower". The following is some general statements from Johannes Meuiner of MGS that he is happy to have published. His direct e-mail address is at the end. "I would appreciate it, if you could give the advise of heating up resin / hardener when they are crystallised. This may help homebuilders to achive a better quality and learn more about the specific working properties of these products. However, there are some resins that come out cloudy, due to some additives in them, for example our L418 ( a resin system for higher temperature applications >100°C). No matter how much you heat that up, it will stay cloudy, because it IS cloudy - however, this is not crystallisation. For the L335 and L285 which is mostly used in the homebuilder scene, it is true, that cloudiness is a signal for crystallisation. I would not state in the advice, that even when the products are crystallised, they still have good properties, because they may not, and some people may think they don´t need to worry if it crystallises. And I want them to worry. We are building airplanes and I want our materials to be worked in the way the are supposed to be, to make sure there is ALWAYS the quality an airplane requires. We were lucky in your case, because it was only a small amount of crystallisation. If this becomes significantly more, or worse, the crystallisation occurs in the hardener instead of the resin, the effect on the properties of the material may be significantly higher. I´d rather see the advise to be given, that if crystallised resins / hardeners have been worked, they should be tested for their quality by a potential Tg determination. It is a normal thing that these material crystallise and most people are not aware of this. If we can do some education in a way that this may be a problem and people should be aware of it, this would be the best we can do. It those people have questions, I´ll try to answer them as I can, and maybe you can insert a link to our website and my email adress. As you know, airplanes and flying is my world too, and I am glad that it is such a small world where people work together with the same intentions. Sometimes this collides with the job I have to do, but you can consider it as a contribution to my own flying... If I can do anything more, let me know. Johannes"""" Meunier@mgs-online.com Hope this helps. Chris Byrne From: JERSKIP@aol.com Date: Wed, 21 Apr 1999 13:23:13 EDT Subject: COZY: (no subject) Being a brand new builder,(plans #768), I'm trying to select resin type to use. I've seen many good comments re: MGS 335, but not many comments about the 285. I live in Florida, so cold is not a problem, and I'm considering post curing the 285 system so I'd have a few more options on colors. Comments? Jerry Schneider Date: Wed, 21 Apr 1999 11:57:08 -0700 Subject: COZY: Re: Epoxy selection From: "Thomas Kennedy" ---------- From: JERSKIP@aol.com To: cozy_builders@canard.com Subject: COZY: (no subject) Date: Wed, Apr 21, 1999, 10:23 AM In reply to... Being a brand new builder,(plans #768), I'm trying to select resin type to use. I've seen many good comments re: MGS 335.... My impression is that the BAD comments outweigh the good. Post curing seems involved. Seen many non-hardening stories. The Safe-t poxy is approved and has worked well for me in the Southern California climate. The stuff stinks (literally) but not that bad and certainly not enough for any neighbor in close quarters to complain about. Due to lack or bond strength after initial set I do not recommend the 2427. I have a canard with this stuff that looks good, but is causing me angst. Use a hair dryer to help with layups particularly the UNI ones. Build a heat box to keep epoxy warm. Keep the dispenser clean. Thomas Kennedy #248 Spar done, wings started (finally) From: DougSheph@aol.com Date: Wed, 21 Apr 1999 16:01:29 EDT Subject: Re: COZY: L285 epoxy system Jerry Schneider wrote: >>...not many comments about the MGS 285... I'm a little bit ahead of you (one fuselage side completed), and I've used the L285 system exclusively. So far I'm delighted with it. It has essentially no smell, it cures beautifully in San Diego-area weather, and the viscosity makes it very easy to work with. I am told it's not affected much by moisture, either, although that's not much of an issue out here in the desert. It's workable as low as 70 degrees, and I'm assured (by Johannes at MGS) that it will cure fully at that temperature, but cure is much faster and it's much easier to work with at 80 degrees. I most often use a 50:50 mixture of the fast and slow hardeners (try that with the other systems!), which gives decent pot life at 70-80 degrees and will cure in 3-6 hours at those temperatures. On those dog days, I mix a little more of the slow hardener into my epoxy pump, keeping rough track of the extra and how much I've used so I can get it back down to 50:50 when the weather cools off again. I suspect the 'non-curing' problem seen by some is caused by crystallization, which every epoxy system is susceptible to, to one degree or another. My suggestion there is to keep the epoxy (including full cans) ovenized at 90 degrees or so and inspect for cloudiness before each use. Use the documented procedure if you see any sign of crystallization (I never have). Also, and perhaps most importantly, don't let the project sit idle for weeks. I've found that if I work at least a little on the project every day, the epoxy stays fresh, the pump stays limber, and I stay excited about the project. Doug Shepherd From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: Epoxy brand compatibility Date: Tue, 27 Apr 1999 10:27:22 -0500 John Epplin Mk4 #467 wrote: > Need some expert knowledge. > > I made my wings and winglets from Aeropoxy PR3660/2032 epoxy. Soon will > come the time to join these parts. I have been using the MGS 285 for some > time now and wonder if it will make any difference using MGS for the > attachment over the Aeropoxy. The Aeropoxy has been peel-plied at all the > mating surfaces. I am quite sure they will stick together, just wonder if > there are any known problems switching systems. > The two resin systems should be fully compatible. Surface preparation is still the most important thing for obtaining good secondary bonds. If the peel ply has been in place right up to the point of laminating the next layer, very little to none is needed. However, if you removed the peel ply many days, weeks or months ago, you should abrade the surface completely with at least 80-100 grit sand paper. Gary Hunter EAA Technical Counselor Crew Chief - The EXXON Flyin' Tiger Date: Tue, 27 Apr 1999 16:40:32 -0400 From: Jeff Russell Subject: Re: COZY: Epoxy brand compatibility Epplin John A wrote: > Need some expert knowledge. > > I made my wings and winglets from Aeropoxy PR3660/2032 epoxy. Soon will > come the time to join these parts. I have been using the MGS 285 for some > time now and wonder if it will make any difference using MGS for the > attachment over the Aeropoxy. Don't forget that you need to post cure the MGS system. -- Jeff Russell/AeroCad Inc. E-mail: Jeff@aerocad.com 2954 Curtis King Blvd. Ft. Pierce, FL. 34946 Shop# 561-460-8020 7:00am to 3:30pm Home# 561-344-6200 Website: http://www.Aerocad.com Composite workshop info: http://www.Sportair.com From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: Epoxy brand compatibility Date: Fri, 30 Apr 1999 09:34:02 -0500 Jeff Russell wrote: > Jeff, > >Don't forget that you need to post cure the MGS system. > John replied: > Are you suggesting that MGS requires a post cure while other epoxy systems > don't ? If so, what do you base this on ? > Regards, > John Slade Cozy Mk IV #757, N386JS > Jeff, Hope you don't mind me chiming in here.... John - This is based upon the manufacturer's product technical bulletins. MGS themselves prescribe a post cure for their products. The MGS systems were specifically formulated for the production of commercial sailplanes and motorgliders in which the factory production schedule utilizes oven post curing as a norm. They were not formulated for applications that require a Room Temperature (RT) cure alone. Incidentally, a friend of mine was telling me he found the internet site for the European equivalent of our NTSB and was horrified to see that about 10% of the aviation accident reports in their system involved sailplanes and motorgliders having major structural failures. All them aerobatic certified aircraft. There is no way to tell how many, if any of these aircraft were built from MGS systems. But, given the location and aircraft type, I would say the probability is pretty high that some of them were. Do not misinterpret what I am saying. There are no indications that MGS systems are inferior in any way. The structural failures in these aircraft could be simply overstress or design related, and the fact they may have been built from MGS resin a pure coincidence. However, considering the above, the requirement of a post cure, and given the flawless tract record of the Safe-T-Poxy system (now EZ-Poxy) I am curious as to why anyone would even consider using anything else. Gary Hunter EAA Technical Counselor Shell Epoxy Resins Technical Service From: "Nat Puffer" Subject: COZY: Epoxies-post cure Date: Fri, 30 Apr 1999 11:11:35 -0500 Dear Cozy Builders, It so happens that I have been collecting data on all of the epoxies which have been approved for wet layups and room temperature cure, and there is not one of them which reaches full cure and full properties without post curing. The most important temperature related property is heat deformation temperature, at which temperature the epoxy begins to soften and begins to lose mechanical properties. Here is the data I have for heat deformation temperature vs cure temperature in degrees F.: Epoxy R.T.Cure Elevated Post cure RAE 120 151 Safe-t-Poxy 118 171 2427 117 162 EZ Poxy 125 158-170 PTM&W --- 202 MGS 335 130 185 MGS 285 150 240 I can tell you that there were many (including mine) Variezes and Long EZs made with RAE epoxy without post curing (in the technical sense) and there have been no structural failures attributed to lack of post curing. As a matter of fact, my Varieze, after it changed hands, sat outside on the ramp in Chandler AZ for 2 years at least in the hot Arizona sun in ambient temperatures which have been known to reach 122 deg. F, and the airplane did not melt nor did the wings droop. One of the reasons might be that the resin continues to post cure as it sits at higher temperatures, and the heat deformation temperature always increases with cure so that it is 40 to 50 degrees above the temperature at which it has been soaked. I have built and flown 3 Cozys which were built with RAE and not post cured, and none of them have melted nor fallen apart. As you can see from the above, the MGS resins have