Soldering Flux Overview

Soldering is a process whereby similar or dissimilar metals are joined using a soldering alloy that typically includes tin combined with silver, lead, copper, antimony, bismuth, indium or other alloys.  Increasingly, lead-free solders are specified for soldering applications. Soldering covers a temperature range of 140 – 850°F / 60 – 445°C.

Flux is used to clean the base or surface metals of oxides before and during the soldering process. Each flux has an activator package that start working at different temperatures, depending on its application. No matter the form – liquid or paste or powder – flux cleans the metals chemically. Without flux, the joint will fail to make a solid connection with the filler and base metals.

During soldering, the flux follows several steps. First, it cleans off existing oxides from the surface to make way for the filler alloy. Next, the flux protects the surfaces to prevent further oxidation of the metals. The filler alloy can now smoothly flow onto the prepared surfaces. After the solder joint is cooled enough to be moved, the flux should be removed according to the spec sheet. Or course, no-clean fluxes are designed to be able to skip this step by being strong to clean and with low enough residues leave on afterwards.

Superior Flux offers three categories of soldering flux, Industrial Soldering Flux, Aluminum Soldering Flux and Electronics Soldering Flux.
Our most popular soldering flux is Superior No. 30 Supersafe™ Soldering Flux.

Learn more about our RubyFluid Flux line.

Aluminum Soldering Flux

Superior Flux is pleased to present the following flux solutions for aluminum soldering:

For other areas of metal joining, please review our wide selection of Aluminum Flux, Brazing Flux, and Welding Flux.