Harris Welco Harris O Phos Copper alloy is primarily used to join copper to copper, copper to brass, and brass to brass. The phosphorus content serves as a “self-fluxing” agent in joining copper to copper. When brazing brass to copper or brass to brass, use Stay-Silv® White Brazing Flux. The phos/copper and silver/phos/copper filler metals are not recommended for brazing steel or nickel alloys. The amount of phosphorus in the phos/copper filler metals (AWS-BCuP series) is critical in determining precise melting range and performance. Proprietary computer based technology is used to accurately control the phosphorus content to exacting standards. Each heat of metal is precisely checked before pouring to assure users a phosphorus content to within + or - 1/10 of a percent. Even more significant, a liquidus variation of no more than +or- 60 F. The advantages of this precise control is apparent in automated brazing operations, where even modest variations in flow temperatures can significantly increase the incidence of rejects. Equally important, manual operators no longer need to make adjustments in heating practice from one batch of filler metal to the next to achieve uniform results.