FORT LAUDERDALE, Fla. — Uniweld’s UNI-4300 Soft Solder Kit is designed to simplify the process of joining dissimilar metals, enabling HVAC technicians to join them with low heat, minimizing the possibility of melting the base metal, such as aluminum. The company’s UNI-4300 instructional video demonstrates one of the methods used to join an aluminum tube to a copper tube. The instructional video is available in both English and Spanish.

HVAC technicians many times have difficulty joining dissimilar metals like aluminum to copper, aluminum to brass, or copper to brass. This comes about due to the low melting property of aluminum itself, 1,218°F, and the application temperature of the most common and economical aluminum brazing alloys, which can have application temperatures of close to 1,000°. This leaves very little margin for error when heating the aluminum metal, and simultaneously, trying to achieve the appropriate application temperature of the brazing alloy.

To solve this problem, the low application temperature of UNI-4300 of 500° provides ample margin for working with aluminum. UNI-4300 also has the added value that it provides a very high tensile strength of 20,000 pounds. The kit comes with a 10-foot coil of soft solder, a 2-ounce bottle of flux, and a flux applicator with a metal tip. The flux applicator makes it easier to reach tight spots and the metal tip allows you to apply flux to preheated tubing without melting the tip.

Uniweld Products is a leading manufacturer of tools for the HVACR industry as well as oxy/fuel welding and cutting equipment and accessories. For more information, visit

Publication date: 1/29/2016

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