Try he

http://www.budgetcastingsupply.com/

They sell inexpensive furnace controllers for just your application.


"David Anderson" wrote in message
t...
Can anyone point me in the right direction to find a schematic diagram for
automatic temperature control on a home made electric shop oven? Inside
furnace dimension about 6x6x6 inches plus premolded insulation. My heat
source is a discarded 1500-watt 230 volt spiral wound element from a
domestic stove. My cost = $0. I would like to operate at about 1000-deg
F for burnout on lost wax investment molds. The best control would be
ramp up to around 250-deg F and hold 30 minutes for the preliminary melt
out, then go up to 1000 deg for one hour final burnout. Furnace is
already constructed and works great on manual control using one type "K"
TC and a hand held readout, but of course this requires hands-on
attention. TIA Dave