I went ahead and gave it a shot TIG welding ... do what you know best and all that. Used 25 amp, DC, pulsed a 4/sec ... just got it hot enough to fuse the SiBr rod. On some test pieces I didn't see any degradation in spring'ness or any tendency to crack with bending ... but I have no doubt the repair won't last as long as the original spring did. I did give it plenty of overlap with the old spring to give it some additional strength.
