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bisque firing

updated wed 14 dec 11

 

Cynthia Semel on mon 22 jul 96

I just opened my first bisque firing at ^012 and it came out great- meaning
it didn't burn off. Now, is it necessary to fire the pieces again? If so,
what are the risks of the burnish burning off in the second firing?
Cynthia

Joyce Lee on mon 28 jun 99

Do any of you bisque fire in your gas kiln? Any special problems related
to this practice? I know many of you once-fire in either the electric or
the gas kiln, but I don't know about bisque. Thank you.

Joyce
In the Mojave

Joyce Lee on tue 29 jun 99

Thanks for all the sage words about firing bisque in my gas kiln. I'm
changin' my ways next firing well fortified with words from wise
clayarters. One such post came from Matt Alexander who is teaching in
Japan and has a chockfull home page ... no pots ... but delightful shots
of his school, students, friends, family, sights. What a bright one he
is! My reward for all your help is to give you his url:

http://www.biwa.ne.jp/~malexand

Joyce
In the Mojave thinkin' about Mel&Dannon's workshop going on in San
Marcos right now ... Terry from Nottingham says it's going great ... of
course.

mel jacobson on sun 18 jul 99

one of the most important lessons that ron roy has given us is:
slow down the bisque firing.
take a long time, go slow.
15-20 hours.
take your time.
it will pay big dividends.
and it costs the same.
10 hours at 10 amps...or 20 hours at 6, or 2 hours at 50 amps.
you want good pots....fire bisque slow.
thank you mr. roy.....you are a friend to the list.
(even though you cannot tap center worth a damn.)
mel.mn.
near canada, but not one. (well in some ways)
http://www.pclink.com/melpots
from minnetonka, minnesota, u.s.a.

Wade Blocker on tue 21 dec 99


Sherry,
You should fire your work to cone 06 for the bisque firing. Some
clayarters fire to cone 04.
For the glaze firing you fire to cone 6 so that your clay body becomes
mature and vitrified. Mia in ABQ

Edouard Bastarache on fri 22 jun 01


Hi all,

I glaze fire at c/9=BD and bisque by "the eye and the nose".
If the inside of the electric kiln is red/orange to orange
and it stinks sulfur strongly enough in the room I turn off
all the switches.
Why waste cones, I have been doing that for 33 years.

Later,

Edouard Bastarache
Irr=E9ductible Qu=E9becois
Sorel-Tracy
Dans / In "La Belle Province"
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
----- Message d'origine -----
De : Snail Scott
=C0 :
Envoy=E9 : 22 juin, 2001 19:28
Objet : Re: bisque firing


> At 08:14 AM 6/22/01 -0700, you wrote:
> >Is there an optimum temperature for firing bisque?
>
>
> I can go as low as ^012-014 with good results,
> depending on glazing methods and recipes.
> Why fire higher, unless you are using low-
> fire glazes which react badly to outgassing?
> It just takes longer and costs more.
>
> If I am planning to use a low-fire commercial
> red glaze, for instance, I may bisque as high
> as ^03, to make sure that nothing new is going
> to outgas in the ^06 glaze firing.
>
> If I am making a simple one-piece work, I may
> single-shot the firing, with no bisque at all.
>
> If the piece is delicate or needs things done
> at an awkward angle, I bisque to around ^08,
> because I bought a lot of that cone on sale!
> It's high enough to allow me to handle the
> piece without breakage during glazing, and
> no higher than it needs to be. I also bisque
> low for my multi-part pieces, since I often
> make parts that cannot be test-fitted together
> while green, and a low bisque allows me to
> take an angle grinder and true up the contact
> surfaces without undue wear and tear on either
> the work or the grinding disc.
>
> For those last applications, any temperature
> between ^012 and ^08 is just fine, and I could
> go higher or lower with no real problems.
>
> Note: I brush my surfaces, which may include
> slip, underglaze and engobes more often than
> glaze. If I dipped my work, I would be more
> concerned about consistency of temperature.
> Which temperature would be less important than
> picking one that works and being consistent,
> since the absorbency of the bisque increases
> with the decrease in temperature, and the
> thickness of the glaze coating will be affected.
> Check your thickness!
>
> (Wetting the piece will help the brush
> move more freely on absorbent bisque.)
>
> Note: When wiping oxides and such for a stain
> effect, a lower bisque will allow more color
> to be absorbed by the clay and not be wiped
> off. This may or may not be a good thing,
> depending on your intentions for the piece.
>
> In summation: Unless your highest glaze firing
> will include one of the 'sensitive' low-fire
> colors, it doesn't matter much what your bisque
> temperature is. There are differences, but they
> usually don't amount to much. Pick a temperature
> based on which results are important to you.
>
> -Snail
>
>
_________________________________________________________________________=
___
__
> 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.