a higher heat deformation temperature after both a room temperature and elevated temperature cure (with the possible exception of PTM&W). It is my opinion, based upon my investigation and experience that the MGS resins are superior to what I have used in the past and would be my first choice if I were building another airplane today. When it comes to structural failures of sailplanes in Europe, one would have to determine what loads the structure was designed for, and what loads it was subjected to, and even then it would be hard to pin a failure on the epoxy used. The first thing to suspect is not enough glass. Maybe one reason RAE and Safe-t-Poxy have such a good record is that the Long EZ was designed for 12 to 18 gs, which even the human body could not withstand without failing. As long as you remember to add the hardner, and add the right amount, I don't think you need to worry about having a structural failure because you didn't post cure the epoxy. But as one person aptly put it, nothing that an engineer has ever designed cannot be made to fail (double negative intended). Best regards, Nat Date: Fri, 30 Apr 1999 17:44:18 -0700 From: marcna Subject: Re: COZY: 2427 Revisited My complete airframe, canard, main spar, and wing was completed with 2427. Now that I am two months away from doing my first flight I should redo my whole project, to late to turn back now. Marc Parmelee Michael Link wrote: > > > Dear Builders, > > I have only been a subscriber to this group for a short while, so I > don't > know what had previously been said about 2427 epoxy resin. I know that > the > Cozy newsletter discussed problems that some people had experienced and > that the product had been withdrawn from the approved epoxys. I used > 2427 in the final construction phase for non-structural applications > such as armrests, wheelpants, etc., and experienced no problems using > the material. The 2427 behaved and looked similar to the RAE epoxy of > which most of my plane is constructed . > > I recently caught my left wheelpant on a small "curb" when pushing the > plane into the hangar. When I surveyed the damage, I was surprised to > find that several layups had delaminated. The 2 inch BID strip that held > the wheelpant halves together, as well as the lip that holds the > nutplates for the "pie pan" portion of the assembly had pulled away from > the pant. Did I thoroughly prepare the surface with 80 grit paper? Did > I peel ply the BID tapes to avoid a stress riser? Did I thoroughly > inspect the assembly for air bubbles, etc. Is the Pope Catholic? > > I was (negatively) impressed with how easily the laminations could be > seperated.It was not unlike tugging on a zipper. I don't want to be an > alarmist, but if you have anything critical in your airplane made with > 2427, > you had better consider removing it . The layups that I did were not > done in a high humidity environment and looked great until stressed. In > my opinion, it is better to make a painfull decision now, than to risk a > disaster later. > > Regards, > Michael Link COZY MK-IV N-171ML Date: Fri, 30 Apr 1999 21:55:46 -0400 (EDT) From: "George A. Graham" Subject: Re: COZY: 2427 Revisited On Fri, 30 Apr 1999, marcna wrote: > My complete airframe, canard, main spar, and wing was completed with 2427. > Now that I am two months away from doing my first flight I should redo my > whole project, to late to turn back now. I also used 2427, and I have tested it inflight in the most severe turbulence, where I was afraid the wings might come off. So far so good. My one really hard landing spread the main gear hoop out so far as to scrape the brake calipers on the runway (the main gear hoop is one that I made also with 2427). Of course I wonder why there are problems, but I am certain that mine is solid, even the fuel strakes are without trash or leaks. George Graham RX-7 Powered Graham-EZ, N4449E Homepage From: DougSheph@aol.com Date: Fri, 30 Apr 1999 23:59:05 EDT Subject: Re: COZY: 2427 Revisited As far as the epoxy issue goes, I would definitely side with Nat and the others who maintain that the 2427 problems (after FULL CURE) are so minimal that they're not worth worrying about much. On the other hand, I have to admit that I probably would worry about it a bit, at least until the airframe had proven its ruggedness. What would I do if I was in that situation? Do what Johannes suggested, rent an auto paint shop's curing booth for an overnight post cure of the whole airframe. Then I'd fly it, secure in the knowledge that a) the materials in the plane are guaranteed to be fully cured and at the peak of their performance, and b) as Nat pointed out, NO accidents of this family of aircraft have been shown to be related to epoxy failures anyhow. Date: Sat, 01 May 1999 17:46:46 -0500 From: Kent Ashton Subject: Re: COZY: 2427 Revisited FWIW: I skinned a wing with 2427. I did the work in my basement so the environment was probably cooler and slightly higher humidity than outside conditions. Later, I had a spot on the wing delaminate when I removed some bondo and I started to pick at it. I found I could strip off all the layers of wing skin, except the bottom layer next to the foam, by pulling up a 1-2" wide strip and ripping it off. I ended up ripping off the skin and reglassing with RAE. All my other work was done with RAE or EZ-Poxy and I haven't seen that kind of weak peel strengh with those two. Michael Link wrote: > > I recently caught my left wheelpant on a small "curb" when pushing the > plane into the hangar. When I surveyed the damage, I was surprised to > find that several layups had delaminated. The 2 inch BID strip that held > the wheelpant halves together, as well as the lip that holds the > nutplates for the "pie pan" portion of the assembly had pulled away from > the pant. From: "Hunter GA (Gary) at MSXSCC" Subject: COZY: Apology Date: Fri, 7 May 1999 14:32:58 -0500 I owe you COZY listers an apology. I probably confused many of you by accidentally referring to 2427 as an Aeropoxy product rather than Hexcel and for that I am sorry. It was an honest mistake. You guys have it easy with 7 or 8 different products to keep track of. In my job at Shell Chemical Company I have to keep track of 400 of my own products plus my competitors products that go into making the 8 or so products you guys have to select from. Talk about confusing. Fact of the matter is, both the early version of Aeropoxy and the Hexcel 2427 had problems associated with it's chemical make-up that neither producer anticipated because it was not field tested in all conditions before release. Now, Hexcel 2427 is gone and reformulated Aeropoxy products are as good as the others. In recent years, we have all been introduced to a host of "new" resins. They aren't new at all. They are simply different blends of old technology that has been around since the 1940's. The "formulators" that produce these new resins, all believe they have a better mouse trap. After all, it is free enterprise system here in the USA. Competition is good for the consumer, it tends to drive prices down - but I don't think we have seen that here. While all these formulators are reputable outfits doing their very best to provide a good product, their developments are all conducted under laboratory environments that do not always represent the real world. My goal is to help you understand what can go wrong, why it happens, how you can prevent it, and what to do if it happens. If I am succeeding or failing at my goal, I would appreciate feed back to that effect. Below are my TOP TWO TIPS for countering potential problems with ANY Resin System: Shop Temperature Control - This is cheap insurance. A $400 window air conditioner is the single best investment you can make for the benefit of your project. The problems most often encountered with epoxy resins occur when field conditions don't match the lab conditions in which the resin system was formulated by the supplier. It only makes sense that if you match those lab conditions you can expect it to perform as the supplier intended it to. Laboratory temperature conditions 25C (77F) are perfect for storing the resins, curing agents, and the various reinforcements. A constant temperature insures consistent resin properties - constant viscosity gives consistent wet out and resin to glass ratios. Since these conditions are very hospitable for the builder too, it is more likely you will work on the project more often resulting in faster completion times. Post-Curing. - Nat is absolutely correct about the EZ airframe design family. The differences in HDT or Tg between the various resins systems, with or without a post cure is not going to make a flip. The airframes are so over-designed, they aren't going to melt into the tarmac in the hot Arizona sun. And, yes, the resin will post cure itself over time as it is exposed to more and more heat over it's life span. And there is a pile on non-post cured airplanes flying out there today without a hitch. Nevertheless, post curing helps to make up for those nights when the shop temperature dropped too much, and the lay-up was still sticky in the morning. Or, "It sure was hard sanding in that tight little corner, I hope the resin sticks good". Or, "I wonder when that ratio pump started messing up - I hope this layup is OK." And, "Will autogas or the next generation Avgas attack my fuel tanks ?" Think about it. It is simply more cheap insurance, peace of mind when you need it most, and added value for when it comes time to sell it. Once again - my apology for getting too technical and confusing you with an information overload. Have a nice weekend. Gary Hunter EAA Technical Counselor Shell Technical Service From: "Will Chorley" Subject: COZY: MSG Epoxy and Pumps Date: Sun, 9 May 1999 19:41:05 -0500 Having run through approx.. 