Kiln Heat in Room -

Kiln Heat in Room

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Kiln Heat in Room

Postby lbailey » Wed Nov 14, 2012 11:12 am

Setting up the work space in our garage, preparing for the kiln arrival, arranging for the 220 breaker install, etc. In planning the location for the kiln (probably the Olympic 20"x20"x13.5" clamshell), I realized that I don't really know what to expect re: heat around the kiln and how much it may heat up the room. I understand that it needs to be placed away from walls about 12"-18" to be safe, but when it is running and closed what level of heat will it radiate into the room? The garage is about 20'x25' with 8' 8" ceiling and we are going to install heating and AC so need to know what effect the kiln may have on those systems.

I believe that a glass kiln will not typically generate fumes/smoke and many shops do not appear to have a hood or vent above the kiln. But if we open the kiln while hot for combing (one day) or open it to inspect the glass won't that release a big hot wave that rises? Wouldn't it be prudent to have some sort of hood or ceiling vent that moves this hot air out of the room?

Just trying to cover all the angles, thanks!

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Re: Kiln Heat in Room

Postby Judd » Wed Nov 14, 2012 1:21 pm

Not really. As long as you're a foot away from the wall, you should be fine. I'm not sure if your garage is sheetrock or cinder block. Just make sure flammable materials aren't too close. My studio is 10' x 15'. I use a bathroom air vent to pump out the heat, but it's more for creature comfort than necessity. I don't open my kiln though.

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Re: Kiln Heat in Room

Postby Jeanne » Wed Nov 14, 2012 2:58 pm

My studio is in a section of my basement (15' x 21' with an open rafter (no sheetrock) 8' ceiling). My largest kiln is a 25 x 41 coffin kiln. Radiant heat does escape when I'm running it and it does warm up the room. In the summer I'll open up the windows and I have a large fan hanging in front of it (I have an uninsulated, concrete block, walk-out basement). In the winter the kiln will bring the studio up to about 81 degrees which I, personally, have no problem with. You can stand right near the closed kiln when it's at 1500 without any problem. I have a thermostat in the studio and a heater/blower hooked up to my boiler. You would have to have a separate thermostat for your garage that would dictate whether your heat/a/c kicks on or not.
Last edited by Jeanne on Wed Nov 14, 2012 9:14 pm, edited 1 time in total.

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Re: Kiln Heat in Room

Postby Morganica » Wed Nov 14, 2012 3:03 pm

Will the kiln(s) heat the room? Yup. I can walk into the garage and know where the kiln is in the firing schedule by the warmth of the air. My kiln is well-insulated, but it's still putting out enough heat to warm up the room (especially while I'm venting). I have a couple of exposed pipes on an exterior garage wall not far from the kiln, and if it gets below 20F at night they're liable to freeze I make sure I've got a kiln at at least 800F on those nights--the pipe stays warm through the night. The flip side is that, in the summer, it can get awfully warm with the kilns firing.

Whether or not you need to exhaust the heat/outgassing from the kiln depends on what you're firing. I don't think you need to worry about it for normal fusing practices, but it's essential in casting, especially if you make larger pieces.

If you're casting with a lost wax process and have residual wax in a mold, you should exhaust the fumes from the burning wax, which are toxic. And even if you're not using lost wax, the extended drying period for most plaster/silica molds puts a lot of water vapor into the air. It must be vented out of the kiln (otherwise it can scum up the glass and damage the kiln). If that water vapor keeps escaping into the room, it'll eventually rust out every bit of exposed metal there, so it needs to be shunted to the outside.
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Re: Kiln Heat in Room

Postby Franzeska » Wed Nov 14, 2012 3:35 pm

We're in south Florida, so we were worried about kiln heat in our attached garage. We have an Olym. 18" square 13.5 " clamshell, a mite smaller than yours. Our garage is pretty hot to begin with, especially on a summer afternoon with the sun glaring into the garage from the west. We keep the garage door open when ramping up and most of the way down. We start in the morning, because we want to be awake when the kiln is at its hottest. We close the garage door when annealing, which is towards evening. While the kiln warms up the garage even more than the sun, it is surprisingly not excessive. The kiln is 12" away from a concrete block wall and we weren't worried about that. We were concerned about the wall between the garage and the house, which is drywall. We mounted a thermometer on the wall, which is about 7 feet way from the kiln. The temperature has not gone over 97 degrees at that distance, and that was in August. Of course, it is hotter in the immediate vicinity of the kiln, but not so hot that we are uncomfortable getting close to it. In fact, as newbies, we just had to peek in to see what's cooking. We wore insulating gloves (or we couldn't even touch the handles). We stood back, with arms extended for the initial opening - to get our faces and bodies away from the whoosh. Then we peeked quickly and shut it. No burns yet... Actually, with a few months under our belts, we don't feel the need to open it (unless we're trying something new).

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Re: Kiln Heat in Room

Postby lbailey » Wed Nov 14, 2012 8:53 pm

Thanks so much guys, this is all very helpful.

Franzeska, our garage sounds very much like yours, door facing West, sun baking the interior in the afternoon. (We are in SE Alabama.....)

I really want this space cooled and reasonably comfortable to work in during Summer months, so planning on a mini split heating/cooling unit. It will have it''s own thermostat in the garage and we'll adjust it separately as needed. We will wall in the garage door opening, insulate that wall and put a shade on any glass in the new (regular) door to manage the afternoon heat from the West

I just hope that a 1 or 1.5 ton mini split will be able to keep up with the ambient heat generated by the kiln, is that realistic?


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Re: Kiln Heat in Room

Postby dawnsud » Thu Nov 15, 2012 10:23 am

I took a low cost approach to venting. My husband built a small shelf under one of the windows in my studio. I can put a 8" Vornado fan on it and face it to the outside. It sucks the hot air out. In the winter, I have a panel that fits in the open window and cut a round hole in it. This keeps the cold air from coming in. I find that most of the smell of ThinFire and glues starts at about 600 degrees and lasts until 1000 degrees. I always use the fan during that part of the cycle to keep the smell from getting in the living room down the hall from the studio.
Take care.

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Re: Kiln Heat in Room

Postby Lauri Levanto » Thu Nov 15, 2012 1:48 pm

All the energy, in my case 8-12 kWh, turns to heat which at some point leaves thekiln and warms the room. It helps a little in the cold Scandinavian winter, but not enough.

Opening a hot kiln. Sure it delivers a hot blow enough to burn your eyelashes.
That is the short term effect. Be really careful!
The long term effect is easy to calculate. Your garage has a volume of 4000 cuft.
I assume your kiln has 4 cuft. Mixing 4 cuft 1000 deg air into 4000 cuft air rises the average temperature with one degree.

Morganica mentioned the fumes. Fiber paper smells nasty, water vapor does not but is a bit corrosive. I am more worries of some glues, f.ex. cyanoacrylate instant glue.
Worst of all i have a recent reason to warn about leaving a level in the kiln. That fills the room with really nasty and dangerous smoke. It was difficult to dive in the kiln room to turn the power off.

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Re: Kiln Heat in Room

Postby lbailey » Thu Nov 15, 2012 2:02 pm

All good input, thanks.

I'll try to post a pic of what I end up with but lots of prep work to do, so may be a while.

(Note to self, don't leave level or other tools in the kiln........) 8-[

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