Today's cars have panels that aren't welded on they are glued, The roof on a new Cadillac is glued on. I own a bodyshop and we use panel bonding glue all the time for Qtr Panels, boxsides, cabcorners, roof panels. You can get it at any autobody supply stores. 3M makes it and so do Duramix. It's good stuff and I would use that before JB Weld. My opinion. So you caddy guys don't get mad at me the front and rear of the roof panel is welded on. You can get the stuff to dry in 3minutes if that isn't fast enough put some heat on it w/heat gun and it will dry really fast.