This is the most commonly asked question we receive from people who have never worked with fluxes.

FLUX: A chemical composition critical to the heat joining methods of soldering, brazing, and welding that:

A substance that aids, induces, or otherwise actively participates in fusing or flowing, as:

  • A substance applied to a surface to be joined by welding, soldering, or brazing to facilitate the flowing of solder and prevent formation of oxides.
  • A mineral added to the metals in a furnace to promote fusing or to prevent the formation of oxides.
  • An additive that improves the flow of plastics during fabrication.
  • A readily fusible glass or enamel used as a base in ceramic work.