Surface Corrosion on Outer Skin

DHeal · Post by **DHeal** » Fri Sep 06, 2002 9:15 pm

I'm looking at a '54 170B that is for sale. It has been sitting unused in a hangar for over 25 years. The only noticeable corrosion is widespread, light surface corrosion on the unpainted portions of the skin - nothing deep, just a light powder coating - the Alclad layer may be slightly etched.

At some point in the future (in a year or so?), I'd like to polish the skin back to natural aluminum or strip and paint the entire plane. Can anyone suggest an interim treatment that would remove/halt/stabilize the existing surface corrosion and preserve the skin until I polish or paint it in a year or two? I've thought about using some 3M plastic buffing pads and either ACF-50 or Corrosion-X to do the initial treatment. The down side of this is that you shouldn't paint the plane until the ACF-50/C-X has evaporated for a year or so. Any words of wisdom out there?

Many thanks -- David

Post by **GAHorn** » Fri Sep 06, 2002 10:17 pm

If the exterior is in that condition, what about the interior? If the interior is that way I'd pass over the airplane unless you're willing to spend a ton of time/money reskinning it. (Which will likely be the least of the problems discovered in the process.)
Anyway, if by some miracle the interior surfaces are not also corroded just as badly, then why not just go ahead and polish it now? Not only would that remove surface corrosion,...it would also tell you whether or not it's possible to make it look good by polishing. (Unlikely according to your description. It's likely to be too pitted to polish out pretty, but maybe not.) Decide whether to paint/polish again later.

Tom Downey · Post by **Tom Downey** » Sat Sep 07, 2002 3:05 am

Etch it with aluma prep, from Spruce and specialty and then alodine it. that will halt the corrosion process.

DHeal · Post by **DHeal** » Mon Sep 09, 2002 5:01 pm

The interior surfaces are very good - very little surface corrosion is evident (this will be the tenth plane I've owned over the past 35 years, so I've looked at a lot of doggy planes in that time).

If I aluma prep/alodine the exterior, does this process change the color of the aluminum or does it remain "natural aluminum" color? Does this aluma prep/alodine process effect the existing original paint?

Many thanks for the input! -- David

Post by **GAHorn** » Mon Sep 09, 2002 5:49 pm

Aluma prep is an acid-etch that removes corrosion. Alodine is a suface conversion treatment that acts similar to anodizing. The alodine will turn the skin a yellow color if left on for only a minute and will get darker the longer you leave it on. It is normally applied to airplanes intended for painting. It will polish off if you later change your mind. (Although some efffort may be required at seams and rivet heads.) It should not affect painted areas, but there's no reason to apply it there.

lowNslow · Post by **lowNslow** » Tue Sep 10, 2002 4:25 pm

Actually there are two types of Alodine. Alodine 1201 is the "visible" type and will turn yellow. Alodine 1001 is the "invisible" and leaves a clear coating.