Wednesday, September 29, 2010

Kilns in Freezing Temps

My student just purchased an electric kiln that she'll keep in her tobacco barn. The kiln manual reccommends that you don't fire it in temperatures below freezing. Any one have any idea why? I know I've fired electric kilns in freezing temps plenty of times.

6 comments:

Sue said...

I've had experiences where due to extreme cold weather - the whole electrical system (ie Progress Energy or whomever) has such high demand that the kiln will not correctly fire the glazes even though you reach temperature and then it will certainly cool faster than normal. (I think it was explained as something like a brown-out on the power grid).I choose not to fire (bisque or glaze) during the days/nights when it has been an extensive period of below freezing weather such as last December. For what that's worth - hope it helps. -Sue

Lynda Gayle said...

It might also cause more wear and tear on the coils to heat up from such a cold temp. And like our computers at home, the kiln computer might incur problems working right in extreme hot or cold temps. Here's to hoping for a milder winter this year so we can fire more days and better build up our inventories!

Lee Love said...

Got me stumped. The normal seasonal differences in temp are so small when you compare it to the temperature variation of the kiln under normal use. I suppose, the least you might have to do is warm up the controller before you turned the kiln on. Could do that s hair dryer or directional heater or even heating tape.

Bill said...

A manual kiln will probably be fine in below freezing weather. If the kiln has a programmable controller, then there may be an issue. The chip in the controller has temperature limitation ranges, usually 32F - 120F.
A small portable heater might be needed at start of a firing in below freezing temps until the kiln heats up enough to provide the controller warmer temps. The opposite is true in hot weather, when a small fan may be needed to cool down the controller.
Bill Schran

carole epp said...

Living in cold cold Saskatchewan, Canada I've had to deal with this. I have a programmable skutt and talked to skutt about this when i had it set up in an uninsulated garage at my inlaws. Temperatures here can be down well into the negative 40's celcius for weeks at a time and there is no option to wait for warmer temps. I was told that this is an issue for the programmable kilns because of the electronics. It doesn't have to do the elements but rather the computer sending the message to the elements. It's a moisture issue. If there is any moisture then it can fry the computer. I was told to bring the temperature of the kiln to +10 celcius before turning it on. I would leave the breaker switch off when not using it. I used a radiant heater rather than a forced air heater as this does a better job of heating the object. At really cold temperatures this would sometimes take 2 hours to have the control panel box reach +10 but i never had any problems with my firings. The elements aren't impacted as far as I know since it's really not a big temperature difference from -40 to say +10 (feels like it to a human though!) I haven't had to replace elements any sooner than if i wasn't firing in cold conditions.
Hope that helps.

Sue said...

Hi again - I only have manual kilns and had the below freezing temperature (around 4 F as the low for a period of time - when living near Columbia, SC) affect glaze results. I agree that it will affect a computer controlled kiln as discussed - but it goes beyond the kiln & controller or sitter.