just finished the experiments, and after lots of flying sparks, burning wire and melting plastic I managed to get some results :wink:

took some of the tips posted here and the end result looks good - to be honest, I'm really surprised by the strength of the weld, but having said that I did not try to break the weld yet.

started off with thin piece of wire



and locked it in place with a soldering iron along the joint



clamped it an connected it to a 6v battery (had to replace those thin leads as they stared smoking and melting in no time! A pair of jump leads did the job - they got a bit warm anyway!)



Close up of the seam



and finally a test - that's a solid block of steel weighing about 15kg, left it for 15min and didn't break... tried to shear it off with my hands - no good. But I think if I had to clamp it and hit it with a hammer it will give in...