Cone question

I just finished my first glaze firing (Olympic 2827H with V6-CF
Controller) to ^6 and it apparently got too hot (even though the
temperature readout indicated it was at the correct temp) b/c my 7
cone melted. How can this affect my pieces?
LMac

Well done for putting a cone in, always wise with the first firing.
I guess your controller was set to give you a fairly slow firing, which
means the heatwork required to melt the cone took place before the
controller shut it down. When you next fire, be there to watch the
cones, note the temperature that 6 goes down at and adjust the
controller to shut down at that temperature. Check it every 8 to 10
firings. If your pieces look OK then you haven't done any damage.
We find that some glazes rated at a particular cone are better at the
next one up the scale.

Steve
Bath
UK


In article , L.Mac
writes
I just finished my first glaze firing (Olympic 2827H with V6-CF
Controller) to ^6 and it apparently got too hot (even though the
temperature readout indicated it was at the correct temp) b/c my 7
cone melted. How can this affect my pieces?
LMac

--
Steve Mills
Bath
UK

Thank you very much for your response. I will definitely follow your
suggestion.

LMac

On Fri, 25 Jul 2003 07:58:38 +0100, Steve Mills
wrote:

Well done for putting a cone in, always wise with the first firing.
I guess your controller was set to give you a fairly slow firing, which
means the heatwork required to melt the cone took place before the
controller shut it down. When you next fire, be there to watch the
cones, note the temperature that 6 goes down at and adjust the
controller to shut down at that temperature. Check it every 8 to 10
firings. If your pieces look OK then you haven't done any damage.
We find that some glazes rated at a particular cone are better at the
next one up the scale.

Steve
Bath
UK


In article , L.Mac
writes
I just finished my first glaze firing (Olympic 2827H with V6-CF
Controller) to ^6 and it apparently got too hot (even though the
temperature readout indicated it was at the correct temp) b/c my 7
cone melted. How can this affect my pieces?
LMac

since we're talking about cones....

I test fired my new Bailey 2927-10 kiln to cone 6 yesterday. The kiln only
had four shelves in it and no ware. This Bailey comes with both a
controller and a kiln sitter as a backup. I used the "Fast Glaze" setting
to cone 6 on the controller.

I used a cone 8 bar in the kiln sitter and two sets of witness cones inside
the kiln (5,6,7). The kiln sitter shut down the kiln *before* the
controller had a chance to. The witness cones indicated that temp didn't
quite get up to cone 6 (bent about 90 degrees over). The preview readout on
the controller said it reached 2195 F before the kiln sitter shut it down.

I'll do another test firing and use a cone 10 bar in the kiln sitter next
time and watch the witness cones and controller closely to make sure they
agree.

Why would the kiln sitter shut down with a cone 8 bar in it when the witness
cones indicate it didn't quite get up to cone 6? Was this because the
sitter cone is close to the wall and elements or what?

Thanks,
David


From: Lindsay MacArthur
Organization: Posted via Supernews, http://www.supernews.com
Newsgroups: rec.crafts.pottery
Date: Sun, 27 Jul 2003 07:27:56 -0400
Subject: Cone question

Thank you very much for your response. I will definitely follow your
suggestion.

LMac

On Fri, 25 Jul 2003 07:58:38 +0100, Steve Mills
wrote:

Well done for putting a cone in, always wise with the first firing.
I guess your controller was set to give you a fairly slow firing, which
means the heatwork required to melt the cone took place before the
controller shut it down. When you next fire, be there to watch the
cones, note the temperature that 6 goes down at and adjust the
controller to shut down at that temperature. Check it every 8 to 10
firings. If your pieces look OK then you haven't done any damage.
We find that some glazes rated at a particular cone are better at the
next one up the scale.

Steve
Bath
UK


In article , L.Mac
writes
I just finished my first glaze firing (Olympic 2827H with V6-CF
Controller) to ^6 and it apparently got too hot (even though the
temperature readout indicated it was at the correct temp) b/c my 7
cone melted. How can this affect my pieces?
LMac

Two factors here;
The weight of the sitter bar on the mini-cone DOES have an effect.
The mini-cone has a smaller mass than a standard cone, and therefore may
accumulate its heat-work a little in front of a standard cone.
The combination of the two sent it *down* earlier than the witness
cones.
The Pyrometer which governs the actions of your controller measures
Temperature, the cones measure Accumulated Heatwork. The two are not the
same.
I fired my production kiln (55 cu.ft. gross) to cone 9 in reduction over
a 17 hour period. When 9 went down (nominally 1285oC, 2345oF), the
pyrometer I used to monitor progress never read more than 1220 (2228oF);
I had accumulated enough heatwork over that period of time to mature my
glazes without physically reaching 1285oC on the Pyrometer.

