Replaced the 250 watt aquarium heater with a light bulb. Not sure on the wattage will have to check. Soldered to the button on the bottom of the bulb and wrapped 12ga solid copper wire to the threads and soldered to the wire. The metal threads would not take solder. Dipped the base of the bulb in plati dip to insulate and water proof. This will eventually be used in a paint locker and not immersed in water.
The wattage seems to be a good match. Pattern is nearly at sine wave at freezing. Outdoor temperature on the right side of the graph is over 60F. The right hand gauge and graph below it are from a sensor sitting in the shop window.
The furnace is drying on a shelf in my office. Has about a week to go air drying.
Looks a bit pocky but should be ok. Need to look for an electric knife at the thrift store to make a vibrator probe to settle the refractory. But the consistency I am using now maybe too stiff for that to work. Something else to play with.
Need to figure out something small I to centrifigual cast in brass.