2/3 of a gallon of MGS epoxy weighing it out, I have been thinking of converting my old pump to pump this stuff as I have come to like working with it. I have had no bad batches with the weighing method, but the pump is certainly much easier, less messy, and, I suspect, more accurate for small amounts. I've noticed much correspondence on the use of pumps with the MGS epoxy, and the major problem reported seems to be that of crystallization of the hardener. One correspondent changed from the poly containers to using the metal cans that the hardener comes in to try to avoid the crystallization problem, has anyone else tried this? I keep the pump and my epoxies in a temp controlled cupboard and have been keeping the epoxy and hardener at 80 degrees and have had no trouble with the resin or hardener in the can. Thanks, as always, for any help, Will From: "John Slade" Subject: Re: COZY: MSG Epoxy and Pumps Date: Sun, 9 May 1999 21:30:49 -0400 Will, My MSG is in the standard plastic pump containers in a hot box. I occasionally get a bit of crystallization of hardner on the output nozzel which I scrape off with an old drill bit. Other than that I have had no problems at all with the standard pump. John Slade From: "cliffordfamily" Subject: Re: COZY: MSG Epoxy and Pumps Date: Mon, 10 May 1999 14:18:14 -0400 We keep our MSG in the plastic pump containers in a heated cabinet. We also cap the ends of the spouts at the end of the day. We are well into chapters 6 and seven on two Cozy MK IV,s and have used the MSG resin and hardeners with the pump since the start.. We have only had a problem at the beginning before capping off the spouts. None since. Dave and Mike. From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: PTM&W Appearance Date: Mon, 10 May 1999 08:18:23 -0500 Will wrote: > I just got some PTM&W from Wicks. I am switching to this from RAE, so I > have > not ever used it before. The resin seems cloudy to me - I can not see the > bottom of the can (1 gallon) by shinning a light in from the top. I know > what crystals look like because I had an RAE resin can get crystallized > once. The PTM&W doesn't look like that, but it seems cloudy. I don't know > if > this is normal or not. Is it usually cloudy like this, such that you can't > see the bottom of the can? Can someone who is familiar with this stuff let > me know. Thank you. > > Will Drexler > It shouldn't be cloudy Will, it is most likely crystallized. Crystallization is visually evidenced by varying degrees of haziness, or cloudiness, with thickening to the point of a waxy or curd like consistency. Sometime it will form two layers, one clear the other cloudy. This is all nothing more than crystallization. ALL epoxy resins are susceptible to crystallization. Some brands worse than others, and some batches within a brand name are worse than others. They are meta-stable super cooled liquids, and as such they are naturally prone to crystallization. The melting point for the crystals is between 120 and 140F. To reconstitute (de-crystalize) the resin, place the sealed container in a bucket of hot tap water. Agitate every 15 minutes by rotating the can, and replenish the hot water each time. Depending on the size of the container, it will take about 4 hrs. to bring the entire contents of the resin container up to a temperature sufficient to melt the crystals. The resin must remain warm enough long enough to completely melt ALL the crystals. If you do not completely melt all the crystals, you are simply leaving a "seed" to accelerate re-crystalization of the entire container again. Once de-crystalized, it should be good for several months when stored at 75+/-5F. Long before there is any visual evidence (hazy, cloudy appearance) of crystallization, it may be occurring. The only way to detect it in the early stages is to precisely measure the viscosity. Since we can't do that easily in our shops, it would not be a bad practice to go through the reconstitution procedure before using a new shipment or a container that has been sitting around the shop for few months, especially in the winter time. It is not necessary to keep the resin hot all the time, but it won't hurt either. Conversely, refrigeration simply accelerates crystal formation. Gary Hunter Date: Mon, 10 May 1999 08:26 -0500 (CDT) From: Michael Pollock Subject: Re: COZY: PTM&W Appearance Will, I currently use PTM&W from Wicks on my Cozy MKIV and am very pleased with the results. A couple things that I have noticed is: The epoxy does not like moisture - so keep the humidity down in shop The epoxy does not appear to cure well over two days if the cure temperature is kept below 65 degrees F. I use 78 degree shop temperature most of the time and can sand parts the next day. The epoxy appears cloudy when at room temperature - I use a heat box made of foam with a 15 Watt light bulb inside next to the pump. It keeps the temperature around 90 - 100 degrees in the box and the cloudy look becomes clear. Other than that, I really like the stuff. I used Hexell 2427 then SafetyPoxy when I helped to build our Velocity. I did not like the smell. The PTM&W basically has no smell, even though the fumes are still dangerous - as all epoxy's are. I would, however, use SafetyPoxy in the tank area due to the proven results with aviation fuel. From: "John Slade" Subject: Re: COZY: Epoxy brand compatibility Date: Tue, 11 May 1999 10:26:46 -0400 Hi Gary, I hate to bring this up again, but, on the other hand, I dont like to see incorrect information sit out there unchallenged. was written >Incidentally, a friend of mine was telling me he found the internet site for >the European equivalent of our NTSB and was horrified to see that about 10% >of the aviation accident reports in their system involved sailplanes and >motorgliders having major structural failures. The following information comes from an LBA (German aviation authority) report. Hard copy of this report is available on request. Of all accidents involving gliders or motorgliders in Germany or under German registration in a foreign country during 1998. 48 Accidents occured in off airport landings after lack of thermal activity (normally gear failure after hard touch down or collision with obstacles like trees, fences or rocks) 35 Accidents occured when airplanes came short of the runway and collided with obstacles or landed too hard. 17 Accidents occured during winch launch, either when the towing rope broke, or the airplane got into an uncontrolled attitude. 13 Accidents were Mid- Air- collisions 9 Accidents occured from uncontrolled attitude normally after a stall 4 collisions with obstacles (3flew against a mountain, one hit a hydroline) 2 airplanes took off with an unlocked canopy and lost the canopy 1 accident happened when the elevator was not connected 1 engine fire I hope this clarifies the issue of structural failures in Germany. regards, John Slade From: ZeroGCorp1@aol.com Date: Fri, 14 May 1999 18:41:09 EDT Subject: COZY: MGS Epoxy-first look After talking to John Slade a bit, I couldn't help but try out the MGS (I have the 335). After working for nearly 4 weeks with the EZ-poxy all I can say is WOW! This stuff has virtually no odor, though I still wear an organic respirator, gloves, etc... and is a dream to wet out on the glass. Even at 74 deg f, it was extremely thin as compared to what I have become used to working with. As it goes on the cloth, it literally disappears on the waxpaper. Downside is that it will be much harder to see the fiber bundles to make sure they are straight. The "sticky stuff" dispenser also worked like a dream. I need to get an electronic balance and calibrate it, but I will see how this first layup goes. I think I will be happy with this epoxy system. More info as it becomes available. Might do a GC Mass spec on the vapor to see what is coming off that is nasty.... Thanks for all the advice out there. I can live without all of that styrene monomer smell. Ray Cronise From: ZeroGCorp1@aol.com Date: Sat, 15 May 1999 09:40:46 EDT Subject: Re: COZY: MGS Epoxy-first look Here is the overnight scoop on the MGS 335. Used just the slow catalyst (pot life approx. 6 hrs.) shop temp 74 deg F 5:20 p.m. mixed epoxy (using sticky stuff dispenser) 5:20 p.m.- 7:20 p.m.- virtually no noticeable change in viscosity as far as wetting cloth goes. Wets out extremely easy. 9:20 p.m. - approaches starting viscosity and wetting characteristics of EZ poxy when first mixed. 11:20 p.m. - becoming thick. Could work with it, but not as easily. 12:20 a.m. 1:00 a.m. past pot life, think and very pliable, but not very spreadable. Part still easy to bend, shape, etc... 5:20 a.m. - 8:20 a.m. Perfect knife trim consitancy....soft like a stick of gum. This will be ideal as I do layups in the morning and in evening. the 10 Hr knife trim (at least while temperatures are cool) will work out great. My guess is this will drop down to 6-8 hrs. as summer gets here and I'm no longer able to maintain my shop at 74 deg F. Hope this helps out to all that have considered MGS. I still can't believe this stuff has absolutely no odor. Even my wife made the comment last night "that stuff isn't nearly as bad as the stuff you have been using." I guess as long as she can get here car in the garage, I'm ok..... I'm going to play with post cure a bit now... Ray Cronise CZ#770 Date: Sun, 16 May 1999 11:54:21 -0400 From: bil kleb Subject: Re: COZY: MGS Epoxy-first look ZeroGCorp1@aol.com wrote: > > I still can't believe this stuff has absolutely no odor. Even my > wife made the comment last night "that stuff isn't nearly as bad > as the stuff you have been using." imho, it is good to hear that you are still using a respirator. that is the major thing about ez-poxy that i like: it smells! you quickly get the idea that there is danger cruising around; no mistaking it. (kind'a like the stink they add to natural gas?) -- bil From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: Epoxy in General Date: Thu, 20 May 1999 08:34:23 -0500 > MGS doesn't have an odor, but are the "Invisible" fumes still as hazardous > as the "Smelly" products? > Actually, the invisible fumes can be more hazardous than the smelly products.... The invisible part of MGS is Isophorone Diamine (the most volatile component). The American Industrial Hygiene Association (AIHA) recommends an 8 Hour Time Weighted Average (TWA) airborne exposure limit of only 10 ppm. Which is rather strange considering OSHA has not established any Permissible Exposure Limit (PEL) or 8H TWA limit on this compound as of YET. Styrene monomer has had an OSHA PEL/TWA of 100 ppm for years, and has been reduce to 50 ppm about 5 years ago. The Short Term Exposure Limit (STEL) is 100 ppm (short term meaning - up to 15 minutes) The following is not to lessen your respect and desire for safety (which I highly encourage), but to simply to give you some degree of relevance as to what these numbers mean. I have been personally monitored in the work place for exposure to Styrene when I worked with Vinyl Ester Resins that contain on average 40% wt. styrene monomer. The monitoring device's lower detection limit was 5 ppm and it never detected styrene with the ventilation on. Without ventilation it rarely detected styrene at the 5-10 ppm level at the face level. Placing the monitoring device directly over the fiberglass laminate (within 1" of the surface) produced a reading of approximately 100 ppm with no ventilation. 