Built myself a resistance soldering rig, and it doesn't set itself on fire!
well chuffed!
the Transformer is a 10A multiple output jobbie (2V -12V) probably won't go beyond 6V though.
all the other bits are regular lab connectores, some of which I have had to modify to take the 4mm² wire.
the probe:
I used a pinvise, a useless soldering iron, and some 3.15mm pencillead
A closeup of said probe
the test setup, all wiring is 4mm²
All the bits awaiting a proper housing to make it look good, on the left is the steel plate I'll use as a ground plate (used steel so magnets can help with holding stuff)