In a kiln with a sitter I habitually use one cone higher in it than any
witness cones I may put in as well.

Steve
Bath
UK


In article , Hotmail
writes
since we're talking about cones....

I test fired my new Bailey 2927-10 kiln to cone 6 yesterday. The kiln only
had four shelves in it and no ware. This Bailey comes with both a
controller and a kiln sitter as a backup. I used the "Fast Glaze" setting
to cone 6 on the controller.

I used a cone 8 bar in the kiln sitter and two sets of witness cones inside
the kiln (5,6,7). The kiln sitter shut down the kiln *before* the
controller had a chance to. The witness cones indicated that temp didn't
quite get up to cone 6 (bent about 90 degrees over). The preview readout on
the controller said it reached 2195 F before the kiln sitter shut it down.

I'll do another test firing and use a cone 10 bar in the kiln sitter next
time and watch the witness cones and controller closely to make sure they
agree.

Why would the kiln sitter shut down with a cone 8 bar in it when the witness
cones indicate it didn't quite get up to cone 6? Was this because the
sitter cone is close to the wall and elements or what?

Thanks,
David


From: Lindsay MacArthur
Organization: Posted via Supernews, http://www.supernews.com
Newsgroups: rec.crafts.pottery
Date: Sun, 27 Jul 2003 07:27:56 -0400
Subject: Cone question

Thank you very much for your response. I will definitely follow your
suggestion.

LMac

On Fri, 25 Jul 2003 07:58:38 +0100, Steve Mills
wrote:

Well done for putting a cone in, always wise with the first firing.
I guess your controller was set to give you a fairly slow firing, which
means the heatwork required to melt the cone took place before the
controller shut it down. When you next fire, be there to watch the
cones, note the temperature that 6 goes down at and adjust the
controller to shut down at that temperature. Check it every 8 to 10
firings. If your pieces look OK then you haven't done any damage.
We find that some glazes rated at a particular cone are better at the
next one up the scale.

Steve
Bath
UK


In article , L.Mac
writes
I just finished my first glaze firing (Olympic 2827H with V6-CF
Controller) to ^6 and it apparently got too hot (even though the
temperature readout indicated it was at the correct temp) b/c my 7
cone melted. How can this affect my pieces?
LMac



--
Steve Mills
Bath
UK

You certainly know your stuff Steve, there's no cones about it !

On Mon, 28 Jul 2003 23:41:21 +0100, Steve Mills
wrote:

Two factors here;
The weight of the sitter bar on the mini-cone DOES have an effect.
The mini-cone has a smaller mass than a standard cone, and therefore may
accumulate its heat-work a little in front of a standard cone.
The combination of the two sent it *down* earlier than the witness
cones.
The Pyrometer which governs the actions of your controller measures
Temperature, the cones measure Accumulated Heatwork. The two are not the
same.
I fired my production kiln (55 cu.ft. gross) to cone 9 in reduction over
a 17 hour period. When 9 went down (nominally 1285oC, 2345oF), the
pyrometer I used to monitor progress never read more than 1220 (2228oF);
I had accumulated enough heatwork over that period of time to mature my
glazes without physically reaching 1285oC on the Pyrometer.

In a kiln with a sitter I habitually use one cone higher in it than any
witness cones I may put in as well.

Steve
Bath
UK


In article , Hotmail
writes
since we're talking about cones....

I test fired my new Bailey 2927-10 kiln to cone 6 yesterday. The kiln only
had four shelves in it and no ware. This Bailey comes with both a
controller and a kiln sitter as a backup. I used the "Fast Glaze" setting
to cone 6 on the controller.

I used a cone 8 bar in the kiln sitter and two sets of witness cones inside
the kiln (5,6,7). The kiln sitter shut down the kiln *before* the
controller had a chance to. The witness cones indicated that temp didn't
quite get up to cone 6 (bent about 90 degrees over). The preview readout on
the controller said it reached 2195 F before the kiln sitter shut it down.

I'll do another test firing and use a cone 10 bar in the kiln sitter next
time and watch the witness cones and controller closely to make sure they
agree.

Why would the kiln sitter shut down with a cone 8 bar in it when the witness
cones indicate it didn't quite get up to cone 6? Was this because the
sitter cone is close to the wall and elements or what?

