Soldering/Brazing

Soldering and brazing are similar in that a third material is added to form the joint.  Soldering and brazing are perhaps the oldest known welding processes used by humans, possibly because of their simplicity.  All you need is a heat source and a filler metal; you do not need focused laser light, flowing electrons, or ultrasonic vibrations - all recent inventions.

Quite often, soldering and brazing are distinguished by the melting point of the filler metal.  Typically, filler melting below 400C are considered solders and those above are considered brazes.  There are additional metallurgical differences as well that can play an important role in evaluating the joints.

Of all the joining processes, soldering/brazing offer the widest variety of heat sources that can be used.  Most common for manual soldering is the soldering iron; hydrogen torch is an option.  Others soldering processes, typically used for automated soldering include reflow ovens, wave soldering, and induction soldering.  Newer technologies that are now vying for attention include white-light (or laser light) soldering and ultrasonic soldering.  White-light soldering is similar to laser welding in that an intense beam of light is used to melt the solder.  Ultrasonic soldering uses ultrasonic energy (delivered through the soldering iron or through a solder pot) to remove the oxides on the surface and allow the laser to form a bond.  Ultrasonic soldering has been shown to work even with aluminum without using a flux.  Soldering is commonly used to form bonds where one of the main functions of the bond is to conduct electricity.

Brazing is typically used to form a structural bond.  Common heat sources are brazing torches and furnaces.  Typical issues with soldering/brazing are:

1.  Part design and materials

2.  Surface condition and plating

3.  Production volume

If you need help with any aspect of the soldering/brazing process, please contact us for more details.