Alternative Metals: Tips for Soldering Copper and Brass
Likely due to the rising cost of silver, there's been a lot of buzz of the forums recently about soldering copper as well as soldering copper to silver or brass—something that I was curious about, as well. Here are some great tips and suggestions about soldering copper and brass that I learned from those posts, by experienced Interweave members and Lapidary Journal Jewelry Artist experts.
Soldering Copper: Use the Right Torch the Right Way
"Pencil torches just don't produce enough heat to make a quick job of soldering copper. If you are going to use a butane torch, try getting one of the larger torches and having as big a flame on your torch as you can get. Copper is a really hard metal to solder because of the oxidation that forms on the surface. Also if you are using silver solder, try to use only easy or easy-easy as these melt at slightly lower temperatures than medium or hard." (posted by member BogIron)
Great soldering advice no matter what metal you're using: "Remember, the torch does not melt the solder; the torch heats the metal, which in turn causes the solder flow." (posted by Lapidary Journal Jewelry Artist contributing editors Tom and Kay Benham)
Soldering Copper: Use the Right Solder
"I also found that using extra easy silver solder was the trick for me … so I only had to go up to 820° F and was joining copper to sterling [with a] small butane pencil torch … when I used the easy [silver solder], I think all the flux was heated away before the solder and the metals could reach 1200° F." (posted by member leigh ann wilmot)
"When I solder copper I use silver solder, and when I pickle my piece, I put a piece of steel in the acid and it copper coats the silver solder … I use binding wire to coat my copper pieces and it works fine … Once the steel is out of the pickle, I do believe it will not affect future sterling silver … at least I have never had a problem, once I take out the steel." (posted by member JanineB@7)
"Once you use the steel in your pickle pot, it actually removes the copper residue from prior pickle baths. So your pickle solution is almost just like new!" (posted by member Cat_P)
Soldering Brass: Successful Pickling
If your brass isn't so brassy after pickling, "mix a solution of two parts hydrogen peroxide [to] three parts white vinegar [and] soak the piece in it for 20 to 30 minutes, and the brass should be brass again. It takes the copper off the brass. Do not store this in a closed container … You may need to use a scrubbie to get the brown grunge off." (posted by member LeeAnne70)
After soldering with brass, "rather than pickling to get the old flux off, I just boil it in plain water, not pickle. When you put brass in most pickles, you are doing a sort of depletion gilding; instead of bringing the silver to the surface, you are bringing the copper to fore by removing the zinc from the brass, and that is the pink color you are getting, so I just put mine in boiling water to dissolve the old flux." (posted by member BogIron)
Thanks to all of these members and experts for sharing their experience and advice on the Interweave jewelry-making forums! You can also learn more about soldering copper and brass from Lexi Erickson.