PhosCopper Brazing Alloys

Aufhauser controls the phosphorus content to tolerances that exceed industry standards.


Aufhauser PhosCopper Brazing Alloys are free from impurities that cause ruptures or leaks. By providing you with the highest quality products, we ensure the lowest cost of purchase and maintenance.

The phosphorus content in Aufhauser PhosCopper alloys acts as a fluxing agent. However, phosphorus will not act in a similar fashion on other metals. Aufhauser White SilverFlux must be used on all other metals to promote wetting, bonding and flow throughout the joint. Do not use PhosCopper alloys on ferrous or nickel-containing alloys (i.e. steel, iron). Phosphorous will react with iron or nickel to create a brittle joint. Aufhauser controls the phosphorus content to tolerances that exceed industry standards.

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Usage Guide to Silver Alloys

Aufhauser product descriptions

Product Cross Reference Chart

Cross reference to AMS, AWS, ASME, Fed Spec. QQ-B-654A, H&H, JW Harris

Alloy Density: Lb./Cu.In. ( Oz.T./Cu.In. )
Diameter :
Feet/ Lb: ft./lb
Inches/ Troy Ounce : in./Oz.T.
Rod Length :
Rods/Lb : Rods/Lb


Aufhauser Product Name
Ag Cu P
AWS A5.8
Other Names Description
PhosCopper 0 0 92.75 7.25 BCuP-2 FOS-FLO Copper and phosphorous alloy offering excellent liquidity for tight fitting joints. Used extensively in the HVAC industry to make preform rings for evaporators/condensers.
PhosCopper 2 2 91 7 BCuP-6 SIL-FOS 2 / Stay Silv 2 Combination of low silver with high phosphorous creates very good fluidity. While not quite as liquid as PhosCopper 0, tight fit-up is recommended.
PhosCopper 5 5 89 6 BCuP-3 SIL-FOS 5 / Stay Silv 5 Delivers moderate liquidity and improved gap filling compared to PhosCopper 0. The 5% silver content provides good economy when compared with PhosCopper 15.
PhosCopper 5HP 5 88.25 6.75 BCuP-7 SIL-FOS 5F Similar to PhosCopper 5. Developed especially for use as a preform alloy. Higher phosphorous content delivers good liquidity.
PhosCopper 6D 6 87.9 6.1 - SIL-FOS 6M Developed to mimic performance of the PhosCopper 15 alloy at lower cost. Similar to Dynaflow®.
PhosCopper 6HP 6 86.75 7.25 BCuP-4 SIL-FOS 6/Stay Silv6HP For copper or brass. Fluid alloy for controlled clearances of 0.001-0.004". Good for automated brazing applications.
PhosCopper 15 15 80 5 BCuP-5 SIL-FOS 15 / Stay Silv 15 This very popular alloy offers superior ductility and strength. It is suitable for wide gap applications. Joint clearances of 0.002-0.006". Easy to use, good control. Used extensively in copper tube joining applications.



Nominal Composition



Solidus - Liquidus Range