12" above the laminate was about 10-20 ppm. The interesting part of Styrene is that it has a very low odor threshold. i.e., You only need 250 parts per BILLION (or 0.25 ppm) in the air in order to smell it. So, as you can see, the low odor threshold of Styrene gives you a false indication of exposure levels. I have never been monitored for exposure to Isophorone Diamine and therefore will not speculate as to what kind of exposure levels one might see with this compound in the CBF. No matter, you should be pro-active in reducing your exposure levels to any of these chemicals, just as if you are handling pesticides. The most significant and direct route of exposure is dermal - simply wear gloves and keep it off of you. > If You are in a CBF with a window unit type Air Conditioner, how much > ventalation is enough? Will a simple oscilating fan be enough, or do you > need some more robust method of providing fresh air? > The amount of ventilation you need is not that great - Both Styrene and IPDA will rise into the air - so, a good size bathroom exhaust fan strategically placed over your work area will be far better than nothing when all the doors and windows are shut. > Airconditioning here in Texas is a must, but so is heating. What would > the best way to Heat the CBF? Could I get a unit that does both? > A window air conditioning unit can heat and cool - AND they can provide ventilation assistance to the bathroom exhaust fan by bringing in fresh air as opposed to recirculation of room air. Hope this helps :-) Gary Hunter Date: Thu, 20 May 1999 11:45:04 -0700 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: RE: COZY: Epoxy in General Gary Hunter wrote: >I have been personally monitored in the work >place for exposure to Styrene when I worked with Vinyl Ester Resins that >contain on average 40% wt. styrene monomer. Gary, I have always been curious about Vinyl Ester, but have absolutely no knowledge about it. It certainly has built a lot of good, reliable Glassairs. Could you tell us a little about it? Specifically comparing it to Epoxy for properties, cost, advantages, disadvantages, etc. Why isn't it in wider use? Stoddard Hamilton is a sharp outfit, and one of the best in the business, and they certainly have had a lot of success with it. Thanks. Howard Rogers From: "Hunter GA (Gary) at MSXSCC" Subject: COZY: Vinyl Esters Date: Fri, 21 May 1999 10:33:13 -0500 Gary, I have always been curious about Vinyl Ester, but have absolutely no knowledge about it. It certainly has built a lot of good, reliable Glassairs. Could you tell us a little about it? Specifically comparing it to Epoxy for properties, cost, advantages, disadvantages, etc. Why isn't it in wider use? Stoddard Hamilton is a sharp outfit, and one of the best in the business, and they certainly have had a lot of success with it. Thanks. Howard Rogers This is probably a lot more than you asked for - but here it goes any - and put it in the archives. First of all, it is probably interesting for you all to know that Vinyl Ester Resins are chemically manufactured from various types of EPOXY resin feedstocks. The epoxy reactive sites (oxyrane bridges) are used to react with an methacrylic acid to form the "vinyl ester" Essentially the "back bone" of the primary compound, is the same "back bone" as that of an epoxy resin. The resulting vinyl ester is very viscous (tar like), thus a reactive diluent is added to the resin. Styrene monomer is the diluent and it can be as high 50% by wt. - but more typically 37%-45% these days. Other diluents like - Di-Vinyl Benzene - Para - Methyl Styrene can be used - but Styrene is the CHEAPEST - and toxicology studies are abundant by comparison to the others. Vinyl esters are inherently unstable and will slowly polymerize or gel on their own. Inhibitors are added to the vinyl ester/styrene solution to enhance the products shelf stability. Vinyl esters are not cured or crosslinked with curing agents like epoxies. They are catalyzed like "boat resins" or "polyester resins" through the use of various different types of peroxides, the most common being MEKP. A metal salt promoter (Cobalt Napthenate - purple in color) is added to the resin to help generate what chemists call "free radicals" when it is combined with the peroxide for speeding the natural reaction along. The free radicals overpower and consume the inhibitors allowing the resin to polymerize and crosslink. Typically, to cure a vinyl ester - one must first add the Cobalt - Usually, 0.1-0.4 % wt. (virtually a few drops), STIR IT IN, then add anywhere between 1 - 2 % wt. MEKP - stir again. You must avoid letting the MEKP come in direct contact with the Cobalt as this will result in very violent and somewhat explosive reaction. If the temperature is too cool, a 4th component called dimethylaniline (DMA) can be added as an accelerator (before the MEKP step). Most of the time, you get your best combination of cure speed in the laminate and potlife when you adjust the promoter and catalyst level to obtain about a 30 minute gel time in the mixing cup. In my book, a good digital balance capable of weighing tenths of a gram (0.1 grams) is a must for working with this product. However, I have seen people work up alternate measuring systems using calibrated measuring cups, hypodermic syringes, and even counting drops. Quite a pain compared to whoopin' up a batch of epoxy - even if you have to use Burt's old beam balance. By using a temperature activated or latent catalyst, you can have an extremely long pot life resin (days), that cures quickly when you heat it to 180F or better. I believe Glassair uses this type catalyst system for producing the vacuum bagged pre-fab parts of their kit plane. The builder uses the latter. Sounds ugly, - but like anything else - you get used to it. Vinyl esters have a limited shelf life - typically 9 - 18 months depending on the storage temperature. With refrigeration, it can be extended up to another year or so. As the product ages the inhibitor level declines allowing the resin to react on itself and grow in viscosity. As you can imaging - the older a resin is, the less catalyst it needs to produce the same gel time. Which really complicates "whoopin up a batch" with any consistency. Vinyl Esters have many pros and cons like any of the epoxy resins we have become familiar with. Probably the most notable PRO is that they develop a larger percentage of their "ultimate" thermal and chemical resistance properties with just a room temperature (RT) cure than do epoxies. They are inherently "tough". They also have superior thermal and chemical stability over the typical epoxies that we use, and the "polyester boat resins" used to make many of the prefab parts on other kit planes like the RV. They develop this kind of stability with a simple ambient cure because the reaction is highly exothermic. Even thin laminates can generate a considerable amount of heat - but vinyl esters benefit from a post cure just as an epoxy does. ( I had to say that ). CONS - We already talked about the rather inconvenient mixing ratios and hazards. They inherently shrink more than epoxies (about twice). Except for EZ-Poxy, they smell (styrene) compared to epoxies. They always produce a sticky surface on cure. This is caused by air inhibition of cure - similar, but not quite the same as the amine blush in epoxies. And as with epoxies, peel plying will take care of it. As with just about any chemical compound, they are skin and eye irritants, and some people develop a sensitivity to them and become allergic (usually, this is from the styrene component more than anything else). They are flammable liquids in the uncured state. The peroxide catalyst can blind you if you get it in your eyes. In 55 gallon drum quantities - vinyl esters cost about $2.75 / lb. (about $24 / gal.) The price increases exponentially as the container size decreases, just like it does for epoxies. The catalysts are several times more expensive than the resin. However, at the small usage levels required, they only contribute ~.25-.50 cents / lb. ($2-4 / gal.) to the total system cost. For comparison, my favorite epoxy/curing agent system (EPON Resin 862 / EPI-CURE 3234) drum price is $2.33 / lb (about $21 / gal.). As far as epoxies are concerned, this system is about as cheap as it gets. So, add middle man costs for making the epoxy into an MGS, Aeropoxy or EZ-Poxy system and the epoxy will cost about the same as the vinyl ester. The reason we CAN'T use vinyl esters for building our airplanes (EZ types) is that the Styrene component in the vinyl ester resin will dissolve the styrofoam used for the core in our wings. PERIOD. NOW, I know what you are all thinking. EZ-Poxy has styrene in the hardener, - how come it doesn't dissolve the styrofoam cores ? The level of styrene in the EZ-Poxy hardener is very low compared to that in the vinyl ester. In addition, I have been told by CPD that the styrene is somehow complexed with the hardener component (methylene dianiline or MDA), thus it really doesn't behave like styrene any more. Likewise, the MDA doesn't behave like MDA anymore - at least from a crystallization standpoint. This is proprietary technology and details are sketchy - but I'll go as far as to speculate that not all the styrene is complexed and residual quantities of styrene (probably less than 1%) are sufficient enough to retain the odor. As, I said before - it only takes 0.25 ppm of styrene in the air in order for it to smell as if you have your head inside a bucket with it. So, it gives you a false indication as to the actual level of pure styrene in the hardener. In actuality, the level of residual virgin styrene is not enough to change the overall solubility parameters of the epoxy resin/hardener mixture to dissolve or hurt the styrofoam. In fact, polystyrene foam is a very non-polar substance - meaning it is difficult for epoxy to bond to it. This is why Rutan wants us to be certain to force epoxy micro into the pores of the foam to obtain a mechanical lock or bond to the foam. The small level of residual virgin styrene in EZ-Poxy is probably somewhat beneficial in this scenario. Based on my background and experience in the area, I will, again, go as far as to speculate that the styrene level could be just enough to "bite" into or "etch" the non-polar surface of the styrene and may actually improve the adhesive characteristics of the resin to the foam without hurting it. After all, polystyrene is made from styrene monomer. WOW - I can't believe wrote the whole thing. Hope this is clear :-) Gary Hunter Date: Fri, 21 May 1999 12:20:18 -0700 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: Re: COZY: Vinyl Esters Gary Hunter wrote: ... >4th component called dimethylaniline (DMA) can be added as an accelerator >(before the MEKP step). In >addition, I have been told by CPD that the styrene is somehow complexed with >the hardener component (methylene dianiline or MDA), thus it really doesn't >behave like styrene any more. Thank you, Gary, for shedding light on this subject. I'll stick to my epoxy of choice, thanks, which brings me to one more question: I have been off the EZ project for some time, but I may finally be getting my life ordered such that I can resume. My