William & Susan Schran User on tue 23 aug 05
On 8/23/05 5:35 PM, "Barbara Arner" wrote:
> But it always seems I have a few or sometimes all (!!) that explode in the
> firing. I have my ideas why perhaps --- too thick pieces, not dry enough,
The answer is in your question - not dry enough.
I also would imagine the controller has a "slow bisque" schedule already
programmed in it.
--
William "Bill" Schran
Fredericksburg, Virginia
Earl Brunner on tue 23 aug 05
In the art center, we have thick, damp pots often as well. I use the
following programmed bisque cycle and seldom lose a pot.
Ramp 1 50 degrees per hour to 190, hold anywhere from 4 to 6 hours,
depending on the thickness and dampness.
Ramp 2 50 degrees per hour to 210 hold 30 minutes
Ramp 3 250 per hour to 700 hold 0 minutes
Ramp 4 500 per hour to 1700 (or whatever your target cone is) hold 20
minutes
end
Earl Brunner
Las Vegas, NV
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Barbara Arner
Sent: Tuesday, August 23, 2005 2:36 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Refresher Course on Firing Greenware
Okay this should remain fairly simple -- I have a digital Skutt kiln 1227 (I
think...) and I have been firing for a while now. But it always seems I have
a few or sometimes all (!!) that explode in the firing. I have my ideas why
perhaps --- too thick pieces, not dry enough, I didnt soak thge kiln long
enough. Well if you can add to that list to make me more self-aware why I
have these explosions...And if someone is familiar with this kiln can you
please tell me how you program your greenware firing?
Thank you,
Barb
--
Barbara Arner
330 Bay Lane
Mantoloking, New Jersey
08738
USA
908 447 2826
bfa1231@comcast.net
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Barbara Arner on tue 23 aug 05
Okay this should remain fairly simple -- I have a digital Skutt kiln 1227 (I think...) and I have been firing for a while now. But it always seems I have a few or sometimes all (!!) that explode in the firing. I have my ideas why perhaps --- too thick pieces, not dry enough, I didnt soak thge kiln long enough. Well if you can add to that list to make me more self-aware why I have these explosions...And if someone is familiar with this kiln can you please tell me how you program your greenware firing?
Thank you,
Barb
--
Barbara Arner
330 Bay Lane
Mantoloking, New Jersey
08738
USA
908 447 2826
bfa1231@comcast.net
Tony Ferguson on tue 23 aug 05
Barabara,
Set your program to: slow, cone 010 (or whatever you are bisquing too). The Slow firing bisque to cone 010 is a 10 hour program roughly. If your work is wet or damp, do a hold for 6 hours to dry it out and then continue to your bisque temp. If really thick and wet, hold temp at 170 degrees with lid open overnight and then continue to bisque. Best wishes to you.
Tony Ferguson
Tony Ferguson
...where the sky meets the lake...
Duluth, Minnesota
Artist, Educator, Web Meister
fergyart@yahoo.com
fergy@cpinternet.com
(218) 727-6339
http://www.aquariusartgallery.com
http://www.tonyferguson.net
---------------------------------
Start your day with Yahoo! - make it your home page
Valice Raffi on wed 24 aug 05
Hi Barbara,
Here's a Ramp/Hold program that has worked well for "questionable" work.
It's probably overkill but I've never had anything blow up using this
program.
* press Ramp/Hold View"
select #1 (for program #1) press ENTER
select user ID# (1 will work)
select "6" (for # of segments) press ENTER
* SEGMENT #1:
Rate of Temp: 104 F (per hour) press ENTER
Hold Temp: 210 F - press ENTER
Hold Time: 3.00 (three hours) press ENTER
* Segment #2:
Rate of Temp: 212 F per hour - press ENTER
Hold Temp: 932 F press ENTER
Hold Time: 00.00 (NO HOLD) press ENTER
* Segment #3:
Rate of Temp: 122F per hour - press ENTER
Hold Temp: 1122F - press ENTER
Hold Time: 00.00 (NO HOLD)
* Segment #4:
Rate of Temp: 212F per hour - press ENTER
Hold Temp: 1292 F press ENTER
Hold Time: 00.00 (NO HOLD) press ENTER
* Segment #5:
Rate of Temp: 122 F per hour - press ENTER
Hold Temp: 1652 F - press ENTER
Hold Time: 00.30 (thirty minutes) press ENTER
* Segment #6:
Rate of Temp: 212 F per hour - press ENTER
Hold Temp: 1940 F (^04) press ENTER
Hold Time: 00.30 (thirty minutes) press ENTER
Good Luck!
Valice Raffi
Potter's Council member
Las Cruces, New Mexico (USA!)
>Okay this should remain fairly simple -- I have a digital Skutt kiln 1227
>(I think...) and I have been firing for a while now. But it always seems I
>have a few or sometimes all (!!) that explode in the firing. I have my
>ideas why perhaps --- too thick pieces, not dry enough, I didnt soak thge
>kiln long enough. Well if you can add to that list to make me more
>self-aware why I have these explosions...And if someone is familiar with
>this kiln can you please tell me how you program your greenware firing?
