the brazing surfaces and prevent their new build-up in order to allow a thorough wetting of these surfaces by the liquefied brazing alloy. Fluxes have to be activated already at a temperature below the working range of the brazing alloy. They are selected mainly according to the working temperature of the brazing alloy and the base material to be joined.

Since the residues of fluxes are hygroscopic and can cause corrosion they have to be removed completely after the brazing process in very hot or boiling water. Depending on the type and process used, fluxes are being applied in liquid form or as powders or pastes.