DS Pipe and Steel Supply


Sil-Fos is a brazing alloy consisting of copper, phosphorus, and silver. It is widely used in the field of metal joining, particularly for brazing applications. Brazing is a process that involves joining two or more metal components by melting a filler metal (like Sil-Fos) and flowing it into the joint between the base metals. Once the filler metal cools and solidifies, it forms a strong, durable bond, effectively connecting the components.

Here are some key characteristics of Sil-Fos:

  • Composition: Sil-Fos typically contains approximately 6-7% silver, 6-7% phosphorus, and the remaining percentage is copper. The presence of silver and phosphorus gives Sil-Fos its excellent brazing properties.
  • Low Melting Point: Sil-Fos alloys have a relatively low melting point compared to their joining base metals. This is advantageous because it allows for the brazing process to occur at lower temperatures, minimizing the risk of damaging or distorting the base metals.
  • Good Flowability: Sil-Fos alloys have good fluidity when molten, allowing them to flow easily into narrow gaps and crevices between the joined metal parts. This ensures a tight, leak-free bond.
  • Strong Joints: Sil-Fos brazed joints are known for their strength and durability. The resulting joints can withstand mechanical stress, temperature variations, and corrosion, making them suitable for various applications.

Sil-Fos is commonly used in various industries, including plumbing, HVAC (heating, ventilation, and air conditioning), refrigeration, automotive, and aerospace. It is used to join copper alloys and steel and stainless steel components. Sil-Fos brazing typically produces clean and ductile joints with minimal distortion of the base materials. This is important in applications where appearance and precision are crucial.