KappZappR™ - Rosin-Flux Cored Silver Solders for Stainless-Steel-to-Stainless-Steel-and-Copper in Electrical/Electronic Applications

KappZappR™ solders contain a central core of Rosin soldering flux to break the oxide, layer the parts, and promote a strong metallic bond between the solder and parts. Rosin is a naturally occurring, mild acid derived from pine trees. The Rosin core is designed specifically for soldering Stainless Steel and Copper parts in electrical and electronic components. The resulting joints have high tolerance to vibration and stress, with tensile strengths to 33,000 psi on Stainless. The flux residue can be is removed with warm water or alcohol and a clean rag.


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Benefits and Uses

KappZappR™ Rosin-cored solders are used in electrical/electronic applications on Stainless Steel and Copper. For example, KappZapp3.5R is used in soldering Copper leads to Stainless Steel heating elements in fluid heating systems. The Rosin flux breaks the oxide layers on the parts, without creating the acidic residues common with stronger acidic fluxes. These stronger acidic residues can shorten the life of soldered Copper and Stainless Steel joints.

Low melting temperatures prevent loss of properties and minimize distortion on thin parts and sheets. KappZappR™ Tin-Silver alloys are used for fabrication, electrical and electronic connections, Copper plumbing pipe, and cooling coils for refrigerators. In many instances, a stronger overall assembly exists after joining with KappZappR™ Tin-Silver solder than with higher temperature Silver brazing alloys.

This alloy and flux are Food and Potable Water Safe.

The most popular of the low temperature Silver bearing rosin-core solders is the 430°F (221°C) eutectic solder KappZapp3.5R™ - 96.5% Tin, 3.5% Silver with a 3% Rosin-Core. This alloy minimizes heating of delicate parts, while producing a strong conductive bond. Kapp Alloy also produces KappZapp7R™ - 93% Tin, 7% Silver with a 3% Rosin-Core for applications requiring a higher temperature range and/or higher Silver content for superior strength, vibration resistance and conductivity.

The following chart illustrates the properties of KappZappR™ soldered joints. Many factors, such as materials, temperature, and method of application determine the solder joint strength and characteristics. Call Kapp for engineering assistance to discuss your specific needs. We recommend testing appropriate alloys in your specific application to ensure suitability. Samples of Kapp alloys are always available upon request.

Physical Properties & Technical Data
Composition 96.5Sn - 3.5Ag 93Sn - 7Ag
Solidus(°F) /(°C) 430°F / 221°C 430°F / 221°C
Liquidus(°F) /(°C) 430°F / 221°C 570°F / 299°C
Tensile Strength (copper) 14,000 psi 15,500 psi
Tensile Strength (stainless) 25,000 psi 31,000 psi
Shear Strength 11,600 psi 14,000 psi
Elongation 48% 49%
Electrical Conductivity (%IACS) 16.4 20.1