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Discussion Starter · #1 ·
I never had much luck getting paint to stick to galvanized pipe. I just gave up trying. I have a job that I need to paint some pipe coming up. Any suggestions for getting a quality paint job that will stick indefinitely? Would automotive etching primer be a good primer for this?
 

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Discussion Starter · #7 ·
i just got curious about a bottle of OSPHO that have in my shop. Its a phosphoric acid thats used to convert rust to a paintable hard surface. Kinda like "RustMort". I read the instructions on the back and ist recommended for galvanized metal as an acid etching wash prior to painting. Never tried that product for galv metal.........any opinions on that over using vinegar?
 

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Thom
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Oftentimes pipe is oily. You may need to remove the oil residue prior to etching. The acid in vinegar will etch a galvanized surface but it probably won't clean and penetrate the oily residue.
 

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Oftentimes pipe is oily. You may need to remove the oil residue prior to etching. The acid in vinegar will etch a galvanized surface but it probably won't clean and penetrate the oily residue.
THOM.... has a simple but really important fact.

I don't know OP's use, but I use/install alot of horizontal decorative pipe rail (so it's easy to push snow off Colorado decks).

I pickle it, clean it thoroughly with laquor thinner, use a tinted galvanize primer and a good exterior latex.

Now the pipes don't get alot of wear per se, but they are exposed to harsh and varying weather conditions.

I've never had any problem or callbacks. (On my own home, I got close to twenty years out of my first coat.... and even the repaint was not really any adhesion problem... just general cleanup of dirt and tree sap crap.)

Best
 

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If zinc galvanized metal has weathered over 60 days, it requires only washing before priming. During the weathering, a film of zinc carbonates forms, which is essentially inert, slightly water soluble, and highly adherent.
 
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