I been a certified welder for 8 years and was taught in the field by people who used to weld Subs. We mainly use mig and stick but have the equipment to do tig. I would say don't bother. Something made to precision like that will never come out the same. The heat will warp it, it would have to be precision ground inside and out. It would never be the same and would probably just re-break around the welds after a few throws.
Cut your losses and find a new one.