Homemade Spot Welder

Step 4 Assembly

A second piece of narrow plywood was required to extend the base for the electrical components. Being the first time I have attempted to make a spot welder I had to improvise on a few things. I would have chosen a longer piece if I had been able to see that far ahead.

I added an 8 gauge copper wire from a clean source as the copper on the pipes was quite tarnished at least on the outside. I forced the secondary wire into each of the tubes and wrapped the 8 gauge wire around the remaining exposed copper on the secondary wire. A pair of vice grips and channel locks crimped the tubes closed as tight as my hands would allow. Note: the 8 gauge wire runs up to the bolts at the front.

I had read a fair amount about spot welders prior to starting but I could never quite figure out the timer and custom power supplies. I had also heard talk of MOTs having power factor issues as well. I decided to just forge ahead and put a light switch on it. The switch is rated for 15A so I figured I couldn't go wrong. I put a red and black dot on the switch for quick reference. The box also provides a good (safe) place to connect the plug and all the wires.