- Brazing Filler Metals
- Sil-fos™ and Copper-flo™ Filler Metals
Sil-fos™ and Copper-flo™ Filler Metals
Sil-fos™ filler metals are recommended for the fluxless brazing of copper. On brass, bronze and other copper alloys a separate flux is needed. Sil-fos™ is the most ductile of this range Sil-fos™ 6 has the best flow of the group but has less alloy ductility. Sil-fos™ 5 provides the best combination of ductility and flow of the group making it the filler metal of choice for joining tubes in HV ACR components.
Copper-flo™ filler metals are recommended for the flux-less brazing of copper most commonly for joining tubes and pipes in heating, refrigeration, air-conditioning and heat exchanger components. They have lower ductility than the silver-copper-phos products.
Sil-fos™ Plus is the most free flowing filler metal from the Sil-fos™ range. It is used in niche applications where its low melting temperature, flow properties and electrical conductivity are an advantage. Sil-fos™ Plus is not particularly ductile and should not be used in applications where vibration, stress or deformation of the joint in service are possible.
644 - 800°C
Sil-fos™ is a widely used product being the most ductile of the silver/copper-phosphorus brazing filler metals and the only one available as a foil. It is used extensively in electrical engineering applications where it is used to make electrically conductive joints. It is also used in heating and ventilation and refrigeration applications to join copper pipes.
644 - 718°C
Sil-fos™ 6 is one of the most free flowing filler metals from the Sil-fos™ range making it popular in heat exchanger, air conditioning and refrigeration (HVAC&R) applications. It is also one of the least ductile and should not be used in applications involving exposure to strong vibrations, impact loads or where some deformation of the joint might be expected in service.
644 - 815°C
Sil-fos™ 5 provides the best combination of flow and ductility of all the silver/copper-phosphorus type brazing filler metals. As a result it is extensively used in heat exchanger, air conditioning and refrigeration (HVAC&R) applications for flux-free brazing of copper pipes and tubes. It is also used for joining copper and copper alloys in electrical engineering applications.
644 - 825°C
Silbralloy™ sits between Sil-fos™ 5 and Copper-flo™. It is less ductile and free flowing than Sil-fos™ 5 but more ductile whilst being less free flowing than Copper-flo™. It is used in HVAC&R applications for flux-free brazing of copper pipes, tubes and seams where these properties and its cost are acceptable. It is also used in some electrical engineering and plumbing applications.
714 - 810°C
Copper-flo™ is the most free flowing copper-phosphorus filler metal, however, due to its high phosphorus content it is one of the least ductile. It is best suited for making copper joints of the true capillary type and should not be used in applications involving exposure to strong vibrations, impact loads or where some deformation of the joint might be expected in service.
690 - 825°C
Copper-flo™ No.2 is a specialised copper-antimony-phosphorus filler metal. It was specifically designed for flux-less brazing of copper cylinders for domestic and industrial heating systems where it is used for seam joints. The antimony in this filler metal improves its flow characteristics whilst allowing the phosphorus level to be kept low hence optimising ductility.
714 - 890°C
Copper-flo™ No.3 is a low cost, relatively ductile filler metal (when compared to Copper-flo™), which is not too fluid when molten so can be held in the joint area when brazing. These characteristics make Copper-flo™ No.3 a popular choice for air-conditioning and refrigeration applications. Where greater ductility is required Sil-fos™ 5 should be used.
640 - 680°C
Stan-fos™ is not self-fluxing on copper and must be used with a brazing flux such as Easy-flo™ Flux Powder. It is free flowing and produces a smooth fillet. Stan-fos™ is brittle/not ductile and should therefore not be used in applications involving exposure to strong vibrations or impact loads. It is used primarily on copper to copper alloy joints.