[justanassembler]

Meg, on 06 March 2013 - 09:31 PM, said:

I'm not suggesting that it's a good idea- I know that it's not- but I DO leave my electric programmable kiln to fire over-night and shut itself down. I do worry about the possibility of losing my studio, but it's a separate old building, on a property 15 minutes from my home. It just doesn't work for me to stay. Mine is a Bartlett controller and you can program an alarm to go off at a particular temperature. I used to set up a baby-monitor next to the kiln and it would beep when I needed to go check. Great feature.

For the best repeatable results with a finicky glaze, you should watch the cones and shut it off yourself. But remember that the worst gases for your health are those that you cannot smell, at the end of a firing. Especially in a glaze firing if there are metals in your glaze. No matter what kind of ventilation you have, they're still there. Try not to hang out with a firing kiln any more than you absolutely have to.

Your bartlett controller also likely includes a feature that allows you to start your firing on a delay so that you can time it so you are present for the duration of the firing.

[Pres]

Arnold Howard, on 07 March 2013 - 10:26 AM, said:

OffCenter, on 07 March 2013 - 09:02 AM, said:

I went outside just in time to put out a fire in my kiln shed. Part of one wall was flaming and the ceiling was about to catch on fire. I put the fire out with the electrical fire extinguisher I keep near the kilns. (My electric kilns are in a shed that would probably cost less than $1,000 to replace.) Somehow the plug to this kiln had worked loose enough to expose a little of the plug prongs which caused an electrical arc that started the fire. Jim

I have heard of electrical fires that involved a kiln. But I have never heard of a fire caused by the heat from a properly installed kiln. If a kiln overfires, the elements eventually burn out, and the kiln then cools down. But the heat is contained within the kiln.

When the kiln is not in use, the lid should be kept closed. We also advise disconnecting the power.

Sincerely,

Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com

I am direct wired, so I always use the circuit breaker to cut all power to the unused kiln.

[neilestrick]

Arnold Howard, on 07 March 2013 - 09:26 AM, said:

I have heard of electrical fires that involved a kiln. But I have never heard of a fire caused by the heat from a properly installed kiln. If a kiln overfires, the elements eventually burn out, and the kiln then cools down. But the heat is contained within the kiln.

When the kiln is not in use, the lid should be kept closed. We also advise disconnecting the power.

Sincerely,

Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com

Ditto. Every fire I have heard of came from the wiring in the walls, the plug, or from something combustible being too close to the kiln. A properly installed kiln cannot melt down. Sticky relays are somewhat of an issue, but the odds of more than one sticking are extremely low. The only time I have seen a sticky relay cause overfiring was on a 18" tall kiln going to cone 06 where one of the two relays stuck. Even then it did not melt the clay, just made the glazes run a bunch. The most damage happens when the clay melts and flows into the bricks.

On a 27" tall, 3 relay kiln, if one relay sticks it will just prevent the kiln from cooling completely. It usually hangs out around 1400 degrees or less depending on the size of the kiln. If two relays from neighboring rings of the kiln stuck it could cause those areas of the kiln to overfire a bit if the shelves were tight, but not likely enough to puddle a cone 6 clay. I think at worst you would only ruin shelves. You're probably more likely to win the lottery than have 2 relays stick at the same time. Zone control comes in handy here because it's easy to see if a section is running hot, and once a section gets too hot you'll get an error code that will shut down the firing.

[Benzine]

Pres, on 06 March 2013 - 09:35 PM, said:

Benzine, on 06 March 2013 - 08:05 PM, said:

I set my classroom kiln to candle over night, and will leave during the cool down, but that's it. I know the odds of anything bad happening are pretty slim, but I don't want to be the teacher, that burns down half school......I'll leave that to the Chemistry or Industrial Tech teacher.

I did the same, many many a time. I made certain that nothing was around the kiln space, that the vent and blowers worked, and that the janitor knew I was candling on purpose. I even told him that if he noticed anything suspicious to not get near the kiln but shut it off at the breaker box, which I had well marked. Ceiling and walls in my basement room were industrial height, and made of concrete and brick.

That's exactly what I do. The area is cleared of combustible materials, and I give the custodial staff a heads up. I also have a program set on a delay, so it doesn't even start warming, until the middle of the night. By the time I get there in the morning, it's not hotter than an oven. Luckily, my kiln is wired directly into its own box, and none of the wiring is inside a wall. I do kill the box for the summer, though I could honestly do it more often. Another good point, is keeping the kiln lid closed, when not firing. I am terrible at this. I unload, and just leave the thing ajar. There's no reason I do so, other than the end of the term, when I turn around and refire. Time to make some changes!

[rebbylicious]

I use a cone sitter electric kiln and peek out in my garage to check on it every hour. I have left my house for 15 minutes to get my kids from their bus stop but thats it. When it shuts off I feel pretty safe to go run errands as it cools.