« on: 01/08/2011 03:03:29 »
I read the thread about Vinegar removing rust.
I need to remove some rust from a car body panel where I've welded in some new stuff but left it out in the rain and the welds themselves and part of the new steel all got rusty (even though I sprayed it with undercoat).
Vinegar sounds great. But I think you must soak it in vinegar for some time, right? I can't just rub with vinegar and expect it to chemically alter the rust, can I?
Well, I can't soak the car in vinegar.
the thread mentioned ketchup as a good alternative... I think that's out, too.
So maybe I need to make a paste of the vinegar, somehow, and smear that on.
So how would I make a paste for this purpose? i.e. a paste that doesn't neutralise the vinegar?
And that old thread mentioned that the effect of these weak acids is also to coat the metal with a coating that makes further rusting a little harder to do.
So I wonder about that and washing? I suppose to apply modern auto paints or undercoats onto such a surface after the vinegar treatment one would have to wash all the residue vinegar off? Definitely have to wash the treated (black sludge?) rust off, rather than a good wipe, I guess?
It would be so much better if the treated rust, wiped down to the thinnest layer, could be painted over, wouldn't it, rather than introducing water into the mix.
But all of that gets into the chemistry of today's paints, I guess... too esoteric for this forum or not?