From: "Nathan D. Puffer" <cozy@extremezone.com>
Subject: COZY: Corrosion protection
Date: Tue, 17 Dec 2002 10:13:17 -0700

Dear Builders,
We received the RAF newsletter CP 109 Saturday. In it, there was an
extensive discussion of the corrosion problem with the Varieze wing attach
fittings. The worst example was of a Varieze in the Northeast, which had
been parked outside (in the rain) near the coast for over 20 years. This is
of little concern to Cozy builders, because our wing attach is a completely
different design, not related at all to the Varieze, and not nearly as
vulnerable to damage by corrosion. What was of more concern, however, was
corrosion damage discovered on the Varieze elevator torque tube and hinges.
The corosion on the torque tube was underneath the fiberglass and evidenced
by little bumps in the fiberglass. It was found that underneath the bumps
there was pitting corrosion of the torque tube. Another Varieze builder
reported finding evidence of corrosion of his elevator hinges inside the
canard core, where they had been floxed in place in high density foam. He
solved that problem by removing them and replacing them with hinges made of
stainless.
Even more disturbing was the report that severe corrosion had been
discovered in a Long EZ aileron torque tube. It is suspected that moisture
might have found its way into the A10 tube where the hinges are attached by
pop rivets (see section I-I, chapter 19, page 14), and caused corrosion in
the confined space.
As a result of these findings, it is recommended that Cozy builders inspect
the elevators and ailerons closely before every flight, and at each annual,
for any evidence of corrosion, paying particular attention to the torque
tubes. If any evidence is found, report it to Co-Z Dev., and ground the
airplane until the problem is corrected. For new builders, it is recommended
that all aluminum parts be protected from corrosion by cleaning first with
Alumiprep 33 or metal prep #79, and then soaking in Alodine 1201 which is a
visible (golden brown) moisture barrier, greatly increasing resistance to
corrosion. This also acts as an excellent surface to bond epoxy or paint.
Even if you do not live near the coast, the airplane you are building could
some day end up there.
     We have not observed any problems with our Cozy III or Cozy Mark IV,
prototype or plans model. But of course, we live in the desert where
humidity is generally low, and our airplane is hangared. However, we have
noticed when we fly to Florida and park outside at Sun n Fun, and even at
Oshkosh, our airplane is wet with dew every morning. If we parked outside
near the coast year-round, I am sure we would have to be greatly concerned
and inspect our airplane very carefully for any sign of corrosion.
     Newsletter #80 is already in the mail, but there will be more on this
subject in the next newsletter, #81. For reasons like this, we recommend
that builders continue to subscribe to the newsletter, even after their
airplane is completed and they are flying.
Best regards,
Nat