We had a problem at the seam of the roof an quarter when we first started bonding, with the seam becoming visable after the repair was completed. So after about 2 jobs going from good to worse we now weld anywhere there is a seam an bond where the pinchwelds are. The bonding with glue is as strong has welds plus it offers a corrision protection inbetween panels that is very hard to get otherwise.
We build race cars, bonding carbon fiber, etc.. high end stuff, Daytona, F1, etc.. metal just needs to be prepped, but it's not an issue... Heck if you've flown in a turbo prop or jet liner, many panels are bonded.. especially the new Air Bus 800, it's mostly bonded.. just think you're flying 30,000 ft in the air in a glued together plane.. Actually, a secondary fastening, such as riveting causes less adhesion in carbon panels due to deformation, and in the shear plane, rivets don't do much.. but I'm starting to babble.. In the end, it's all about prep.. and miniscule contamination in the laminate / bond, then there will be corrosion.. I wouldn't do it with old metal..
I had this all ready to be my first glue job, but wimped out and welded it. I like welding and get perfect results, so why change? Got past the warpage thing years ago. I'm not on the clock anyway, it's just an out of control hobby. Plus, I had already welded on the rockers, full trunk floor, shock towers, and inner/out wheel wells. I did do some tests with the glue first though. You'll actually tear the sheetmetal adjacent to the glue before it lets go. Then I tried mild local heat(like propane, not MAPP or oxy-acetylene), and the glue let go without any damage to the metal.
You can weld and bond you know as long as you use the proper spacing between the glue and the weld due to the heat produced by the weld.. Paul
My job includes using new technology in assembly. So all due respect to the folks gluing. However, if I were asked to look at a car for someone, as I have many times, and determined glued joints or joints other than as close to or exact to factory, I'd have big reservations with that car. I know I'd be a hot knot if I paid for a panel restoration and got a repair. I guess a bigger question than whether gluing works or not is....... is it going to help or hinder the cars value as opposed to a factory type repair.
