Brazing & Soldering Products

Lucas-Milhaupt offers the most comprehensive inventory of alloys and forms in the industry and our expertise in brazing and soldering ensures that we can find the best-matched products for your needs.

Technical Documentation

Visit our knowledge base for SDS and other technical documentation.

Download Technical Documents

Copper/Phosphorus Alloys


Self-Fluxing Copper/Phosphorus Brazing Alloys

FOS-FLO® alloys are copper based filler metals that are self-fluxing on copper by virtue of their phosphorous content. Because of their self-fluxing nature, you save time and money by eliminating the steps necessary to flux a joint before brazing. However, copper alloys such as brass and bronze should be fluxed with HANDY FLUX™ or Sure Flo Brazing Flux to assure a sound braze joint.

The level of phosphorous also changes the fluidity and ductility of the material. The greater the percentage of phosphorous in the filler metal the more fluid the material will be. While this alloy is widely used in the air conditioning and plumbing industries, it is not for use on ferrous or nickel based materials because the joint will become brittle and may fail. 

A Silver-Free Alternative to SIL-FOS®

FOS-FLO® alloys have many of the same characteristics of the SIL-FOS® alloys, except that they are free from silver, which significantly reduces the price of the material. Alloy forms available include wire, preforms and powder.

Request a Quote

* Login required for document download.

Product SolidusLiquidusNominal Composition, %AWS & International Standards Technical Documents* SDS Safety Documents
°F °C °F °C Cu P Other

(Formally FOS-FLO® 7 / SILVALOY® 0) An economical, very fluid medium temperature filler metal for use with copper, brass and bronze. Withstands moderate vibration. Recommended joint clearance: .001 to .003 (.025 mm to .076 mm). Fast Flow.

1310 710 1460 (1350) 795 (730) 92.75 7.25   BCuP-2

An economical filler metal with a wide melting range and moderate flow. For use where close fit-ups cannot be maintained and ductability is important. Recommended joint clearance is .003 to .005 (.076 mm to .127 mm).

1310 710 1570 (1375) 854 (746) 93.85 6.15    
FOS-FLO® 670

Very free flowing alloy for tight fit-ups, Silver Free and low temp melting point.

1215 657 1270 687 87 6 7 Sn
FOS-FLO® 671

A low temperature Silver-free alloy; very free flowing. Available in paste and powder only.

1134 612 1260 682 85.3 6.2 7 Sn
1.5 Ni

Note: NOTE: The SIL-FOS® and FOS-FLO® filler metals are for use with copper and copper alloy base metals. Do not use these materials to join ferrous materials as brittle phosphide compounds will be formed at the interface. The SIL-FOS® and FOS-FLO® filler metals have a unique characteristic called the "Flow Point" (listed in parentheses). The "Flow Point" is defined as the temperature at which the filler metal is fluid enough to capillary through a joint even though not completely liquid (i.e. above the liquidus temperature).