Nothing to this welding stuff, huh? Now that you have the complete weld seam done, here I'll normally do any final planishing to address any highs/lows and then grind it down just a bit more and then finish off with about an 80 grit sanding disc. On the stiffener for the running board/step, once bolted up the stiffener is going no where. So what I've done in similar situation (once holes are drilled) is to epoxy prime both inside of fender and complete stiffener. Let flash, spray another coat, and quickly bolt the two together. Epoxy will cure and hold the stiffener in place, and once bolted it will be there for good. Best part is no welding done to burn off the protective coatings between the two pieces, for better rust protection than originally there.
