Bodymans tape?

Never heard of such! Hardly anyone does lap joints anymore. Most are butt welded joints nowadays. To do a lap joint, you need a step flanging tool that goes in an air chisel. You use that to make a step in one of the pieces of metal you are welding together, usually the one on the car. Then you cut your patch to fit just inside that stepped flange. Then you weld in the ditch with spot welds, and if you don't weld it solid from one end to the other it will crack the filler eventually. If the dude is taping stuff together to weld it....I don't believe I'd be letting him sandblast a car!