Wing corrosion

[Helicopter Roy]

I am restoring a '56 Cessna 172. I finally got a right wing but it has some little bumps of corrosion and the surface feels rough to the touch.
Before I damage the surface, can anyone tell me the procedure to clean the wing for painting?
I tried testing a small area with a fabric wheel attached to a drill-results negative.

TNX
Roy

[cub builder]

This is a job for a chemical paint stripper and scotch bright worked by hand wearing your butyl gloves. Or if you want to media blast the surface, try soda blasting or perhaps walnut shells. Don't use anything abrasive and mechanically driven unless you want to think about reskinning the wing and bucking a few thousand rivets.

-Cub Builder

[Helicopter Roy]

This is a job for a chemical paint stripper and scotch bright worked by hand wearing your butyl gloves. Or if you want to media blast the surface, try soda blasting or perhaps walnut shells. Don't use anything abrasive and mechanically driven unless you want to think about reskinning the wing and bucking a few thousand rivets.

-Cub Builder

I definitely don't want to damage the skin. Te wing is already stripped so maybe some scotch brite and a cleaning chemical?

[cub builder]

Since it's already stripped, I would suggest media blasting it, either soda or crushed walnut shells, although you might try some phosphoric acid etch with a wet scotchbrite pad. Be sure to rinse well as you complete a small section.

-Cub Builder

[Helicopter Roy]

Since it's already stripped, I would suggest media blasting it, either soda or crushed walnut shells, although you might try some phosphoric acid etch with a wet scotchbrite pad. Be sure to rinse well as you complete a small section.

-Cub Builder

That sounds like a plan !!!!! I always hated the stripping and painting part of the rebuild process. I did a Tri Pacer years ago and it was a real Pain in the Neck.

Thanks a bunch !!!!!

Roy

[cub builder]

I supervised a ground up restoration of a Tripacer a few years ago. The owner used soda blasting to clean the aluminum parts in the wing (leading edge, ribs, spars). That did a nice job.

Due to the size of the project, he bought a media blasting feed tank and laid out a large tarp to capture as much of the soda as possible. He sifted and recycled the soda through the media tank. He also had a fairly large capacity (5 hp) compressor. However, if you are only cleaning small spots, a small hand held media blaster is relatively inexpensive and can be done with a more modest (1 - 2 HP) compressor. A 50# bag of soda goes for around $40. Wear a respirator and eye protection, but cleanup is to just wash down the area with water since the baking soda is biodegradable.

-Cub Builder

[WLIU]

Take it easy on the air pressure when using any blast media. I have seen wing skins stretched so as to require replacement when this method was used by an overenthusiastic individual. Bright shiny panels that were no longer airworthy and required drilling out all of the rivets and replacing with new. Get some one with experience to run the gun.

Best of luck,

Wes

[Eric Brown]

Since it's already stripped, I would suggest media blasting it, either soda or crushed walnut shells, although you might try some phosphoric acid etch with a wet scotchbrite pad. Be sure to rinse well as you complete a small section.

-Cub Builder


I would be really careful when using an acid etch. If the acid gets in between the skin lap overs, you may not get all of it out by flushing with water. If the acid remains in the lap's bare metal, you will have a REAL corrosion problem. How are the insides of the wings ?