DIY Spot Welder from Re-Purposed Microwave Oven Transformer

[Mark Presling]

Scotsman Hosie,
I was keen to do some more development of the laminated secondary coil and I had a lot more strips of copper that I could have added but at the end of the day the final version with the 00B&S wire turned out to be suitable for what I wanted. That's interesting regarding the surface effect. The original spotwelder made by Aston had used copper shim as the laminations in the secondary. The shim would have only been a few thou thick. I had a assumed this was to make it more flexible where it joined directly to the moving electrode arm. Unfortunately I couldn't dismantle it to see if it was formed in a loop rather than just a U shape.
Regards,
Mark