Copper paste solder

THIS COPPER SOLDER PASTE IS REPLACING THE WIRE SOLDER PREVIOUSLY SOLD.

This paste solder is self-fluxing, copper-based, and contains phosphorus. Although it appears gray in the syringe, it blends with copper far better than silver or low-karat gold solders—and it even patinas like copper. The solder has a melting point of 1240°F and a flow point of 1325°F. While it already contains flux, adding a bit of extra flux will help the solder flow more smoothly.

Before soldering, make sure the metal surfaces are clean and fluxed. Lightly sand each area to be joined, then wash with dish soap (Dawn is ideal), rinse, and dry thoroughly. Any dirt or skin oils will prevent the solder from flowing properly. If you need to keep solder from flowing into certain areas, you can use a product such as Fire Shield as a flow inhibitor.

For the best color match to copper, use the smallest amount of solder possible and pickle as usual. If you still see a visible line, lightly sand the seam, then reheat, pickle, and sand again. Repeat as needed. This process brings more copper to the surface and reduces the silvery look that copper solder can leave behind.

Another way to enrich the copper color is to place a small piece of steel (such as binding wire or a scrap) in your warm pickle pot and then add your piece. The steel will cause the solder to shift to a copper/pink tone. Be sure to remove the steel afterward so it doesn’t contaminate the pickle and discolor your silver pieces.

Keep in mind that high-copper-content solders flow more slowly than silver solder, so allow extra time at temperature for it to fully flow.