Tony Ferguson on sun 11 may 03
Thanks everyone thus far.
Where I was thinking on this was Bamboo Karen's mention of the 20 minute
cone 10 firing in the mini-gama. I am a bit intrigued by this as I had
learned (not tried YET) that anything less than around 8 hours for a cone 10
firing (start to finish--when you close the door) would be too hard on the
pots--that even a year or two later they could crack on someone's shelf from
the stresses caused from too fast a cone 10 firing and a stressful
relationship between the clay and glaze interface--not to mention a lack of
glaze color diversity. Of course kiln size would contribute to the firing
time do to overall mass affecting necessary time to heat everything up. I
am thinking of one of my portable raku kilns that I over fired because I was
yapping to someone and the heat color was white--so I am thinking above 2000
degrees and the pots were fine--but they were raku! Makes me wonder about
copper reds and other glazes that depend on a certain atmosphere maintained
in order for the glaze to develop as intended over a period of time, not 20
minutes--not to mention adequate cooling time. Perhaps it will manifest as
another attraction for the firing practices in La Crosse?
Thank you.
Tony Ferguson
On Lake Superior, where the sky meets the Lake
Stoneware, Porcelain, Raku and more
by Coleman, Ferguson, Winchester...
www.aquariusartgallery.com
218-727-6339
315 N. Lake Ave
Apt 312
Duluth, MN 55806
----- Original Message -----
From: "David Beumee"
To:
Sent: Sunday, May 11, 2003 10:29 PM
Subject: Re: minimum cone 10 time
> >What length of time does anyone feel is minimally necessary to fire to
cone
> >10 without any clay body/ glaze problems or defects?
>
> I say 8 hours is a minimum time to reach cone 10,
> and I recommend slowing down the firing at cone 9
> by turning down the gas pressure and easing in on cone 10
> slowly. Turning down the gas pressure with also ease up on the
> reduction, hopefully taking the atmosphere into straight oxidation.
> This really helps with glaze defects and brightens glaze colors.
>
> David Beumee
> Earth Alchemy Pottery
> Lafayette, CO
>
>
>
>
>
>
>
>
> 5/11/03 4:38:58 PM, Tony Ferguson wrote:
>
>
> >
> >
> >Thank you.
> >
> >Tony Ferguson
> >On Lake Superior, where the sky meets the Lake
> >
> >Stoneware, Porcelain, Raku and more
> >by Coleman, Ferguson, Winchester...
> >www.aquariusartgallery.com
> >218-727-6339
> >315 N. Lake Ave
> >Apt 312
> >Duluth, MN 55806
> >
>
>___________________________________________________________________________
___
> >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.
> >
>
>
____________________________________________________________________________
__
> 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.
>
Greg Johnson on sun 11 may 03
Tony,I fire my pots in about 5-6 hours @ ^10 and get great colors. Rutile bearing glazes I fire go for about 7 hours. Nils Lou at the college here in McMinnville (linfield) fires in like 4 hours.Greg JohnsonMuddy Valley Pottery www.geocities.com/muddyvalleypottery
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Tony Ferguson on sun 11 may 03
What length of time does anyone feel is minimally necessary to fire to cone
10 without any clay body/ glaze problems or defects?
Thank you.
Tony Ferguson
On Lake Superior, where the sky meets the Lake
Stoneware, Porcelain, Raku and more
by Coleman, Ferguson, Winchester...
www.aquariusartgallery.com
218-727-6339
315 N. Lake Ave
Apt 312
Duluth, MN 55806
David Beumee on sun 11 may 03
>What length of time does anyone feel is minimally necessary to fire to cone
>10 without any clay body/ glaze problems or defects?
I say 8 hours is a minimum time to reach cone 10,
and I recommend slowing down the firing at cone 9
by turning down the gas pressure and easing in on cone 10
slowly. Turning down the gas pressure with also ease up on the
reduction, hopefully taking the atmosphere into straight oxidation.
This really helps with glaze defects and brightens glaze colors.
David Beumee
Earth Alchemy Pottery
Lafayette, CO
5/11/03 4:38:58 PM, Tony Ferguson wrote:
>
>
>Thank you.
>
>Tony Ferguson
>On Lake Superior, where the sky meets the Lake
>
>Stoneware, Porcelain, Raku and more
>by Coleman, Ferguson, Winchester...
