Lye Stripper rust problem

E Sturm · Sep 15, 2013

I used lye and corn starch to make paint remover and stripped my M-37 military truck to the bare metal. It worked great. As noted, vinegar is the neutralizer for lye. After I completed the job stripping the paint, I put vinegar in a pump up sprayer and sprayed the entire truck. To my surprise, I had rust all over the truck surface. I now have tried to re-wet the surface with various solutions(ammonia, various heavy duty cleaning agents, wax remover )with no success. When I spray vinegar on the surface again, it does dissolve it to the degree I can remove some of the rust with my power washer. But in doing so, I just get more rust wherever the vinegar goes. It has become a nightmare. Any suggestions as to what I can put on the surface that will soften the rust enough to power wash it off without continuing to cause rust.

showcrop · Sep 15, 2013

Get phosphoric acid instead of vinegar. The phosphoric will convert the rust to black inert iron phosphate. Keep it wet with the solution for fifteen minutes. You can expect some residual white powder from excess phosphoric acid but you pressure washer should remove it. You can get it at any dairy supply or restaurant supply.

E Sturm · Sep 16, 2013

Thanks for the info. Is there anything that will just wash off the rust as the vinegar did or is it necessary to convert it as you indicated with the phosphoric acid. I assume you meant that the phosphoric acid would covert the rust completely. Will the surface take primer and paint with the rust converted?

I had the truck down to bare metal with just a few old rust spots on it. After the vinegar, the rust is completely covering the truck. I guess my question is, is there something that will remove this flash rust? I"m new at this sort of thing but was impressed by the paint remover but disappointed about the vinegar. I guess I should have skipped that step. lol

Thanks again for your help.

showcrop · Sep 17, 2013

(quoted from post at 14:23:07 09/16/13) Thanks for the info. Is there anything that will just wash off the rust as the vinegar did or is it necessary to convert it as you indicated with the phosphoric acid. I assume you meant that the phosphoric acid would covert the rust completely. Will the surface take primer and paint with the rust converted?

I had the truck down to bare metal with just a few old rust spots on it. After the vinegar, the rust is completely covering the truck. I guess my question is, is there something that will remove this flash rust? I"m new at this sort of thing but was impressed by the paint remover but disappointed about the vinegar. I guess I should have skipped that step. lol

Thanks again for your help.

Yes, it is called acid wash. It is phosphoric acid. You need it to neutralize the paint remover, and conveniently enough it also cleans up the flash rust. When I painted my dump truck body I followed up the acid wash with a abundant application of final prep.

Lye Stripper rust problem

E Sturm

New User

showcrop

Well-known Member

E Sturm

New User

showcrop

Well-known Member

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