The stuff made by FUSOR is crazy strong. I've seen where they have bonded two pieces of metal then pulled on them. The metal gave way before the bond broke.
I don't know about on a quarter panel though. Worked great for bonding my new firewall to the old one
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"A ship in port is safe, but that's not what ships are built for."
See Bad Penny run the cones:
https://www.youtube.com/watch?v=8GUPPIX-92U
1971 Chevelle Wagon - Roadster Shop Chassis ProCharged Shafiroff LS and lots of yada yada
1968 Camaro - Project Track Rat - 440 RHS LS