Waveski, the problem with welding is that you'll have to remove all traces of the lead solder (or whatever they used) which would contaminate a weld. The other issue with welding is that you run the danger of blowing holes in the thin metal of the tank. It takes some skill to get a good weld joint on thin metal. Silver solder is a better solution than just 50/50 lead-tin solder. It's an alloy that has no lead, but yet melts at low temperature like 50/50 does, so can be done with an old school soldering iron (a block of copper on a with a handle heated by a torch or furnace) on thin metal or a propane torch. I'd recommend Bridgit Lead Free Solder. You should be able to find that at a plumbing supply house. I've used it with good results. It flows nicely and forms a strong joint. Be sure to clean the joint beforehand, whatever method you use.
