Good jewellery soldering begins before the torch is lit. A close-fitting joint, clean metal and a carefully placed coating of flux all deserve attention. The humble flux brush belongs to that preparation: it helps put the flux where it is needed, with control over the area you coat.
What does flux do?
Heating metal encourages oxidation, which can interfere with solder flowing across the joint. A suitable flux helps protect the prepared surface during heating. It supports the soldering process, but does not replace careful cleaning, a well-fitted joint or appropriate heat control.
Borax is a traditional choice for jewellery soldering. A borax cone and dish can be used with water to prepare a paste; ready-made fluxes are also available. Choose a flux intended for your metal and solder, and follow its own preparation and safety instructions.
Why use a dedicated brush?
A brush reserved for flux is easier to keep separate from polishing compounds, paint and bench debris. Metal-free flux brushes also avoid a metal ferrule that could corrode and introduce rust particles into the mixture. Keeping the brush and the flux clean is a small, useful part of a consistent bench routine.
Choosing a size
The right brush is one that lets you reach and coat the intended area comfortably. A smaller head can be useful around a fine joint; a fuller head can cover a wider area. Overall length alone does not describe the head, so consider both reach and the amount of flux the bristles carry.
Our borax flux brushes are available in small, medium and large sizes, approximately 55mm, 75mm and 85mm overall, or as a set containing one of each. The larger brushes have fuller heads.
A considered preparation routine
Prepare and fit the metal first. With the work cold, use the brush to apply the chosen flux to the intended joint. Put the brush safely aside before heating: it is an applicator, not a tool for use in the flame or against hot metal.
Keep the soldering area organised and use the ventilation, protective equipment and heat-resistant support required for your process. After use, follow the flux supplier’s cleaning guidance and store the brush away from dust and other bench materials.
A good brush will not make a joint for you. It makes one small part of preparing that joint more deliberate.
Explore the borax flux brushes and three-brush set.
Editorial illustration: the dish, flux and silver ring are shown for context and are not supplied with the brushes.