Quote Originally Posted by performance View Post
No, you can't butt weld 3/8" steel. The "capability" we and our competitors refer to is not typically a buttweld joint. It is an edge prepared joint. It takes approx 1 amp per .001" of metal thickness to make a "butt weld" and get anywhere near 100% penetration.
I've done some butt welding with MIG, just keep the wire over close to the weld puddle.

In this video below, Jody shows a weld on a corner joint, downhill, at 4:00 and 4:30 minutes into the clip where he uses the puddle to MIG with a gap.

Side note: Even though my downhill welds were always beautiful, I'd always been told, "You can't weld downhill because it will introduce cracks into the weld." He does it in the video below, though. Was I told wrong?