At first I pretty much wrote the original tank off. Too many dents. Too much rust. I sourced another tank that also had a few issues, but was still better off than this tank. Then I started taking auto restoration courses at Washtenaw Community College again. I figured I had nothing to lose by attempting to repair the old tank original tank, so I brought it in to class. One of the instructors there was Tom Rose, an ex-motorcycle racer who had a day job at a local high-end restoration shop. Tom was a talented metal worker who took the tank and showed me how it's done. The before pics show most of the damage on the tank. The after pics were taken midway through the process so there are areas that haven't been finished yet. Bottom line, Tom did a great job knocking this thing back into shape. It's going to take a lot less filler than I had imagined it would, in fact much of the final work can be done with high build primer.
We (ok, he) started out by welding a tab on the tank and pulling the dent on top of the tank, but I wasn't all that thrilled with the idea of doing so much welding and grinding, so we bit the bullet and cut some access holes in the base of the tank. The next step was to work the metal out by hitting a wooden stick with a hammer. This got it into rough form, which Tom then finished with a body dolly and hammer. The pictures don't do his work justice, it's amazingly smooth.
July 2005: Those of you who have done this before probably saw those photos and thought "you should strip ALL the paint before doing any work on the tank." Oh how right you are. I put a bunch of time into welding the tank back together, only to strip the paint and find some major bondo work on the front section. I gave up on this tank and went with the replacement I had bought earlier!