Relic M40 rust removal w BKF

[Pablo]

I used Bar Keeper's Friend (BKF) to remove rust from this helmet. I dumped a can (350 g) of BKF in 15 L of water and immersed my helmet for 8 hr. I scrubbed with a wet ScotchBrite pad until no more rust (brown residue) came off. I noticed the color of the helmet changing to a blue/gray and thought I might have a Luftwaffe helmet under the rust. I then rinsed the helmet with high pressure water and the scrubbed some more with sodium bicarbonate to neutralize. Then I rinsed thoroughly again with water.

When the helmet dried, it turned green! BKF contains 5-10% oxalic acid as well as surfactants and abrasives. So is this green color the original paint or is it residual oxalic acid? Should I use something stronger like ammonia to neutralize? Any comments/advice would be appreciated. Thanks.

[davejb]

I think what your seeing is salt residue, plus i think you may have removed too much which is now down to bare metal, you said it yourself BKF contains an abrasive and surfacants, then you scrubbed the helmet with an abrasive pad, its too much for what you needed to do

[Glenn66]

I have to agree with Dave, you got a bit carried away there Pablo. Best to put this one down to experience, maybe use it as a restoration project now that the original finish is ruined?

[Eddie]

I used a small amount of BKF on my WW1 M16, and rinsed it thoroughly which worked pretty well. I think I just used a damp rag to apply and scrub, that worked pretty well. My helmet was also in pretty nice shape to begin with. Is residual salt residue harmful to helmets? I just rinsed mine off with water, should I use something to neutralize the Oxalic acid? I hope you get the right Lufty helmet to make your grandpa's, I think it's a cool story and I like seeing you progress towards that goal.

[qotd]

Look at the before and after shots....which one looks better and more desirable? Which one Has character?? Like was said before, a learning experience....

[Pablo]

Unfortunately, I suffer from "Putzer's Syndrome" where I can't help but putz around with a helmet, (e.g. removing rust or paint to see what's underneath) that comes into my possession. Until I get treatment, I need to stay away from these helmets for a while and maybe find a support group. From other posts in this forum I don't think I'm the only one. Any recommendations on self-help would be appreciated. Maybe I should just take photos of helmets and putz around with photoshop....less destructive.

[Glenn66]

haha, don't stress it! Look on the bright side...now you have a nice shell for that M40 DD SS lid you've always wanted!

[Inf Div 121]

Put it somewhere outside and give weather to do it's job, it will look almost the same after several months. For neutralising I use calcinated soda or baking soda.

[don_kihotis7]

Repaint it and place some decals. It will be nice again

[Pablo]

If it is any consolation, I was informed that this helmet was sandblasted in its previous life, so it probably had no paint left on it anyway. I thought it odd that it would turn a solid green color that would not wash off. I would think the iron oxalate salts would be water soluble, but is seems to be tightly bound to the surface. Maybe I could try some acetone.......but wait....I promised no more putzing......at least for now. But I'm afraid after a few beers I'll lose my inhibitions and head back to my man cave for more putzing.