WELDCOTE 15 is a Phos-Copper brazing alloy formulated to join copper, brass and bronze. This alloy is the standard of the industry for many air conditioning and refrigeration applications as well as electrical. Weldcote brazing flux is needed when working on brazeable grades brass or bronze. Phos-Copper alloys are self-fluxing on copper but should not be used on copper alloys containing more than 10% nickel, steels, and ferrous metals or in any sulfurous atmospheres. Aluminum bronze requires the use of Aluminum bronze brazing flux.