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clayshapes

drying ware on top of the kiln

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clayshapes    9

The other day I had some pieces drying in my kiln room - and decided to place some on the lid of the kiln, which was on for a bisque firing. These were small pinch pots that I'd made to do glaze tests on, so I wasn't terribly concerned if something happened to them - it was an experiment.

They dried quickly, of course, and when I fried them a few days later on a fast bisque setting, there was no problem.

I'm wondering though if this is something others do? The reason I did this is because I wanted to see if it would dry more evenly -- the bottom is always the last to dry and there's always the risk of cracking on the rim when I dry pieces in my normal way.

Is it dangerous to dry pieces so quickly on top of the kiln while it is firing? (this was early stage of the firing -- the temp inside the kiln was below 1200F at that point). I remember seeing something here about someone doing this -- I recall cringing at the time -- thinking it was NOT a wise idea to dry pieces so quickly.

Thoughts?

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OffCenter    82

Depends on how wet and how hot. Too wet and too hot can result in blowing up the pot just like in the kiln. Put a kiln shelf on top of the kiln because that will spread the weight out to the edges. Kiln tops aren't made to support much weight. Also this helps graduate the heating of the pot.

 

Jim

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Mark C.    1,798

(thinking it was NOT a wise idea to dry pieces so quickly.

Thoughts?

You can dry things as fast as they can take it-any faster they crack or blow up-This is how you learn what the limits are-not by a book or teacher but by doing.

Pots can usually take a quick dry if they are small or even walls or without handles-even with these things they can be dried faster than most think.The clay body will really make a difference in fast dry as well.

As noted above spread the weight out so lid of kiln does not sag in middle or put them on the edge.

Mark

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yedrow    8

I've dried pots on the top of the kiln quite a bit. I don't think it should be a habit, but if you need to you can. I like to wait until the pot is no longer shrinking. If the "water of plasticity" is still present the more dry part can deform the wetter part and when the wetter part catches up it can introduces cracks into your piece. Once the water of plasticity is gone, generally speaking, you can pretty much dry it as fast as you want. Otherwise, it is best to quickly dry a pot within an envelope of even humidity, slowly pulling the water out of the atmosphere.

 

When you sit them on a kiln that isn't too hot, the thicker bottom will dry faster than it normally does, sometimes more evenly relative to the thinner top.

 

 

Joel.

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Pres    896

I've dried pots on the top of the kiln quite a bit. I don't think it should be a habit, but if you need to you can. I like to wait until the pot is no longer shrinking. If the "water of plasticity" is still present the more dry part can deform the wetter part and when the wetter part catches up it can introduces cracks into your piece. Once the water of plasticity is gone, generally speaking, you can pretty much dry it as fast as you want. Otherwise, it is best to quickly dry a pot within an envelope of even humidity, slowly pulling the water out of the atmosphere.

 

When you sit them on a kiln that isn't too hot, the thicker bottom will dry faster than it normally does, sometimes more evenly relative to the thinner top.

 

 

Joel.

 

 

I have a sectional kiln that I no longer use the hinges. The lid is lifted on and off, as needed. So I really don't like to dry pots on the lid, figuring that sometimes I may not put the same side up. At the same time, as far as drying goes, I hate to dry one area of the pot quicker than another. However, I had two downdraft tables in my HS studio. Talk about being able to dry fast-we could dry student slab, coil, extruded pots on top of these tables in around and hour or two. That is from completed construction at leather hard to bone dry! Mad it easy to run week long classes with JH students in a summer program. Take home pots on last day, throwing experience on the wheel also. One fire last bunch of pots the night before.

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clayshapes    9

Thanks for all the responses to my query. Just to update -- I'm getting ready for a big craft show so my kiln is going almost every day -- I've successfully dried pots on top of the kiln all week -- in a couple of hours!!!-- and they have bisqued and glaze fired beautifully the next day. I've been doing this with both stoneware clay and low fire earthenware clay. I'm careful to do it before the kiln gets too hot. Not saying it will work for everyone, and everyone's kiln will be different etc., but it's working fine for me. I'm just keeping a close eye on the pots as they dry and close watch on the temp inside the kiln too.

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Chris Campbell    1,084

I have done this too with forgiving clay bodies ... often with thick pieces that I want to make sure are totally dry. I put them around the edges of the kiln lid making sure that all my vent holes are clear. Nothing in the middle of the lid.

Although I do know one experienced potter who totally lost his mess when he saw a pot sitting on the lid of his kiln .... thought it would wreck the kiln lid to have any weight on it during a firing.

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yedrow    8

I hate to dry one area of the pot quicker than another. However, I had two downdraft tables in my HS studio. Talk about being able to dry fast-we could dry student slab, coil, extruded pots on top of these tables in around and hour or two. That is from completed construction at leather hard to bone dry! Mad it easy to run week long classes with JH students in a summer program. Take home pots on last day, throwing experience on the wheel also. One fire last bunch of pots the night before.

 

 

Wow, that is fast. What exactly is a downdraft table?

 

I don't like to dry pots unevenly either, but where I work it is virtually impossible. If the top gets pretty dry I can put the pot on a kiln and catch the bottom up. I should note though that I mean a warming kiln, in the early stages.

 

Joel.

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Mark C.    1,798

Its a table usually screened to suck fumes to the outside-used in soldering applications like stained glass(I have a friend with a large stained glass business with two of them) and wielding to suck fumes to the outside.

The ones I have seen are very powerful. They use them in industry. Not sure about High school use?

Mark

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DAY    8

20 years ago I started drying ware on a piece of drywall that was atop a flea market electric blanket.

Now I have the same set-up, but the heat comes from radiant ceiling panels- drywall with wires embeded.

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Pres    896

Its a table usually screened to suck fumes to the outside-used in soldering applications like stained glass(I have a friend with a large stained glass business with two of them) and wielding to suck fumes to the outside.

The ones I have seen are very powerful. They use them in industry. Not sure about High school use?

Mark

 

 

I really don't remember the brand of the tables, but they were not vented, wer about 6'X6' in size. they were very similar to the link below, but the bottoms were metal with wood top like in the link. The fan was so large that it sounded like a turbojet revving up. It took a while(few seconds) to get to speed. They were originally bought for dust in the room, but as they were so noisy, I did not use them in normal classes, occasionally only at the end or when cleaning by myself. But they would really dry pots fast!

 

http://www.rockler.com/product.cfm?page=10169&site=ROCKLER

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neilestrick    1,381

As a kiln tech, my official answer is to never ever set anything on top of your kiln. It is a kiln, not a table. However when you do it, just be careful you're not setting anything too heavy in the middle of the lid. Keep things out at the edge where the lid is supported by the walls. And don't sit stuff directly on the brick. It will heat too quickly and blow up, possibly causing injury to nearby people. Prop them up on a piece of soft brick (ideally), or a kiln post.

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