Section 56.75-5 - Filler metal (modifies 128.2)(a) The filler metal used in brazing must be a nonferrous metal or alloy having a melting point above 1,000 °F and below that of the metal being joined. The filler metal must flow freely within the desired temperature range and, in conjunction with a suitable flux or controlled atmosphere, must wet and adhere to the surfaces to be joined. Prior to using a particular brazing material in a piping system, the requirements of § 56.60-20 should be considered.(b) The brazing material used must have a shearing strength of at least 10,000 psig. The maximum allowable working pressure for brazing piping must be determined by this part.(c) Fluxes that are fluid and chemically active at the brazing temperature must be used when necessary to prevent oxidation of the filler metal and of the surfaces to be joined and to promote free flowing of the filler metal.CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by CGD 77-140, 54 FR 40615, Oct. 2, 1989; USCG-2003-16630, 73 FR 65184, Oct. 31, 2008