Marilu on thu 19 feb 04
Hello, I am new and so glad this site is here! You have a lot of great
people and information. I have just fired my first bisque.
I tried searching but can't find out this really basic
question-I have a L and L kiln and used a 3 hour preheat
with the slow bisque to cone 04 easy fire setting. I am
using Laguana #50 cone 6 stoneware. I fired a light
load of ware to cone 04. The cycle is complete and
the temperature is down to 1238 now and I know I am
suppose to wait but I can't find out how long to wait -what
temperature should I wait for on the display before I lift the lid?
I also have the sure vent on. Does anyone else use
this clay and is it really necessary to use this long
of a preheat if the ware is beyond the cold to touch
stage when you put it in? Also I read that you can bisque
leather hard clay and even wet clay- Does anyone have any
advice on how to do this? Thanks for any information-Marilu
Carol Tripp on fri 20 feb 04
Hi Marilu,
Are you in a rush? Firing leatherhard or even wet pots is problematic -
doable if done really slowly but unless you are up against a deadline, it
would be better to wait until your ware is bone dry; not just no longer
cold. Perhaps you need to make a few sacrificial pieces. Break one open
when it is no longer cool to touch. See if it is dry. If not, wait longer
and then break another. Get to know what your clay feels like when it is
bone dry. And then if you are still not quite sure your ware is dry, then
do a few hours candling at the start of the bisque firing.
As for when to open the kiln - there are people with lots of patience and
they say to wait until the kiln is cooled off and you can touch it without
any yelping. The rest of us have ants in the pants. I tend to wait until
it is at least down to 150C or lower. Lower is definately better.
Get yourself a notebook so you can record each bisque and glaze firing with
info such as time started, time finished, light load, heavy load, type of
ware, degree of dryness of the ware, glazes used, where the pots were
placed, firing program used (you will make up your own schedules as you
become more experienced).
Good luck.
Best regards,
Carol
Dubai, UAE
Marilu wrote:
>Hello, I am new and so glad this site is here! You have a lot of great
>people and information. I have just fired my first bisque.
>I tried searching but can't find out this really basic
>question-I have a L and L kiln and used a 3 hour preheat
>with the slow bisque to cone 04 easy fire setting. I am
>using Laguana #50 cone 6 stoneware. I fired a light
>load of ware to cone 04. The cycle is complete and
>the temperature is down to 1238 now and I know I am
>suppose to wait but I can't find out how long to wait -what
>temperature should I wait for on the display before I lift the lid?
>I also have the sure vent on. Does anyone else use
> this clay and is it really necessary to use this long
>of a preheat if the ware is beyond the cold to touch
>stage when you put it in? Also I read that you can bisque
>leather hard clay and even wet clay- Does anyone have any
>advice on how to do this? Thanks for any information-Marilu
>
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Krista Peterson on sat 21 feb 04
> The cycle is complete and
>the temperature is down to 1238 now and I know I am
>suppose to wait but I can't find out how long to wait -what
>temperature should I wait for on the display before I lift the lid?
>I also have the sure vent on. Does anyone else use
> this clay and is it really necessary to use this long
>of a preheat if the ware is beyond the cold to touch
>stage when you put it in? Also I read that you can bisque
>leather hard clay and even wet clay- Does anyone have any
>advice on how to do this?
I would wait until it gets below 500 degrees to crack the lid. Or just go do something else, forget about it and wait until it is completely cool if you don't have any deadlines. I have seen a wet firing done before, but it was in a gas kiln. I don't believe you can do a wet firing in an electric kiln, kind of dangerous. When I saw it done in a gas kiln, the whole inside of the kiln was soaked with water, repeatedly before loading. I believe the idea was to have the same moisture content in the clay as well as the kiln and then the whole thing was fired very slowly. It seemed more trouble than it was worth to me. I think it's just as easy to quick dry something in a warm kiln or on top of one that is firing. But then that also depends on exactly what you are trying to dry quickly.
