I find that black flux is very helpful when soldering copper alloys.
Black flux is made to work at higher temperatures, so it does not
"burn off" like other fluxes. Black flux is also useful when
silver-soldering stainless steel. It used to be that you needed to
go to a welders supplier to find it, but now I see that Rio Grande
carries it. Other jewelry suppliers may have it, too.
Black Flux for soldering copper alloys
Though I have purchased this flux in the past with the simple name
Black Flux, It is listed in the Rio Grande catalog as:
Handy Flux Type B-1 for Stainless Steel and Nickel Silver
Every time I go to Airgas to get my gas tanks exchanged, I usually
look at their flux and solder supply, and there's always black flux
and whiteflux on hand. I sometimes buy the white flux when I'm low
on flux. Iwill have to buy black flux next time I'm at Airgas,
exchanging empty tanks for full tanks.
I find copper is a heat hog - it requires a shitload of heat to get
it hot enough for the darn solder to flow. I work a lot in copper
and use itfor students to learn so I know how copper behaves. Silver
and gold is easy to work with in comparison. Just flux very
liberally and use plenty of heat when you use copper. Dandix or
Grifflux or Handyflux works well for copper but it have to be a
heavy layer so that the copper stays oxide-free when you are
soldering. I do mock inlay, so I have to glob on the flux
many, many years ago, when I was just a lad, my dad taught me how to
sweat a joint in copper piping for the water system in our house.
that has let me solder copper in the jewelry business. yes it is a
heat hog, and you really need to practice. i'm glad i grew up with
copper pipes and not the plastic that is used today. just can't hold
metal together with abs glue.
Joy- You are so right about copper being a heat hog.
I find that if I use a pumice pan when trying to heat large areas of
silver and copper helps a lot. It does a nice job of reflecting the
heat back onto the piece.
Have fun and make lots of jewelry.