Borax is used as a base in flux when soldering jewellery metals such as gold or silver. It allows the molten solder to flow evenly over the joints. Borax is also a good flux for “pre-tinning” tungsten with zinc – for soft soldering to tungsten. Also used for forge welding flux, brazing flux & a constituent of arc welding flux.
Another great use for borax is preparing the crucible for melting by creating a glaze in it.
This is How to Prepare a Crucible:
- Fill your brand new crucible halfway with Methylated spirits, allow it to soak into your crucible.
- Heat up your crucible (be careful as the flame will be larger than usual due to the spirits), then pour in around 2-4 heaped tablespoons of borax powder (there might be some fluffy bits of borax flying around – this is normal)
- Concentrate your flame onto the powder until it starts becoming see-through glass gel.
- Swirl this glass around the crucible until it coats the whole inside & glazes the surface evenly.
Then its ready to use!
Always be careful when working with open flames, gas & metal- Safety First.
Don’t forget sprinkle some borax which will help keep the impurities out of the metal!