I have welded a lot of galvanized. It is harder to get a decent weld by a large factor and the risks of breathing the toxic fumes is something to be taken into consideration. I use a decent fan blowing across the work side to side to break the convection currents which will, if left undisturbed, unerringly curl up and into your welding shield/helmet. I now have a 240 volt spot welder which does fairly serious gauge galvanized quickly, easily, and with less exposure to toxic fumes.
If welding galvanized can not be conveniently avoided at least take reasonable precautions such as a respirator mask and ventilating fan.
Powder coat works well on galvanized.
There are a lot of old wives tales, well intentioned good ole boys, and misinformation floating around about painting galvanized. You may hear about lemon juice, vinegar, and who knows what all. Galvanized can be painted successfully and without "aging" it for years.
As with most painting the three most important things are: 1. Prep, 2. Prep, and 3. Prep. There are industrial coating companies that make primers formulated just for Galvanized and done right you can paint galvanized as successful as painting anything else. I emphasize DONE RIGHT. Galvanized is less forgiving of errors in prep and application but it isn't Rocket Surgery! Nor is it Brain Science!
Primers for galvanized (like the paints formulated to go on over rust with no primer) is still filtering down the food chain and at least one brand was on the shelf at Lowe's this year. I'm pretty sure it was Rustoleum brand, I have a couple quarts in the downstairs shop.
I haven't used the Rustoleum yet. Previously my research for proper materials found only very expensive ones in 5 gal min sizes. Before I retired if something needed painting I just specified it needed proper painting and let the "process" take care of it. Now I have to DIY and don't want 5 gal buckets of expensive primer I have little use for. I have had great success over the decades with Rustoleum products and am confident their galvanized primer will git 'er done if I do my part right. And... They sell it by the quart!
I have a significant amount of galvanized flashing exposed on the new house at the many dormers and such. the galvanized stands out in contrast to my shingles like a diamond shining in a goat's -ss. I will be priming it with the galvanized primer and topcoating with a color coat more resembling the saturation and hue of my shingles. Similarly I have a rectangular box in plain sight on the roof. It is aluminum and houses a remoted range hood blower. It too will get primed and painted, even though I have heard tell, "you can't paint aluminum."
patrick_g
