From: "Ron Larock" Subject: COZY: foam cores Date: Thu, 25 Mar 1999 18:38:21 -0500 I know that cutting cores with a hot wire is very accurate, but I would think that finding new and possibly more accurate ways of doing things is also what we are about. If a lazer can cut the foam to a much higher degree of accuracy and faster, maybe this group may have found a way to make building composite airplanes faster and cheaper. It may bring others that aren't as mechanical into the airplane building business. It may also find its way into a factory built composite that is affordable to a larger group of people.From ???@??? Thu Mar 25 21:15:02 1999 Return-Path: owner-cozy_builders@betaweb.com Received: from twc2.betaweb.com (majordomo@betaweb.com [206.43.209.18]) by acestes-fe0.ultra.net (8.8.8/ult/n20340/mtc.v2) with ESMTP id SAA15502 for ; Thu, 25 Mar 1999 18:31:50 -0500 (EST) Received: (from majordomo@localhost) by twc2.betaweb.com (8.8.5/8.8.5) id RAA25473 for cozy_builders-list; Thu, 25 Mar 1999 17:46:51 -0500 X-Authentication-Warning: twc2.betaweb.com: majordomo set sender to owner-cozy_builders@betaweb.com using -f Received: from a1.aris.com (firewall-user@a1.ariscorp.com [206.63.69.66]) by twc2.betaweb.com (8.8.5/8.8.5) with ESMTP id RAA25467 for ; Thu, 25 Mar 1999 17:46:47 -0500 Received: by a1.aris.com; id PAA03987; Thu, 25 Mar 1999 15:57:54 -0800 (PST) Received: from unknown(199.184.186.2) by a1.aris.com via smap (4.1) id xma003855; Thu, 25 Mar 99 15:57:26 -0800 Received: by hqexch.aris.com with Internet Mail Service (5.5.2232.9) id ; Thu, 25 Mar 1999 14:41:23 -0800 Message-ID: <51D4B406960BD211833600AA00C1EBAD016BFB29@hqexch.aris.com> From: Todd Carrico To: "'Nat Puffer'" , All Subject: RE: COZY: Laser cut foam cores Date: Thu, 25 Mar 1999 14:41:21 -0800 X-Mailer: Internet Mail Service (5.5.2232.9) Sender: owner-cozy_builders@betaweb.com Precedence: bulk Reply-To: Todd Carrico X-UIDL: e5775b84e83862f323c08fe7eba0c962 Oh, I would not buy such a machine. My experience with this sort of thing is that by the time you get it setup, you could have done the job by hand. If you are making ten of them, then maybe it would be worth it (make sure you buy ten copies of the plans ), you also would not need a helper. I have plenty of help, and not plenty of money ;) tc -----Original Message----- From: Nat Puffer [mailto:cozy@extremezone.com] Sent: Thursday, March 25, 1999 2:25 PM To: Todd Carrico; All Subject: Re: COZY: Laser cut foam cores Todd, Where is your pride, your joy of accomplishment, the satisfaction of your urge to be creative, your self esteem? You miss all the fun if you have someone else do all the work. You might as well buy a factory built! Best regards, Nat ---------- > From: Todd Carrico > To: All > Subject: RE: COZY: Laser cut foam cores > Date: Thursday, March 25, 1999 11:19 AM > > Price was $1550.00 US. that was with a 40" cutting width. Bigger tables on > request. I don't know about modifying it for longer pieces. He said that > it would put in Wash Out/in, taper, sweep. Would work for turtle decks, > julian fries, etc. > > tc > > -----Original Message----- > From: Bill Theeringer > [mailto:Composite_Aircraft_Accessories@compuserve.com] > Sent: Wednesday, March 24, 1999 11:36 PM > To: All > Subject: COZY: Laser cut foam cores > > > Check out http://www.teeka.com/cbhobby/ > for precut foam cores :)= > > Bill T. From: cdenk@ix.netcom.com Date: Thu, 25 Mar 1999 17:12:37 -0600 (CST) Subject: RE: COZY: Laser cut foam cores was said I can't see where there is any major time savings, hot wiring is easy, the equipment can be had for around $100, and many times can be borrowed. A very large pecentage of the EZ's flying, the builder's personally had there hands on the process, with just fine results. Date: Thu, 25 Mar 1999 17:51:52 -0600 From: Tom Brusehaver Subject: Re: COZY: foam cores >I know that cutting cores with a hot wire is very accurate, but I would = >think that finding new and possibly more accurate ways of doing things = >is also what we are about. If a lazer can cut the foam to a much higher = >degree of accuracy and faster, maybe this group may have found a way to = >make