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anxious to do a bisque firing -- too wet?

updated tue 23 aug 05

 

Paul Herman on fri 19 aug 05


Hi Mary,

One of the things you will learn from this pursuit (clay) is patience.

Dry your work slowly and evenly, and fire it when it doesn't feel cool
if you touch the foot with your lips. Yes you have to kiss the pots.

You could use your electric kiln to finish drying them (on low) but the
moisture is not good for the electric kiln.

Patience, patience, and test test test,

Paul Herman

Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/



>> I am really excited about this firing and still have some dampish pots. Is
>> it safe to do a preheat and go for it; or do I HAVE to wait til they are
>> bone dry? How can I tell if they are dry enough?

Mary/Adams on fri 19 aug 05


I am really excited about this firing and still have some dampish pots. Is
it safe to do a preheat and go for it; or do I HAVE to wait til they are
bone dry? How can I tell if they are dry enough?

M

Marcia Selsor on fri 19 aug 05


If they feel cool to your cheek/face then they are too wet. You could
put your kiln on low for and hour or two and then shut it off. Let
the pots stay in there overnight. That should dry them out.
Marcia in Montana
On Aug 19, 2005, at 2:40 PM, Mary/Adams wrote:

> I am really excited about this firing and still have some dampish
> pots. Is
> it safe to do a preheat and go for it; or do I HAVE to wait til
> they are
> bone dry? How can I tell if they are dry enough?
>
> M

Jane Murray-Smith on fri 19 aug 05


DON"T DO IT....you are sure to loose something(s). You can 'candle'...put
the kiln on at about 200'F until a mirror stuck in shows there is no more
moisture coming out. This is not good for your elements as an ongoing
practice, but I do it all the time.
Do this if you aren't sure and you won't loose anything.
Jane

----- Original Message -----
From: "Mary/Adams"
To:
Sent: Friday, August 19, 2005 1:40 PM
Subject: Anxious to do a bisque firing -- too wet?


>I am really excited about this firing and still have some dampish pots. Is
> it safe to do a preheat and go for it; or do I HAVE to wait til they are
> bone dry? How can I tell if they are dry enough?
>
> M
>
> ______________________________________________________________________________
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>

William & Susan Schran User on fri 19 aug 05


On 8/19/05 4:40 PM, "Mary/Adams" wrote:

> I am really excited about this firing and still have some dampish pots. Is
> it safe to do a preheat and go for it; or do I HAVE to wait til they are
> bone dry? How can I tell if they are dry enough?

I always advise waiting for clay to be bone dry prior to firing, then there
is much less of an issue with anything exploding.

If the work allows, when it is sufficiently stiff, turn upside down to dry
more evenly.

To test if the pot is dry enough, hold the rim against your cheek (the cheek
on your face!), then hold the bottom of the pot against your cheek. If both
feel the same, then it's probably dry enough for firing.

--
William "Bill" Schran
Fredericksburg, Virginia

Rick Bonomo on sat 20 aug 05


On Aug 19, 2005, at 2:40 PM, Mary/Adams wrote:
> I am really excited about this firing and still have some dampish
> pots. Is
> it safe to do a preheat and go for it; or do I HAVE to wait til
> they are
> bone dry? How can I tell if they are dry enough?

For what it's worth:

I have a woodburner in my basement where I throw pots
When I was throwing fireclay a while back, I was able to pick a pot off =
the wheel and put it directly on the woodburner, (over a short air space =
and a kiln shelf). Dried real quick. I'm sure this would work with raku =
clay, too. I tried this with Standard 259, and the bottoms cracked. So =
now I wait until they are mostly dry, then light the stove and dry them =
completely before bisqueing. Gets pretty toasty down there in the =
summer.

Rick Bonomo

Snail Scott on sat 20 aug 05


At 01:40 PM 8/19/2005 -0700, you wrote:
>I am really excited about this firing and still have some dampish pots. Is
>it safe to do a preheat and go for it; or do I HAVE to wait til they are
>bone dry?


As long as the temperature remains below the boiling=20
point of water, you can go ahead and preheat. Keep=20
it below 200=BAF to be safe. Depending on how thick the=20
clay is, and how damp it still is, you may need to=20
preheat ('candle') for several hours. Better safe than=20
sorry. (I put a old oven thermometer on the top shelf=20
of the kiln, where I can pull it out with a bent=20
clothes hanger.) The top shelf will tend to stay=20
coolest while the lid is cracked open, but as long as=20
that thermometer is under 150=BAF, it seems to be OK.
If your kiln is manual (not computerized), turn
just the top element to 'low' and let it ride overnight
with the lid open a few inches.

-Snail

Scott & Vanessa on sun 21 aug 05


We do use our electric kiln to dry out any dampish pots. Maybe not ideal
but it does work. I set the controller to do a 7 hour preheat at 200F,
then the bisque fire starts as per usual. My kiln is vented so I don't
worry about the moisture and it's usually only a couple pots in the load.


On Fri, 19 Aug 2005 20:46:26 -0700, Paul Herman
wrote:

>Hi Mary,
>
>One of the things you will learn from this pursuit (clay) is patience.
>
>Dry your work slowly and evenly, and fire it when it doesn't feel cool
>if you touch the foot with your lips. Yes you have to kiss the pots.
>
>You could use your electric kiln to finish drying them (on low) but the
>moisture is not good for the electric kiln.
>
>Patience, patience, and test test test,
>
>Paul Herman
>
>Great Basin Pottery
>Doyle, California US
>http://www.greatbasinpottery.com/
>
>
>
>>> I am really excited about this firing and still have some dampish
pots. Is
>>> it safe to do a preheat and go for it; or do I HAVE to wait til they
are
>>> bone dry? How can I tell if they are dry enough?
>
>__________________________________________________________________________
____
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.

Arnold Howard on mon 22 aug 05


From: "Mary/Adams"
>I am really excited about this firing and still have some dampish pots. Is
> it safe to do a preheat and go for it; or do I HAVE to wait til they are
> bone dry? How can I tell if they are dry enough?

Mary, I agree with the other answers you've received: The ideal is to place
only dry pots in the kiln. But sometimes the pots are difficult to dry
completely, such as in humid weather.

As Snail said, dry the ware completely by heating the kiln on low. Do not go
past 200 degrees F until all moisture has disappeared. If you begin firing
hotter too soon, the kiln will waste electricity, and the moisture will rust
the kiln.

Sincerely,

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

Louis Katz on mon 22 aug 05


I routinely dry student work in my kilns. In my opinion it shortens the
life of the casing of the kiln but this is anecdotal. My elements seem
to be holding up well. The humidity during the semster in my studio is
very high from high humidity outside and frequent floor and table
washing. I dry the pots at a setting of 190 degrees. I do this with a
downdraft Bailey vent and the top spy out. If I am in a real hurry I
prop the lid 1 inch or so. It is the band around my lid that takes the
real beating. With 1/4 thick stoneware I figure about 15 hours from
well past leather to dry. If most of the pots are dry I use less time.

I use a glass in front of the opening or top spy to look for
condensation to determine if the kiln is dry.

I then ramp to 235 F and hold for an hour. I do this because of
occasional explosions of previously wet work in the center of the
bottom of my kiln. I rarely tell a student not to fire something
because of thickness. Routinely sculpture is up to 3/4 inch thick.

I do disagree that the best way to dry work is outside the kiln. this
is true if you have a hot box. It is better to dry at a high
temperature and high humidity than a low temp and low humidity, you get
less cracking.

If you build a hot box make sure it won't catch fire. Keep all your
combustable stuff away from the kilns.

BTW I run multiple dehumidifiers in the studio near the end of the
semester to speed drying.

Louis




> From: "Mary/Adams"
>> I am really excited about this firing and still have some dampish
>> pots.


>> How can I tell if they are dry enough?
>