epoxy of choice has always been Saf-T-Poxy/ EZ poxy. I seem to remember that Burt swore off the stuff because of the MDA. How bad is it? Is EZ-poxy the only only one we commonly use that has the MDA? I don't have that much glass structure to go (mostly little stuff), and I'm not fond of the idea of switching horses in the middle of the stream. I would have to do some "gearing up" to go with MGS, but if there is a signifigant health risk with the MDA, I will definitely consider it. -Howard Rogers From: "Hunter GA (Gary) at MSXSCC" Subject: COZY: MDA in EZ-POXY - was Vinyl Esters Date: Fri, 21 May 1999 15:49:51 -0500 > I seem to remember that Burt swore off the stuff > because of the MDA. How bad is it? > Rutan is concerned about liability, a valid reason to change positions. MDA is probably one of the most widely mis-understood compounds from a safety and handling stand point. MDA does not volatilize into the air unless it is heated to extreme temperatures (over 200F). So, at ambient temperature conditions, MDA poses less hazard from a respiratory standpoint than more volatile amines like the IPDA . The most significant route of exposure is dermal. Keep it off you, and you will be fine. > Is EZ-poxy the only only one we > commonly use that has the MDA? > Yes > I don't have that much glass structure to > go (mostly little stuff), and I'm not fond of the idea of switching horses > in the middle of the stream. I would have to do some "gearing up" to go > with MGS, but if there is a signifigant health risk with the MDA, I will > definitely consider it. > In my opinion - the health risk is no greater than any of the other products available. If you keep take the proper precautions to avoid over exposure as you should with any other epoxy resin and curing agent combination, you will be just as safe with EZ-poxy. Wear gloves, have ventilation and keep it off of your skin. And, if you accidentally get some on you (and you will) do not wash it off with solvents. Use soap and water. The best plan is keep them off of you. ANY RESIN or CURING AGETN - PERIOD. Gary Hunter Date: Fri, 21 May 1999 16:02:59 -0500 (CDT) From: Tom Brusehaver Subject: Re: COZY: MDA in EZ-POXY - was Vinyl Esters >Rutan is concerned about liability, a valid reason to change positions. >MDA is probably one of the most widely mis-understood compounds from a >safety and handling stand point. MDA does not volatilize into the air >unless it is heated to extreme temperatures (over 200F). So, at ambient >temperature conditions, MDA poses less hazard from a respiratory standpoint >than more volatile amines like the IPDA . The most significant route of >exposure is dermal. Keep it off you, and you will be fine. I thought MDA caused liver cancer? Date: Fri, 21 May 1999 15:52:38 -0700 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: Re: COZY: MDA in EZ-POXY - was Vinyl Esters >Wear gloves, have ventilation and keep it off of your skin. And, if you >accidentally get some on you (and you will) do not wash it off with >solvents. Use soap and water. Thankfully, I have always followed the advice above (almost). I haven't always been too careful about the breathing exposure, but I plan to pay more attention to that in the future. Also, I usually kept some ethyl alcohol handy for wiping off a drop or two of mixed resin, should I accidentally get some on my skin. It would have taken a lot longer, and been a lot more difficult to wash with soap and water, most of the time. Besides, I didn't get the impression that the stuff was very soluable in water. could you elaborate? > >The best plan is keep them off of you. ANY RESIN or CURING AGETN - PERIOD. > >Gary Hunter Amen! I reacted to epoxy once, requiring cortisone shots, etc. It was on my first day of work here, in 1976. I have been REAL careful ever since. The type: Epon. Sorry, I don't remember which one. Howard Rogers From: N27EZ@aol.com Date: Sat, 22 May 1999 00:34:18 EDT Subject: COZY: Re: [c-a] Vinyl Esters In a message dated 5/21/99 7:20:12 PM, GH334766@MSXSCC.shell.com writes: << Gary, I have always been curious about Vinyl Ester, but have absolutely no knowledge about it. It certainly has built a lot of good, reliable Glassairs. Could you tell us a little about it? Specifically comparing it to Epoxy for properties, cost, advantages, disadvantages, etc. Why isn't it in wider use? Stoddard Hamilton is a sharp outfit, and one of the best in the business, and they certainly have had a lot of success with it. Thanks. >> Vinyl ester is cheap, strong, stinks like hell, gives you a headache, and makes your gloves all sticky within minutes. It must be promoted with rocket fuel and has a short shelf life. Every chance I get I use epoxy and I could not wait to finish critical areas on the glastar so I could switch over to West Epoxy on non critical structures. John Steichen, glastar, Defiant, varieze Date: Tue, 29 Jun 1999 05:20:01 -0700 (PDT) From: "Jim H." Subject: COZY: Epoxy (MGS) hardener question While on the subject of epoxy and hardeners, does anyone have information from MGS as to whether or not it is acceptable to pre-mix the fast and slow hardener? (I learned early in organic chemistry that the order of mixing components can be very important, i.e. if the fast and slow hardener have any components that react with each other the final product won't be acceptable.) Thanks Jim Hocut jhocut@mindspring.com _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com From: "John Slade" Subject: Re: COZY: Epoxy (MGS) hardener question Date: Wed, 29 Sep 1999 09:30:33 -0400 Jim, I think mixing the MGS hardeners in advance is normal and not a problem. I typically pour half a can of each into my pump's hardner container, use the pump until the level gets low, then add some more. How else could you do it with a pump? John Slade Cozy #757 N386JS Chap 13 http://kgarden.com/cozy > >While on the subject of epoxy and hardeners, does anyone have >information from MGS as to whether or not it is acceptable to pre-mix >the fast and slow hardener? (I learned early in organic chemistry that >the order of mixing components can be very important, i.e. if the fast >and slow hardener have any components that react with each other the >final product won't be acceptable.) > From: Militch@aol.com Date: Tue, 29 Jun 1999 10:22:47 EDT Subject: Re: COZY: Epoxy (MGS) hardener question In a message dated 6/29/99 12:21:16 PM, stylemismatch@yahoo.com wrote: >While on the subject of epoxy and hardeners, does anyone have >information from MGS as to whether or not it is acceptable to pre-mix >the fast and slow hardener? I believe I saw an earlier submission on this list from the MGS manufacturers that talked about the flexibility of MGS. The slow and fast hardeners can certainly be mixed at the instant you measure them out to make a cup of epoxy, and there were no caveats about doing this before-hand. Also, others on this list have said that they premix their MGS for use in a pump. I prefer to do it in real time. Sometimes I want a fast set, sometimes I want to maximize the working time, and sometimes I want it in the middle. I have also found that using the fast hardener only, in my quite cool basement, still results in an exotherm almost every time, so I only use 100% fast-stuff when I am mixing up a very small quantity and am going to use it all in the next couple of minutes. Peter Militch Cozy Mark IV #740 Chapter 6 Date: Tue, 29 Jun 1999 08:20:39 -0700 (PDT) From: "Jim H." Subject: Re: COZY: Epoxy (MGS) hardener question > I typically pour half a can of each into my pump's > hardner container, use > the pump until the level gets low, then add some > more. How else could you > do it with a pump? Well, I don't use a pump, I use a scale and store epoxy and hardener in plastic squeeze bottles which stay sealed when not in use, and it's still a pain to have to figure out how much fast and how much slow to use every time. My point is that, not knowing the chemistry of the hardener, there is a small possibility that there is some component in the fast hardener that, over time, will react with something in the slow. After enough time and enough of that reacting you will no longer have the proper ratio of hardener to resin when you mix your epoxy. I seriously doubt if there's any problem with doing this, but since my butt and my wife and kid's butts are going to be flying in this plane I want to err on the safe side instead of making an assumption about the suitability of doing this. Jim _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com From: "Hunter, Gary GA PECCHEM" Subject: RE: COZY: Epoxy (MGS) hardener question Date: Tue, 29 Jun 1999 11:06:19 -0500 Jim asked: > While on the subject of epoxy and hardeners, does anyone have > information from MGS as to whether or not it is acceptable to pre-mix > the fast and slow hardener? > Yes, you can premix the curing agent components prior to adding to the resin. This is totally acceptable and normal industry wide. Gary Hunter Date: Sat, 03 Jul 1999 23:57:06 -0400 From: George Berven Subject: [Fwd: RE: COZY: Epoxy (PTM&W)hardener Gary Hunter writes: FOR MOST EPOXY HARDENERS - "When stored in the proper and/or original container (not including the pump reservoir, under normal (70+/- 15F) temperature conditions, free from moisture and sunlight and other contaminants, the hardener should have unlimited shelf life." Scott from AEROPOXY technical support confirms this for PH3990 hardener. He also said to watch out for a pink hue in the hardener because this means it has started to oxidize. Today I opened my two year old can of hardener. On the top rim (before prying the stopper plug) it was dark & pink, as advertised. After opening and transfering to a clear container, the color was an AMBER very similar to motor oil or a light maple syrup. --------Should it (PH3660) be this dark?------- BTW, the resin was fine (no crystalization), almost clear. Thank again, George gberven@erols.com Presently driving myself crazy, wife too, with all the small details. From: "Russ Fisher" Subject: Re: [Fwd: RE: COZY: Epoxy (PTM&W)hardener Date: Sun, 4 Jul 1999 09:34:48 -0400 -----Original Message----- From: George Berven >Today I opened my two year old can of hardener. On the top rim (before >prying the stopper plug) it was dark & pink, as advertised. After >opening and transfering to a clear container, the color was an AMBER >very similar to motor oil or a light maple syrup. > >--------Should it (PH3660) be this dark?