Just don't say it's dangerous & try to scare others away from doing it when you have no documentation otherwise.
Flip the coin Friend.
I've never seen "documentation" of a warranted "Gun Barrel Welder" service ever offered in my life, CF or ML,,
Extraordinary services are offered and preformed, yet those options are usually a bit more beyond a typical,
"Sure, no problem, bring it back here, the welder is in that shed out back"
And I know a lot of gun smith services offered locally and nationally.
You go ahead, weld on them barrels to your hearts content, make sure your kids, pass them barrels/guns on to your Grandkids, just keep'm in the family.
Please, don't take offense. You may well be one of those skilled people that have and can preform the proper techniques.
But if you are, then you should know sharing with the 20,000+ members here, (that view randomly) that's it Ok,,,,,,,,,,,,,,,,,,,,