Lord Fusor is another good panel adhesive. I’ve used it quite a bit. It can be bought with different curing times. The quick is QUICK I’m also one of the old school bodymen. When I started in the early 70s we only used torches to weld or braze. No migs or tigs or plasma cutters. That all changed in 80 when the auto makers changed the metal and you couldn’t torch it anymore.