What is the purpose of using flux? What is it made of?
Oxidised metal surfaces cannot be brazed and thus need cleaning beforehand. This cleaning action is performed by the Flux. Flux reacts chemically with the metal oxides and dissolves them and prevents oxides from reforming. Flux becomes fluid at brazing temperatures and adheres to the base metal. Flux is then displaced by the molten filler in the brazing process. Flux is required when brazing ferrous metals with filler rods not containing Phosphorous. Fluxes are formulated from many chemicals e.g. acid, Borates, Fluorides, Fluoborates, Deoxidizes, water & wetting agents and are available in the form of powder, paste and liquid.
