a couple of paint questions

admin

i think i remember reading a post from zap that said that if you paint over flux-core it sort of eats away at the paint. i was just wondering if this is the same with stick? because stick electrodes have flux too?thanks for the help
Reply:I've Stick welds were the flux was left on and painted over that had the paint stick for years. However, any job that you want to count on a quality paint job all flux of any kind needs to be removed.
Reply:Big problem with painting over the slag is that the slag can loosen up over time underneath the paint. It is brittle, and usually mechanically adhered, rather than chemically adhered (tied into the surface roughness of the weld), so as it fractures, it seperates.No impact or bending to fracture and loosen up the slag, it may last forever. Some slags do have chemical makeups that can be a problem for paint (leading to discoloration or chemical damage to the cured film)... I dont know off hand which ones.
Reply:Very good question. I guess I'm the guy to answer it too. I work full time as a painter. Been working on a big factory job recently painting steel structures. We almost always paint right over the slag. If the millwrights don't chip it off we dont worry about it. Now the primers we use are very expensive industrial grade. Kem Kromic primer. So we never have a problem with slag cause the welds to shed their paint. Like said. Unless there is alot of movement of the part, you'll probably never see the paint come loose.If the part is cleaned of slag and smoke discoloration then the use of a good metal primer will make the paint last for a long time. As with everything else, its all in the prep work.Patriot Performance AutoLincoln Power Mig 255CLincoln AC-225 StickVictor Journeyman O/AQuincy QT-5 Compressor
Reply:Some electrodes have sodium in em (stick) and some have acidic properties in the flux.  Its just a good idea to remove it.  Id say (I personally dont have any experience) that it may rust the weld out, but wouldnt the paint seal away the oxygen?  hmm.  Its not that hard to remove, and if concerned about little specs, use a wire cup brush on your grinder.Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.