Borax Cone Flux

Borax cones are the traditional soldering flux jewellers have used for generations, and they're a solid alternative if you'd rather not use Handy Flux.

To use one, grind the cone with a few drops of water in an unglazed ceramic borax dish until it forms a smooth paste, then brush that over your join before you solder. The flux keeps oxygen off the metal while it heats, which stops firescale and oxidation building up around the join and keeps your solder flowing cleanly into the seam.

The cone dries out after each use rather than being used up, so one cone gives you many soldering sessions before it needs replacing. It suits gold, silver, and most other metals used in jewellery making.

This borax cone is also available as a set with a ceramic borax dish, if you don't already have one to grind it in.

Worth knowing:

• Weighs 100g, and measures 113mm high, tapering from a 45mm diameter base to 15mm at the top
• Keep the cone dry between uses so it doesn't dissolve or soften before you're ready to grind it again