OK, I'm new to welding, doing some plug welds on test pieces, there going good, but as soon as I move over to the car I'm working on, I can't run a bead. It just pops and leaves little balls og weld. Its the same thickness. What I've got to do first is when I pulled the radiator support out, I pulled a little chunk of sheetmetal with it from the piece it was attached to. So I'm trying to weld in a little piece in to fill the space. Now, this is the inner fenderwell and upright assembly, its doublewall, but the whole is only missing from the top piece I'm trying to fix, ant ideas?