MIG and painted metal

    --Seems like just about every time I see MIG welding on TV the guy does some sort of joint with one surface that's unground and still has paint
on it. That's *got* to affect weld quality, yes?
--
"Steamboat Ed" Haas : Politics is a sinkhole for
Hacking the Trailing Edge! : people without hobbies...
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Yes!
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It will with any weld. But the more experience you have, the better your ability is to watch the puddle and know when the slag inclusions, rust, paint, and gook are boiled to the surface. Still, it is best to prepare the surface of ANY weld as good as you can and remove "stuff" and get down to the virgin base metal.
Oilfield welding is done on metal of horrendous conditions due to rust, water, corrosion, paints, etc. You just do the best with what ya got. A good oilfield welder is a Rembrandt in taking junk and making it work. Anyone can weld in a clean shop with still air.
As an aside, I find 99.9% of the TV welding sequences a joke. Some blonde with big hair. OA rig with no O2 and black boogers floating off a pure acetylene flame, and the big blonde with big hair wearing a welding helmet. Guys welding with T shirts, even tacking. That adds up and the formula melanomas. Dumb stuff that in the real world will get you a few days off or a permanent medical condition.
Don't ask me how I know.
Steve
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    --Yah that's what I figure. I was just wondering if there's some technique I've yet to master that allows one to push the paint out of the way, so to speak.. Looks like we'll do a shitload of grinding this coming weekend! :-)
--
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Hacking the Trailing Edge! : people without hobbies...
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An acetylene torch works well for making paint disappear. I set mine up with a cutting tip and hit the oxygen. Follow up with a knotted wire brush on a grinder. It makes a project look better than going after the paint with a grinding wheel. Steve
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