i was talking with one of our tig welders at work who is very experienced as i asked him previously about welding titanium
titanium is very hard/ tricky to weld, alot of care needs to be taken
also from memory has to be performed in a clean seald room to get perfect weld.
i havnt tried doing it, just going buy what he has told me. This would also explain why titanium products are not cheap as materials and labour to do the job are expensive