sapre:
Nne thing i did struggle with was measuring the resistance with the multimeter. Everything i measured (primary, secondary coils and a piece of thick wire) seemed to give the same reading of 0.5 ohm! i believe that DMMs are not very accurate at low resistance, so assume that this was the problem.
Correct, they are not good at really low resistances. Did you also measure the resistance of the work piece you are trying to weld?
Good news is that the spot welder is working well. other good news is that i learnt a thing or two along the way!
Good! 