Hendrix, Taylor J. on sun 16 feb 03
Hey all:
We are currently trying to unravel a kiln problem. The kiln in question
is a paragon with digital controller (touch 'n fire?). It is three
"rings" high, approx. 7 cu. ft.(sorry about not having most of the
specifics, but it may not matter). Regular firings are ^06 bisque and
^6 glaze firings. We suspect a problem. When we test fired it to cone
7 with 30 minute soak at the top, the self supporting cone 6 cone at the
bottom of the kiln didn't touch and the one on the top shelf wasn't even
halfway down. This was an empty firing. We have been suspecting a
problem for some time, but the results are intermittent. Sometimes the
firings seem okay and at other times they are terrible. This could be
an element problem (teacher hasn't changed the elements in a long time),
but I would expect if that were the case, the time to target temperature
would just grow longer and longer 'til it reached infinity, not what we
saw--a regular cycle and shutdown. It could be the thermocouple, but
teacher said she has had that replaced recently. Could it need
calibrating? Is it possible to calibrate with the digital computer
controls? I'm planning on helping teacher buy new elements, and I will
install them, but I'm not sure this is going to solve this problem. I
can't think of any other thing that would cause under firing while
allowing the controller to cycle through as if everything were
okeydokie. Ideas?
I am doing my homework regarding orton cones just in case there is a
problem with their use, but I don't think this is the problem either.
Taylor, in Waco
Arnold Howard on tue 18 feb 03
The kiln you are describing is probably a TnF-24-3. It sounds like the
elements are okay.
Do you know which controller the kiln has? You can tell by the model #
printed on the plastic faceplate. Each controller in the series we have
produced behaves a little differently.
Though the thermocouple was just replaced, the problem may still be the
thermocouple. That's what it sounds like. How did changing the
thermocouple affect the way the kiln fired?
Sincerely,
Arnold Howard
Paragon Industries, L.P.
www.paragonweb.com
----- Original Message -----
From: Hendrix, Taylor J.
> We are currently trying to unravel a kiln problem. The kiln in
question
> is a paragon with digital controller (touch 'n fire?). It is three
> "rings" high, approx. 7 cu. ft.(sorry about not having most of the
> specifics, but it may not matter). Regular firings are ^06 bisque and
> ^6 glaze firings. We suspect a problem. When we test fired it to
cone
> 7 with 30 minute soak at the top, the self supporting cone 6 cone at
the
> bottom of the kiln didn't touch and the one on the top shelf wasn't
even
> halfway down. This was an empty firing. We have been suspecting a
> problem for some time, but the results are intermittent. Sometimes
the
> firings seem okay and at other times they are terrible. This could be
> an element problem (teacher hasn't changed the elements in a long
time),
> but I would expect if that were the case, the time to target
temperature
> would just grow longer and longer 'til it reached infinity, not what
we
> saw--a regular cycle and shutdown. It could be the thermocouple, but
> teacher said she has had that replaced recently. Could it need
> calibrating?
Hendrix, Taylor J. on sun 23 feb 03
Hey Arnold and all:
I just read your thermocouple post and I will definetally check that out =
on teach's kiln (I just love taking things apart!). The controler is a =
DTC 600C according to my teacher. The thermocouple was replaced awhile =
back, and teacher says things seemed fine. The most recent firing =
(bisque to cone 06) was a bit hot according to teacher, so I will =
definetally check the thermocouple, and thank you for your reply.
Taylor in Waco
-----Original Message-----
From: Arnold Howard [mailto:arnoldhoward@ATT.NET]
Sent: Tuesday, February 18, 2003 9:33 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Paragon firing conundrum
The kiln you are describing is probably a TnF-24-3. It sounds like the
elements are okay.
Do you know which controller the kiln has? You can tell by the model #
printed on the plastic faceplate. Each controller in the series we have
produced behaves a little differently.
Though the thermocouple was just replaced, the problem may still be the
thermocouple. That's what it sounds like. How did changing the
thermocouple affect the way the kiln fired?
Sincerely,
Arnold Howard
Paragon Industries, L.P.
www.paragonweb.com
----- Original Message -----
From: Hendrix, Taylor J.
> We are currently trying to unravel a kiln problem. The kiln in
question
> is a paragon with digital controller (touch 'n fire?). It is three
> "rings" high, approx. 7 cu. ft.(sorry about not having most of the
> specifics, but it may not matter). Regular firings are ^06 bisque and
> ^6 glaze firings. We suspect a problem. When we test fired it to
cone
> 7 with 30 minute soak at the top, the self supporting cone 6 cone at
the
> bottom of the kiln didn't touch and the one on the top shelf wasn't
even
> halfway down. This was an empty firing. We have been suspecting a
> problem for some time, but the results are intermittent. Sometimes
the
> firings seem okay and at other times they are terrible. This could be
> an element problem (teacher hasn't changed the elements in a long
time),
> but I would expect if that were the case, the time to target
temperature
> would just grow longer and longer 'til it reached infinity, not what
we
> saw--a regular cycle and shutdown. It could be the thermocouple, but
> teacher said she has had that replaced recently. Could it need
> calibrating?
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Hendrix, Taylor J. on thu 27 feb 03
Hey all:
The mystery continues. As per Arnold Howard's suggestion, I cracked
open teacher's kiln (hehe) control box and examined all thermocouple
connections. Connections at the ceramic block looked good, but I re cut
and connected the controller wires. They were quite crushed and may
have been intermittent. The business end of the thermocouple does seem
to be corroded with very slight separation at the tip. I have no idea
what a "bad" thermocouple looks like, so I don't know if this is normal
wear and tear.
The latest firing (programmed cone 7 with a 20 min hold) bent the Orton
self-standing cone 6 to a little more than tip touching the shelf. So,
a bit hotter than cone 6 but not a 7, which was programmed.
Anybody think this is something other than a bad thermocouple? Still
don't think that it is the elements although teacher did say it has been
"years" since she has changed her elements.
Taylor, perplexed in Waco
william schran on fri 28 feb 03
Taylor wrote: to be corroded with very slight separation at the tip. >
If the "business end" of the thermocouple has a slight separation,
it's shot. Need to replace it. I've replaced the thermocouples in all
5 kilns at school with the "bi-metal" type. Ordered just the
thermocouple and used the connection block from the old twisted metal
thermocouples. The bi-metal ones cost more up front ($50 - $60), but
after replacing the old ones about every year or two, I haven't had
any problems with the first bi-metal one I got three years ago.
Bill, in Fredericksburg, Va., where the snow continues - about
another 4 -6" until we're through.
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