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Explosion In The Kiln And Firing In Winter


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Hi all,  I have a two questions.  First, I had a blow up on an undertpainted piece that I was bisquing.  I cleaned out what I could but how you are supposed to clean out whatever falls into the grooves where the elements sit??? One little piece got stuck under the element.  I couldn't get it out, couldn't get the element out to remove the piece either but I fired it to cone 6 anyway and it seemed to fire fine.  Still, I want that piece out. Already tried vacuuming. Someone at paragon suggested I pick it up and turn it over.  It's too heavy. 

 

Second question, on how cold of a day is safe to fire?  I ask because i fired yesterday and this morning the kiln was at 185, it's usually hotter the next morning. I'm sure it's because it was a little chilly last last.   I don't want things to cool down to fast and blow up.  I have a small paragon XL with a controller if that helps.  Thanks :)

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turn off the power and try digging it out with a needle tool. maybe you can lift the element a little, but don't force. Try tweezers. 

 

I have fired in very cold weather. My kilns were outside, protected on 3 sides and had a roof. This was in Montana. The ambient (outdoor air) even in Montana

won't bother the kiln unless there is moisture condensed somewhere or in the pots. I have often fired at temperatures below freezing.

But best to go slow. You may want to soak at 200F if the clay could possibly be frozen before starting.

 

Marcia

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Hey,

Concerning the spalling a.k.a explosions any moisture becomes steam at 212 degrees at sea level. Moisture/water expand 17 times its volumn when turning to steam. I've seen the bottom of a vessel blow out leaving the rest intact...so there are a couple of things I do to prevent that.

 

1. I might trim more than usual, including a foot.

2. When the kiln temperature rises to around 210 degrees, I sometimes shut it off for an hour..then restart.

3. Sprinkle crushed bisque under neath the pot in question allowing moisture to escape. It takes trapped moisture longer to evaporate when the bottom of the vessel is sealed against the floor of the kiln.

 

Sometimes I place a piece of glass near the top spy port to see if it fogs up from steam.

 

I might apply one of these once or twice a year, whenever I think there's a chance of an impending disaster looming over a vessel in the kiln.

 

See ya,

Alabama

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Hey,

Concerning the spalling a.k.a explosions any moisture becomes steam at 212 degrees at sea level. Moisture/water expand 17 times its volumn when turning to steam.

 

 

 

Water actually expands 1600 times its volume when turning to steam.

 

Cold weather is only an issue if you have a digital controller. They'll usually work fine  a bit below freezing, but they can't read below 0 degrees F. If it's behaving oddly due to the cold, simply put a small space heater near it for a while before turning it on. Once the kiln gets hot enough it will keep itself warm.

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Thanks everyone all very helpful tips. It never gets that cold here so I should be good.

 

Can't get that piece out though, I have tried everything. it's wedged under the element and the element is kind of jammed in where it connects to the panel, I think I'd have to break it to remove it.  The plan now is to fire it until it burns out then just rip it out and replace it.  I can't think of anything else.

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Thanks everyone all very helpful tips. It never gets that cold here so I should be good.

 

Can't get that piece out though, I have tried everything. it's wedged under the element and the element is kind of jammed in where it connects to the panel, I think I'd have to break it to remove it.  The plan now is to fire it until it burns out then just rip it out and replace it.  I can't think of anything else.

 

Next time just get what you can with a shop vac. If it isn't going to easily come out, there is little sense in possibly damaging the elements while removing it.

 

Thicker/wetter pieces can be place upside down or near the edges. I have only seen pieces explode on the bottom shelf and the center of middle shelves.

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