Going thru the car I have found a crack in the heavy metal surround piece behind the aluminum at the rear bulkhead. Iam trying to remove the 2 thin aluminum sheets and gussets but they seem bonded to each other and to whatever is behind- first problem. Second once I get it off they'll probably need to be made but how am I going to weld the crack ( one seen so far) without melting or destroying the composite. Can anyone tell me the rivet lenghts (assuming I get by all that) for installing the new aluminum. Third I am only assuming that the heavy metal surrounding the outside edge of the tub IS metal you can weld. Fourth does anyone supply precut jabroc?