------- My 3660 has always been pretty dark - should be no problem. Russ Fisher Date: Mon, 28 Jun 1999 14:39:48 -0400 From: George Berven Subject: COZY: Epoxy hardener Another quickie, I've read and understood the archives about resin crystalization and reconstitution by heating; BUT, nothing is mentioned about the hardner WRT shelflife. In {Sport Aviation (May '99 pg.107),} Ron Alexander writes, "Resins may be stored for several years prior to being used. This is termed thier "shelf-life." However, with epoxy resins the accompanying hardner usually has a shelf life of less than one year." Is there any concrete information out there? I have not done a lay-up with the stuff and therefore haven't scratch tested it. It's AEROPOXY but that shouldn't really matter. Hardner is 2+ years old. Thanks, George... gberven@erols.com Date: Mon, 28 Jun 1999 14:17:25 -0700 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: Re: COZY: Epoxy hardener >Is there any concrete information out there? I have not done a lay-up >with the stuff and therefore haven't scratch tested it. It's AEROPOXY >but that shouldn't really matter. Hardner is 2+ years old. > >Thanks, George... gberven@erols.com My favorite saying, in this situation, is "When in doubt, pitch it out!" Actually, I usually end up being able to use the stuff for some non-aircraft project. Amazing how many things you can think of to build, once you know how to do it with glass! -Howard Rogers From: "Russ Fisher" Subject: Re: COZY: Epoxy hardener Date: Mon, 28 Jun 1999 20:42:05 -0400 George, Call PTM&W at (800) 421-1518 and ask for Scott in support. I had a similar question and I think that as long as the container is unopened, the shelf life is fairly long. My hardener was in my pump for about 9 months and froze the pump up solid. He recommended that I discard that hardener and replace with fresh. Russ Fisher >Another quickie, > "Resins may be stored for several years prior to being used. This is >termed thier "shelf-life." However, with epoxy resins the accompanying >hardner usually has a shelf life of less than one year." > >Is there any concrete information out there? I have not done a lay-up >with the stuff and therefore haven't scratch tested it. It's AEROPOXY >but that shouldn't really matter. Hardner is 2+ years old. > >Thanks, George... gberven@erols.com From: "Hunter, Gary GA PECCHEM" Subject: RE: COZY: Epoxy hardener Date: Tue, 29 Jun 1999 06:30:28 -0500 George asks: > Is there any concrete information out there? > Concrete is not even related to epoxy resins and hardeners..... Just joking.... FOR MOST EPOXY HARDENERS - When stored in the proper and/or original container (not including the pump reservoir, under normal (70 +/- 15F) temperature conditions, free from moisture and sunlight and other contaminants, the hardener should have unlimited shelf life. One exception to the rule is the MDA containing EZ-Poxy hardeners that contain some styrene monomer that can form a gel over time. In addition, these hardeners can crystallize. If stored properly, it should have at least a 1 year shelf life, and quite possibly 2 and even 3 years. Particularly if you refrigerate it. Like, I said - this is an exception to the rule and the only curing agent I know of that refrigeration will enhance the storage life of the product. When in doubt as to the age or condition of a resin or curing agent, it would be prudent to conduct a test lay-up and do scratch tests as Rutan prescribed prior to using it in your structure. And, if that doesn't make you more comfortable about it, you can always use it for non-structural applications, or as another lister suggested, other projects around the house. Don't pitch it needlessly. Gary Hunter From: "Hunter, Gary GA PECCHEM" Subject: RE: RE: COZY: Epoxy hardener Date: Tue, 29 Jun 1999 07:20:00 -0500 Rego Burger comments: RSA > Jokes aside some builders (engineers) use an Epoxy system for concrete > strength enhancements here in this country... > :-) > Yes, here too. Known as epoxy fortified concrete. Shell's EPI-REZ WD510 is most commonly used in this application. It is a water dispersible epoxy resin. Washes up with water. Just trying to get a chuckle... Gary Date: Mon, 28 Jun 1999 14:58:46 -0400 From: Phillip Subject: COZY: Humidity.... Is there a humidity level at which you should not do a layup?? Phillip Sill, #707 Finishing Chapter 4 From: "Russ Fisher" Subject: Re: COZY: Humidity.... Date: Mon, 28 Jun 1999 20:49:19 -0400 Phillip, There has been all kinds of controversy on this topic - check the archives. Some have problems while others seem to have none. Check with the manufacturer of your resin also. They would have specific numbers, although they will probably recommend that you lay up in as low a humidity as possible. Russ Fisher >Is there a humidity level at which you should not do a layup?? > >Phillip Sill, #707 >Finishing Chapter 4 > From: "Hunter, Gary GA PECCHEM" Subject: RE: COZY: Humidity.... Date: Tue, 29 Jun 1999 06:45:58 -0500 Phillip Sill, #707 asked: > Is there a humidity level at which you should not do a layup?? > It is best to avoid rain and fog producing conditions. Some hardeners are worse than others in developing an "amine blush" or "sweat-out" under these conditions. Gary Hunter Date: Tue, 29 Jun 1999 08:14:33 -0400 From: Paul Krasa Subject: Re: COZY: Humidity.... Hopefully, the distinguished gentleman from Texas, Gary Hunter, will chime in on this one. Here are my two cents. Each epoxy resin system is unique. Systems such as EZ Poxy are less susceptable to humidity problems like amine blush where as other systems which are well discussed in the archives are highly susceptable to amine blush. Other problems related to humidity are bond strength. The same systems which have amine blush problems often have a bond line strength problem. My personal recommendation to the group and all starting builders is use EZ Poxy. It has a long proven track record in varying environments. It may stink, but it does not exhibit the problems of other epoxy resin systems. Paul Long EZ 214LP At 20:49 6/28/99 -0400, Russ Fisher wrote: >Phillip, > >There has been all kinds of controversy on this topic - check the archives. >Some have problems while others seem to have none. Check with the >manufacturer of your resin also. They would have specific numbers, although >they will probably recommend that you lay up in as low a humidity as >possible. > >Russ Fisher > > >>Is there a humidity level at which you should not do a layup?? >> >>Phillip Sill, #707 >>Finishing Chapter 4 >> > > > From: "Chris Byrne." Subject: COZY: RE:MGS Hardener Date: Wed, 30 Jun 1999 08:33:11 +1000 I am using the L335 and posed the same question to Johannes Meunier at MGS last year, he replied with the following. >You can mix the two hardeners and store them for a longer period of time without loss of quality. Important is, that the hardeners are not exposed to air. Amines react with the Carbondioxide of the air, forming white crystals which reduces the quality of the material. To avoid this, always keep the buckets thoroughly sealed, then the material is storable for min. 1 year. Mixing of the two hardeners is common practice for that system and is accepted by the German Federal Aviation Authority. This system was specially designed for being able for that mixing in order to allow users to be flexible in the potlife they need. The mechanical properties stay the same as well as the heat resistance of that system.< Chris Byrne Sydney From: Gunrider@aol.com Date: Tue, 13 Jul 1999 10:53:30 EDT Subject: COZY: CHANGING EPOXY I have run out of my RAES and it has been discontinued. I have the Sticky Stuff dispenser at a 4 to 1 ratio. Wicks reccomends the Composite epoxy CPD 4426 to keep the same ratio. Is this stuff good enough or should I take the risk of changing my pump ratios? I don't need the slow cure anymore because I'm working in a/c. Thanks for your reply. Hugh Farrior The canopy is next! From: "Hunter, Gary GA PECCHEM" Subject: RE: COZY: CHANGING EPOXY Date: Tue, 13 Jul 1999 10:54:10 -0500 Composite Polymer Design now produces the RAES and RAEF systems you have been using. However, they have been given new names - They are as follows: RAEF is now - CPD 4426 (Resin) / CPD 9376 (Curing Agent) RAES is now - CPD 4426 (Resin) / CPD 9377 (Curing Agent) The slow curing agent has a blue die in it now to help you differentiate which of the two curing agents you are using when you have both on hand. You can use these products in place of the older RAE systems without worry. Gary Hunter > -----Original Message----- > From: Gunrider@aol.com [SMTP:Gunrider@aol.com] > Sent: Tuesday, July 13, 1999 9:54 AM > To: cozy_builders@canard.com > Subject: COZY: CHANGING EPOXY > > I have run out of my RAES and it has been discontinued. I have the Sticky > > Stuff dispenser at a 4 to 1 ratio. > Wicks reccomends the Composite epoxy CPD 4426 to keep the same ratio. > Is this stuff good enough or should I take the risk of changing my pump > ratios? > I don't need the slow cure anymore because I'm working in a/c. > Thanks for your reply. > Hugh Farrior > The canopy is next! Date: Tue, 13 Jul 1999 08:55:39 -0700 From: Michael Antares Subject: Re: COZY: CHANGING EPOXY At 10:53 AM 7/13/99 EDT, you wrote: >I have run out of my RAES and it has been discontinued. I have the Sticky >Stuff dispenser at a 4 to 1 ratio. >Wicks reccomends the Composite epoxy CPD 4426 to keep the same ratio. >Is this stuff good enough or should I take the risk of changing my pump >ratios? >I don't need the slow cure anymore because I'm working in a/c. >Thanks for your reply. >Hugh Farrior >The canopy is next! > I switched to the CPD 4426 after RAE and frankly don't notice any difference at all which is to say I'm very pleased with it. 1456 Jasmine Circle Rohnert Park, CA 94928 707.773.1475 Systems engineering hardware/software Date: 21 Jul 99 19:54:05 EET DST From: Cevat SUNOL Subject: COZY: MGS epoxy on fuel tank Hii When I looked to discusion between yours my questions about engines and propelers are very simple but I need some informations about props and Lycoming O-320 series engines dash number. I think to use 160 hp engine suitable for variable pitch prop. Please send your suggestions. and one more questions about epoxy on fuel tank. I am using MGS L285 / H286 epoxy system on my Cosy Classic and I want to learn that anyone used this epoxy system on fuel tank or know something about this . Regards Cevat Sunol ____________________________________________________________________ Get free e-mail and a permanent address at http://www.netaddress.com/?N=1 Date: Sat, 07 Aug 1999 23:08:38 -0600 From: "Capital Steel Inc." Subject: COZY: Epoxy Unless my hearing is getting even worse G A Hunter at the EAA forum, Friday afternoon at 1600hrs said, "Non of the West system Epoxies are suitable for your composite and besides they are too expensive". Here in Canada they are second cheapest of the ones I priced. Second they are very user friendly and Third the 105/209 is in the approved list of the Cozy letters (56-6). Is this his private opinion? Does anyone know how RAF/Nat test or approve these and are the test results available even if at a price. Joe Toop From: "Russ Fisher" Subject: Re: COZY: Epoxy Date: Sun, 8 Aug 1999 10:52:46 -0400 Joe, >Unless my hearing is getting even worse G A Hunter at the EAA forum, >Friday afternoon at 1600hrs said, "Non of the West system Epoxies are >suitable for your composite and besides they are too expensive". All of the West System epoxies except the ProSet are designed for boat use and are WAY too soft to use as a laminating resin. The ProSet is the very expensive one Gary referred to. >Here in Canada they are second cheapest of the ones I priced. Second >they are very user friendly and Third the 105/209 is in the approved >list of the Cozy letters (56-6). Indeed, 105/209 is listed as an approved resin, ONLY for finishing and contouring, NOT for laminating. Look in your plans, chapter 3, page 5, the last paragraph of Cold Temperature Tips. It clearly states that West System 105/206 (209) is softer and should not be used for laminating. >Is this his private opinion? No, it is fact. I hope you are not very far in your building progress if you have used 105/209 as your laminating resin. It MUST be scrapped and done over. The resin was formulated for use in coating or bonding fiberglass to wooden boat hulls. It is made softer because a hull is subject to more abrasion and impact than an airplane, therefore has to have the resilience to withstand such abuse without cracking. It depends upon the stronger core materials such as plywood and planking for its strength and resistance to bending. Foam core does not have the strength. Regards, Russ Fisher Date: Mon, 09 Aug 1999 09:03:26 -0400 From: Paul Krasa Subject: Re: COZY: Epoxy What Gary said was that the West Systems Epoxies are not suitable for structural components. Most people do use them for fillers or non-structrual layups. I would be suprised if Nat approved West for structural layups as you imply. West Systems says its epoxies are not for aviation use. Paul At 23:08 8/7/99 -0600, Capital Steel Inc. wrote: >Unless my hearing is getting even worse G A Hunter at the EAA forum, >Friday afternoon at 1600hrs said, "Non of the West system Epoxies are >suitable for your composite and besides they are too expensive". >Here in Canada they are second cheapest of the ones I priced. Second >they are very user friendly and Third the 105/209 is in the approved >list of the Cozy letters (56-6). >Is this his private opinion? >Does anyone know how RAF/Nat test or approve these and are the test >results available even if at a price. >Joe Toop > > > From: "Hunter, Gary GA PECCHEM" Subject: COZY: RE: Oshkosh Forum / RUBBER GLOVES Date: Mon, 23 Aug 1999 10:54:30 -0500 Thanks, Gary, I received both the e-mail and hard copies of the forum material and other literature you sent. I really appreciate it. Just knowing that my unopened SAFE-T-POXY hasn't self destructed because it is over 2 years old has made the time spent sweating out the heat at the Oshkosh forum worth while. One question (one MORE question, actually!); Lots of builders use latex gloves. I remember reading somewhere or hearing that latex did not provide adequate protection since the gloves actually have microscopic holes in them that allows the bad stuff to get through. And that barrier creams should not be used under gloves. Although I've used nitrile gloves, the ones I have are pretty thick and not as nice to work with as the thinner latex disposable gloves. So is latex no good and where can you get thin nitrile gloves? Aircraft Spruce sells latex and butyl. Again, thanks a lot. Fred Fred, In actuality, any rubber glove type can have microscopic holes in them. When it comes mass produced, "cheap" and "thin" gloves, there is no guarantee they will not have holes in them unless they are tested like condoms. When it comes to gloves there is a lot truth in the saying, "You get what you pay for". Latex gloves were developed for the medical field. Main emphasis was "good feel" (sensitivity) and adequate protection from human body fluids, and "CHEAP". Never, were they intended to provide long term protection from industrial chemicals. But, because they are cheap, and have good "feel", people like you and I find them easy to work with. They do provide some level of chemical protection too. However, recently, the medical industry has discovered people are developing a sensitivity and in some cases deadly allergic reactions to latex gloves. This is not good. As part of my job, I have attended training courses on gloves for worker safety. In short, NO glove is completely impervious to all chemicals. They are tested and rated for PERMEATION RATE for each different type chemical. Certain type rubber compounds (latex, nitrile, butyl) have lower permeation rates with certain chemicals than others. The thicker the rubber glove, the longer it takes for a chemical to permeate. In many cases, a rubber that is exceptionally good at resisting permeation of epoxy resins and curing agents, are really bad at other things you just happen to be working with at the same time - like solvents - Acetone, MEK, Lacquer Thinner, etc. (as is the case with nitrile) Gloves that provide many hours of protection. (a full "worker shift") primarily what chemical companies are interested in) are relatively thick and designed for use in harsh environments (high abrasion) over long periods of time. And as such, they have poor feel and are relatively expensive. Butyl rubber gloves are perhaps one of the best at providing good permeation resistance to a fairly broad spectrum of chemicals. But they are fairly expensive, and as such we have a tendency to re-use them over and over, and even perhaps beyond the point of their protective life span. Cleaning the glove off with a solvent to allow future use of the glove doesn't work either. Many times, the solvent will act as carrier, making the hazardous resin or curing agent permeate even further and faster into the rubber, shortening the protective life span of the glove in total. >From these training courses, one can easily conclude that ANY glove is adequate protection, provided you change them out frequently enough to keep ahead of the permeation rate. In our scenario as homebuilders, we need a glove that will last a least an hour or two. Latex has proven quite adequate for many and is certainly better than no glove at all. If you are concerned about the adequacy of latex protection or the toxicity of the latex itself, you should consider alternatives. CHEAP seems to be the primary denominator in the homebuilding world. In my opinion, nitrile rubber gloves are a good alternative although they do not resist solvents very well. I am not referencing the industrial or harsh environment grades that are thick and have poor feel. I am referring to the thinner versions packaged in boxes of 100 much like latex gloves. They have pretty good feel, maybe not as good as latex. They are more expensive than latex, but still cheap enough to be seriously considered - DISPOSABLE. I buy them from Harbor Freight, - typically a box of 100 (50 pair) is $12 and on sale they can be had $10 / box. - 20-24 cents / pair ain't bad. Other industrial supplies are located in major cities throughout the country. But expect the price to be double Harbor Freight. Depending on what job I am about to do I will put on a double layer of gloves. i.e., If it's ten minute job, one pair is sufficient. If I have a job I think will either be long in duration, or has the potential to cause a tear, or may "gook" up the glove beyond the point of usefulness, I will put on a second pair over top the first pair - before starting any work with the resins. What this does is: 1). Increases the life span of the "glove protection" considerably. What little gets through the first glove, will take much longer to get through the next layer. 2). Sweating hands inside the glove makes changing gloves "on the fly" a real challenge (unless you are particularly adept at putting baby powder on). Personally, I have found it much easier and quicker for me to peel off the outer layer of glove and put on a new glove right pronto. This works really well for those instances when a glove is just too gunky to keep working with it. It is even handy when you accidentally cut a glove. Even if you cut both layers of glove - if you stop before any resin contacts your hand, you can peel off the outer layer glove and slip a new glove on in a matter of seconds. This is far better than continuing to work with a hole in your glove, and much quicker than removing gloves from both hands, re-powdering and placing new gloves on. I never re-use my gloves. If I run out of gloves, I simply don't work until I get more. DO NOT use Barrier Creams inside the gloves. Barrier creams work best when they are dry. Since our hands tend to sweat profusely inside the gloves, the barrier cream dissolves in the sweat and becomes less effect. In the event a glove tears after your hand has begun sweating, the barrier cream won't be of much benefit. Simply put, it is a waste of money under a glove. It would be cheaper and more effective to put on two layers of gloves. HOWEVER, DO put the barrier cream on your forearms - from the wrist up to about your elbow or maybe beyond depending on how sloppy you are with epoxy resin. Since nitrile gloves are not that good in solvents, avoid "deliberately" using them in solvents and acquire a thicker butyl glove specifically for that purpose. Solvents tend to come into play when we clean our tools after a lay-up. It is more difficult to avoid the use of clean-up solvents when it comes to scissors and expensive squeegees. But, we can avoid the use of solvents when it comes to brushes. Again, "cheap" is the common denominator here and Harbor Freight sells 2" wide "chip brushes" for about $12 / box of 36. Use them once and throw it away. I know what many of your are going to say - "They tend to shed hairs into your lay-up". Yes they do, and "you get what you pay for" pertains here too. BUT, I have found that if you cut off about half the length of the brush hairs, the loose hairs will "fly out" out of the brush more easily and completely when you "flick" it over your hand, the corner of the bench top, or the sticky side of a piece duct tape. This process gets the bulk of the loose hairs out of the brush, but you will still get few inclusions in your lay-up from time to time. Personally, I am not that concerned over "a few" camel hairs in my lay-up. And if I am not mistaken, I believe it is permissible by Rutan inspection criteria to have "a few" brush hair inclusions. Another good reason for cutting the brush hairs short is that it improves "stroking" and "stippling" performance of the brush considerably. I know this is lot more than you asked for, but it is the best complete answer I can give. Gary Hunter From: "Russ Fisher" Subject: Re: COZY: RE: Oshkosh Forum / RUBBER GLOVES