Calling on Kiln experts

I just discovered that our studio bought a skutt cone 6 kiln which is used
to do cone 6 glaze firings. We do probably 2 firings a week when things are
busy. Needless to say our brand new kiln is dropping in performance and we
will soon have to buy new elements. So.... Would it help significantly to
lower our glaze firings to cone 5? We are getting at least one cone
difference between the top shelf and the bottom shelf. Would firing to a
lower temperature but holding it for at least 30 minutes even out the
firing, give us a higher heat work while possibly extending the life of the
elements? ... Any ideas would be appreciated.

"DKat" wrote in message
...
I just discovered that our studio bought a skutt cone 6 kiln which is used
to do cone 6 glaze firings. We do probably 2 firings a week when things
are busy. Needless to say our brand new kiln is dropping in performance
and we will soon have to buy new elements. So.... Would it help
significantly to lower our glaze firings to cone 5? We are getting at
least one cone difference between the top shelf and the bottom shelf.
Would firing to a lower temperature but holding it for at least 30 minutes
even out the firing, give us a higher heat work while possibly extending
the life of the elements? ... Any ideas would be appreciated.

I believe in always doing a 30 minute soak. It gives glazes time to mature
and allows the evening out of temperature in the kiln. I always do a
thirty minute soak when doing a bisque too.
Dropping the temp might extend the life of the elements a little, at my
local club (I have my own kiln though) we dropped from cone 8 to cone 6
firings, we also introduced a kiln firers test and certificate ) and the
maintainance bills dropped away significantly. However from cone 6 to cone
5?? Cone 5 is getting fairly low for domestic ware, plus you would have to
check out that all the glazes still worked. Cone 51/2 would be worth
looking at I guess. I think though that at our local club having the kilns
loaded properly, doing soaks and having a kiln firers test are the things
that improved results and reduced maintainance bills.
A

DKat wrote:
I just discovered that our studio bought a skutt cone 6 kiln which is used
to do cone 6 glaze firings. We do probably 2 firings a week when things are
busy. Needless to say our brand new kiln is dropping in performance and we
will soon have to buy new elements. So.... Would it help significantly to
lower our glaze firings to cone 5? We are getting at least one cone
difference between the top shelf and the bottom shelf. Would firing to a
lower temperature but holding it for at least 30 minutes even out the
firing, give us a higher heat work while possibly extending the life of the
elements? ... Any ideas would be appreciated.


In most electric kilns, and probably fuel kilns as well, there's at
least a one cone variation in different parts. In electric kilns, the
cylindrical shape and tendency for heat to rise make the top hotter.
Also the cracks where the lid and body of the kiln meet probably
contribute to the problem. Some electric kilns try to help the bottom of
the kiln by adding a coil in the floor of the kiln.
The best workaround is to use a fairly tall stilt for the bottom
shelf--I prefer 6 inches as a minimum. If, as you say, it's a new kiln,
the elements should not need replacing for at least 50 glazes, and
possibly as much as 100 glaze firings at cone 6. Firing down (soaking)
may help alleviate the temperature fluctuations. But you can also learn
which glazes work best at a solid cone 6 and which (usually glossy)
glazes can take a lower temperature.
You'll know when to change elements when they start to burn out, or when
the length of firing becomes unacceptably long (they lose heating
potential as they age).
There's one other fix for uneven heating--getting a thicker coil for the
cool area, usually from an element company like Duralite or Euclid's.
This will add amperage to the kiln load, so may trip the breaker, so
should only be used as a last resort.
Brad Sondahl

--
For my pottery how-to videos, original art, music, pottery, and
literature, visit my homepage
http://sondahl.com

To reply to me directly, don't forget to take out the "garbage" from my
address.

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

On Thu, 21 Apr 2005 08:18:00 +1200, "annemarie"
wrote:

snip.
Dropping the temp might extend the life of the elements a little, at my
local club (I have my own kiln though) we dropped from cone 8 to cone 6
firings, we also introduced a kiln firers test and certificate ) and the
maintainance bills dropped away significantly.

Annemarie, I have to ask: What is a "kiln firers test
and certificate"?

Thanks!


