Of the phos-copper brazing fill materials, SILVALOY 15 has more ductility and better electrical conductivity than the lower silver content phos-coppers. It has good flow and wetting properties on copper, brass and bronze. The phosphorous content of SILVALOY 15 acts as a fluxing agent and no flux is necessary when brazing copper-to-copper joints. However, when used with other brazeable metals, a brazing flux must be used to promote wetting, bonding, and flow throughout the joint. Of the phos-copper filler metals, SILVALOY 15 has the most "sluggish" flow characteristics. This enables it to fill gaps better. The recommended joint clearances are between 0.001" and 0.005" Melting of SILVALOY 15 is virtually complete at 133f (720c) even though the liquid is not yet reached.