Thanks,
David


From: Lindsay MacArthur
Organization: Posted via Supernews, http://www.supernews.com
Newsgroups: rec.crafts.pottery
Date: Sun, 27 Jul 2003 07:27:56 -0400
Subject: Cone question

Thank you very much for your response. I will definitely follow your
suggestion.

LMac

On Fri, 25 Jul 2003 07:58:38 +0100, Steve Mills
wrote:

Well done for putting a cone in, always wise with the first firing.
I guess your controller was set to give you a fairly slow firing, which
means the heatwork required to melt the cone took place before the
controller shut it down. When you next fire, be there to watch the
cones, note the temperature that 6 goes down at and adjust the
controller to shut down at that temperature. Check it every 8 to 10
firings. If your pieces look OK then you haven't done any damage.
We find that some glazes rated at a particular cone are better at the
next one up the scale.

Steve
Bath
UK


In article , L.Mac
writes
I just finished my first glaze firing (Olympic 2827H with V6-CF
Controller) to ^6 and it apparently got too hot (even though the
temperature readout indicated it was at the correct temp) b/c my 7
cone melted. How can this affect my pieces?
LMac

Steve Mills has noted some key factors in how temperatures and pyrometric
cones relate, and some things about cones that make them different from a
pyrometer reading. another factor that is in play with a kiln sitter is
the nature of electric heating via kiln elements made usually from a
special alloy called Kanthal A-1 (or similar alloy).
Heat energy produced by a Kanthal element comes from the flow of
electricity (electrons actually) along the coiled wire, and can be
calculated: amperage squared times resistance in ohms, I2R. as the energy
builds up, the element glows and emits radiation (electromagnetic
radiation, EMR) in the infra-red and visible light range of the EMR
spectrum.
since heat is transferred via radiation, moreso than by
convection (hot-gas flows), the radiating source has to be hotter than
the ware receiving the radiation, otherwise the process would reverse.
In actual practice, element wire is perhaps as much as 50 C (120 F)
higher in temperature than the ware being heated (and the pyrometer
probe jutting out from the kiln wall).
So the space close to the element wire is hotter than elsewhere,
which means the sitter's minibar (or minicone) receives more heat energy
per minute/hour than does a cone pack on a shelf.
if you want to fire to Cone 6 bent to 3 o'clock, then place
a Cone 7 minibar in the kiln sitter's probe.
for a given kiln, with unusual setup, the minbar may be Cone 8 to
achieve a bent Cone 6 among the ware. There is a learning curve involved
in firing a new electric kiln; one should track how the kiln behaves, and
make adjustments as needed. and then trust the sitter to shut-off
the kiln at the appropriate point in the firing, rather than
use pyrometer readings to do the same thing if you use a PLC system
(programmable logic controller).
However, a different procedure will come into play if your
glazes need soaking or downfiring. Then the PLC becomes the shut-off
device, and the sitter's cone changed.
good firing. peace. Tom Buck

Tom Buck aa563 at hwcn.org) -- primary address. Tom.Buck at hwcn.org
"alias" or secondary address.
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada

Unfortunately, b/c of the computer, my kiln does not have a sitter.
Should I adjust my final temp to one cone lower or something?

On Mon, 28 Jul 2003 23:41:21 +0100, Steve Mills
wrote:

Two factors here;
The weight of the sitter bar on the mini-cone DOES have an effect.
The mini-cone has a smaller mass than a standard cone, and therefore may
accumulate its heat-work a little in front of a standard cone.
The combination of the two sent it *down* earlier than the witness
cones.
The Pyrometer which governs the actions of your controller measures
Temperature, the cones measure Accumulated Heatwork. The two are not the
same.
I fired my production kiln (55 cu.ft. gross) to cone 9 in reduction over
a 17 hour period. When 9 went down (nominally 1285oC, 2345oF), the
pyrometer I used to monitor progress never read more than 1220 (2228oF);
I had accumulated enough heatwork over that period of time to mature my
glazes without physically reaching 1285oC on the Pyrometer.

In a kiln with a sitter I habitually use one cone higher in it than any
witness cones I may put in as well.

Steve
Bath
UK


In article , Hotmail
writes
since we're talking about cones....

I test fired my new Bailey 2927-10 kiln to cone 6 yesterday. The kiln only
had four shelves in it and no ware. This Bailey comes with both a
controller and a kiln sitter as a backup. I used the "Fast Glaze" setting
to cone 6 on the controller.

