I'm having a bit of trouble picturing your current troubles, but I've thrown in some possibly useful idea starters below.
I am electrical engineer and I have some experience on various systems. Therefore I'm little apprehensive when I push componenets beyond their intended use. The way low voltage circuit works on resistance spot welding machine is simple on most of the aspects, but there was very little at the university that prepared me to work few volts and thousands of amps...
Right now I'm consentrating on a bit that connects secondary coil conductor on the stationary and moving electrode holder.
The conductor has very fine multistrand braid, about 35mm2, should be fine for short pulse of 1100A.
Electrode holder is 20 mm pure copper bar used on electrical cabinet construction.
This piece has two functions:
1) To connect tranny secondary to electrode holder with minimal resistance, this is not one time operation, but must allow mechanical adjustment.
2) Mechanical: Attach mechanically bar to arm.
This is a small part, maximum linear dimenssion 40 mm, 20 mm hole trough it.
Have you checked your local building store for a solid copper grounding rod? No idea of the alloy or quality but you'd hope it would conduct well considering the application. Maybe you guys use something different there?
Here copper grounding rodds are steel core, copper cladding.
Near the grounding rods you should also find heavy grounding cable. Here it's used for grounding 100A and 200A electrical services. It's not the most flexible stuff to work with but if you're considering bus bars already then flexibility doesn't seem a big concern. You can put them in parallel if you need something with even less resistance.
Yesh. We have that type cable too, often consumer grade is 16mm2, not sure of it's composition.
Do you or any of your friends have a furnace that's hot enough to melt copper? The melting point is almost double that of aluminum, but not outside the realm of home foundry setup. Scrounge whatever small pieces of copper you can (plumbing, electrical, whatever) and cast your own large block whatever size you need.
I'm trying to avoid printtin or castig at this point. Too much to swalow at this point - would set me back months instead of weeks :lol