Re:
It’s worth reading a bit about ti welding. It is fickle stuff, and some owners of very well know US brands know a thing or two about ti cracks. Or five. I have only had good experience - Litespeed-made 1990 ti Team Marin frame, 2014 Stanton Slackline 26-er. Having looked at this issue after a friend’s Titanium Red developed a chainstay crack, I got a few insights from builders and research. The main thing for you is not only the failure of the original repair, but the site of the original failure. For joint failure, the cause can be poor mitre-ing of the joint and/or contamination of the weld during the welding process. And Ti welding has changed a lot over the past two decades, so if your is a Vit T, then quite a lot of procedures have improved. Contamination during the welding process is a cause of a lot of Ti failures - the metal formation during welding, and the bonding of the weld to the old metal surface must not include any oxidation at all, hence the need to weld in an inert environment. Yours is at the chainstay-BB joint? If the original weld failed through contamination - and that is very likely - then the first repair would have been unlikely to endure. That then places a challenge for the repair, which necessitates removing all the old weld, and then welding with a totally perfect uncontaminated second procedure, with the tube mitred exactly to mate with the BB surface. That’s pretty demanding, and there are only a couple of builders in the UK who can work to those kinds of standards with Ti. You sure can re-weld ti, but not if there are elements of the old, brittle weld in evidence. If the failure has occurred somewhere along the length of the tube - unusual, but that’s what happened to my friend’s Ti Red - then the repair is relatively simple. Vernon Barker are recommended, also Enigma. But it won’t be cheap I am afraid. I hope this helps.