Good evening,
I have brass brazed them, nickel rod arc welded them and on areas where I cant reach I have metal epoxy glued them on, but that has to be thick enough to hold and you can see it.
There are people that tig with nickel and also mig weld them.
The problem with brazing is so much heat is needed at one time that a lot of the cylinder is heated up that the uneven heat my be risky for for deformation or cracking. But, I have done a lot of it and am not aware of a problem.
When people tig or mig weld them, they do not preheat, they do bits at a time.
look for videos.
Good luck,
Scooter