Spot welding is a process by which the surfaces of two metallic pieces are joined together through heating. The heat that melts the surfaces is generated by an electrical current. Copper is a highly conductive metal, often used as the metal of the conducting electrode ends of spot welders, complicating the process of spot welding it. Spot welding copper requires special electrodes and brazing paste in order to achieve the same sturdy welding job that can be more easily achieved with metals such as steel.
Things You'll Need
Molybdenum or tungsten faced electrodes
Apply brazing paste in between the two points to which you will apply the electrodes of the spot welder.
Lower the electrodes of your spot welder and pinch the two pieces of copper you will spot weld.
Activate your spot welder for quick bursts, turning the welder off and removing the electrodes after each burst.
Molybdenum and tungsten faced electrodes conduct electricity at a slower rate than typical electrodes such as copper alloy, essential for spot welding a extremely conductive material such as a copper.
Brazing paste contains metal alloys that melt faster than base metal and which form connections between surfaces when it cools.
Because copper is so conductive, letting the spot welder discharge for longer lengths of time could cause the entire inner surfaces of the two pieces to melt and weld together.