Cold gal vs primer

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Which is better for which application? I use them both. I tend to use cold gal for things that I won't be able to get at once installed. I'm always dubious about cold gal, though, because it doesn't seem like a very hard wearing coating. I guess it doesn't have to be hard wearing given that it gets a top coat? Is cold gal really better than primer?Scott
Reply:Cold galvanizing penetrates the surface of the metal some and protects even if there are chips or scratches in the surface of the coating.  Galvanized coatings wear down over time and can wear quite quickly if conditions are bad.  Primer coatings can seal out water (not the rattle can stuff) which will protect the material indefinately barring any moisture getting underneath through chips and bad adhesion.  Cold galvanizing dries faster for faster assembly time.  Cold galvanizing works best where materials overlap, under bolt heads, and where the coating may see a lot of wear or impact.  Primer works best everywhere else.
Reply:I've never had any luck with cold galv. Its usually rusting before the end of the day. We use a zinc rich paint now and then and it works pretty well. I think its made by Farwest Paints. Its really thick and you brush it on. It dries in a few minutes. A gallon weighs about 70#.
Reply:Thanks guys.So cold gal with an enamel topcoat should be pretty long lasting? I use the primer more to coat unfinshed jobs before I get back to them.I've got a 2 pack epoxy that I use on structural steel sometimes. I'm about 7klms from the coast, so at least we don't get any salty air in my part of Sydney. Spuddown, I'd say in Alaska the conditions are probably a bit harsher than in Sydney. You guys get that white snow stuff, don't you?I'm going to see what 'zinc rich paint' I can find.
Reply:Paints don't adhere to galvanized surfaces that well.  You have to treat it kind of like aluminum, maybe even etch it.  If you're going to top coat, stick with the primer.I think I had an experience with that zinc rich paint, spud.  I hated it.  It was the most indestructable paint I've ever dealt with.  It was used to coat a 50 year old potable water tank inside and out.  Not even a hint of rust.  It was my job to cut the tank apart.  First, I tried cutting it as is.  The zinc rich paint protected the steel from the oxygen jet of the cutting torch and couldn't maintain a cut.  I got smart and ground the paint off the outside.  But, as I cut, the paint on the inside would remain intact and redirect the molten slag from the cut into my hair.  Yep, most amazing paint I've ever dealt with and I hated it.  Never seen anything hold up to the torch like that before.  It was like trying to cut stainless steel.
Reply:Yaa I live on the coast so we'll get a couple feet of snow then it will rain it all off. Then do it again. The upside is we don't get the severe cold. I had my fill of that in Wyoming before I moved here. Seems funny to move 1000 miles north to get to a warmer climate. Things really rust here too. Its either in direct cotact with salt water or in the salt air.
Reply:Originally Posted by 76GMC1500I think I had an experience with that zinc rich paint, spud.  I hated it.  It was the most indestructable paint I've ever dealt with.  It was used to coat a 50 year old potable water tank inside and out.  Not even a hint of rust.  It was my job to cut the tank apart.  First, I tried cutting it as is.  The zinc rich paint protected the steel from the oxygen jet of the cutting torch and couldn't maintain a cut.  I got smart and ground the paint off the outside.  But, as I cut, the paint on the inside would remain intact and redirect the molten slag from the cut into my hair.  Yep, most amazing paint I've ever dealt with and I hated it.  Never seen anything hold up to the torch like that before.  It was like trying to cut stainless steel.