Brazing is a versatile joining process. It is used to join most metals and alloys used in engineering. It is a thermal joining process in which a molten brazing alloy is drawn into a capillary gap between the metals being joined. Brazing alloys have a melting point above 450C but always below the melting point of the metals being joined.

Flux is a chemical compound applied to the parent metals to protect them from oxide formation during heating and to promote flow wtting of the brazing alloy.