Take care
Krista Peterson
-----Original Message-----
From: Marilu
Sent: Feb 19, 2004 12:01 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: New Bisque question
Hello, I am new and so glad this site is here! You have a lot of great
people and information. I have just fired my first bisque.
I tried searching but can't find out this really basic
question-I have a L and L kiln and used a 3 hour preheat
with the slow bisque to cone 04 easy fire setting. I am
using Laguana #50 cone 6 stoneware. I fired a light
load of ware to cone 04. Thanks for any information-Marilu
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logan johnson on sun 22 feb 04
Hi Krista!
My teacher taught me that the rule of thumb was to cool for twice as long as you fire.
How good that information is I will leave to the experts to decide should they feel the need. The explanation I had been given was my kiln would last longer & if it was a glaze firing my glazes would not get cracks it wasn't ment to as long as my glaze fit my clay body. Also that it was better for my elements. In my opinion (for whatever it's worth) ceramics is all about paitence. I didn't want to cultivate the bad habit of rushing my kiln & taking the risk of crazing my glazes. I just wait 'till my kiln is cold to the touch & at the peepholes before I look into the kiln for the first time. I won't unload untill I can comfortably handle things with an unprotected hand. Just make sure the shelfs are cool enough to handle SAFETY FIRST!!! Sometimes those shelfs can suprise you. This is the only opinion I can give you others who know far more than I do will have to help with the rest! Hope the clay gods/godesses smile on your efforts! Logan
Krista Peterson wrote:
> The cycle is complete and
>the temperature is down to 1238 now and I know I am
>suppose to wait but I can't find out how long to wait -what
>temperature should I wait for on the display before I lift the lid?
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.
Logan Johnson Audeo Studios
www.audeostudios.com
"Carpe Argillam!!"
Cindi Anderson on sun 22 feb 04
Hi
I can answer one question from first hand, hot off the press experience.
Last night I decided at the last minute that I needed to bisque some test
tiles in a kiln load that had to fire that night. I made them and put them
in the kiln completely wet and started up the kiln. I didn't know how long
of a candle I would need, so I programmed a 5 hour candle, then the
remainder of the bisque firing. The pieces were fine, none exploded or even
cracked. They were poorly constructed as it was 3 am and I was barely
awake. I thought there would be cracking due to thick/thin areas, but there
wasn't. Warpage wasn't even too bad compared to what I expected. I have
gotten worse warpage when I tried hard not to get it :-)
I wouldn't try this with regular work unless I had to, but sometimes you
have to. So actually I may run an experiment with a bowl and see what
happens. I would mainly be worried about warping, but maybe there are other
things to worry about that others can tell us about.
As to your other questions, I never candle (preheat) if my pieces are dry
enough (except thick sculptures which I always candle). Usually I don't
fire often so my greenware sits around forever. This week I am working on
pieces for my first show and every minute counts, so I have been doing short
candling when things aren't completely dry. I think you will learn that you
usually don't need 3 hours candling.
Also I was very anxious to open the kiln to get it cooling faster. Again I
usually am patient and wait, but I don't have time now. Most things I read
said under 400F was ok, of course under 300F even better. So I cracked it
at 350F. (It takes as long to go from 500 F to 300 F as it does from 1200F
to 500F, which is excrutiating when you need the kiln for your next load!)
There was pinging, but only on the pieces that were c.6 glazes on c.10 clay.
The c.6 glazes on c.6 clay didn't ping. So I suspect the former will craze
eventually. I'm not sure, is pinging "always" a sign that crazing is to
come? Or do pieces sometimes ping in cooling but the fit is ok and they
don't craze?
Cindi
Fremont, CA
----- Original Message -----
> Marilu wrote:
I have a L and L kiln and used a 3 hour preheat with the slow bisque to cone
04 easy fire setting. I am
> >using Laguana #50 cone 6 stoneware. I fired a light load of ware to cone
04. The cycle is complete and
> >the temperature is down to 1238 now and I know I am suppose to wait but I
can't find out how long to wait -what
> >temperature should I wait for on the display before I lift the lid?
