Hi Dan; This past weekend I had to repair a couple 3/8" holes in a one inch frame. I just inserted an overlength 3/8 copper rod and welded up slowly with the 110v mig welder. Weld a little and tap the copper rod to make sure it was still loose. Repeat until done. Just dont let the heat build up enough to melt the rod and the weld will not stick to it. Regards Don Plummer