Painting galvanized

Dec 11, 2012 3 Replies

I got a lot of steel panels, and constructed a large (32' x 40') structure out of two 40' containers. I used a lot of painted Fabral MightyRib panels, but had to use some galvanized ones, because I got a killer deal on them. Now it is time to paint the whole thing. For the galvanized, what is the best way to prep the surfaces so the paint will stick? We get blazing hot temperatures in the summer, upwards of 150 degrees surface temperature, 110 plus air temps, and 130 plus inside the containers. Winters bring weather in the 20-40 degree night time temps.



A friend of mine a long time ago, who was a professional painter, used some common vinegar to paint some for me similar to these. It was for a commercial job, and I never did go back and look at how it aged. I never got a call from the company that there was anything wrong with them, so just plain don't know if they did good or not.



Besides vinegar, is there any other treatments? Estimated 150 square feet, uneven vertical surface.



Thanks.



Steve


Depending on how long you want the paint to last you might take a look at

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Clean thoroughly, and prime with a primer for galvanized. Most metal primers will not work with Galvanized.

Vinegar works because of the acid in it. You mix white vinegar 1:1 with distilled water then brush it on. Let it set a couple minutes and wipe off the surface, then prime it with either single stage or epoxy primer. The acid in the vinegar dissolves the layer of zinc oxide on the surface of the galvanizing and allows the primer to bond to the clean metallic zinc under it.

The much easier way is with two part etching primer. It will dissolve the oxide layer AND seal and prime the area in one fast application. Then you can paint over it with pretty much any type of other paint.

If you want the paint to really last I would wash the entire thing really well, then treat the galvanized area with two part etch primer, then spray all of it with epoxy primer. Over the epoxy you can use basically anything you like as a top coat.

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