Re: Copper Tubing Fuel Tank
"Problem is there about 12-14 square inches of copper a 1/4 inch thick to heat up enough to pull a 3" cap off a 3" tube. I'd need 3-4 torches like that to do it."
I don't think that's true. I've taken a lot of old copper pipe apart. It shouldn't take much more heat to make the old solder molten than it did to solder it up in the first place. Ask a plumber if he uses three or four propane torches to solder up a joint in 3" copper pipe. I don't think so. But do what you want.
Someday when I grow up I will probably lose interest in toys with wheels, but until then...