Eleanor on fri 22 jun 01


Is there an optimum temperature for firing bisque?

I use clay rated ^6 and fire electric. I was bisquing at ^04 until a
few months ago when I read mel's suggestion that ^06 is
better---"sucks up the glaze" I think he said. ^06 seems fine but I
was wondering if going even lower would work.
I am also considering my electric bills.
TIA
Eleanor Kohler
Centerport, NY, which is on Long Island and where we may well be
paying the highest electric rates in the country.

Charles Moore on fri 22 jun 01


Eleanor,

I am entering this discussion even though I thought that I have signaled "NO
MAIL" for a while. I bisque to cone 09. Glenn Nelson, in his early book
called (I think) "Ceramics," uses cone 010.

I suspect that studios where people share space--especially in school
situations--, cone 06 might be best. I find, however, that 09 works just
fine.

Charles Moore
Sacramento, CA
Making a massive household move at this time. Movers on Monday!

Subject: bisque firing


> Is there an optimum temperature for firing bisque?
>
> I use clay rated ^6 and fire electric. I was bisquing at ^04 until a
> few months ago when I read mel's suggestion that ^06 is
> better---"sucks up the glaze" I think he said. ^06 seems fine but I
> was wondering if going even lower would work.
> I am also considering my electric bills.
> TIA
> Eleanor Kohler

Snail Scott on fri 22 jun 01


At 08:14 AM 6/22/01 -0700, you wrote:
>Is there an optimum temperature for firing bisque?


I can go as low as ^012-014 with good results,
depending on glazing methods and recipes.
Why fire higher, unless you are using low-
fire glazes which react badly to outgassing?
It just takes longer and costs more.

If I am planning to use a low-fire commercial
red glaze, for instance, I may bisque as high
as ^03, to make sure that nothing new is going
to outgas in the ^06 glaze firing.

If I am making a simple one-piece work, I may
single-shot the firing, with no bisque at all.

If the piece is delicate or needs things done
at an awkward angle, I bisque to around ^08,
because I bought a lot of that cone on sale!
It's high enough to allow me to handle the
piece without breakage during glazing, and
no higher than it needs to be. I also bisque
low for my multi-part pieces, since I often
make parts that cannot be test-fitted together
while green, and a low bisque allows me to
take an angle grinder and true up the contact
surfaces without undue wear and tear on either
the work or the grinding disc.

For those last applications, any temperature
between ^012 and ^08 is just fine, and I could
go higher or lower with no real problems.

Note: I brush my surfaces, which may include
slip, underglaze and engobes more often than
glaze. If I dipped my work, I would be more
concerned about consistency of temperature.
Which temperature would be less important than
picking one that works and being consistent,
since the absorbency of the bisque increases
with the decrease in temperature, and the
thickness of the glaze coating will be affected.
Check your thickness!

(Wetting the piece will help the brush
move more freely on absorbent bisque.)

Note: When wiping oxides and such for a stain
effect, a lower bisque will allow more color
to be absorbed by the clay and not be wiped
off. This may or may not be a good thing,
depending on your intentions for the piece.

In summation: Unless your highest glaze firing
will include one of the 'sensitive' low-fire
colors, it doesn't matter much what your bisque
temperature is. There are differences, but they
usually don't amount to much. Pick a temperature
based on which results are important to you.

