Brazing is the joining two or more metals by filling a molten filler metal, or a brazing alloy. The melting point of these alloys is usually above 840°F and below the melting temperature of the base metals that are to be joined. The base metals are heated to temperatures slightly above the liquidus temperature (temperature above which the metal liquidifies) of the filler metal. The filler metal is then placed marginally in the region that has to be joined. The liquefied filler material is permitted to penetrate the joints of the base metals by capillary action.