Painting Galvanized metal?

[Bert]

Hi guys, new to welding....SO many questions, so little time... So I read the forum as time allows...Anyway, my first project is this small gate, using galvanized metal. I''ve seen truck racks painted, then 2 months later, paint starts peeling off. Someone told me there is something called galvawash that etches it for painting. Local paint store never heard of it, neither Home Depot. Paint Store has a primer from Zinsser for $26/gal. Can't I use muratic acid or something?
thanks for all the help
bert

[DDA52]

I have seen vinegar or acetic acid used several times. No idea how or strength or anything like that. When I smell it, I run. Vinegar will give me a tremendous headache withing minutes of smelling it.

[dabar39]

You should use a self etching primer or a primer containing some form of zinc

[yorkiepap]

Hey Bert,
Painting galvanize takes some thoughtful prep.. You must get the surface to a "scored" condition....a flap wheel in 40 grit would do nicely. Then a good surface wipe with acetone or toluene to get it chemically clean. dabar39 is quite correct regarding zinc. You must use a zinc-rich primer to get a good paint bond. It's the only way. Another thing that helps is after the metal is thoroughly cleaned, warm it to evaporate any moisture. Hope that helps a bit....Good Luck....Denny

[paulrbrown]

Muriatic acid will strip the galvanizing off, Ospho, which is phosphoric acid can be used to etch the zinc to get the paint to stick, it is also a 'rust reformer' changing ferric oxide 'rust' to phosphoric oxide, which is stable and can be painted with out worry about latter rusting. Do make sure you use a high zinc solids primer [above 90%] as stated earlier. Hope this helps, Paul

[paulrbrown]

Galva-wash is Product of Sinclair Paints. I could not find a ready link to them, but have found references to their product being specified by the state of California. Hope this will help, Paul

[Bert]

Thanks guys!!!
I think they are all great ideas, and will have scrap left.
Sooo....I'm going to try each of the techniques, and see which one will last the longest!!! Pretty rainy where I live and where the gate will be. I will keep a progress report
bert

[Bert]

Oh, btw, I'm going to grind the galv off in the places that I'm going to weld, then spray or brush it with zrc. That stuff works great for a zinc primer...

[paulrbrown]

Bert, don't worry about grinding,it is hard to get all the zinc off sometimes, just put Muriatic acid on and wait for it to stop bubbling, it may take a couple of applications, then rinse with water, and put a final rinse of 1lb baking soda to one gallon of water on to neutralize, I have had bare steel outside for over 6 months after this with no rust. Hope this helps,Paul

[Bert]

Paul,
THANKS !!! I'll try that first! I'm taking off this Wed through Fri to layout and build the gate. 1st REAL project, so I need time to do it right (measurements, etc.) the FIRST time!!! Real simple looking gate, it'll be embarressing to post pics, so I won't... Gonna use my MM251, since I sold my ThunderboltXL, and saving for my Dynasty 200 in 2 months...
bert