-Snail

Ron Roy on sat 23 jun 01


Hi Eleanor,

I have always bisqued at 04 for a number of reasons.

Forget the electricity cost between the two - too small to be a consideration.

Many potters bisque at 06 and if everything is going OK there is no reason
to change up - however...

At 04....

Less chance of dunting during the cooling at the quartz inversion because
the ware is stronger - an important consideration for those making bigger
ware and/or working with porcelain. Bigger factor in fast cooling electric
kilns - which most are.

Cleaner bisque - important when firing in reduction using iron bearing clays.

Your glazes have to be a bit thicker - this is an advantage especially with
those glazes that tend to settle out - and - you don't have to stir the
glaze as much between pots when glazing.

I have always thought - when deciding on which techniques I am going to use
- to make sure those techniques are going to be appropriate for larger
ware. What you don't want - is to have to change to a higher bisque firing
for any of the above reasons - in the middle of something. You would need
to change the consistency of your glazes at that point and that will take
some trial and error.


My advice is to say where you are.

RR

>Is there an optimum temperature for firing bisque?
>
>I use clay rated ^6 and fire electric. I was bisquing at ^04 until a
>few months ago when I read mel's suggestion that ^06 is
>better---"sucks up the glaze" I think he said. ^06 seems fine but I
>was wondering if going even lower would work.
>I am also considering my electric bills.
>TIA
>Eleanor Kohler
>Centerport, NY, which is on Long Island and where we may well be
>paying the highest electric rates in the country.

Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513

Lee Love on sat 23 jun 01


----- Original Message -----
From: "Eleanor"


> Is there an optimum temperature for firing bisque?

They seem to bisque lower here in Japan, around ^012? Some of the bisque from
the Noborigama is very soft. They don't go by cone, but by color of the kiln.

I sponge all the bisque at the workshop with a water soaked sponge
(enough water to lay an even layer on the bisque, but not enough to run or
drip.) Because I do this, I touch every single piece of work that is fired at
the workshop. If there is not enough water, the glaze will pinhole when it is
applied. I think the other reason for wiping all the bisque is because it gets
any dust off the work that is left from the scraping of the zogan.

I've had a couple Matchawan break in my hands while I was sponging them.
Sensei didn't bat an eyelid, just asked my Sempai (elder brother apprentice) to
get another one.

We just finished loading a small kiln today. Will be fired on monday (it is
saturday here right now.) I enjoy watching Sensei decorate with slip trailing
from the ladle.

--

Lee Love
Mashiko JAPAN Ikiru@kami.com
Interested in Folkcraft? Signup:
Subscribe: mingei-subscribe@egroups.com
Or: http://www.egroups.com/group/mingei
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PERRY STEARNS on mon 25 jun 01


Ron Roy says most electric Kilns are fast cooling. My Kiln when firing =
at ^04 takes as long to cool to 200 as it does to reach ^04 when firing =
at medium, longer when firing fast. Would this be considered fast =
cooling?

If this IS considered fast cooling, would it be beneficial to get a =
thermal blanket to throw over the Kiln at what temperature after heat =
has cut off? Could such an action be useful in slowing a glaze ^06 =
cooling in an electric Kiln? This Kiln is a Skutt 1027 w electronic =
controls.
Fran Stearns

Ron Roy on tue 26 jun 01


Hi Fran,

If you have a pyrometer in your kiln you will be amazed at how fast the
cooling is from top temperature down to about 400C - and I am using an
insulated model. I wish some one would watch a kiln cooling and record the
temp drop every hour - it would be enlighting for all of us.

The problem in bisque firings is the quick cooling as the ware goes through
the quartz inversion at 573C - that is the only time we need to be
concerned. Some solve it by using a controller to turn the kin back on say
from 650 down to 500C. It is the uneveness of the cooling that results in
dunting - not the speed.

