Kilns, Build or Buy

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- R. Weisbloom
  
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posted
20 years ago

Sat, Aug 9, 2003 9:27 PM

I am planning on getting at least 2 kilns. One for my studio here in Canada and the other for my Studio in Israel. I do stained glass, fused glass and slumping. I am considering trying my hand at beads, lamp working. The questions are: Does anyone know where I can get plans to build an electric kiln? I'll need one for North American current 110V and one for European 220V. As for size, I'd like to make it as large as possible, As Portney's Law always seems to come into play. No matter how large, it is never large enough. Do people think it is feasible, cost effective and safe to go this route or should I buy my Kilns? Any help would be greatly appreciated. Thanks, Robert Weisbloom, snipped-for-privacy@sympatico.ca

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- Henry Halem
  
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posted
20 years ago

Sun, Aug 10, 2003 5:09 PM

Why do you want 110 for the US and 220 for Israel. We have 220. You will have problems with 110 as it cannot deliver the watts needed to build a kiln of any dimension. You calculate the size of the oven by the watts that are available at the location where the oven will be and the maximum temperature of the oven. Ohms law will calculate the watts for you as you will know the power available when you check the breaker that will be dedicated to your oven. Volts X Amps = watts. Here is a general calculation to determine the power needed for an annealing oven after determining the dimensions of the oven. (2-2.5 W/in2) You calculate the square inches of all the internal surfaces of the oven. Obviously the higher number (2.5) will give you a faster oven. Example: an oven with a dimension of 24 in. long x 18 in. wide x 10 in. deep calculates to 1704 sq. inches of surface. 1704 times 2.5 watts per sq. in. = 4260 watts which calculates to 20 amps at 220 volts. Hopefully I've done the math correctly. If you are on a 20 amp breaker you will eventually have problems if you wind your elements to draw a full 20 amps as resistance decreases as the elements age so the rule of thumb is to wind your elements to 80 percent of available power. Have fun.

R. Weisbloom

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- nJb
  
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posted
20 years ago

Sun, Aug 10, 2003 9:13 PM

I've worked maintaining furnaces in the metals and petrochemical industries for over 30 years.

These books:

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this site:

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have more info than you will need. I am now building my third kiln,second (and third)glory hole, and second (and third)crucible furnace.The first attempts all work exceptionally well. If you decide to buildyour own make use of the knowledge offered by the above sources.