Quote:
Originally Posted by El Campo
Do you ever have a problem with MIG welds cracking when you are hammer and dollying them? I MAY be able to borrow a TIG from a friend of mine but if not will be forced to use the Miller 252 on my sheet metal. I always have this fear that with all my zillion spot welds that I will get cracking. And do you leaves a wire widths gap (0.23 or so) or do you butt your pieces back together as close as you can get them?
|
El Campo,
I never meant to insinuate that a nice job can't be done with a mig because it can. 95 percent of my truck is mig welded. Yes you can crack a mig weld, but the only time I cracked them was when I've done excessive hammering on dolly. I just try to use as little filler as possible so I do a lot of hammer and dolly work. In the cases that I did cracked them I just tacked it again no big deal. I still find it takes a heck of a lot of hammering to crack a mig weld. But than again I do a lot of hammering.lol
I love tig welding sheet metal because I have control over the heat, a lower profile bead which equals less grinding, and a softer bead which does not crack under my excessive hammering and dolly. But tig is not need to do a great job. The machines cost too much and most hobby builders only care to own one machine. If I had to chose I would own a mig hands down over a tig because the mig is way more versatile and more forgiving. Your metal has to be clean man and I mean clean for tig welding.
Now as far as gaps on sheetmetal. I try to make them butt or no wider than the welding wire for mig. For tig I want them to butt, mig is more forgiving than tig. I hope I answered your questions.