I've considered ways of slowing down an electric kiln using some insulating
material but have rejected it. I am sure some do it - and I'm sure that
sealing the kiln well at the end of the firing would help. In the end the
vast majotity of electric kilns are under insulated - for economic reasons
- a false economy to be sure.

I must warn about using kaowool blankets and such in this way - those
fibers are not what you need to be breathing - period.

So I have to ask - how long to 04? I just fired a bisque and shut off at
10pm last night - It was cool enough to unstack at 5PM today. If I had had
larger platters and plates in it I would have made sure I slowed the
cooling down between 650 and 500C.

In the end - if you are not getting cracking you are not cooling too fast.
The main problem for most of us is plates and platters. Raising them a bit
off the kiln shelf is a good way to help em cool more evenly from rime to
foot rim.

RR


>Ron Roy says most electric Kilns are fast cooling. My Kiln when firing at
>^04 takes as long to cool to 200 as it does to reach ^04 when firing at
>medium, longer when firing fast. Would this be considered fast cooling?
>
>If this IS considered fast cooling, would it be beneficial to get a
>thermal blanket to throw over the Kiln at what temperature after heat has
>cut off? Could such an action be useful in slowing a glaze ^06 cooling in
>an electric Kiln? This Kiln is a Skutt 1027 w electronic controls.
>Fran Stearns

Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513

KYancey on tue 26 jun 01


Ron Roy wrote:

> Hi Fran,
>
> If you have a pyrometer in your kiln you will be amazed at how fast the
> cooling is from top temperature down to about 400C - and I am using an
> insulated model. I wish some one would watch a kiln cooling and record the
> temp drop every hour - it would be enlighting for all of us.
>

You are right. I did an hour by hour temp check, and it changed the way I cool my
kiln.
Here are my first results.

Time deg. F.
8:30AM 667.4
9:00AM 701.6
10:00AM 993.2
11:00AM 1151.6
12:00PM 1250.6
1:00PM 1679
1:35PM 1779.8
2:00PM 1472
3:00PM 1112
4:00PM 842
5:00PM 647.6
6:00PM 530.6
7:00PM 422.6

This was supposed to be a cone 06 bisque, but I did not have witness cones. My
sitter dropped at 1779.8. I now have witness cones.

This is using a 30 yr old Jen-Ken Kiln 24 X 31 with 21/2" brick.
I replaced the elements about a year ago. I fire an avarage of twice a month.

I have since recorded two other firings. Another bisque and a cone 6 glaze. If
anyone would like to see these results, let me know.

Ken

Fredrick Paget on tue 26 jun 01


Ron,
As you requested I am posting the cooling curve for my Bailey ConeArt
electric kiln. It is double walled - a layer of insulating brick and one
inch of fiber board . I also had a piece of one inch fiberboard laid on the
top. (Lid closed all the time.)
These readings were read off of a chart recording from my Partlow recording
pyrometer. It has a pen that draws a line on a circular chart. I run the
recorder when I am experimenting with crystal glazes.
It just so happens that this crystal growing cycle ends at 1065 C which is
in the bisque range. Then the kiln is shut off and cools naturally. Here
are the readings from the point of shutoff of the elements. I tried to
interpolate the readings as well as I could but the divisions on the chart
are a minimum of 25 deg. F so I may be a little off on some of the
readings. If you plot these on graph paper and draw a smooth curve through
them it will expose any that are off. I converted to C using a little hand
held Franklin Translator/Travel Ace calculator. It has a built in
conversion for temperature (among other things). If there is any error
there it is my fault and the F reading rules.

