Corrosion of Aluminum and Its Alloys: Forms of Corrosion :: Total Materia Article

I need to read this and maybe it will help someone else too. My immediate need is to make paint stick to corroded aluminum. (potmetal) Jeep mirror base.

If you insist on paint, aluminum chromate is the primer you need. Personally, I'd powder coat them. Some anodizing companies have a chromate process that will prime it properly for you, however.

There are choices available...it just depends on how much you're willing to spend.

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1987 560SL
85,000 miles

Is your mirror mount aluminum, or pot metal? Usually I think of potmetal being zinc or similar.

(Tangentially connected) I've also wondered if zinc sacrificial anodes would help keep cars from corroding, the way they do ships and such.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

Which is it? Pot metal or aluminium?

If it is indeed pot metal then the high zinc content is going to make it almost impossible to find anything that will stick to it. Your best bet would be to powder coat it as JP suggests.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Well you know, seems like the big three have been priming and painting potmetal stuff like the mirror stations-to body corners like a 70 grand prix since the 40's or 50's.......................


and matter of fact, trying to strip off old paint on old pot metal ornaments I buy from 30's thru 50's,,, its just as difficult as any hunk of old metal.

Also they both tend to have the same kinda corrosion except in aluminum the extreme examples- its more ~flaky, seen it with lots of aircraft hardware.
I would bet this jeep mirror base is potmetal, and if the owner is in the northeast... its already kinda ate up, so you gotta etch out the pits buggering up , and fill with something, I wouldn't bother with anything more than u-pol dolphin glaze putty , then sand, primer with whatever primer and repaint.

They were painted BEFORE corrosion began. Big difference.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

I do not understand what you apparently misunderstand...




What difference?




of course they were painted originally .


I have never seen a problem with normal paints of old type or new- not sticking to potmetal, ever. ive spent plenty of time reconditioning stuff like that-that still had the 75 yr old layer, or covered over with a few more

The thread title indicated he was confused- raised the question if they were perhaps aluminum,
none of the auto makers made parts like this out of aluminum,
from the 20's to the 80's it was potmetal . then they started using cheap fiber reinforced plastic crap fo all kinds of stuff.

Mouse over to Zoom -

Pot metal is generally zinc. PPG makes a product called Speedhide, which is a galvanized metal primer, and galvanization is the addition of zinc to a metal. Not sure if it will work in your application, but it's worth looking into.

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1987 560SL
85,000 miles

I've found that cheap acid toilet bowl cleaner works well on black oxidation,cheaper and safer than muratic acid.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

Jeep Wrangler TJ: Weak Links, Strong Fixes - Four Wheeler Magazine

So it turns out I am not the only one with this issue.