> >I also have the sure vent on. Does anyone else use this clay and is it
really necessary to use this long
> >of a preheat if the ware is beyond the cold to touch stage when you put
it in? Also I read that you can bisque
> >leather hard clay and even wet clay-
claybair on mon 23 feb 04
I have an L&L JD230.
Saturday I bisque fired about 20 plates.
Some were dry but quite a few were leather hard.
There were filler pieces that were still pretty wet.
So I programmed it to 5 hours candle overnight.
When I came down in the morning it was at 1500+
..... BIG Oops. I expected a massive disaster and
a month of work exploded.
I waited to 170 degrees and opened the kiln....
Only 2 filler pieces on the bottom shelf
popped with minimal dispersal of bisque shards.
Now I wouldn't do this as practice and will continue to candle
when pieces are still cold or thick or too valuable to lose.
Plus I'll check my program to ensure no more potential late
night disasters occur.
I think I know why my plates didn't blow!
My local pottery supply didn't have the plate sitters I wanted.
So I made some small balls of clay and stacked the plates with 3 balls
between each of them. There were 3 to 4 plates to a stack.
Because they were raised plus they could move I think they fared
better. The clay balls act like ball bearings.
I still need the plate sitters as this system won't work on a glaze firing
but I think they saved my last bisque firing.
Gayle Bair
Bainbridge Island, WA
http://claybair.com
-----Original Message-----
From: Cindi Anderson
Hi
I can answer one question from first hand, hot off the press experience.
Last night I decided at the last minute that I needed to bisque some test
tiles in a kiln load that had to fire that night. I made them and put them
in the kiln completely wet and started up the kiln. I didn't know how long
of a candle I would need, so I programmed a 5 hour candle, then the
remainder of the bisque firing. The pieces were fine, none exploded or even
cracked. They were poorly constructed as it was 3 am and I was barely
awake. I thought there would be cracking due to thick/thin areas, but there
wasn't. Warpage wasn't even too bad compared to what I expected. I have
gotten worse warpage when I tried hard not to get it :-)
I wouldn't try this with regular work unless I had to, but sometimes you
have to. So actually I may run an experiment with a bowl and see what
happens. I would mainly be worried about warping, but maybe there are other
things to worry about that others can tell us about.
As to your other questions, I never candle (preheat) if my pieces are dry
enough (except thick sculptures which I always candle). Usually I don't
fire often so my greenware sits around forever. This week I am working on
pieces for my first show and every minute counts, so I have been doing short
candling when things aren't completely dry. I think you will learn that you
usually don't need 3 hours candling.
Also I was very anxious to open the kiln to get it cooling faster. Again I
usually am patient and wait, but I don't have time now. Most things I read
said under 400F was ok, of course under 300F even better. So I cracked it
at 350F. (It takes as long to go from 500 F to 300 F as it does from 1200F
to 500F, which is excrutiating when you need the kiln for your next load!)
There was pinging, but only on the pieces that were c.6 glazes on c.10 clay.
The c.6 glazes on c.6 clay didn't ping. So I suspect the former will craze
eventually. I'm not sure, is pinging "always" a sign that crazing is to
come? Or do pieces sometimes ping in cooling but the fit is ok and they
don't craze?
Cindi
Fremont, CA
----- Original Message -----
> Marilu wrote:
I have a L and L kiln and used a 3 hour preheat with the slow bisque to cone
04 easy fire setting. I am
> >using Laguana #50 cone 6 stoneware. I fired a light load of ware to cone
04. The cycle is complete and
> >the temperature is down to 1238 now and I know I am suppose to wait but I
can't find out how long to wait -what
> >temperature should I wait for on the display before I lift the lid?
> >I also have the sure vent on. Does anyone else use this clay and is it
really necessary to use this long
> >of a preheat if the ware is beyond the cold to touch stage when you put
it in? Also I read that you can bisque
> >leather hard clay and even wet clay-
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