Matthew Borgatti, a designer and engineer, decided to create a spot welder using parts from a microwave that would otherwise be taken to the dump, amongst other items he put together. With a bit of ingenuity, and keeping space in mind, he was able to create a spot welder that is practical and compact.
Why a spot welder? Borgatti explains:
Spot welders are great for making sheet metal enclosures, building wire structures, attaching threaded fasteners permanently to metal forms, and tacking things together for more industrial welding later.
From researching various tutorials, Borgatti doesn’t cover every single lasting detail, but does include supplemental materials used and documentation of his build.
At the core, he opened up a microwave he found on a sidewalk, tore apart the transformer and used thick cable to rewind it; this allowed him to turn the high voltage low current supply to a low voltage high current supply—a perfect environment for welding.
He also laser cut the enclosure and arms of the spot welder, and rigged a timing circuit from a rotary potentiometer and Arduino to keep welds uniform. That’s not all, Borgatti even built a trigger mechanism, allowing him to spot weld multiple items quickly.
Needless to say, this project is impressive, but is also a dangerous one dealing with high amps, temps, and AC power. Thus, build it at your own risk. Thankfully you can check out Borgatti’s project documentation from Thingiverse.