>www.aquariusartgallery.com
>218-727-6339
>315 N. Lake Ave
>Apt 312
>Duluth, MN 55806
>
>______________________________________________________________________________
>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.
>
ASHPOTS@AOL.COM on sun 11 may 03
Hi there Tony, I have a old Alpine 24 updraft. I have high pressure burners
that Marc Ward set up for me. I turn my left burner on about 10 or 11 on 1 or
2 pounds till about 5 AM where i turn on my right burner on 2 Lbs. I bump it
up every hour after that. I go 4 lbs a then 6 lbs. By that time about 9 AM
its at ^ 010 . I put it into reduction using my Axner Oxy probe. Its about 75
to 80 on the probe for a hour. I then adjust it so its about 65 to 75 on the
probe. It just fires its self till about 7 PM when i see ^8,^9,^10 bending.
This old kiln finishes off about 8:30PM and i open the top for 5 to 10
minutes for oxygen.Then its done.
I have also started firing about 9PM and get in to reduction about 11PM or 12
PM and go to sleep and get up at 5 AM and the firing is over by 9AM. My
firings are pretty even top & bottom. You tell me how long it takes to fire
my kiln. I think it takes about 50 Lbs of propane
I love my kiln, look at the pots it produces
www.lookoutmountainpottery.com
Mark
PS. the more i think about i have to say something. Howard Axner republished
Charles Counts books. Im sure he is not going to make gobs of money from
these books. I really think Howard Axner is a special person for doing this,
Thanks
Karen Sullivan on mon 12 may 03
Tony....
I absolutely agree that the amount of
time one takes to fire....has a profound influence
on the clay and the glazes....
I think the principle of the minigama is
to experiment with kiln design...watch what happens
on a small scale...understand the principles of fire...
and just think...you could collect toothpicks
every time you go out for dinner and collect
enough fuel to fire a sake cup....
I once fired a fast freddie wood kiln in
four hours...and the work that came out made
everyone wonder .... what was the point...
yellow/pale/ugly pots...
By contrast...there was a story of a potter
who traveled to any wood fire kiln that was
being fired and placed the same sculpture in
for another firing...after a dozen firings the
piece had acquired a rich patina of the flame
and the process....One could estimate how many
hours the piece had lived in the flame..
I think of the two as distinctly different
processes... the minigama is a kick...fun to
work with....
Sound firing principles and the affect of heat
on clay and glaze are best used with wisdom when
firing most work...
bamboo karen
julie milazzo on mon 12 may 03
Hey Tony, I've done it in my kiln anywhere from five hours a firing (accidently), including an hour and a half of candling time. The pots were fine, but the glazes looked like really bad cone 6 glazes. They covered up the texture, and appeared to just sit on top of the pieces, not marry into them. Also, I got a bunch of pinholes. My last firing went to 22 hours, mainly because my gas gauge is broken, and I was too cautious, since the last firing was that quick one. I did speed it up at the end, however, because it was around four in the morning. Anyway, I hit cone ten rapidly, after hovering around eight for awhile. The result? Better color and texture, but still some pinholing. I like the suggestion from another Clayarter (sorry, can't remember who...) that as you approach cone ten, you should back off on the gas a bit. That seems to be where most of the magic is at. Good luck. Happy potting! Jules
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Cindi Anderson on mon 12 may 03
That is very interesting, because previous discussions have concluded that
the firing up speed won't affect the look of the glazes much, rather it is
the cooling that affects them. Did you cool the same both time?
Thanks
Cindi
----- Original Message -----
From: "julie milazzo"
I've done it in my kiln anywhere from five hours a firing (accidently),
including an hour and a half of candling time. The pots were fine, but the
glazes looked like really bad cone 6 glazes. They covered up the texture,
and appeared to just sit on top of the pieces, not marry into them.
Vince Pitelka on mon 12 may 03
> That is very interesting, because previous discussions have concluded that
> the firing up speed won't affect the look of the glazes much, rather it is
> the cooling that affects them.
