Some of my 45s have had the die setscrew overtightened and the die hole is slightly stretched at the top. A small strip of .004" brass shim stock will center them up again with the top punch and help stop leaks. Something else that helps is a slightly thicker o-ring.

As for heat, I either use a heat gun (mostly for "jump starts"), a SMALL clamp-on spot lamp ($4 at Homeless Despot) and incandescent bulb, or for one of them I bought a slab of 5/8 x 4 x 14 aluminum from a member here and employed a steam iron that I, literally, found in the middle of the county road one day going to work as if the casting gods had put it there for me to find.

The magnetic block heater and a wall timer capable of handling the amperage may be the best idea yet. I suppose one could also hook it up through a PID controller, but that's more tinkering for tinkering's sake the way I see it.

Gear