Diyspotwelder

Projects
Participants
Skills	Electronics, Metal- and woodworking, Soldering electronics programming
Status	Planning
Niche	Mechanics
Purpose	Infrastructure

Lately, hackaday et al. have been supplying a number of reviews/buildlogs of DIY spotwelders. They all seem to be based around taking a used/surplus microwave transformer and removing the secondary (highvoltage) core , replacing it with a few turns of thick copper-cable which instead take the power from the primary coil and turns it into low-voltage, high-power.

Current state: We've liberated a transformer from a microwave; removed the secondary coil with a hacksaw. Saved the 'shunts'. It's now stored on a shelf below the 'woodworking-tables', next to the 'printer parts box'.

Meanwhile, Justa has found a nice two-conduit cable, used for supplying -48V power to telco-equipment. They contain 2 conductors, both consisting of 5-6 solid-core copper wires normally used to supply 20A+ each. Total cable-length is around 2meters, supplying up to 4 meters of heavy-duty copper-cable, useful for secondary coil. On one side, the copper cable has been finished with a galvanized-metal ring-lug; possibly to be replaced with a set of 'copper offset clamps' which seem perfect for the job.

The plan:

• Start with a simple test-setup to check if everything works like it should
• Add proper welding-terminals and enclosure
• Make an assembly with spring-loaded clamping system
• Add timing and/or power-control to it
• Add a foot-pedal system to it to allow two-hand operation

References: https://www.youtube.com/watch?v=vrlvqib94xQ - Handheld spotwelder design http://www.instructables.com/id/How-to-Make-a-Spot-Welder-for-Cheap/ - Instrucable page belonging to video above.

https://www.youtube.com/watch?v=hTaGa93lOGU - How to modify the transformer http://hackaday.com/2014/07/21/spot-welder-dont-buy-it-build-it/ - the/a hackaday article.