Vulcan G-51 Aluminum Brazing Rods (1/2 LB) and Flux (4 oz) For use with a torch on all known weldable and brazable aluminums. Melting of the base metal is not necessary. Deposits have good color match to aluminum, high strength, and good electrical conductivity. Flux indicates temperature as it goes from powder to paste to liquid with increased temperature. Flux thoroughly cleans, quickly melts, and easily spreads the filler metal.