Hi, For silver bearing brazing alloys you need Heat, I use a propane torch for normal types of job, for the biggish ones then it is Oxy/propane. I have not made a boiler, so I do not have the gear for that. Just a point of interest, Silver solder is hall markable, silver bearing alloys are not. Over the years the term has been corrupted by the great and godly.
Nemesis