Bsmith

Thanks a bunch for the info. I would love to TIG it but this a poor boy operation and the old used mig welder is what I have to work with. The welds are fine and penetrate without burn thru if I weld an inch, skip an inch then come back and fill in the skips. The soot doesn't seem to be a problem and you can actually weld right thru it, (you just can't see where you're going) so I wire brush it off, but man it is some ugly welding no matter how you do it.

I'm completely new at this so I'll try not to ramble. I'm building a copper sink out of .064 copper and I'm welding (just learning to weld also) it with an old Cebora 200 amp welder, cranked all the way up and wire feed about as fast as it will go I think about 350-400 IPM, using .035 deoxydized copper wire and 100 percent argon at 40CFH. It works 1-1/2" at a time before burn thru, but there is a huge amount of soot covering the weld and about an inch of the metal on either side. There is also lots of splatter at the start of the weld, Is this normal?