Date: Mon, 23 Aug 1999 19:12:56 -0400 >nitrile rubber gloves are a good alternative although they do not >resist solvents very well. I am referring to the >thinner versions packaged in boxes of 100 much like latex gloves. They have >pretty good feel, maybe not as good as latex. >Depending on what job I am about to do I will put on a double layer of >gloves. i.e., If it's ten minute job, one pair is sufficient. FWIW, I use a triple layer: First, a cotten liner - relatively inexpensive and washable. This is used to absorb the inevitable perspiration. I get mine through the hospital I work at, not sure where they are available to the gen. public. Second, the thin nitrile gloves mentioned above. These provide the added protection of nitrile over latex, but are more expensive than latex. Third, cheap latex gloves. These are used only once and then disposed of. They protect the nitrile. I reuse the nitrile gloves dozens of times since they are more expensive. I have found no problem with sensitivity while doing a lay up. Working with squeeges, paint brushes, mixing sticks & cups, not much sensitivity is really needed. >But, we can avoid the use of >solvents when it comes to brushes. Again, "cheap" is the common denominator >here and Harbor Freight sells 2" wide "chip brushes" for about $12 / box of >36. Use them once and throw it away. I know what many of your are going >to say - "They tend to shed hairs into your lay-up". Yes they do, and "you >get what you pay for" pertains here too. I keep a small bottle of thin CA glue (Hot Stuff, Jet, Super Glue, etc.) nearby and run it along the bristles where they enter the ferrule. The thin glue wicks right into the bristles and glue them to one another. It doesn't take much, a 1 oz bottle goes a long way and no more lost bristles. If you soak your brushes in acetone between lay ups, like I do, you have to reapply the CA as it will be dissolved by the solvent. Just make sure all the solvent has evaporated before applying the glue. >BUT, I have found that if you cut >off about half the length of the brush hairs, the loose hairs will "fly out" >out of the brush more easily and completely when you "flick" it over your >hand, the corner of the bench top, or the sticky side of a piece duct tape. >Another good reason for cutting the brush >hairs short is that it improves "stroking" and "stippling" performance of >the brush considerably. Have not tried cutting them, but sounds like a good idea. Will try it on my next lay up. My $.02 worth. Russ Fisher Date: Mon, 23 Aug 1999 22:29:03 -0400 From: bil kleb Subject: Re: COZY: RE: Oshkosh Forum / RUBBER GLOVES Russ Fisher wrote: > I use a triple layer: First, a cotten liner [...] Second, the thin nitrile > gloves [...] Third, cheap latex gloves. [...] that's exactly the recipe i've been using. i get the materials from lab safety (http://www.labsafety.com/ or 800 356-0783). they recently split their 1900+ page catalog into 7 bits. they also have tech reps available for consulting. -- bil From: "John Slade" Subject: Re: COZY: RUBBER GLOVES & BRUSHES Date: Mon, 23 Aug 1999 20:53:10 -0400 >I use a triple layer: First, a cotten liner - relatively inexpensive... I use one layer of latex with my MGS epoxy. I'm in Chap 14 and have had no allergy problems so far. >If you soak your brushes in acetone between lay ups... I never use the same brush twice. During large layups I often go through 3 or 4 brushes. I've probably spent $15 on brushes so far. By the time the plane is finished my "brush budget" might hit $30. Is it worth the trouble and possible problems of solvent in the next layup? My 2c John Slade Cozy #757 From: "Russ Fisher" Subject: Re: COZY: RUBBER GLOVES & BRUSHES Date: Tue, 24 Aug 1999 00:33:55 -0400 John, >I use one layer of latex with my MGS epoxy. I'm in Chap 14 and have had no >allergy problems so far. I am very glad to hear that. However, why can one person build three airplanes using only barrier cream and have no problems, yet another will develop a reaction after only a few lay ups using gloves? Because we are all different with very wide-ranging sensitization levels. What works for you does not necessarily work for everyone. Unfortunately, none of us knows our own sensitization level. I therefore have chosen to be as careful as I can. >I never use the same brush twice. During large layups I often go through 3 >or 4 brushes. I've probably spent $15 on brushes so far. By the time the >plane is finished my "brush budget" might hit $30. Is it worth the trouble >and possible problems of solvent in the next layup? I suppose it depends upon your definition of trouble. Pull the brush out of the jar of acetone and shake it out - 5 seconds. By the time I have my gloves on the brush is dry - acetone evaporates VERY fast. Squirt some CA glue on the bristles - 5 seconds. By the time I mix my first batch of resin the CA is cured. After lay up, wipe brush and put back in acetone - 5 seconds. I think I can afford 15 seconds per lay up to save a brush and a little space in the land fill (of which I'm using more than my share building this airplane). On very large lay ups, the resin starts to cure in the brush, so yes, I must discard it. But I can do MANY small lay ups before a brush gets too flat to be usable. See ya, Russ Fisher Date: Mon, 23 Aug 1999 23:21:25 -0700 From: Martin Orro Subject: Re: COZY: RUBBER GLOVES & BRUSHES Cotton liners are an excellent procedure. In dentistry, I wear gloves 6 to 8 hours a day, changing them every 15 minutes but sometimes for an hour or more during long procedures. The problems mentioned are minimized by the cotton liners. Sensitivities are caused by: 1- "impure latex"- proteins bound in the latex matrix 2- porosity's- testing in our offices has shown >60% of the gloves sampled leak water. (Fill like a water balloon and hang for a few hours over a dry surface.) Very few manufacturers (<30%) have decent quality control. 3- powder- talc is the least problematic. Many gloves utilize cornstarch - bad juju many organisms thrive in sweat and starch - besides it makes your hands stink 4- prickly heat rash- sweat glands become plugged and breed beasties which cause a prickly burning sensation with attendant spotted rash. 5- bad hygiene- wash em before putting on the gloves, avoid petrolatum based hand lotions (screws up the latex) and keep the powder out of your eyes (conjunctivitis is painful) martin orro From: "John Slade" Subject: Re: COZY: RUBBER GLOVES & BRUSHES Date: Tue, 24 Aug 1999 10:24:22 -0400 Russ, >>I use one layer of latex with my MGS epoxy. I'm in Chap 14 and have had no >>allergy problems so far. >Unfortunately, none of us knows our own sensitization level. Agreed. I've been following comments on this issue very carefully. Certainly there is risk. I met one guy who had to give up epoxy building half way through his project. His skin was in very bad shape. I've met others who have never experienced a problem after using epoxy for long periods without protection. I suspect that the problem is much worse with some epoxy types than it is with others. I am left with the question "What is the level of the risk?" Statistically how many people develop sensitivity to which epoxy type after how long? I've seen no studies of this nature and I need this information in order to make an informed decision. Everything we do has risk associated with it. As pilots we avoid high risk situations, but accept "low risk" situations (like driving to the airport). We tread the path between the two very carefully using "all available information". My concern here is simply that [relatively unimportant] decisions are being made based on insufficient information. In this forum I've occasionally seen issues get way out of proportion (like the 2.5 inch spar tape for example). I'm wondering if this problem has been hyped out of proportion to the risk involved. Yes, the safest course is to wear 3 pairs of gloves at all times, use protective gel on all other exposed areas of the body and to scrub afterwards - that way we dont have to care about the statistics. But, if we use this logic in everything we do the natural conclusion is that we all need NASA space suits to go outside at all. Just trying to get some perspective. John Slade Cozy #757 Date: Tue, 24 Aug 1999 13:05:02 -0400 From: bil kleb Subject: Re: COZY: RUBBER GLOVES & BRUSHES John Slade wrote: > > Just trying to get some perspective. my perspective is simple: i've had a dream to build one of these planes for over 15 years. i don't want to throw the dream away on some (easily) avoidable epoxy allergy. -- bil From: "Frank Johanson" Subject: Re: COZY: RUBBER GLOVES & BRUSHES Date: Tue, 24 Aug 1999 23:29:38 -0400 Hi John as I have said before I work in a full suit all the time , with pumped in fresh air . if you are interested I will give you details on how to get it and what to do to set it up. I did it for under a hundred bucks. frank Date: Tue, 28 Sep 1999 08:23:57 -0400 From: Paul Krasa Subject: Re: COZY: hexcell You can buy 5 min. epoxy in your local hardware store in convenient double barrel syringe containers. Paul Long EZ 214LP At 21:23 9/27/99 -0500, Nat Puffer wrote: >Dear Dewayne, >The 9935 epoxy is 5-minute epoxy used only for tacking things together >temporarily. You could substitute 3-minute, 4-minute, 6-minute, hot-stuff, >or almost anything that would serve that need. >Regards, >Nat > >---------- >> From: dewayne morgan >> To: cozy_builders@canard.com >> Subject: COZY: hexcell >> Date: Monday, September 27, 1999 10:20 PM >> >> Could you please re-send your messages. my microsoft mail program crashed >> when it downloadedthe mail >> >> thanks >> >> (reason number 10,001 to use linux) >> >> >> In the plans it calls for epoxy (9935 from wick's) . I have looked for >this >> and can not seem to find it. Is there a replacement/substitute for this ? >> >> (Just tryin to build it exactly to plans) >> >> dewayne >> > > From: "John Slade" Subject: COZY: Chap 4 - MGS epoxy won't harden Date: Sat, 6 Mar 1999 21:13:06 -0500 I'm using MGS 335 epoxy with the slow hardner. I tried a test layup 2 days ago and it's still not hard. Today I tried another test and left the remaining epoxy in the cup. 12 hours later the layup is still tacky and the epoxy in the cup is still mobile. ie I can still move the tongue depresser in it and depress the surface with my finger. Temperature has ranged between 62 and 75 during this period. The epoxy is kept in a HOT box. I measured the temp in there and found it was 106f. Tomorrow I'm going to try the "fast" hardner and lower the temp in the hot box to about 85. Anyone have any suggestions or ideas? Is the MGS rep who helped out a week or two ago reading this mail list? Anyone have his email address? I haven't done a "real" layup yet. If the epoxy doesnt cure the part is ruined. - right? John Slade (#757)