HOUR Deg. F Deg.C
0 1950 1065
1 1650 899
2 1425 774
3 1215 657
4 1100 593
4.25 1070 577
4.5 1030 554
4.75 1000 538
5 975 524
6 875 468
7 775 413
8 675 357
9 612 322
10 540 282
11 475 246
12 425 218
13 375 190
14 335 168

16 275 135

18 225 107

20 175 79

22 150 65

24 135 57

Fred Paget

>If you have a pyrometer in your kiln you will be amazed at how fast the
>cooling is from top temperature down to about 400C - and I am using an
>insulated model. I wish some one would watch a kiln cooling and record the
>temp drop every hour - it would be enlighting for all of us.
>
>The problem in bisque firings is the quick cooling as the ware goes through
>the quartz inversion at 573C - that is the only time we need to be
>concerned. Some solve it by using a controller to turn the kin back on say
>from 650 down to 500C. It is the uneveness of the cooling that results in
>dunting - not the speed.
>Ron Roy

From Fred Paget, Marin County, California, USA

mel jacobson on tue 12 oct 04


i always think of ron roy when i bisque fire.
yes, every time.

slow, get out all the crap. slow down.

but to wayne's question, i have
a strong opinion.

it all depends on how you glaze.
or, thinking about lee's thoughts on
bisque. it changes, depending on many factors.

thick glaze.
soft bisque.

thin glaze, hard bisque.

if you layer, as i do, you must
allow a bit more glaze to absorb.

so, i bisque to cone 08.
same for the chinese glaze tests. 08. lots of layers..
and, i use a second hand on a clock to count the seconds
in the glaze. very important. know the thickness, count the
seconds.

i have on some occasions bisque fired to 010.

ron would have us move to a higher bisque.
porcelain for sure. he likes 06.
i just cannot get the results i like at 06.
others will find it very suitable.

bisque firing can be done many ways.
but slow is critical. long and slow.
(stop it tony.)

being consistent, knowing why you are bisque firing
to a certain temperature is important.
what kind of work do you do?
are the impurities burned off?
how much glaze is absorbed?

in my opinion, the claybody is not as important
as `what you are doing with that body and glaze`.

without question the range for bisque firing
in our modern world is 08-06.

and then adjust your glaze to match the firing temperature
and hardness of the bisque.

and, do not be afraid to cover your bisque ware with
a sheet of fine poly. keep off the dust.
and, you can actually buy plastic now. you don't have to
use those old cleaner bags. drop cloth plastic...cut to the
size of your shelf. perfection. i have seen folks using
plastic that is dirtier than the air. oxymoron.
clean, new plastic over bisque. nice.
mel




From:
Minnetonka, Minnesota, U.S.A.
web site: my.pclink.com/~melpots
or try: http://www.pclink.com/melpots
new/ http://www.rid-a-tick.com

Lee Love on tue 12 oct 04


mel jacobson wrote:

> without question the range for bisque firing
> in our modern world is 08-06.


With oil costing $53.00 a barrel, 012 makes a lot of sense.
(side note: is oil drilling picking up in the States? In the '70s,
when oil was cheaper than $53.00 a barrel, there was a lot of domestic
oil drilling.) I met Toshi Okuma at Northern Clay Center in
'91. He bisque fired Continental Super White (a fine white
stoneware) to 012. He told me no one back in Mashiko fired higher,
because electricity or fuel was so expensive there. Also, at NCC,
the price of firing the the electric kiln to 012 instead of 06 was
substantially less, so it made sense to me.

The ware is strong enough at 012. You just have to sponge
wipe the ware (which eliminates the need to cover the bisque) and/or
make the glaze thinner to compensate for the softer bisque.

012 is pretty high compared to the bisque in the
noborigama. I have also found that I get better results with
shinos on a lower bisque.


--
Lee in Mashiko, Japan http://mashiko.org
http://www.livejournal.com/users/togeika/ WEB LOG
http://public.fotki.com/togeika/ Photos!

Maureen Fike on sat 4 jun 05


Can anyone tell me if you can use a household oven to bisque fire regular clay? Maureen


As the eagle was killed by the arrow winged with his own feather,
so the hand of the world is wounded by its own skill. ~Helen Keller

__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
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Wayne Seidl on sat 4 jun 05


I've already written a post about that Maureen. It is in the
archives.
Best,=20
Wayne Seidl

-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Maureen
Fike
Sent: Saturday, June 04, 2005 11:51 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: bisque firing

Can anyone tell me if you can use a household oven to bisque fire
regular clay? Maureen

