Acid wash, then polish?

[cowman57]

Hello All,
I have a 52B model that still is bare aluminum and mostly original paint. The paint is flaking, but it doesn't seem to affect how it flies. When I got it in the fall of 2013, I went gung-ho polishing the fuselage rudder, and the upper side of the stab and elevator, with a few test spots done with the cyclo to see what it could look like. I never really got any further because the undersides of the wings and tail need to be acid washed, especially the control surfaces. I keep reading about alodining the aluminum after the acid wash and rinse to neutralize the acid. I can't do that because I want bare aluminum. I plan on using a pressure washer for rinsing. Any advice would be appreciated.

Thanks...Scott

[Metal Master]

I would not bother to acid was the outside of the fuselage. I assume the issue is corrosion. The acid was will not do much for you unless the parts could be removed and set in a bath and washed. If you are going to polish it and you want to acid wash it, elbow grease and a scotch bright pad might be helpful to get the heavy corrosion off but ultimately you are going to need to be using a buffer polisher to get the corrosion down to a level that polishing with the Cyclo polisher is going to do much good.

In the attached picture I started using the Makita sander polisher to get to this point. You can see the area at the rear of the fuselage clecod into place. I had not polished that area as it had been removed to repair the Tail cone. I did not have the Cyclo polisher at this time and attained the bright polish further forward on the fuselage with just the grinder polisher. Perfect Polish has some great videos on the process. Using anything but the Nuvite polishing compounds is just too much effort. Using the products in the method that perfect polish outlines works fastest. But it is a lot of work, if I had the extra $$ I would just paint it.
After you get it to this point as in the picture the cyclo polisher can used to get rid of swirl marks and polish the skin to mirror like quality.

This is what I started with

N1208D Left view wing bent RS.jpg (41.31 KiB) Viewed 7615 times

This is what I started with

Rudder poilished and rear of fuealage

This is the same area after polishing and assembly. The skins on the top on the Stab are new.

[cowman57]

Yes, the reason I want to acid wash the bottom of the wings and horizontals is to remove the oxidation. My question is...is a good pressure washing enough to neutralize the acid wash. I won't be using alodine.

[Metal Master]

Yes, the reason I want to acid wash the bottom of the wings and horizontals is to remove the oxidation. My question is...is a good pressure washing enough to neutralize the acid wash. I won't be using alodine.

I would not pressure wash it I would just wash it with soap and water and a spry nozzle. That will neutralized the acid wash just fine. The acid wash will not do much for the oxidation though but there is no harm in trying. Mechanical means of removal is about the only way it is going to be affected. For example when cleaning ribs for repairing a wing. I would glass bead the rib. Then acid wash it (Aluma Prep), rinse with water, Alodine and then paint with epoxy primer. The part comes out better than new bare aluminum.Just polishing the airplane will get the oxidation off but it will be tough.

[bagarre]

Instead of acid washing, consider Comet scouring powder.
I'd worry about the acid getting trapped between skins. Pressure washing might just push it further in and there's no way to know if it's all out.

Comet works quite nicely and is far less aggressive than a scotch bright pad.
It's so fine, you can hand rub the scratches out.

I plan to do that with 95D all over and then polish...but leave the belly and wing bottoms unpolished with the Comet sheen.

[cowman57]

Actually I did try acid washing and polishing a small test spot on a flap and was quite pleased with the results. that was two and a half years ago and the flap hasn't dissolved away since then.

[rusty]

When I purchased N2935D, it was in need of a good polish job. I started the process with a rotatory buffer using Nuvite grade's 6,7,C,A, and S. Then, after that process was complete, I used a Cyclo orbiter polisher and repeated the same process. The airplane was polished a total of ten times and took a total of 18 months to complete. Knowing what I know now, I would NOT do this again!! Polished airplanes look the best, as long as someone else does the work!

[blueldr]

I used to have a friend with a polished Bonanza. If you ever wanted to see a guy break out in a sweat. just look like you were going to lean on his airplane with your bare hand on a hot day.