Judy Musicant on mon 7 jun 04
Lewis,
I could be wrong, but it sounds as if you're not watching the cones =
during the firing. Or if you are, you're still relying on the =
temperature number on the controller and not on what the cones are =
telling you. If you turn the kiln off when the cone drops to where you =
want it, you should be in good shape. As Earl says, it doesn't matter =
what temperature the controller reads. My kiln probably needs a new =
thermocouple, as I fire to cone 5 flat and cone 6 just starting to bend, =
and the temperature for that configuration now reads right around 2100 =
F. , down from 2165 F when about 30 glaze firings ago. But I still use =
the same firing schedule and the firings are still right around 9 hours. =
I only need to watch the cones during the last 45 min. of the firing, =
and I still get very good results. =20
Having said all this, I don't know what to do under these circumstances =
if you want to soak at the top temperature, which I don't currently do. =
In other words, since my kiln reaches temperature at a different number =
on the controller every time, I can't program it to soak at a particular =
temperature, since I never know what that will be for a particular =
firing. If someone has some advice about this, I'd love to hear it.
Judy
Arnold Howard on mon 7 jun 04
Judy, it sounds like your thermocouple needs to be replaced. Or maybe
another factor is affecting the accuracy of the controller. For instance,
placing a shelf too close to the thermocouple will throw off the temperature
reading.
A digital controller should give repeatable results. It should not be
necessary to watch the cones with every firing. If the temperature drifts,
it should be gradual.
I would be interested to hear how consistent firing results are for other
owners of digital controllers.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net
----- Original Message -----
From: "Judy Musicant"
My kiln probably needs a new thermocouple, as I fire to cone 5 flat and cone
6 just starting to bend, and the temperature for that configuration now
reads right around 2100 F. , down from 2165 F when about 30 glaze firings
ago. But I still use the same firing schedule and the firings are still
right around 9 hours. I only need to watch the cones during the last 45
min. of the firing, and I still get very good results.
Having said all this, I don't know what to do under these circumstances if
you want to soak at the top temperature, which I don't currently do. In
other words, since my kiln reaches temperature at a different number on the
controller every time, I can't program it to soak at a particular
temperature, since I never know what that will be for a particular firing.
If someone has some advice about this, I'd love to hear it.
Lester Haworth on tue 8 jun 04
Why are you applying a soak at the end of the firing? Do you have other
problems? Are the glazes reaching maturity, or are you using a soak to
minimize pinholing? What brand of kiln do you own, and what is the model
number? Are you using the preset firing schedules or do you program your
own? Sounds like your using a couple of witness cones when firing your kiln,
which is good. Always use cones when firing your kiln. Please provide more
information.
Les H.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Arnold Howard
Sent: Monday, June 07, 2004 10:02 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Controller vs. Cone
Judy, it sounds like your thermocouple needs to be replaced. Or maybe
another factor is affecting the accuracy of the controller. For instance,
placing a shelf too close to the thermocouple will throw off the temperature
reading.
A digital controller should give repeatable results. It should not be
necessary to watch the cones with every firing. If the temperature drifts,
it should be gradual.
I would be interested to hear how consistent firing results are for other
owners of digital controllers.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net
----- Original Message -----
From: "Judy Musicant"
My kiln probably needs a new thermocouple, as I fire to cone 5 flat and cone
6 just starting to bend, and the temperature for that configuration now
reads right around 2100 F. , down from 2165 F when about 30 glaze firings
ago. But I still use the same firing schedule and the firings are still
right around 9 hours. I only need to watch the cones during the last 45
min. of the firing, and I still get very good results.
Having said all this, I don't know what to do under these circumstances if
you want to soak at the top temperature, which I don't currently do. In
other words, since my kiln reaches temperature at a different number on the
controller every time, I can't program it to soak at a particular
temperature, since I never know what that will be for a particular firing.
If someone has some advice about this, I'd love to hear it.
____________________________________________________________________________
__
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You may look at the archives for the list or change your subscription
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Judy Musicant on wed 9 jun 04
Les,
What I'd like to do is be able to hold the kiln at the temp. at which I =
see the cone 5 starting to bend in order to minimize pinholing. For =
instance, if the cone starts to bend at 2100F., I'd like to hold it at =
that temp. until I see the cone 5 completely down. If, during the next =
firing, the cone 5 starts to bend at 2112F, I'd like to hold it at that =
temp. I have a Skutt KM1027 with a kilnmaster controller. I'm not =
using the preset cone firing schedule - I programmed my own. Thanks for =
any advice.
Judy
Date: Tue, 8 Jun 2004 09:06:08 -0700
From: Lester Haworth
Subject: Re: Controller vs. Cone
Why are you applying a soak at the end of the firing? Do you have other
problems? Are the glazes reaching maturity, or are you using a soak to
minimize pinholing? What brand of kiln do you own, and what is the model
number? Are you using the preset firing schedules or do you program your
own? Sounds like your using a couple of witness cones when firing your =
kiln,
which is good. Always use cones when firing your kiln. Please provide =
more
information.
Les H.
Lester Haworth on wed 9 jun 04
Judy,
If you're experiencing pinholing, a soak at the end of the firing cycle
will not cure this problem. Instead of approaching the symptoms you may want
to address the cause of pinholing which is usually improper bisque firing.
Outgassing of the clay body causes pinholing, and proper bisque firing will
eliminate pinholing. The key to proper bisque firing is environment. The
kiln needs plenty of O2 or Oxygen so that the organics in the clay body can
be liberated. If you have liberated the organics from the clay body then
there will be no more pinholing. Any more questions. Just ask.
Les H.
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Judy Musicant
Sent: Wednesday, June 09, 2004 5:35 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Controller vs. Cone
Les,
What I'd like to do is be able to hold the kiln at the temp. at which I see
the cone 5 starting to bend in order to minimize pinholing. For instance,
if the cone starts to bend at 2100F., I'd like to hold it at that temp.
until I see the cone 5 completely down. If, during the next firing, the
cone 5 starts to bend at 2112F, I'd like to hold it at that temp. I have a
Skutt KM1027 with a kilnmaster controller. I'm not using the preset cone
firing schedule - I programmed my own. Thanks for any advice.
Judy
Date: Tue, 8 Jun 2004 09:06:08 -0700
From: Lester Haworth
Subject: Re: Controller vs. Cone
Why are you applying a soak at the end of the firing? Do you have other
problems? Are the glazes reaching maturity, or are you using a soak to
minimize pinholing? What brand of kiln do you own, and what is the model
number? Are you using the preset firing schedules or do you program your
own? Sounds like your using a couple of witness cones when firing your kiln,
which is good. Always use cones when firing your kiln. Please provide more
information.
Les H.
____________________________________________________________________________
__
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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