>Thank you,
>Barb
>
>--
>Barbara Arner
Arnold Howard on wed 24 aug 05
Here's a firing schedule for thick ware that Paragon used with the DTC 1000
controller:
Degrees are in F
Seg 1 Pre-heat, kiln fully vented
Rate/60
Temp/200
Hold/Until all moisture is released
Seg 2
Rate/80
Temp/250
Hold/0
Seg 3
Rate/250
Temp/950
Hold/0
Seg 4
Rate/110
Temp/1100
Hold/0
Seg 5
Rate/225
Temp/200 below the final temp
Hold/0
Seg 6
Rate/90
Temp/Final cone temp
Hold/0
Seg 6 Slow Cooling
Rate/150
Temp/1000
Hold/0
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
----- Original Message -----
From: "Valice Raffi"
> * press Ramp/Hold View"
> select #1 (for program #1) press ENTER
> select user ID# (1 will work)
> select "6" (for # of segments) press ENTER
> * SEGMENT #1:
> Rate of Temp: 104 F (per hour) press ENTER
> Hold Temp: 210 F - press ENTER
> Hold Time: 3.00 (three hours) press ENTER
> * Segment #2:
> Rate of Temp: 212 F per hour - press ENTER
> Hold Temp: 932 F press ENTER
> Hold Time: 00.00 (NO HOLD) press ENTER
> * Segment #3:
> Rate of Temp: 122F per hour - press ENTER
> Hold Temp: 1122F - press ENTER
> Hold Time: 00.00 (NO HOLD)
> * Segment #4:
> Rate of Temp: 212F per hour - press ENTER
> Hold Temp: 1292 F press ENTER
> Hold Time: 00.00 (NO HOLD) press ENTER
> * Segment #5:
> Rate of Temp: 122 F per hour - press ENTER
> Hold Temp: 1652 F - press ENTER
> Hold Time: 00.30 (thirty minutes) press ENTER
> * Segment #6:
> Rate of Temp: 212 F per hour - press ENTER
> Hold Temp: 1940 F (^04) press ENTER
> Hold Time: 00.30 (thirty minutes) press ENTER
Linda Arbuckle on thu 25 aug 05
During a bisque, water turns to steam at 212 deg F. It moves from areas
of greater concentration (inside your piece) to lesser (outside). If
there is a lot of steam and it builds suddenly, it will blow the wall of
your piece out as it moves.
People using controller kilns should think about how that system works.
The elements are either ON of OFF. On LOW the elements are on less
often, on HIGH the elements are on longer or continuously. If you set
your controller to hold at 212, the pieces next to the elements have to
get hotter than that for the heat to even out and make the temp at the
end of the sensor read 212.
If you can set the ramps on your controller, I'd recommend going slowly,
maybe 60 degrees per hour or so, up to about 180 and holding there for
several hours before crossing the 212 deg threshold. We've found at
school that heavy sculptural work (in humid FL) may need to be held
below 212 for as long as 8 hours to dry it out, but ordinary pottery
thickness things are good after 2-3 hours hold. This is assuming that
you're firing work that is dry (or as dry as things get here in summer).
If you're firing damp work, it may take a bit longer hold.
Linda
Linda Arbuckle, Professor
University of Florida
School of Art and Art History
P.O. Box 115801
Gainesville, FL 32611
http://www.arts.ufl.edu/artex02/html/ceramics/arbuckle.html
(352) 392-0201 x 219
Donald Schnell Studio on thu 25 aug 05
We prefer to hold at 140 F for 3 hours and ramp up again to 170 F for 3
hours. While not for everyone, a lot of our stoneware is very thick and
ensures everything is bone dry.
We used to go up to about 180 and hold for awhile but found that over
time as thermocouples wore and became insensitive and elements were
replaced, that going straight up to that temp was cutting it too close
to the boiling point unnecessarily. The same effect could be achieved
going up temps a little lower. This also allows you to ramp up at a
higher rate per hour to get to your temp faster (given that you are
already starting out with greenware that is already dry to the naked eye
& touch).
Just our two cents.
-----Original Message-----
From: Clayart [mailto:CLAYART@lsv.ceramics.org] On Behalf Of Linda
Arbuckle
Sent: Thursday, August 25, 2005 10:52 AM
To: CLAYART@lsv.ceramics.org
Subject: Re: Refresher Course on Firing Greenware
During a bisque, water turns to steam at 212 deg F. It moves from areas
of greater concentration (inside your piece) to lesser (outside). If
there is a lot of steam and it builds suddenly, it will blow the wall of
your piece out as it moves.
People using controller kilns should think about how that system works.
The elements are either ON of OFF. On LOW the elements are on less
often, on HIGH the elements are on longer or continuously. If you set
your controller to hold at 212, the pieces next to the elements have to
get hotter than that for the heat to even out and make the temp at the
end of the sensor read 212.
If you can set the ramps on your controller, I'd recommend going slowly,
maybe 60 degrees per hour or so, up to about 180 and holding there for
several hours before crossing the 212 deg threshold. We've found at
school that heavy sculptural work (in humid FL) may need to be held
below 212 for as long as 8 hours to dry it out, but ordinary pottery
thickness things are good after 2-3 hours hold. This is assuming that
you're firing work that is dry (or as dry as things get here in summer).
If you're firing damp work, it may take a bit longer hold.
Linda
Linda Arbuckle, Professor
University of Florida
School of Art and Art History
P.O. Box 115801
Gainesville, FL 32611
http://www.arts.ufl.edu/artex02/html/ceramics/arbuckle.html
(352) 392-0201 x 219
________________________________________________________________________
______
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.
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