This is a good project to learn how to solder copper. While soldering copper is similar to soldering silver, it’s a little harder because copper is a ‘dirty’ metal, which means that when you hit it with the torch, it oxidizes very quickly. And unless you protect your solder joint from that oxidation, you won’t be able to get your solder to flow, or you’ll have an incomplete joint. That’s the bad news. The good news is that it’s VERY difficult to melt copper because it transfers heat so well. That’s not to say
you can’t melt it, but you really have to try!
With that in mind, here are a few things to keep in mind when soldering copper. First of all, I don’t like copper solder. It is more brittle than silver solder, so it will break if you do any forging on the joint. It also isn’t really copper in color. Since we
can copper plate our piece to hide the silver solder anyway, I don’t see the point using copper solder –we’ll stick with the silver solder.
Next, since copper gets dirty so quickly when you are soldering, you need to have a hot torch which will heat the piece quickly. One of the biggest mistakes people make when trying to solder copper is they heat the piece slowly, which builds up the fire scale and makes the piece so dirty your solder will never flow. The good news is that copper is such a good heat conductor that it’s a lot harder to melt than silver. Another remedy to the fire scale buildup is to use Prip’s flux, as it holds up longer under heat and allows you to keep your joint clean until your solder flows.
Finally, after every soldering operation, make sure to pickle your piece and rinse it off. Then take your brass brush and a little dish soap (I like Dawn), and give it a quick once-over to remove any remaining residue. These little precautions will enable you to solder copper like a pro, so let’s get started.