On Friday, 4 October 2019 20:54:16 UTC+1, Rod Speed wrote:

I have found that German silver (nickel silver) makes very nice
brazed joints on stainless steel. I used the white powder flux
that is supplied for dental orthodontic work. I suspect it is
borax based.
I tried oxy-acetylene, oxy-hydrogen, oxy-butane and oxy-propane
and found that oxy-propane gave good results without charring
the flux or unduly oxidising the stainless steel. I was working
on very small items.

John