Folks,
I want to modify my furnace from Propane to electricity.
First question: can standard incoloy elements handle the temperatures required? I suppose 1200 deg F to be safe?
They are comparatively cheap and can be custom made to fit the furnace.
Second question: Approx what power am I looking at? Inner dimensions with lid on is: dia 8 inches , height 10 inches. Wall thickness 4 inches. I guesstimate 2 kw will do.
Third question: How do I do the temp control cheaply?
...
There's a Gingery book on how to build an electric AL smelter from scrap. It should answer all these questions and more. Get it from Lindsay Books. IIRC, the cost was like $4
Karl
or just buy a 2nd hand pottery kiln. a cone 10 will go up to 2300f. you could then use it to make your own ceramic vessel to contain the metal.
My oven is bigger than yours I use a clothes dryer element and it will reach 2000.deg using 120volts. Take an ohm meter and cut the lenth of the coil down untill it reads
6.5 ohms. the coil will be about 5 to 6 feet long .so you may have trouble fitting them inside your oven.
I have had reasonable success with a homemade temperature control by making a strip of metal that is made of two different metals with differing coefficients of expansion. One end is secured ant the other end is free to swing at the temperature changes. Mount a contact nea rthe swinging end and let it control a power relay.
A salvaged electric cooktop controller works pretty well. It's a proportional controller, i.e., the higher you set it, the more the current is "on" in comparison to the total on-off cycle. You have to experiment a bit to achieve a certain temperature, as they are not thermostats. These are 240v units. Old cooktops are easy to find, and when you snag one, you get a controller and 3 spares.
Gary Brady Austin, TX
To attach to them - use screw clamps. Solder won't stay cold ! Besides it is hard to solder to these anyway.
How about oven or stovetop calrad burners ? 120 / 220.
Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder
tim wrote:
Good idea, Jerry! What might not be apparent is that the thermostat you have specified does not have to be in the hottest part of the oven. It could be "proximity" calibrated to gauge and control the oven temperature by mounting it at some distance from the inside of the oven, say, in a probe that communicates with the inside.
I suppose.. I don't know what incoloy is in regards to heating elements. Typical alloy used is called nichrome.
3" wall will do. If possible, go with 1-2" light insulating brick or castable refractory, then wrap that with an inch or so of kaowool or similar product. And if you really want to go over the top, slather on some ITC-100!You don't. I mean you don't bother at all: why run your elements at anything less than full power when you need all that heat in the pot to melt the metal? People who build electric furnaces say "I always leave it at max anyway". Even then, a melt takes a few hours, which does give you time to ram a mold.
Tim
-- Deep Fryer: a very philosophical monk. Website:
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