So that one evening me and Samu decided to build a capacitive spot welder from scraps.
safety first (in case the caps blow up on fast discharge aka shorting).
A nice audio transformer
The resistors are to limit the current for charging.
Pulse duration and stuff was done on a Jockiboard and as high amp drivers we used some (maybe 3 in parallel) mosfets (hexfets) from old motherboards.
Some testing:
(thin metal)
(tea light aluminum cups)
We never got around to finishing the spot welder … but who knows maybe someday.