Sanding aluminum is generally not a good thing when painting an airplane but is it acceptable to prepare 74 year old metal via light sanding? I see no other option to get things smooth on my Widgeon prior to painting. The scotchbrite really isn't cutting it. I would prefer not to sand but I'm not sure I have this luxury.

Most paint shops I have visited are sanding the aluminum and I'm not really seeing corrosion or other issues.

Let me know what your thoughts are.

Mike,

The Alclad if very thin and I would not sand it... What are you trying smooth, is there still paint residue on the skin? Years ago when working at a shop we kept applying stripper and elbow grease until clean, then wipe down with thinner, then a conversion coating, then a "chromate primer". We would then put on a high fill sanding primer light sand to smooth it up then top coat. This is ofcourse after fixing the body work as needed with light weight filler or in extreem cases skin replacement.

Even worse, Grumman seaplanes are anodized. Virtually no corrosion after 73 years!

I guess I'm just getting tired. I've reached a point with the stripping (4th coat) where I'm getting minimal returns now for the time and materials. 99.5% of the paint is gone.

Should I just keep scrubbing???

Mike

Any teenagers looking for gas money nearby? I wouldn't want to remove any anodized material either.

What a cool project! I love all the grumman flying boats, please keep posting updates.

Never sand. All of the paint should be gone. Clean up small problem areas with a small stainless wire wheel on a dremel (not a big one)

Is your bird a Grumman G44 or SCAN? You might want to check, but if my old memory seves me correct, Grumman birds were alcad and SCANs were anodized?

I found some rubber sanding discs, with 100s of little rubber fingers 3/4 " long. About 2" in diameter. Works good, but slow. Maybe to clean rivet lines.

Call a dry ice blaster? Might be just the thing to finish up. That is my plan for gear wells. My understanding is the ice isn't very good on polyurethane, but if you have it mostly stripped...?

Maybe a plastic bead outfit to clean up now that most of it is gone? Had some guys say they could do mine, but I don't like the idea of residue when blasting inside.

It's a real Grumman which are anodized (not alcad), the SCANs have no corrosion protection and metric fittings.

stainless wire brushes are ok?? I've heard this is a no no?

Go easy on the sanding.
Watch the rivets! I see too many aircraft with sanded down rivets.

I have great respect for rivets....I've seen this too and know the horrors.

They also make brass wire wheels for Dremels, that might be the better choice than stainless.

stainless wire brushes are ok?? I've heard this is a no no?

They also make brass wire wheels for Dremels, that might be the better choice than stainless.

AC 43.13-1B allows Stainless Brushes, also aluminum oxide abrasives like Scotch Brite. It prohibits:

(c) Steel wool, emery cloth, steel
wire brushes (except stainless steel brush)
copper alloy brushes, rotary wire brushes, or
severe abrasive materials should not be used
on any aluminum surface.