I need to get advice on how to repair body work that's 60 years old.( on a 1941 car ) The hood has been pancaked , fender seams have been filled in with lead too. What I have noticed that the under side of all seams need more support to prevent cracks from showing up. This is a custom rare car that was done by using a stick welding and lead. I want to work on the underside of all seams by giving more support by using new type of products. Would seam sealer work on the underside where seams were joined together ? Or use something else? I do know how to make my own metal panels, Thanks for your advice.