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31896 - Harris Sil-Fos 15 Silver Brazing Alloy 3/32" - 1lb Tube

Packaging: 24 rods in a pack
$423.00/pak

In stock

SKU: SF15-332-1 Categories: ,

OVERVIEW

Premium Silver Brazing Alloy for Critical Applications

The Harris Sil-Fos 15 (15% Silver) Brazing Alloy is the premier choice in the phos-copper family, designed for high-integrity joining of copper and copper alloys. With a composition of 15% silver, 5% phosphorus, and the balance copper, this alloy meets the rigorous AWS BCuP-5 classification. It is widely recognized in the industrial gas and HVAC/R sectors as the standard for brazing refrigerant systems where joint integrity is paramount. The addition of 15% silver significantly enhances the ductility of the brazed joint, making it far more resistant to the stresses of vibration and thermal expansion/contraction compared to lower silver alternatives like Sil-Fos 5 or Dynaflow.

One of the key metallurgical advantages of Sil-Fos 15 is its wide melting range (Solidus 1190°F to Liquidus 1475°F). This "plastic range" allows the alloy to transition slowly from solid to liquid, giving the operator excellent control when bridging gaps or dealing with poor fit-ups. While it is fluid enough to penetrate tight capillaries, it can also be manipulated to cap joints effectively. For copper-to-copper applications, the phosphorus content acts as a self-fluxing agent, eliminating the need for separate flux and streamlining the brazing process. This reduces cleanup time and minimizes the risk of flux inclusion in the system.

This 1 lb pack contains approximately 24 rods of 3/32" diameter, offering a convenient quantity for service technicians and fabricators. While primarily used on copper, Sil-Fos 15 can also be used to braze brass or bronze components; however, a white brazing flux (such as Stay-Silv White) is required for these base metals to remove oxides. It should strictly not be used on ferrous metals (steel, iron) or nickel alloys, as the phosphorus can form brittle intermetallic compounds that compromise joint strength.

Key Technical Specifications

  • Composition: 15% Silver, 5% Phosphorus, 80% Copper
  • AWS Class: BCuP-5
  • Melting Point: Solidus 1190°F (643°C)
  • Flow Point: Liquidus 1475°F (802°C)
  • Electrical Conductivity: 9.9 (%IACS)
  • Density: 0.305 lbs/cu.in.
Additional Information
Packaging Description:1 lb pack, 24 rods in a pack
Diameter:3/32"
AWS Classification:BCuP-5
Material Composition:15% Silver, 5% Phosphorus, 80% Copper
----- new values below ----
AWS Classification:BCuP-5
Material Composition:15% Silver, 5% Phosphorus, 80% Copper
Solidus Temperature:1190°F (643°C)
Liquidus Temperature:1475°F (802°C)
Fluidity Rating:3.5
Recommended Joint Clearance:0.002" - 0.005"
Silver Content (%):15
Diameter:3/32"
Packaging Description:1 lb pack

INCLUDED

  • 1 x 1 lb Pack of Sil-Fos 15 Brazing Rods (Approx. 24 Rods)

APPLICATIONS

  • HVAC/R Refrigerant Systems
  • Air Conditioning Coils
  • Evaporator and Condenser Coils
  • Medical Gas Piping (Copper)
  • Electrical Conductors and Bus Bars
  • Heat Exchangers
  • General Copper-to-Copper Plumbing

FAQ

If you are brazing copper to copper, no flux is required because the phosphorus in the rod acts as a fluxing agent. However, if you are brazing brass or bronze, you must use a flux like Stay-Silv White.

No. Phosphorus-bearing alloys like Sil-Fos 15 should never be used on ferrous metals (steel, iron) or nickel alloys. The phosphorus reacts with iron to create a brittle phosphide layer that will cause the joint to fail.

Sil-Fos 15 contains 15% silver, while Sil-Fos 5 contains 5%. The higher silver content in Sil-Fos 15 makes it more ductile (less brittle) and better at withstanding vibration. It also has a wider melting range, making it better for filling gaps.

Sil-Fos 15 has a solidus temperature (starts to melt) of 1190°F (643°C) and a liquidus temperature (fully melted) of 1475°F (802°C).

For the 3/32" diameter, a 1 lb pack typically contains approximately 24 rods.

Yes, Sil-Fos 15 is commonly used for medical gas piping installations due to its high quality, strength, and cleanliness when used on copper piping.

This product meets the AWS A5.8 classification for BCuP-5.

Yes, it can be used for copper water piping, but it is more commonly used in HVAC/R due to its cost and specific properties. Standard plumbing often uses lower silver content or tin-silver solders depending on code requirements.