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How Do You Know When The Clay Is Dry?

ceramic clay stoneware porcelain sculpture handbuilt drying time dry

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#1 Melissa M.

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Posted 24 July 2013 - 09:38 PM

Hi everyone! I'm new here, and new to ceramics.  :)

 

I will be hand building miniatures. My main question right now is, how can you tell when the clay pieces are dry? I've searched online, and the only answer I have found is that they are dry when they no longer feel cold when touched against your face/wrist. 

 

I have created some pieces to test my clay samples (various types of stoneware and porcelain clay). After 3 weeks, they still feel fairly cold on my face.  :( They are about 1/2" thick, and I realize that drying will take longer with this thickness. But, it seems like they have felt the same (against my face/wrist) for the last 3 days now, and I'm wondering if dry clay still feels slightly cold? Is there another method to check when they are dry enough for the bisque firing?

 

Thanks for any advice!  :)

 

Melissa



#2 Marcia Selsor

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Posted 24 July 2013 - 10:06 PM

are they set on sticks or som how getting air under the bottom?
If not, get some 1x2sticks and e your piece up to get the bottom dried out

Usually the piece won't feel cool if I is dried.
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#3 Melissa M.

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Posted 24 July 2013 - 11:11 PM

Thanks, Marcia!

 

They are not on sticks (they are really small pieces, so I'm not sure how I can place them on sticks), but I have been rotating the pieces every few days. They spent about a week sitting upright (on their bottoms), then I put them on their side for about a week, then the other side for the final week. I'm not sure if that would work just as well as the sticks, but I would think so.  :unsure:



#4 JBaymore

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Posted 24 July 2013 - 11:34 PM

Technically it is not fully dry until it hits 212 F (100 C). If the air has moisture in it...... and in most places it does.... then the clay will stabilize with some moisture in it.

The "is is cool" on your cheek test is a decent gauge. If there is water still evaporating.... it uses heat energy to do so. making the piece feel cool.

best,

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#5 OffCenter

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Posted 25 July 2013 - 07:47 AM

Thanks, Marcia!

 

They are not on sticks (they are really small pieces, so I'm not sure how I can place them on sticks), but I have been rotating the pieces every few days. They spent about a week sitting upright (on their bottoms), then I put them on their side for about a week, then the other side for the final week. I'm not sure if that would work just as well as the sticks, but I would think so.  :unsure:

 

They're dry.

 

Jim


E pur si muove.

"But it does move," said Galileo under his breath.

#6 Benzine

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Posted 25 July 2013 - 08:04 AM

Thanks, Marcia!
 
They are not on sticks (they are really small pieces, so I'm not sure how I can place them on sticks), but I have been rotating the pieces every few days. They spent about a week sitting upright (on their bottoms), then I put them on their side for about a week, then the other side for the final week. I'm not sure if that would work just as well as the sticks, but I would think so.  :unsure:

 
They're dry.
 
Jim

I agree with the Dinstinguished Gentleman from Georgia.

A couple weeks for a half an inch thick piece, unless it's really humid there, they should be dry.

And there is a difference between "cool" and "cold". In the winter, depending on the temperature of your clay work/ storage area even projects that have been sitting for a sufficient amount of time, will still feel cool, but not cold.
"Anything worth believing, is worth questioning"

#7 Melissa M.

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Posted 25 July 2013 - 11:53 AM

Thanks, guys. :)

 

Yes, they feel more "cool" than "cold". 

 

It actually has been rather humid here. Aside from one week of about 50-60% humidity, it has been in the 80-90% range.



#8 Darcy Kane

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Posted 25 July 2013 - 07:02 PM

Ok, was I the only one that thought to themselves:

1. I'm sure work is dry when it doesn't explode in the kiln when I fire it. 

2. I'm sure work is dry when a piece comes off in my hand when I pick it up.

3. I'm sure a piece is dry when it shatters to bits when I drop it off a ware board. 

It might be interesting for you to make a few blobs of clay the approximate size of your miniatures and break them open at different time intervals so you can get a "feel" for what not nearly dry, almost dry, and dry as a bone looks like and feels like.  I have learned much more by the pieces I have bashed than any I have fired and sold.  Congrats on finding clay, enjoy the journey!



#9 oldlady

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Posted 25 July 2013 - 08:18 PM

if they are that small, find an old toaster oven and line the rack with something with smaller spacing so your pieces can stand upright.  after you think they are dry, set the temp control  to as low as it will go and put them in the little oven for an hour or so.  if the temp is really low, try 200 degrees for an hour.  make sure the little oven is somewhere safe for that temp for that long.  do not set it on canvas or do anything equally sillly.

 

thrift shops are great places to outfit a studio.


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#10 Melissa M.

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Posted 25 July 2013 - 09:44 PM

Ok, was I the only one that thought to themselves:

1. I'm sure work is dry when it doesn't explode in the kiln when I fire it. 

2. I'm sure work is dry when a piece comes off in my hand when I pick it up.

3. I'm sure a piece is dry when it shatters to bits when I drop it off a ware board. 

It might be interesting for you to make a few blobs of clay the approximate size of your miniatures and break them open at different time intervals so you can get a "feel" for what not nearly dry, almost dry, and dry as a bone looks like and feels like.  I have learned much more by the pieces I have bashed than any I have fired and sold.  Congrats on finding clay, enjoy the journey!

