Jaeger Jaeger @sprite's_grove.com writes:

Hmmmm.... I wonder how hard it would be to design a Homebuilt power
supply for a Resistance welding rig?

Quite a few people have made spot welders by using the transformers
from a pair of microwave ovens... I don't have the URL for the
dropbox handy, but I think I saw a very nice example of one of these
power supplies there.