0 items in your basket
Total £ 0.00 EX VAT
Multi Process Welders
MIG Torches
TIG Torches
Welding Helmets
Welding Gloves & Clothing
MMA Electrodes
MIG Wire
Shop 55,000 Products
SERVICEDEPT.
RAPID BLOG
FEEDBACK
HIRE
Powder flux for welding and higher melting point alloys.
Straight answers to the questions people ask most when choosing and using brazing and soldering flux.
When metal is heated in air, it forms a surface oxide layer that stops the molten filler from wetting and bonding to it. Flux dissolves and keeps out these oxides while you heat the joint, so the filler metal can flow smoothly into the gap and make a sound bond.Without flux, the filler tends to ball up and run off instead of flowing into the joint. Flux does not replace cleaning, but it is what lets the filler wet the metal.
Most brazing needs flux, but some filler metals are self-fluxing in certain uses. For example, copper-phosphorus rods can be used without flux when joining copper to copper, because the phosphorus does the job. They still need flux on brass and bronze, and they are not suitable for joining steel.Some aluminium fillers carry flux in the core. Always check the instructions for the rod you are using, and use flux where there is any doubt.
Watch the flux. As the joint heats, most brazing fluxes bubble, dry out and turn into a clear, watery liquid when they reach working temperature. That is the signal that the metal is ready for the filler.Heat the parent metal, not the rod, and let the heat from the joint melt the filler as you touch it on. If the filler does not flow, the joint is probably not hot enough, or the surface is not clean.
Yes. Flux deals with the thin oxide film that forms on clean metal as it heats, but it cannot cope with oil, grease, paint, thick rust or dirt. Those need to be removed first by degreasing, and by brushing or abrading the surface until it is bright.A clean, close-fitting joint plus the right flux gives the best chance of a strong, neat result. Many failed joints come from poor cleaning rather than from the flux or filler.