Snail Scott on sat 4 jun 05


At 08:51 AM 6/4/2005 -0700, Maureen wrote:
>Can anyone tell me if you can use a household oven to bisque fire regular
clay?=20


A home oven will only reach about 600=BAF; to bisque=20
clay to a conventional standard, you ought to be=20
closer to 1200=BAF, minimum. and most people prefer to=20
go hotter. A home oven can be used to force-dry clay,=20
however, if set on the lowest setting with the door=20
cracked open a bit. Some low-fire clays do seem to=20
sinter slightly at 500=BAF-600=BAF, but not to the point=20
that most people would call 'bisque'. Baking your=20
clay won't do it any harm, though, and may strengthen=20
it slightly for its ride to a kiln.

-Snail

william schran on sat 4 jun 05


Maureen wrote:>Can anyone tell me if you can use a household oven to
bisque fire regular clay?<

Nope, won't get hot enough even in self cleaning mode.
Need to get up to 1800=B0F+.
Bill

Fredrick Paget on fri 19 may 06


>I live in the Bay area and have difficulty finding studios that would allow
>me to experiment bisque firing w/ mixed local clay bodies (as opposed to
>firing pure commercial grade clays) in their kilns. This makes sense due to
>the possibility of the clay exploding and messing up the kilns, etc. I'm
>curious to know for those of you who want to experiment bisque firing w/
>various mixed local clay bodies in your area, do you end up doing this in
>your own kiln(s) somehow? Thanks for sharing any advice!



Over the years I have fired scores of objects made of our local clays
and never had any blow up. Just be sure the ware is really bone dry.
I even made bricks out of reclaim and fired them with no problem.
Marin sits on great deposits of earthenware clay. The main problem in
getting to it is that it is buried deep and you have to watch for
some place where they are digging and dumping the stuff they dig up.
They are usually happy for you to take some because they have to pay
to dump it.
--
From Fred Paget,
Marin County, CA, USA
fredrick@well.com

Charter Member Potters Council

Stella on fri 19 may 06


I live in the Bay area and have difficulty finding studios that would allow
me to experiment bisque firing w/ mixed local clay bodies (as opposed to
firing pure commercial grade clays) in their kilns. This makes sense due to
the possibility of the clay exploding and messing up the kilns, etc. I'm
curious to know for those of you who want to experiment bisque firing w/
various mixed local clay bodies in your area, do you end up doing this in
your own kiln(s) somehow? Thanks for sharing any advice!

Stella on sun 21 may 06


would you happen to know any community clay studios in the bay area (san
francisco/east bay/marin) that would let one bring in your own clay (from
local diggings) for bisque firing? thanks!

Mike Gordon on sun 21 may 06


Stella, Have you tried any local high school ceramic teachers? When I
was teaching I'd fire almost anything a parent brought in.... there was
always an old pot around that I could put questionable ( melting ) clay
in.Mike Gordon
On May 21, 2006, at 12:31 PM, Stella wrote:

> would you happen to know any community clay studios in the bay area
> (san
> francisco/east bay/marin) that would let one bring in your own clay
> (from
> local diggings) for bisque firing? thanks!
>
> _______________________________________________________________________
> _______
> 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.
>

Donna Pfledderer@Virtual Business Connection on sat 25 aug 07


I'm totally confused about bisque firing, or either that I'm really hard
headed and can't grasp it.

But I'm getting conflicting information from what I have read and been
told. So, I'm hoping the experts out
there can help me. PLEEESE!

From the post
"Stoneware should be bisque fired between C/010 & up to C/06." I thought
stoneware should be fired at Cone 4 and up?


I did my first glaze firing weeks ago, pieces were fired by someone else
at Cone 4. I did my first bisque firing myself and was told that I
should fire Cone 6 Clay at Cone 6. The pieces came out a yellowy tan
color. Forgive my description, not sure how to describe it.=20

But I do know that the Cone 4 bisque firing is more porous and pink, so
the glazes will come out "brighter" then the Cone 6 bisque firing.=20

Is there a set rule on how you should bisque fire? The Cone 6 firing is
rough, where as the cone 4 firing is smooth, which I like best. But if
you are using some of the pottery for functional use, to use for food,
what is the best way to fire it? Or is there a best way?

