KappZapp™ - Silver Solders for Stainless Steel to Stainless Steel and Copper

KappZapp™ solders produce strong and ductile joints on Copper and Stainless Steel. The resulting joints have high tolerance to vibration and stress, with tensile strengths to 33,000 psi on Stainless. KappZapp7™ - 93% Tin - 7% Silver is the best Stainless-to-Copper solder available, with high conductivity, ductility and strength.

Kapp Comet™ Flux is designed specifically to remove the difficult oxide layer on Stainless Steel to allow a strong metallic bond on soldering Stainless Steel and Copper.

KappZapp™ Acid-cored Solders are used in structural applications on Stainless Steel and Copper.

KappFree™ Acid-cored Solder is used in potable water applications on Stainless Steel and Copper

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Benefits and Uses

Low melting temperatures prevent loss of properties and minimize distortion on thin wires and sheets. KappZapp™ Tin-Silver alloys are used for electronics, fabrication, ducting, food containers, storage bins, instruments, Copper plumbing pipe, and cooling coils for refrigerators. In many instances, a stronger overall assembly exists after joining with KappZapp™ Tin-Silver solder than with higher temperature Silver brazing alloys.

The most popular of the low temperature Silver bearing solders are KappZapp3.5™ -96.5% Tin, 3.5% Silver and KappZapp4™ - 96% Tin, 4% Silver. The KappZapp4™ - 4% Silver formula is often preferred for hand soldering Stainless and Copper parts. It has a wider slushy or plastic range to allow users to manipulate parts during cooling.

Kapp Alloy also produces Tin-Silver solders with up to 7% Silver for applications requiring a higher temperature range and/or higher Silver content for superior strength and vibration resistance.

The following chart represents Kapp Alloy’s standard Tin-Silver alloys. 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.

Composition							Temperature
Sn	Zn	Pb	Cd	Ag	Cu	Sb	C°	F°	RFQ	Wire	Ribbon	1/8"x18"	Handy Vials	Acid Core	Rosin Core
96.5				3.5			221-221	430-430	137	X	X	X	X	X	X
96				4			221-246	430-475	138	X	X	X	X
95				5			221-254	430-490	139	X	X	X	X
94				6			221-279	430-535	140	X	X	X	X		X
93				7			221-302	430-575	141	X		X	X		X
Sn=Tin, Zn=Zinc, Pb=Lead, Cd=Cadmium, Ag=Silver, Cu=Copper, Sb=Antimony

Physical Properties & Technical Data
Composition	96.5Sn - 3.5Ag	96Sn - 4Ag	95Sn - 5Ag	94Sn - 6Ag	93Sn - 7Ag
Solidus(°F) /(°C)	430°F / 221°C	430°F / 221°C	430°F / 221°C	430°F / 221°C	430°F / 221°C
Liquidus(°F) /(°C)	430°F / 221°C	475°F / 246°C	490°F / 254°C	535°F / 279°C	570°F / 299°C
Tensile Strength (copper)	14,000 psi	14,000 psi	15,000 psi	15,000 psi	15,500 psi
Tensile Strength (stainless)	25,000 psi	28,000 psi	29,000 psi	30,000 psi	31,000 psi
Shear Strength	11,600 psi	12,000 psi	13,000 psi	13,500 psi	14,000 psi
Elongation	48%	49%	49%	49%	49%
Electrical Conductivity (%IACS)	16.4	16.5	16.6	17.1	20.1

All KappZapp™ solid solders are available in bar or wire form. Custom alloys and forms are our specialty.

KappZapp3.5A™ Acid-cored Solder is used in structural applications on Stainless Steel and Copper. This is the same eutectic formulation as KappZapp3.5, but with a 3% Acid core. The flux residue can be removed with warm water or alcohol and a clean rag.

KappFreeA™ Acid-cored Tin-Copper-Silver Solder is used in potable water systems for Stainless Steel to Stainless Steel and Copper. This solder meets ASTM and NSF requirements for Lead-free potable water system soldering. The flux residue can be removed with warm water and a clean rag or simply by flushing with water.