Originally Posted by
merziac
As is often the case there will be many opinions on something like this. I would encourage you to seek out experts in this discipline specifically. My recommendation would be to consult Dave Levy of Ti Cycles in PDX, he is an expert in repair of all things bicycle frames, especially when it is difficult and challenging.
My thought exactly when I saw the OP's post. Tig welded frames are bread and butter for TiCycles. So is repairing anything steel (not just bikes). They are not cheap but you will get the word on if the repair is feasible, how it should be done and what it might cost.
It's a given that they have seen damaged tig welded bikes. The biggest market for theirs is as winter bikes for local racers. Those bikes don't get babied.
Ben