What previous discussions? Recently some of the experts like Ron and John
have advocated controlled cooling to develop beautiful glazes at cone 6, but
who ever said that it doesn't matter how fast you fire? To the contrary,
most glazes require adequate time to melt and for the glaze materials to
disperse, and do not respond well to recklessly fast firing. Ideal glaze
maturity and crystal growth are certainly enhanced by controlled cooling,
but they require proper melting and dispersion.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Office - wpitelka@tntech.edu
615/597-6801 x111, FAX 615/597-6803
http://iweb.tntech.edu/wpitelka/
Tony Ferguson on tue 13 may 03
Karen,
I am quit tickled with the thought (also thinking about ceramic industry
here and the efficiency they have arrived at) of being able to fire is let's
say, 2 hours, to cone 10 and have everyting look great. Your mini-gama,
although an experiment, makes me wonder about the possibilities. Is it
possible to have a quality firing in such a short period of time? I don't
know yet. What I have learned so far is that long and slow is best. Slow
going up and slow going down. None the less, I wonder if a clay body
and a glaze could be augmented
to produce beautiful and sound works in clay fired in a minimal amount of
time? I have fired raku in 45 minutes with beautiful results so why not
stoneware--another1 or 2 hours to temp? I think I will have to try that.
The fore fathers and mothers of clay baking certainly too their time in
early kiln development because they fired with wood and it took so long to
reach temp. Now with industrial refractory materials and alternative fuels
at our disposal, can we reduce this time? Time to play.
Tony
----- Original Message -----
From: "Karen Sullivan"
To:
Sent: Monday, May 12, 2003 10:06 PM
Subject: minimum cone 10 time
> Tony....
>
> I absolutely agree that the amount of
> time one takes to fire....has a profound influence
> on the clay and the glazes....
>
> I think the principle of the minigama is
> to experiment with kiln design...watch what happens
> on a small scale...understand the principles of fire...
> and just think...you could collect toothpicks
> every time you go out for dinner and collect
> enough fuel to fire a sake cup....
>
> I once fired a fast freddie wood kiln in
> four hours...and the work that came out made
> everyone wonder .... what was the point...
> yellow/pale/ugly pots...
>
> By contrast...there was a story of a potter
> who traveled to any wood fire kiln that was
> being fired and placed the same sculpture in
> for another firing...after a dozen firings the
> piece had acquired a rich patina of the flame
> and the process....One could estimate how many
> hours the piece had lived in the flame..
>
> I think of the two as distinctly different
> processes... the minigama is a kick...fun to
> work with....
> Sound firing principles and the affect of heat
> on clay and glaze are best used with wisdom when
> firing most work...
>
> bamboo karen
>
>
____________________________________________________________________________
__
> 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.
>
Gail Dapogny on tue 13 may 03
Cindi,
While there has been --from time to time -- a lot of discussion re the
merits of cooling slowly especially for particular glazes, those same
experts are not suggesting that cooling more slowly means you should or can
fire more quickly. It's just that in the past many people felt that cooling
was not involved in the formation of glaze effects.
If you go back into the archives, you will find most or all of the
respected people on this list advocating taking more time in the actual
firing. As Ron Roy once said (to paraphrase), while there are some glazes
that work just fine when fired quickly, they are exceptions. Over and over
you hear that glaze/clay fit, thermal strength, quality of the glaze,
lessening of flaws all depend upon slower firing plus soak at the top. Not
to mention the aesthetics: non-muddiness, deeper color, etc.
Away from the list, you also find Val Cushing (in his handbook) and Jeff
Zamek , among others, writing very clearly about taking time in firing.
---Gail Dapogny in Ann Arbor
>That is very interesting, because previous discussions have concluded that
>the firing up speed won't affect the look of the glazes much, rather it is
>the cooling that affects them. Did you cool the same both time?
>Thanks
>Cindi
Jocelyn McAuley on tue 13 may 03
On Mon, 12 May 2003, Vince Pitelka wrote:
> What previous discussions? Recently some of the experts like Ron and John
> have advocated controlled cooling to develop beautiful glazes at cone 6, but
> who ever said that it doesn't matter how fast you fire? To the contrary,
> most glazes require adequate time to melt and for the glaze materials to
> disperse, and do not respond well to recklessly fast firing. Ideal glaze
> maturity and crystal growth are certainly enhanced by controlled cooling,
> but they require proper melting and dispersion.
> Best wishes -
> - Vince
Hi Vince
There was an article by Pete Pinnel (I believe, I don't have my article
archive right here) in Clay Times several years back that spoke about fast
firing combined with slow cooling. His story sopke of an "older" potter
putting up with the vastly different firing style of his younger
apprentice/help.
