On Mar 13, 3:48*pm, Cydrome Leader wrote:
What's a good way to keep solder from flowing or wetting copper or brass
parts being soldered- sort of like an anti-flux. I recall seeing something
posted here about it, but can't locate it.

There is such a thing as "anti-flux", you can search on it. However,
when I silver braze, I use an old dodge I read about, which is to use
a soapstone(talc) marker and rub around the work area with it. It
works. Probably anything that spoils the clean metal surface and
resists the action of the flux would work. Talc quailfies since it's
resistant to heat and doesn't react with much of anything.

Stan