I've had several queries concerning my spot welder project. The below pics show a spot welder upgraded to include a weld timer and a power control.
The timer is just a timer relay set to tenths of a second. It is wired delay off and closes the power relay seen in pic 1. The switch on the spot welder itself is wired back to the timer. The power control is a pair of variacs (free from Pete) on a common shaft. the dial can be seen in pic 2
Thanks for all the help.
Karl