Corrosion Protection on Alluminum Sheet Aircraft?

I have been looking at Zenair's Ch 701 STOL and nowhere have I seen any mention
of treating the inside of the sheet alluminum for corrosion protection. I would
have thought spraypainting with green (zincoxide?) paint woudld have been
necessary

On 09 Feb 2004 18:41:46 GMT, (DL152279546231)
wrote:

I have been looking at Zenair's Ch 701 STOL and nowhere have I seen any mention
of treating the inside of the sheet alluminum for corrosion protection. I would
have thought spraypainting with green (zincoxide?) paint woudld have been
necessary


Most commercially built aircraft do not have that type of corrosion
protection unless the 'seaplane' version was ordered. My 1962 C310G
is still doing fine with bare Alclad inside the skins. A lot depends
on the environment in which the airplane is kept. An enclosed hangar
is best. Salty air or continual exposure to water is bad. Zinc
chromate is a pretty good protective coating if you can find it. Just
a light coat on properly prepared metal is enough. BTW, zinc oxide is
white, and not suitable for your purpose. It is the stuff that life
guards used to wear on their noses and looked like seagull **** g.

O-ring

On 09 Feb 2004 18:41:46 GMT, (DL152279546231)
wrote:

I have been looking at Zenair's Ch 701 STOL and nowhere have I seen any mention
of treating the inside of the sheet alluminum for corrosion protection. I would
have thought spraypainting with green (zincoxide?) paint woudld have been
necessary
The 6061 aluminum used on these is very corrosion resistant. On my
murphy rebel the only protection is epoxy chromate between the mating
surfaces assembled wet and the rivets dipped in chromate as well.
spraying with LPS or similar after completion should be all the
protection you need

"DL152279546231" wrote in message
...
I have been looking at Zenair's Ch 701 STOL and nowhere have I seen any
mention
of treating the inside of the sheet alluminum for corrosion protection. I
would
have thought spraypainting with green (zincoxide?) paint woudld have been
necessary

The builders manual for the 601XL which I am building (and I assume the 701
and 801) suggests the use of Zinc Chromate or Zinc Oxide where ever metal
meets metal. Though with the 6061-T6 AL it is not really needed.

To see some photos of how I've done it visit my website at
www.peoamerica.net/N601WR

See this url and scroll down to the third to last photo where the builder
lightly zinc-chromated his aluminum pieces.
http://www.flycorvair.com/601.html
Tom
"DL152279546231" wrote in message
...
I have been looking at Zenair's Ch 701 STOL and nowhere have I seen any
mention
of treating the inside of the sheet alluminum for corrosion protection. I
would
have thought spraypainting with green (zincoxide?) paint woudld have been
necessary

Thank you for playing, Tom!

Yes, the operative word is "lightly",
Actually, a light MIST is plenty.

Most people just wanna paint it green cus it looks better.


Richard

Tom Cummings wrote:

See this url and scroll down to the third to last photo where the builder
lightly zinc-chromated his aluminum pieces.
http://www.flycorvair.com/601.html
Tom

(DL152279546231) wrote in message ...
I have been looking at Zenair's Ch 701 STOL and nowhere have I seen any mention
of treating the inside of the sheet alluminum for corrosion protection. I would
have thought spraypainting with green (zincoxide?) paint woudld have been
necessary

Only if it's going to be used as a floatplane on the ocean. Zinc
oxide (or zinc chromate, which is better but apparently causes cancer)
will offer good protection but adds weight.
Aircraft aluminum sheet has a thin layer of commercially pure
aluminum applied to each side of the sheet, amounting to about 2% of
the total thickness on each side, and pure aluminum will oxidize
almost instantly and form an inert layer that protects against further
corrosion for most applications.
Scratching through this layer is asking for trouble, so an
owner/builder needs to be careful about sanding and so on. Some owners
have destroyed airplanes sanding the paint off them. I was told
recently about an airplane that was sent to an autobody painter who
painted it and put it outside to dry. Wind and sand ruined the job, of
course, so he took a power sander and ground all the paint off and
repainted it. Took off much of the protective aluminum, and ground
flat almost every rivet head. A really expensive mistake.

Dan