Garage sales are good for finding the $2.00, "throw away", Mr. Coffee, or equivalent, makers with busted or missing coffee pots. Hack saw the plastic reservoir off. The remaining "hot plate" is 600w (some are 1000w), decent heat (idk temp), and certainly cheap for pre-heating a mold - but the coffee maker plate will NOT melt lead or lead alloy.
I pre-heat. Before casting set the mold bottom in the liquid alloy for 2-3 minutes. Turn the mold over and do half the time for the spru plate. Then cast. Works for me.