Thanks, Dharsi! :)

 

Your #1 is what I fear most; my work exploding in the kiln. I'm scared to damage my brand new kiln.  :(

 

Thanks for the tips about the brittleness and making test blobs! :D  I hadn't even thought of that. I will do that with my next batch.  :)



#11 Melissa M.

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Posted 25 July 2013 - 09:46 PM

if they are that small, find an old toaster oven and line the rack with something with smaller spacing so your pieces can stand upright.  after you think they are dry, set the temp control  to as low as it will go and put them in the little oven for an hour or so.  if the temp is really low, try 200 degrees for an hour.  make sure the little oven is somewhere safe for that temp for that long.  do not set it on canvas or do anything equally sillly.

 

thrift shops are great places to outfit a studio.

Okay, thanks! I already have a toaster oven (not used for food), so that's a great idea.

 

Speeding up the drying process like that won't damage the ware in anyway? 



#12 Pres

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Posted 25 July 2013 - 09:50 PM

Not to confuse the issue, or negate any of the other advice, but here are my two cents. I used to exclusively use the cheek test, when judging dryness. If it did not feel cool or seem to warm against my cheek-dry. However, after firing student work of varying types and thicknesses, I found that often another day or two was needed. I was firing a tight range ^6 body with fine grog. At the same time, I always took a little more time candling/ water smoking the kiln if the air was humid as it often was in the basement.


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#13 Mark C.

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Posted 26 July 2013 - 12:16 AM

This is like cake baking how do you know whan its done?

Its from experince of testing-With cakes you can bake it more with wet pottery you blow one up and make another one.

Mark


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#14 atanzey

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Posted 26 July 2013 - 07:02 AM

I've determined that the 'cool against the cheek' test method doesn't really work for me - I just checked: my mouse was cool against my cheek, and I'm pretty sure it's dry.  Anything at room temperature feels cool against my cheek, unless the room is really warm.

 

If I have to make sure something's dry, I use my oven.  Yeah, in my kitchen.  The stove is a safe place to dry things, as long as you make sure you're not contaminating food surfaces.

 

And I always candle a long time.  I've only had one blow-up, and I KNEW it wasn't dry - I just thought I had candled long enough, and found out otherwise.  Lessons to be learned!   



#15 GEP

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Posted 26 July 2013 - 08:46 AM

I use a calendar to gauge if a pot is ready to fire. I jot down everything I've made on a wall calendar, then count the days. In the dry winter months, I will bisque four days later. In the humid summer months, I wait at least 7 days. When it's extremely humid I might stretch that to ten. I'm making all functional ware so my thicknesses are pretty consistent throughout. As others have said here, it just takes experience to get to know your own work.

btw, if you explode a pot or two (been there too!), it probably won't damage your kiln. Just vacuum all of the element grooves thoroughly, and you'll be fine.
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#16 Benzine

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Posted 26 July 2013 - 09:02 AM

I've determined that the 'cool against the cheek' test method doesn't really work for me - I just checked: my mouse was cool against my cheek, and I'm pretty sure it's dry.  Anything at room temperature feels cool against my cheek, unless the room is really warm.


Like I said, there is a difference between cool and cold. I am not saying it's a fool proof method for gauging dryness, but it's a place to start. If if feels cool, it might be fully dry, and is n most cases, but if it feels cold, it's definitely not dry.
"Anything worth believing, is worth questioning"

#17 LovesPurple

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Posted 26 July 2013 - 10:56 AM

When I think things are dry and ready to fire, I put them in my oven (yes, in my kitchen) overnight with just the light in the oven on.  It is amazing how warm an oven can get with just the light on!  I have never had anything explode.  

 

I know I will have some haters here, but I have a small test kiln and after I fire it and it is in the cooling off zone (below where the inside glows) I will put what I think should be dry pieces on top of the kiln.  I keep an eye on them , flip them, rotate them, etc.  By the time the kiln is cool, they are ready to go!



#18 OffCenter

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Posted 26 July 2013 - 02:53 PM

They're dry.

 

Jim


E pur si muove.

"But it does move," said Galileo under his breath.

#19 oldlady

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Posted 26 July 2013 - 03:08 PM

i am so tired of walking things up and down the hall to the kitchen oven that if i ever get the new studio i want, it will have a thrift shop kitchen stove in it.  


"putting you down does not raise me up."

#20 OffCenter

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Posted 26 July 2013 - 03:18 PM

i am so tired of walking things up and down the hall to the kitchen oven that if i ever get the new studio i want, it will have a thrift shop kitchen stove in it.  

 

Okay, I must have missed something. Why in the world would you dry pots in a kitchen oven? If you're in such a rush that you can't wait for them to dry in front of a fan, you could just do a bisque load and add a few hours of candling.

 

Jim


E pur si muove.

"But it does move," said Galileo under his breath.





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