Fusor made by the lord company would work.You can get it at any parts store that carries body shop supplies.They have used this stuff to actually glue water tanks to concrete mixer trucks.They used it to put the body panels on the old chevy lumina apv vans.i went to General Motors training class in the 80s they put a long crowbar between the panels and the steel frame and pried the panel off every place the bead of fusor was it ripped the steel off as well.Very strong structural adhesive.Other than that I would just braze it and repaint