Good luck getting mild steel to bond to cast iron. You'll need some sort of nickel alloy MIG wire to flow and blend with the cast. That stuff is horrendously expensive. I seem to remember paying around $10.00 a pound for nickel alloy stick welding rod, and that was several years ago. By the time you factor in labor time and materials cost, it won't take long to make a rehabbed drum impractical, at least in a large majority of situations.
Jerry
