Quote:
Originally Posted by Foot Stomper
Any treatment that involves acid or water as a followup is likely to contribute to rust or coatings failure.
I say this because I've never seen in a technical data sheet (I've read many in the coatings profession) where acid or water is recommended or mentioned.
What I have seen repeatedly is clean, bare steel coated with epoxy primer, then top coated. Absolutely no mention of acid or water...
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I agree with you, I would prefer NOT to use phosphoric acid. But, he has pitted metal with rust in the low spots. I suppose that an arguably better method would be to media blast the panel to get to clean, bare metal, but then, depending on media used, and blaster knowledge/experience, you are possibly going to get into warping issues. Plus, if he sprays epoxy primer over rust, he'll likely run into much bigger adhesion issues than if he neutralized with acid, then cleaned it. The problem with the pitting is HOW to get to clean, bare steel, coated with epoxy, as you mentioned. How would you get there?