Silver / Copper / Phosphorus Alloys

Other Brazing
& Soldering Products

Sil-Fos® 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.

While this filler metal is widely used in the air conditioning and plumbing industries, it is not recommended for ferrous or nickel based materials because the joint will become brittle and may fail. The Sil-Fos® Alloys vary in silver content from 18% to 2% and the percentage of silver and phosphorous does change the melt and flow characteristics of the filler metal. Sil-Fos® alloys are available in wire & rod, powder & paste, preformed rings and shapes. Some Sil-Fos® alloys are available in strip as well.

Use the chart below to compare our most popular silver/copper/phosphorus alloys.

Silver/Copper/Phosphorus Alloys	Solidus		Liquidus		Nominal Composition, %				AWS Class	Technical Documents	MSDS Safety Documents
Silver/Copper/Phosphorus Alloys	°F	°C	°F	°C	Ag	Cu	P	Others	AWS Class	Technical Documents	MSDS Safety Documents
Sil-Fos 18 A ternary eutectic filler metal for joints where good fit-up can be maintained and low melting point is of prime importance. Clearance: .001" to .003" (.025 mm to .076 mm). Very fast flow.	1190	645	1190	645	18	74.75	7.25	0	N/A	145K	92.1K
Sil-Fos 15 For use where close fit-ups cannot be maintained and joint ductility is important. Recommended joint clearance: .002" to .005" (.051 mm to .127 mm). Slow flow. The only phos/copper silver filler metal available in strip or sheet form.	1190	645	1475 (1300)	805 (705)	15	80	5	0	BCuP-5	79K	92.1K
Sil-Fos 6 A very fluid filler metal for close fit-up work. Low melting range makes it ideal where temperature is a factor. Recommended joint clearance: .001" to .003" (.025 mm to .076 mm). Fast flow. Lowest melt and flow in the minimum silver class.	1190	645	1325 (1275)	720 (690)	6	86.75	7.25	0	BCuP-4	54K	92.1K
Sil-Fos 6 M Recommended for use where close fit-up cannot be maintained. Has the ability to fill gaps and form fillets without affecting joint strength. Recommended joint clearance: .002" to .005" (.051 mm to .127 mm). Slow flow.	1190	645	1460 (1300)	795 (705)	6	88	6	0	N/A	61K	92.1K
Sil-Fos 5 Designed primarily for those applications where close fit-ups cannot be maintained. It has ability to fill gaps and form fillets without adversely affecting joint strength. Recommended joint clearance: .003" to .005" (.076 mm to .127 mm). Slow flow.	1190	645	1495 (1325)	815 (720)	5	89	6	0	BCuP-3	79K	92.1K
Sil-Fos 2 A filler metal with comparable characteristics to Fos-Flo 7. Recommended joint clearance: .001" to .005" (.025 mm to .127 mm). Medium flow.	1190	645	1450 (1325)	785 (720)	2	91	7	0	BCuP-6	143K	92.1K
Sil-Fos 2M Has ability to fill moderate gaps in poorly fitted joints. More ductile than Fos-Flo 7 or Sil-Fos 2. Intended for use on copper tube headers and similar applications where a sleeve fit is not practical. Recommended joint clearance: .002" to .005" (.051 mm to .127 mm). Slow flow.	1190	645	1495 (1350)	815 (730)	2	91.4	6.6	0	N/A	51K	92.1K
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).

Lucas-Milhaupt, Inc. 5656 S. Pennsylvania Ave., Cudahy, WI 53110, USA
http://www.lucasmilhaupt.com | info@lucasmilhaupt.com
phone 414-769-6000 | fax 414-769-1093