I used a cone 8 bar in the kiln sitter and two sets of witness cones inside
the kiln (5,6,7). The kiln sitter shut down the kiln *before* the
controller had a chance to. The witness cones indicated that temp didn't
quite get up to cone 6 (bent about 90 degrees over). The preview readout on
the controller said it reached 2195 F before the kiln sitter shut it down.

I'll do another test firing and use a cone 10 bar in the kiln sitter next
time and watch the witness cones and controller closely to make sure they
agree.

Why would the kiln sitter shut down with a cone 8 bar in it when the witness
cones indicate it didn't quite get up to cone 6? Was this because the
sitter cone is close to the wall and elements or what?

Thanks,
David


From: Lindsay MacArthur
Organization: Posted via Supernews, http://www.supernews.com
Newsgroups: rec.crafts.pottery
Date: Sun, 27 Jul 2003 07:27:56 -0400
Subject: Cone question

Thank you very much for your response. I will definitely follow your
suggestion.

LMac

On Fri, 25 Jul 2003 07:58:38 +0100, Steve Mills
wrote:

Well done for putting a cone in, always wise with the first firing.
I guess your controller was set to give you a fairly slow firing, which
means the heatwork required to melt the cone took place before the
controller shut it down. When you next fire, be there to watch the
cones, note the temperature that 6 goes down at and adjust the
controller to shut down at that temperature. Check it every 8 to 10
firings. If your pieces look OK then you haven't done any damage.
We find that some glazes rated at a particular cone are better at the
next one up the scale.

Steve
Bath
UK


In article , L.Mac
writes
I just finished my first glaze firing (Olympic 2827H with V6-CF
Controller) to ^6 and it apparently got too hot (even though the
temperature readout indicated it was at the correct temp) b/c my 7
cone melted. How can this affect my pieces?
LMac

several years back - like around 1994 - orton re-formulated their cones so that
they would all drop at the same rate. it USED to be that their cones would
drop differently between cone sitters, regular cones, small cones, etc. and
they used to drop at slower rates. now once they are dropping - they're down!


if you're still using up an old inventory that may explain the non-uniform
dropping of the cones.

along with other reasons...

see ya

steve




Subject: Cone question
From: Hotmail
Date: 7/28/2003 7:25 AM Pacific Daylight Time
Message-id:

since we're talking about cones....

I test fired my new Bailey 2927-10 kiln to cone 6 yesterday. The kiln only
had four shelves in it and no ware. This Bailey comes with both a
controller and a kiln sitter as a backup. I used the "Fast Glaze" setting
to cone 6 on the controller.

I used a cone 8 bar in the kiln sitter and two sets of witness cones inside
the kiln (5,6,7). The kiln sitter shut down the kiln *before* the
controller had a chance to. The witness cones indicated that temp didn't
quite get up to cone 6 (bent about 90 degrees over). The preview readout on
the controller said it reached 2195 F before the kiln sitter shut it down.

I'll do another test firing and use a cone 10 bar in the kiln sitter next
time and watch the witness cones and controller closely to make sure they
agree.

Why would the kiln sitter shut down with a cone 8 bar in it when the witness
cones indicate it didn't quite get up to cone 6? Was this because the
sitter cone is close to the wall and elements or what?

Thanks,
David


From: Lindsay MacArthur
Organization: Posted via Supernews, http://www.supernews.com
Newsgroups: rec.crafts.pottery
Date: Sun, 27 Jul 2003 07:27:56 -0400
Subject: Cone question

Thank you very much for your response. I will definitely follow your
suggestion.

LMac

On Fri, 25 Jul 2003 07:58:38 +0100, Steve Mills
wrote:

Well done for putting a cone in, always wise with the first firing.
I guess your controller was set to give you a fairly slow firing, which
means the heatwork required to melt the cone took place before the
controller shut it down. When you next fire, be there to watch the
cones, note the temperature that 6 goes down at and adjust the
controller to shut down at that temperature. Check it every 8 to 10
firings. If your pieces look OK then you haven't done any damage.
We find that some glazes rated at a particular cone are better at the
next one up the scale.

Steve
Bath
UK


In article , L.Mac
writes
I just finished my first glaze firing (Olympic 2827H with V6-CF
Controller) to ^6 and it apparently got too hot (even though the
temperature readout indicated it was at the correct temp) b/c my 7
cone melted. How can this affect my pieces?
LMac










steve graber