I'm wondering what would be the best rod to use for overhead welding of mild steel and QT100 plate; with a DC welder. The thickness will be 3/8 and 1/2 inch. I'm guessing rod size to be 3/32 or 1/8. Also what amperage setting for the respective rods? I've done alot of sucessfull flat and verticle welding with 7018 but the overhead just doesn't seem to be working out as well.