building composite airplanes faster and cheaper. It may bring = >others that aren't as mechanical into the airplane building business. It = >may also find its way into a factory built composite that is affordable = >to a larger group of people. Last spring I interviewed with a company that builds automation equipment for manufacturing. The have gantry robots that MacDac uses building F-18's and a large X-Y table used for cutting stuff. The end effector used will determine what they cut, and the quality of the results. The most popular end effector was a waterjet. At > 50Kpsi, it'll cut granite, or foam, with amazing prescision. Several of their customers cut foam plugs that the boat manufacturers use for fiberglass molds. Most of the boat manufacturers use a bullnose cutter, but water does work for long straight cuts. Date: Fri, 26 Mar 1999 08:07:16 +0200 From: "Rego Burger" Subject: COZY: Laser cut foam cores In reply to NAt's comments on doing them yourself.... I found foam cutting fun...one of the few taskes my wife liked to help with...... besides the cost saving ( free labour ) the accuracy of lazer cutting does not = the cost. Rego Burger RSA From: Todd Carrico Subject: RE: COZY: foam cores Date: Fri, 26 Mar 1999 07:29:53 -0800 I used to work in the Die Cutting industry. They use lasers to make the boards they set the knives in. Basically the laser beam is about 3 inches in diameter until it reaches the cutting head. Then it is "Focused" at the center thickness of the board. That is the thinnest part of the kerf. the kerf grows from that point up and down. This would not be very good way to cut a long (anything over 6") foam core. I also have allot of experience with Water jet technology, and they have a worse problem. We used Styro Foam as a bed material (Whatever you use as a bed is destroyed). After the water penetrates the first layer the stream "Diffuses". We cut some pretty thick stuff for a Water Jet at 6" also, but the finish stank, and the tolerances were horrible. The only problem that I am aware of with the hot wire saw is the tendency for the wire to lag. This can cause a sag in the middle of the part, and funny looking corners. If you were to manufacture a hand held Band Saw (It is possible, you would not need that much power, and you could undersize your templates and use a guide that follows your template) you might get away from the sag, but you would have a tough time making the Spar trough, and the other "sharp" (for a bandsaw) corners. The Hot wire saw is just the best tool for the job. Even this Laser machine was just a Hot Wire saw driven by step motors, and hooked to a PC. I agree that we are trying to do things better, but we also need to keep from re-inventing the hot wire saw (er wheel) tc -----Original Message----- From: Ron Larock [mailto:rlarock@mediaone.net] Sent: Thursday, March 25, 1999 5:38 PM To: Cozy_Builders@canard.com Subject: COZY: foam cores Dear List, I know that cutting cores with a hot wire is very accurate, but I would think that finding new and possibly more accurate ways of doing things is also what we are about. If a lazer can cut the foam to a much higher degree of accuracy and faster, maybe this group may have found a way to make building composite airplanes faster and cheaper. It may bring others that aren't as mechanical into the airplane building business. It may also find its way into a factory built composite that is affordable to a larger group of people. Ron From: Militch@aol.com Date: Tue, 3 Aug 1999 22:11:40 EDT Subject: COZY: Foam color change I have my fuselage tub sitting on a couple of sawbenches in the garage, with the bulkheads installed. Work has interrupted building for a few weeks, so the tub has been out there post-curing (we have had 100 degree humid days, and the garage can get quite a bit warmer than outside). I noticed last night when I glanced at the tub that the sheet of foam I used at the rear on each fuselage side has turned from blue to purple. A closer look reveals the same color change just starting to fade in on the sheets used in the middle and at the front. The foam's texture seems unchanged, and it doesn't