Thanks for any help you can give. I may just have to learn from my own
experience and do what I find works best for me. I need to find a book
"Bisque Firing for Dummies".=20

Donna Light Pfledderer

Donna Pfledderer@Virtual Business Connection on sun 26 aug 07


I want to thank all of you who replied to my question about bisque
firing. You all said the same thing, so I am no longer confused. I
figure if 10 say the same thing, then it has to be right and the 1
person who told me her way, must be wrong.

Thanks again!
Donna Light Pfledderer

John Kudlacek on mon 27 aug 07


Please be easy on the person who told you the wrong way to bisque.
Perhaps you just misunderstood her.
John

Joseph Herbert on sun 11 dec 11


Janet wrote:

"I am looking for someone in Chicago's northwest suburbs who would be
willing to occasionally include one or two of my pieces in their bisque
firing. I will of course be happy to pay for this service."

Some years ago, when I started on this clay journey, I had an occasion for
similar thoughts. I had taken a clay class at the West Chester County
Community College in White Plains and a subsequent period of study at the
Craft Guild of Dallas and was becoming more involved in clay. I got a
contract training development job at the South Texas Project southwest of
Bay City, Texas. I found a motel unit with an efficiency kitchen setup at
the Luther Hotel in Palacios, Texas and cast about for additional clay
opportunities. There seemed to be none, so I purchased a wheel and covered
a corner of my little kitchen with plastic. I had to go to Houston or
Austin to get clay, but that was not a problem, both locations had brewpubs
(especially Austin).

After a little bit, I started to have some amount of greenware stacked
around my motel room. This was a sort of problem, since I wanted to
transport it to Dallas to eventually be fired at the Craft Guild. Even as
thick as I make things, greenware is pretty fragile. So, there was a
greenware ceramics studio in Palacios. I was not really interested in
ceramic tissue box holders with a conch shell on the side, but the woman di=
d
have the ability to fire ceramics to cone 04. Just what I needed. After
some convincing on my part, she undertook the task.

I gave her a stack of my greenware and returned after a few days to get bac=
k
a stack of bisque, with two pieces showing dunting. I didn't know what
dunting was. However, there were two pieces that had cracks across the
foot, not extending to the rim. After some research, I knew the name for
what I had: dunting. Later, I gave her another stack of pots, and got no
cracks. I think on the final attempt also had a cracked foot in that load.

After some thought and more experience, I believe I know why I got that
result. The lady was used to firing her slip cast ware that was all of ver=
y
uniform thickness. The uniformity allowed her to fire and cool rapidly,
because the ware, especially If stilted, would cool rapidly without too muc=
h
stress - since it was all uniformly thin walled. The pots I presented were
much different, having wide variations in thickness, especially in the area
of the foot. In addition, the pots (mostly bowls) were stacked in a nested
fashion making the concentration of retained heat even greater. So, when
she cooled my pots like she cooled her ware, the still-hot feet experienced
rapid cooling and then cracking.

If there is a moral, it would be that you should choose a person who
processes ware similar to yours, using clay similar to yours, and who has
tendencies toward care and introspection rather than the routine and
automatic.

Headed back to Texas in 6 days, haven't touched clay for a year. Hope to
change that. I have skin splits anyway - go figure.

Joe

Joseph Herbert
Training Developer

Lee on mon 12 dec 11


I've fired in "other peoples' kilns" for most of my career. I'd
highly recommend getting a small electric to bisque in. Bisque is
much easier to transport than greenware.

It just dawned on me, because of my need to transport work
for bisque and glaze firing, that I've kept the forms strong and
simple, to help cut down on breakage. Now that I am kiln'd again, I
can get back to making more intricate and fragile things.

--
=3DA0Lee Love in Minneapolis
http://mingeisota.blogspot.com/

=3DA0"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D9=
7that is, =3D
"The
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue