Tommy Humphries on sat 23 dec 00
Keeping the humidity high will allow the pot to reach a high temperature
evenly throughout without drying . In industry the pots are heated to almost
the boiling point under high humidity and then the humidity is slowly
lowered, drawing the moisture from the air and pot at the same rate. A
freshly thrown pot can be dried completely in under an hour using this
method.
Tommy Humphries
Photos here http://albums.photopoint.com/j/AlbumIndex?u=939179&a=6869600
----- Original Message -----
From: "Chris Campbell"
To:
Sent: Saturday, December 23, 2000 10:04 AM
Subject: High Humidity Drying??
Rick Mahaffey wrote :
"To dry pots quickly you need high temp and high HUMIDITY (this is what
they do in industry). Any small container that will retain the humidity
coming off the pots will work."
OK, I'll bite ... WHY does having high humidity help a pot to dry faster???
Chris Campbell - in North Carolina - who has gotten into trouble all her
life
cause she always has to know "WHY?".
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Chris Campbell on sat 23 dec 00
Rick Mahaffey=A0wrote :=A0 =20
=20
"To dry pots quickly you need high temp and high HUMIDITY (this is what
they do in industry). Any small container that will retain the humidity
coming off the pots will work." =20
=20
=20
OK, I'll bite ... WHY does having high humidity help a pot to dry faster???
Chris Campbell - in North Carolina - who has gotten into trouble all her lif=
e=20
cause she always has to know "WHY?".=20
John Jensen on sat 23 dec 00
I think the deal with that is to keep the clay from drying out unevenly. If
you hold the humidity high there is a buffer effect in the air and the ware
looses it's water more evenly. Then when the moisture content in the ware
is low enough you let humidity drop. One of the classic examples is the
experiment in which the ware is put into the kiln wet and fired right away.
Somehow it dries without cracking or exploding because of the aforementioned
effect.
John Jensen in Annapolis
Tom Buck on sun 24 dec 00
Ms. Campbell:
A wet pot off the wheel has water (20% by weight) dispersed
throughout. But the paths for it to leave the pot are very minute
passages; water on the surface, close to the surface, has to leave before
interior water comes to leave. However as exterior surface water leaves,
the surface clay particles close in on themselves, and tend to seal off
the interior water. If this remains in the pot, it goes "boom" when you
try to bisque it ("it looked dry").
So by keeping the pot immersed in a "steam bath", the surface
particles stay open, letting the interior water diffuse to the surface and
leave. It really is almost boiling conditions, speeding up the diffusion
of interior water to the surface and exiting the claypot. Experience
will tell how long to maintain the steam bath, and when to go "dry"
atmosphere. Hence, fast, safe drying.
Good pots. Peace., Tom B.
Tom Buck ) tel: 905-389-2339 (westend Lake Ontario,
province of Ontario, Canada). mailing address: 373 East 43rd Street,
Hamilton ON L8T 3E1 Canada
Brian Crocker [S.Australia] on tue 26 dec 00
At "Bendigo Pottery", a large Industrial Potting Firm in Victoria [State]
Australia, they dry both pots and plaster moulds in a huge room with a slow
steady flow of air at no higher than 40c and to my knowlege when working
there, had never seen pots or moulds with cracks in them. The secret, I was
told by several experienced technicians, is to not dry pots or moulds any
faster than the capilliary action causes the moisture to rise to the surface
to be carried away by the warm air.
Regards,
Brian C..
======================
At 21:07 23/12/00 -0600, you wrote:
>Keeping the humidity high will allow the pot to reach a high temperature
>evenly throughout without drying . In industry the pots are heated to almost
>the boiling point under high humidity and then the humidity is slowly
>lowered, drawing the moisture from the air and pot at the same rate. A
>freshly thrown pot can be dried completely in under an hour using this
>method.
>Tommy Humphries
>
>Photos here http://albums.photopoint.com/j/AlbumIndex?u=939179&a=6869600
>----- Original Message -----
>From: "Chris Campbell"
>To:
>Sent: Saturday, December 23, 2000 10:04 AM
>Subject: High Humidity Drying??
>
>
>Rick Mahaffey wrote :
>
>"To dry pots quickly you need high temp and high HUMIDITY (this is what
>they do in industry). Any small container that will retain the humidity
>coming off the pots will work."
>
>
>OK, I'll bite ... WHY does having high humidity help a pot to dry faster???
>
>Chris Campbell - in North Carolina - who has gotten into trouble all her
>life
>cause she always has to know "WHY?".
>
>____________________________________________________________________________
>__
>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.
>
>______________________________________________________________________________
>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.
>
>
end
[(:-) --------------------------------------------------------------(;-))]
end
Brian and Rena Crocker.
4 Erica Street,
Tea Tree Gully, 5091
South Australia,
Australia.
Phone - Fax: 08 8264 4136
E.mail, crocker@esc.net.au
PREVIOUSLY crocker@dove.net.au
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