Re: Thinking about buying a mig-welder...
Weld penetration is very important to safety and MIG has a tendency to blob crap on top of bad surface welds that protrude. Do a lot of sample welds on pieces of the same material and thickness to be welded to get the settings and technique right for full weld bead penetration, checked by inspecting the back side of the welds.
Grinding out welds also weakens them, especially if they are limited depth due to bad penetration already, a weakness of MIG because of its constant feed no matter what's going on at the puddle. Structural joints should never be ground down.
KTM50 Schwinn Chopper - 6000W E-Motard - 52cc Auger BMX - 9sp+CVT 52cc Cagllari Moped