Restoration-oxalic acid

[johnhmcgary]

I have been a member for about 3 years and in some need of help. I have a couple of helmet shells, they are solid but have some rust. I would like to remove the rust and clean them. I have heard about oxalic acid. I have access to Barkeepers Friend (main ingredient is oxalic acid), is that a good cleaning agent or should I attempt to get pure oxalic acid? I have located it on-line and it comes in liquid and dry, which is the best? Once I have it what is the soaking time? I have noticed on WRF times of up to 2 to 3 days. I am asking as I have never used it before and the shells are nice and solid with plenty of original paint on them and want to preserve them the best possible way. Any tips and info would really be helpful. Thanks, John

[davejb]

Can you show these helmets John, you say they have original paint on them so i would assume the rust is a natural oxidization combined with the normal patina, if thats the case i would be loathe to remove the rust especially if its minimal, it could well remove patina, originality, and value

[johnhmcgary]

Dave, I'll try to take some pics tonight and get them posted. Thanks for the quick reply. John

[Pablo]

John,
Did you see my experience with BKF? (Relic M40 rust removal w BKF)

The helmet I tried it on had been previously sandblasted, so I assume there was no original paint left. After treatment with BKF, I came up with a green helmet which I assume was a reaction between the iron oxide and oxalic acid. But after neutralizing with sodium bicarbonate and considerable scubbing under running water, it remained green. BKF is around 5-10% oxalic acid...the rest being surfactants and abrasives. I have to admit that it did a very good job removing the rust! I would use BKF if you want a green helmet without having to paint it.

[davejb]

John, did you manage to take some photos, once shown it will prove how much , if any , restoration is needed.

[johnhmcgary]

Sorry Dave and Pablo but we had a family emergency and had to fly down to Florida, everything is fine now. We'll be back home on Monday. I'll get pics and post them then. Thanks for the response, I need all the help I can get. John

[Frundsberg]

Be careful - oxalic acid is very toxic! Work only in open air and protect Your eyes.

[Glenn66]

You might want to refer to my M35 rust removal thread. There is some considerable information there regarding strengths of the acid and soaking times etc. Personally I wouldn't leave a helmet in the solution for 24 hours especially if there is paint remaining as it will bleach the paint. The oxalic treatment works wonders on light rust but heavy rust is alot tougher to shift. Heavy rust is better removed by electroylsis but for thick steel like a rusty helmet shell the electrolysis might just eat the shell away.

[Zeller]

Oxalic Acid is indeed toxic but less than other acids. Here you can buy pure oxalic acid in the Pharmacy stores. It looks like a white crystal powder. I would go with the pure oxalic because you never know which other components are included in the product you mentioned , and they could damage your helmet paint.
Oxalic acid is pretty safe with decals and paints and it will actually enhance the paint remains. It should be used diluted though. I prefer to use warm water because I noticed a better result.

[don_kihotis7]

Oxalic Acid is indeed toxic but less than other acids. Here you can buy pure oxalic acid in the Pharmacy stores. It looks like a white crystal powder. I would go with the pure oxalic because you never know which other components are included in the product you mentioned , and they could damage your helmet paint.
Oxalic acid is pretty safe with decals and paints and it will actually enhance the paint remains. It should be used diluted though. I prefer to use warm water because I noticed a better result.

Hi zeller, how much diluted? And how many hours should a lid be soaked to remove the rust from it?