Borax cone
The traditional jeweller’s flux, borax is usually supplied as a hard cone. This is ground with a little water on a slate tile or unglazed ceramic dish until a thin creamy liquid is produced.
Borax powder
Often used when melting scrap metal, powdered borax can be used as a soldering flux. Borax has the cost saving advantage that it can be sent from mail order suppliers in the post, whereas other fluxes usually require a courier due to the hazardous nature of the chemicals involved.
Easy-flo
This popular propriety flux is supplied by Johnson Matthey, usually in powder form to be mixed with water. It is a reliable general purpose flux with a working range of 550-800°C. It can also be obtained as a paste with a working range of 575-825°C.
Tenacity No.5
Another powdered flux manufactured by Johnson Matthey, this has a slightly higher working range of 600-900°C.
Pripps flux
This chemical compound can be easily mixed at home. Although it can act as a soldering flux at higher temperatures, its primary use is to prevent oxidation of a metal surface.
Auflux
A popular gold soldering flux; it can also be used when soldering silver. Auflux is supplied in liquid form.
Boric Acid
Boric acid mixed with methylated spirits is a traditional solution used to prevent oxidation and fire stain. 150g of boric acid should be thoroughly mixed with 1 litre of methylated spirit in a lidded container. This solution can be applied by dipping or with a soft brush. Once the work piece has been gently heated with a torch, a white film will be left behind that will act as a protective barrier layer during soldering.
Magic Boric
This is a 'soldering dip' that both protects from surface oxidation and acts as a soldering flux. Because it is water based, it can be safer to use than a methylated spirit and boric acid mixture. Magic boric will protect the polished surface and can be easily cleaned off again with water, making it useful when repairing jewellery.
Argo-tect
This commercially produced powdered compound provides protection against firestain when annealing and soldering by creating a protective layer across the surface of the silver.
