A crafts forum. CraftBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » CraftBanter forum » Craft related newsgroups » Pottery
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

bisque cool down schedule



 
 
Thread Tools Display Modes
  #1  
Old May 22nd 07, 12:45 AM posted to rec.crafts.pottery
[email protected]
external usenet poster
 
Posts: 13
Default bisque cool down schedule

I have been having a lot of cracking/pinging in some of my bisque
ware, and I am wondering if anyone has advice on what rate I should
ramp down. I am firing in a gas kiln, 4 burners, and it's about 8
cubic feet. I am doing cone 05 for bisque, to then fire to cone 5,
and using Laguna B-mix, no sand, and also Hagi porcelain. In the
trouble shooting notes about the clay, they say one reason for cracks
can be from cooling down to fast, what isn't there is any advice on
how to go about the cool down. I usually don't control the cool down,
I just let the kiln sitter trip, and maybe damper down.

What I plan to do with my next bisque fire is put a higher bar in the
kiln sitter, a cone 06, keep my eye on the witness cones that will be
cone 04 & 05, then when cone 05 bends I will turn down the kiln, not
turn it off. My question is, about how much should I lower the temp,
and in what sorta time increments?
Thanks
Sa

Ads
  #2  
Old May 25th 07, 01:39 AM posted to rec.crafts.pottery
Brad Sondahl[_2_]
external usenet poster
 
Posts: 2
Default bisque cool down schedule

wrote:
I have been having a lot of cracking/pinging in some of my bisque
ware, and I am wondering if anyone has advice on what rate I should
ramp down. I am firing in a gas kiln, 4 burners, and it's about 8
cubic feet. I am doing cone 05 for bisque, to then fire to cone 5,
and using Laguna B-mix, no sand, and also Hagi porcelain. In the
trouble shooting notes about the clay, they say one reason for cracks
can be from cooling down to fast, what isn't there is any advice on
how to go about the cool down. I usually don't control the cool down,
I just let the kiln sitter trip, and maybe damper down.

What I plan to do with my next bisque fire is put a higher bar in the
kiln sitter, a cone 06, keep my eye on the witness cones that will be
cone 04 & 05, then when cone 05 bends I will turn down the kiln, not
turn it off. My question is, about how much should I lower the temp,
and in what sorta time increments?
Thanks
Sa

Well, first, the cones with a 0 on it get hotter in reverse of how
you're suggesting--Cone 06 is cooler than cone 05. When you rise above
cone 01 it switches to the way that makes sense...
With a gas kiln, dampering down is essential for cooling, as the draft
would shock pots going through the quartz inversion temperature. You
shouldn't have to fire down, but you might have to block both input and
exhaust areas to keep it from cooling too fast. I think that's probably
the reason most folks bisque with electricity...
Brad Sondahl

--
visit Sondahl.com for original art, music, pottery, photography,
literature, videos and more.
To respond directly, don't forget to take out the "garbage"
  #3  
Old July 7th 07, 08:10 AM posted to rec.crafts.pottery
Sam Kelly
external usenet poster
 
Posts: 10
Default bisque cool down schedule

If you block off the flew and burner ports as soon as you turn the kiln off
you should have no problems. This stops any air entrering the kiln at all
and it will quickly stabilise. Do not open the kiln door under 165DegCelcius
wrote in message
ups.com...
I have been having a lot of cracking/pinging in some of my bisque
ware, and I am wondering if anyone has advice on what rate I should
ramp down. I am firing in a gas kiln, 4 burners, and it's about 8
cubic feet. I am doing cone 05 for bisque, to then fire to cone 5,
and using Laguna B-mix, no sand, and also Hagi porcelain. In the
trouble shooting notes about the clay, they say one reason for cracks
can be from cooling down to fast, what isn't there is any advice on
how to go about the cool down. I usually don't control the cool down,
I just let the kiln sitter trip, and maybe damper down.

What I plan to do with my next bisque fire is put a higher bar in the
kiln sitter, a cone 06, keep my eye on the witness cones that will be
cone 04 & 05, then when cone 05 bends I will turn down the kiln, not
turn it off. My question is, about how much should I lower the temp,
and in what sorta time increments?
Thanks
Sa



  #4  
Old July 28th 07, 05:27 PM posted to rec.crafts.pottery
Bubbles_
external usenet poster
 
Posts: 81
Default bisque cool down schedule


"Sam Kelly" wrote in message
...
If you block off the flew and burner ports as soon as you turn the kiln
off you should have no problems. This stops any air entrering the kiln at
all and it will quickly stabilise. Do not open the kiln door under
165DegCelcius


I have an old potter friend who goes by the rule "If it is too hot to hold,
it is too hot to take out."

That means wait until around 20-30 Deg Celcius - especially with glazed
stuff, I suppose.

Anyway, being patient with kilns has resulted in me having very few problems
with cracking and such.

Marianne


 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Paint for Bisque kklos Pottery 0 March 21st 06 01:19 PM
Two Cool, Cool packages starlia Beads 10 July 17th 04 06:42 PM
Stove top bisque? Sam Pottery 19 April 7th 04 02:14 AM
AD: More Bisque Beads Juanita Floyd Beads 0 March 7th 04 11:24 PM
the color of bisque Seasa Pottery 1 January 25th 04 11:17 PM


All times are GMT +1. The time now is 06:34 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 CraftBanter.
The comments are property of their posters.