For butt welding sheet metal I make a series of small tacks or s little better than tacks. As I move around, I end up with welds spaced about 1/2" apart. For the next round I weld to the right of each one and run back into the side of the adjacent weld. Finally it takes one weld to close the gap in each little strip. I find that when I grind this down, there are no pin holes.
