SUPERFLOW® 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 . Superflow 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.