[john walker's workshop]

undercoat burns fast also. keep a spray bottle of water near you. don't run any beads. after fitting the panel with spot welds every 2 inches, put another one between all of those, another one between those so you're down to about one every 1/2", then fill the 1/2" spaces with an overlapping series of spot welds. keep moving around to a cool place for the next 1/2" series. do not cool with a wet rag. just let the air do it. stop and wait if it feels too hot with your palm. after grinding smooth, put a shop light inside behind the seam and look for pinholes. pinholes allow water through to bubble the paint, so weld them up.