appear to be powdered, or otherwise altered. I have observed some slight color changes on scrap pieces of similar foam left lying under the fluorescent lights in my basement workshop, but the garage has generally been in the dark. I haven't tried scuffing it with sandpaper to see if the change is just surface discoloration. Has anyone else experienced this? Peter Militch Cozy Mark IV Chapter 6 Date: Wed, 04 Aug 1999 06:04:55 -0400 From: Jeff Russell Subject: Re: COZY: Foam color change Militch@aol.com wrote: > Has anyone else experienced this? > > Peter Militch Cozy Mark IV Chapter 6 This is normal for the PVC to darken with any light. -- 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 Date: Tue, 03 Aug 1999 23:03:16 -0400 From: "Marc J. Zeitlin" Subject: Fwd: COZY: Foam color change Pete Militch asks: >..... I haven't tried scuffing it with sandpaper to see if the change is just >surface discoloration. Has anyone else experienced this? Short answer? Yes. This has been discussed and is in the archives. It's caused by exposure to UV, and does NOT seem to affect the properties of the foam - you just get some discoloration. -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/ Date: Wed, 20 Oct 1999 18:34:22 -0500 From: Bulent Aliev Subject: Re: COZY: Foam Required That's why I did mine the two step way. Cut them oversize and not wary about the burns, than sand them down to shape. It worked the second time for me. The first time I used the wrong template on the bottom, so I ended with very skinny winglet cores. I knew that something was wrong and went to another builder's hangar to show them and he discovered my mistake. Bulent Epplin John A wrote: > Also made one of the vertical fins twice, they are hard to get really good, > the difference in sections from the root to tip is not good, hard to keep > from melting too far into the tip end. > > John epplin... From: "Alpha" Subject: COZY: Foam Date: Sat, 23 Oct 1999 12:34:05 -0400 Fellow builders, There is a foam fabricator (custom cuts foam into various sizes) that I pass twice a day. I talked to him a while back and got some foam samples (styrofoam) that appear to be the same as ACS/Wicks product. He gets the styrofoam and urethane in large billets. To save costs in shipping, and perhaps the cost of the foam, I would like to know if anyone can tell me the exact manufacturers (ie. Dow et al) parts numbers for the styrofoam and urethane. I know there is supposed to be a difference in the styrofoam bubble size in the 2 lb/ft^3 product thus for the need for product numbers. I want to get started building with the right stuff but I need to save all the cash I can....my son turns 16 tomorrow and you know how much teenagers can cost!!! Can anyone help? Jim Brewer Albemarle, NC From: Militch@aol.com Date: Fri, 24 Dec 1999 14:08:44 EST Subject: COZY: Use of pour foam There was an article in the last newsletter about using pour foam to form the leading edges of the strakes. I recently downloaded the electronic version of the old Canard Pushers and have been reading them from issue 1. Somewhere in there was a comment by Burt Rutan regarding a large pour foam assembly someone tried. Might have been a wing, but I am not sure. Anyway, he reported that the builder experienced blistering of the wing afterward and attributed it to the foam's properties when exposed to the heat of Summer. Has the composition of pour foams changed enough in the last 10 or 20 years to make it useful for large parts, or is that still likely to be a problem? I think Chris Scida used pour foam to make his nose assembly, and that seemed pretty good when I saw it recently. Regards, Peter Militch #740 From: cdenk@ix.netcom.com Date: Fri, 24 Dec 1999 15:46:07 -0500 (EST) Subject: Re: COZY: Use of pour foam For sure, don't use pour foam any place exposed to more than low to moderate temps. I used it to make a stiffening rib, max. 1/2" thick on my top and bottom cowls. At both areas the foam expanded creating a bulge in the cowl surface. This was both top and bottom, where the bottom heat isn't very high. I would be very careful where used, not any big flat surfaces, or too thick.