I would try building one for the adventure and fun of it. I imagine it would be just another machine that I would use to build and repair other machines. I would like to be able to make custom enclosures for other DIY projects. Need to learn more about sheet metal work!
Theoretically seems to me spot welders are pretty simple machines. A big transformer, a power controller and some thick copper electrodes. But the devil is always in the detail! Based on cursory searches of Youtube the common spot welder DIY begins with a transformer from a junked old microwave oven. One build even uses two such transformers together. I'm still trying to wrap my head around how these things are rated for power. Dan Gelbart recommends machines in the 15 to 25 KVa range. As far as I can tell the PA welder is far lower than that.
years ago I spent (wasted) a bunch of time making one. Started with finding a set of arms in a lot purchase. hmmmm, I can make this....sometimes a project is friggn awesome, other times its a dud. This was a dud
The issue is getting enough current. A welder as a power supply is no good. You want like 1 volt and thousands of amps. I modified a sodium light ballast as a transformer and fed it 240V. I did get some spot welds; not super strong or in thicker material. It was a lot of work and delivered substandard performance unless on really thin stuff. Since I've picked up a used portable one and scrapped this one. The main issue I think was transformer saturation, not something I understand well enough to modify the core etc. Maybe you'd fair better.
A few pics....it has a bell crank link to a foot pedal that clamps the arms and starts the timer. thanks for the walk down memory lane...but really, just buy one lol.
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