After perusing posts about the Gingery furnace and visiting'%20Bertha.shtmlI have bought myself a nice little thermocouple and controller kit on e-bay with the intention of constructing a small tempering and annealing furnace and maybe doing some enameling. Nothing so ambitious as a melting furnace for metal casting.
Anyhow, the question of what to use as a heating element arises. Where does one buy suitable heating coils, and how do you calculate how much you need with respect to the volume of the furnace? Would a stove element do? Or some other clever substitute for expensive purpose built oven elements? I have both 115 and 240 volts available at up to50 amps.