In addition to what Jared said, don't try and run beads or stitch welds on sheetmetal either.
Welding sheetmetal is done through a series of tack welds, (roughly 1 second long) next to one another. Jump around, don't put the welds back to back to back, you'll create too much heat and warp the panel.
If you have compressed air and a blow gun, cool each tack weld for 8-10 seconds afterwards with the air. I do this on all my sheetmetal welds, I find it really helps control the heat and minimizes warping.
D.
Welding sheetmetal is done through a series of tack welds, (roughly 1 second long) next to one another. Jump around, don't put the welds back to back to back, you'll create too much heat and warp the panel.
If you have compressed air and a blow gun, cool each tack weld for 8-10 seconds afterwards with the air. I do this on all my sheetmetal welds, I find it really helps control the heat and minimizes warping.
D.