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

"Brad Sondahl" wrote in message
...
DKat wrote:
I just discovered that our studio bought a skutt cone 6 kiln which is
used to do cone 6 glaze firings. We do probably 2 firings a week when
things are busy. Needless to say our brand new kiln is dropping in
performance and we will soon have to buy new elements. So.... Would it
help significantly to lower our glaze firings to cone 5? We are getting
at least one cone difference between the top shelf and the bottom shelf.
Would firing to a lower temperature but holding it for at least 30
minutes even out the firing, give us a higher heat work while possibly
extending the life of the elements? ... Any ideas would be appreciated.
In most electric kilns, and probably fuel kilns as well, there's at least
a one cone variation in different parts. In electric kilns, the
cylindrical shape and tendency for heat to rise make the top hotter. Also
the cracks where the lid and body of the kiln meet probably contribute to
the problem. Some electric kilns try to help the bottom of the kiln by
adding a coil in the floor of the kiln.
The best workaround is to use a fairly tall stilt for the bottom shelf--I
prefer 6 inches as a minimum. If, as you say, it's a new kiln, the
elements should not need replacing for at least 50 glazes, and possibly as
much as 100 glaze firings at cone 6. Firing down (soaking) may help
alleviate the temperature fluctuations. But you can also learn which
glazes work best at a solid cone 6 and which (usually glossy) glazes can
take a lower temperature.
You'll know when to change elements when they start to burn out, or when
the length of firing becomes unacceptably long (they lose heating
potential as they age).
There's one other fix for uneven heating--getting a thicker coil for the
cool area, usually from an element company like Duralite or Euclid's. This
will add amperage to the kiln load, so may trip the breaker, so should
only be used as a last resort.
Brad Sondahl

an orton vent can even out the temp differences top to bottom pretty well.

"Bob Masta" wrote in message
...
On Thu, 21 Apr 2005 08:18:00 +1200, "annemarie"
wrote:

snip.
Dropping the temp might extend the life of the elements a little, at my
local club (I have my own kiln though) we dropped from cone 8 to cone 6
firings, we also introduced a kiln firers test and certificate ) and the
maintainance bills dropped away significantly.

Annemarie, I have to ask: What is a "kiln firers test
and certificate"?

Thanks!


Bob Masta
dqatechATdaqartaDOTcom

Well there were a lot of people miss firing the kilns. They had work
resting against elements, glaze on shelves, programmed the controller
incorrectly, fired at the wrong temp. You name it any mistake that they
could make they made. Many of these people also thought that they new it
all so trying to talk to them just was not working.
So two of us came up with the idea of a kiln firing test. We sat down one
afternoon and wrote this test out then we intoducted the test and procedure.
Rather like a drivers licence, everybody had to sit the test (even the test
writers before we would be allowed to fire the kilns. Then a certificate
goes on the wall and only people who have a certificate could fire the kiln.
The result of this was that because there was a formal system more people
learned to fire the kilns, those who had been firing for a long time had a
refresher and stopped making mistakes. There were a couple of older ladies
who took offence and left. That was sad. It was necessary though because
the club could not have afforded to continue with the huge maintenance bill.
I don't seem to have a copy of the test any more though. I am not on the
committee now )

Some of the questions were something like this.

How do you stack props in the kiln
What happens if you use an earthenware glaze in a stoneware firing

"annemarie" wrote in message
...

"Bob Masta" wrote in message
...
On Thu, 21 Apr 2005 08:18:00 +1200, "annemarie"
wrote:

snip.
Dropping the temp might extend the life of the elements a little, at my
local club (I have my own kiln though) we dropped from cone 8 to cone 6
firings, we also introduced a kiln firers test and certificate ) and
the
maintainance bills dropped away significantly.

Annemarie, I have to ask: What is a "kiln firers test
and certificate"?

Thanks!


Bob Masta
dqatechATdaqartaDOTcom

Well there were a lot of people miss firing the kilns. They had work
resting against elements, glaze on shelves, programmed the controller
incorrectly, fired at the wrong temp. You name it any mistake that they
could make they made. Many of these people also thought that they new it
all so trying to talk to them just was not working.
So two of us came up with the idea of a kiln firing test. We sat down one
afternoon and wrote this test out then we intoducted the test and
procedure. Rather like a drivers licence, everybody had to sit the test
(even the test writers before we would be allowed to fire the kilns.
Then a certificate goes on the wall and only people who have a certificate
could fire the kiln.
The result of this was that because there was a formal system more people
learned to fire the kilns, those who had been firing for a long time had a
refresher and stopped making mistakes. There were a couple of older
ladies who took offence and left. That was sad. It was necessary though
because the club could not have afforded to continue with the huge
maintenance bill. I don't seem to have a copy of the test any more though.
I am not on the committee now )

Some of the questions were something like this.

How do you stack props in the kiln
What happens if you use an earthenware glaze in a stoneware firing


I like it! As it now stands the only people allowed to fire kilns, mix
glazes, etc. are those given the task to do (members who know what they are
doing, hired student help). Of course our standards change every time a new
resident artist takes charge so this may be the future for our studio.