Ok, so here's the deal. I've searched and read lots of posts, but I still have some questions. So here's the bottom line. I have a MIG welder, not a TIG. I've read that TIG is the way to go, but I don't have one so here I am. So for simplicity sake, let's say we are welding in a square patch. I need to have a small gap all the way around correct? Once I have the piece fitted do I place one small tack on each side of the square? Or do I, very slowly, start filling one side in with small tacks? Then work on another side until I'm finnished. I have noticed that even though I have a gap, once I've placed a few tacks , the patch will move and close up the gap. So my thinking is that if I weld all around at the same time that it will try to pull in all directions and distort worse than ever. Oh and I HAVE been trying to smack the tacks while they are still hot but it doesn't seem to change much.