If you have a simple 220 volt stick welder (A.C.) that does not have reverse polarity, then your best bet is a 1/8" diameter 6013 rod. You get a little better penetration with a 6011 rod, but it is a bit harder to weld with also. (I do all my chassis work with 6013). If it is a more expensive reverse polarity welding (D.C.) machine (which I doubt), then use a 7018 rod. I find that welding on anything up to 1/4" thick, that I get best weld when set at 115 Amps. If I'm welding 1/2" then I set it up for 130 Amps. If it is an A.C. welder, then forget about doing vertical welds----rotate the stuff you are welding untill it is in a horizontal position for welding.