[lincpimp]

When welding material that thick with a mig (or pretty much any welding device) you will need to "V" the ends of the material where you want to weld. That way the weld penetrates the material properly. A bench grinder would do fine, just grind an angle on the piece, and weld in the V that you get when the place the ground piece against the flat piece. Looking at your welds the welder seem to be set about right for voltage, maybe lower the wire speed slightly.

Otherwise i like the result, not going to bend easily. Get good with the welds and you will not have to grind at all on them. I like a nice weld over a ground weld.