Fast firing (400F/hr climb) with slow cooling is how I regularly fire my
glaze kiln loads. My bisque fires are another beast altogether. Perhaps
all the importance lies in the use of "reckless"... I like to think of my
style resulting out of adventurous instead!
thanks
Jocelyn
--
Jocelyn McAuley ><<'> jocie@worlddomination.net
Eugene, Oregon http://www.ceramicism.com
iandol on thu 15 may 03
Dear Tony Ferguson,
About five years ago I attended a lecture by one of the Product Managers =
of Arabia (Finland) who was doing a promotional tour of Australia. At =
that time Arabia were researching the idea of getting a four hour firing =
to cone 10 for their porcelain works. Since then I think one of the =
major European furnace makers has built a plant where the cold to cold =
time is down to thirty minutes. This was done in a rotary kiln which had =
segmented thermal zones to ensure transition through the Quartz phase =
changes without mishap. Both body fabric (Ceramic but not clay as we =
know it. White, Translucent and Rings like a Bell) and glazes are =
designed to mature to a durable product in this time span. I think you =
would find details somewhere in the ACS Bulletin archives.
Best regards,Ivor Lewis
Ron Roy on fri 16 may 03
I agree with Tony on this but every time this comes up I have wanted to
expaln something - time to do it I think.
If anyone fires in two hours you may be sure that the clay body and the
glazes are over fluxed enough to work.
If you take a "normal" cone 10 glaze (means usually fired for at least 10
hours) and fire it in 4 hours it will not mature properly - unless you soak
it at cone 10 long enough for the heat work to be done - and the cone to go
down. Ohterwise - if you don't soak you will have to fire higher to bend
the cone.
Adding more flux to make it melt faster is another way - an interestng
experiment would be to fire a cone 6 glaze to cone 10 in 4 hours - don't
try to bend cone 6 though - it may run depending on the glaze.
If you add more flux you lower the amounts of silica and alumina - both are
factors in glaze durability.
So when industry does tiles in a couple of hours you may be sure - both
body and glazes are over fluxed to compensate for the short firing times
and no cones are used.
Don't fire fast if you are single firing - gotta give the junk in the clay
time to get out. If you want to fire fast make sure your bisque firings are
slow enough to get the junk out of the clay.
RR
>I am quit tickled with the thought (also thinking about ceramic industry
>here and the efficiency they have arrived at) of being able to fire is let's
>say, 2 hours, to cone 10 and have everyting look great. Your mini-gama,
>although an experiment, makes me wonder about the possibilities. Is it
>possible to have a quality firing in such a short period of time? I don't
>know yet. What I have learned so far is that long and slow is best. Slow
>going up and slow going down. None the less, I wonder if a clay body
>and a glaze could be augmented
>to produce beautiful and sound works in clay fired in a minimal amount of
>time? I have fired raku in 45 minutes with beautiful results so why not
>stoneware--another1 or 2 hours to temp? I think I will have to try that.
>The fore fathers and mothers of clay baking certainly too their time in
>early kiln development because they fired with wood and it took so long to
>reach temp. Now with industrial refractory materials and alternative fuels
>at our disposal, can we reduce this time? Time to play.
>
>Tony
>
>
>----- Original Message -----
>From: "Karen Sullivan"
>To:
>Sent: Monday, May 12, 2003 10:06 PM
>Subject: minimum cone 10 time
>
>
>> Tony....
>>
>> I absolutely agree that the amount of
>> time one takes to fire....has a profound influence
>> on the clay and the glazes....
>>
>> I think the principle of the minigama is
>> to experiment with kiln design...watch what happens
>> on a small scale...understand the principles of fire...
>> and just think...you could collect toothpicks
>> every time you go out for dinner and collect
>> enough fuel to fire a sake cup....
>>
>> I once fired a fast freddie wood kiln in
>> four hours...and the work that came out made
>> everyone wonder .... what was the point...
>> yellow/pale/ugly pots...
>>
>> By contrast...there was a story of a potter
>> who traveled to any wood fire kiln that was
>> being fired and placed the same sculpture in
>> for another firing...after a dozen firings the
>> piece had acquired a rich patina of the flame
>> and the process....One could estimate how many
>> hours the piece had lived in the flame..
>>
>> I think of the two as distinctly different
>> processes... the minigama is a kick...fun to
>> work with....
>> Sound firing principles and the affect of heat
>> on clay and glaze are best used with wisdom when
>> firing most work...
>>
>> bamboo karen
>>
>>
>____________________________________________________________________________
>__
>> 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.
>>
>
>______________________________________________________________________________
>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.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
| |
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