Where I am currently casting I cannot run my diesel burner, fire ban and neighbours close by. I have had a fair amount of success by placing a 6” electric stove element in the bottom of it, placing my steel crucible directly on it, and wiring the leads of the element straight to a cable with 220vlt. I don’t recommend this, very risky, I do have the whole set up properly grounded and tied into a 15amp breaker. Problem is the element runs “wide open throttle” until the melt is done, or until it burns out. The elements have been burning out after a half dozens melts, about 12hours run time. I have a PID that I can use to control the temperature which I hope will extend the life of the element. My question is where is the best placement for the probe? I was thinking near the bottom of the crucible.....
Think you should just accept that's about all you can expect of a stove element in that service. Even melting aluminum the furnace temp needs to be a few hundred degrees hotter than the aluminum and stove elements just won't take it. The element probably isn't in run away heat condition anyway if your crucible is sitting on it because it conducts enough heat away from the element. You should consider making yourself a small purpose built resistive electric furnace (aka kiln) with a Kanthal or NiCr element. They are easy to build and several of us here have and use them regularly. There are several detailed build threads here on the forum. I really like mine. Although it likely has bronze capability, I just use it for aluminum. I have my k-type probe in the top center of the furnace lid and it is PiD controlled and set to 1800F, but on the first melt (maybe never if you are just melting) you will find there is no need for active control because the thermal mass of the crucible and metal cool the furnace and cause the metal melt temp to lag the furnace temp by 200-300F and pour temperature is reached before the furnace ever hits the set point. The only way you'll ever encounter a runaway temp situation with a coiled element in this duty is to have a very small gap between the crucible and the wall housing the coiled element. Best, Kelly
Or a propane furnace. They get around a lot of legal nonsense. Build a gravel setup around your furnace and remove all combustibles then invite the fire department guys over to inspect it and ask their approval or for permit and then you're set. Thats what I did a few years back.
