search  current discussion  categories  kilns & firing - misc 

bisque fire cool-down schedule

updated fri 24 oct 97


Talbott on tue 30 sep 97

I fire to ^06 during our bisque firings... How quickly or slowly would you
suggest to allow for cooling? ...Marshall


Details will be forth coming!!!

Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box 4116,
Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call first)
WBS Live Chat Room, Sat Nites 10 PM EDT & Sun Afternoons at 1 PM EDT

Ron Roy on sat 4 oct 97

I don't think it matters much - just turn off the kiln and let it cool

If there is dunting (cracking) it will be happening between 650C and 500C -
in that case turn your bottom elements on low for that period of cooling.
If there is still cracking then turn the bottom element on medium for that

I have that Orton controller you hear me raving about - with the two
pyrometers. If you have one of those you let it cool to 650 then start a
cooling ramp - lets say 50C per hour for big stuff. At 650C the controller
starts the kiln again - evens it out (the bottoms are usually cooler then
the top) - then lets it drop 50C per hour. Then, if you have set the lower
temp. to 500C, turns the heat off in 3 hours and the load cools naturally
without danger of dunting.

There is a feature on that controller which lets you see the difference in
degrees (F or C) between the top and the bottom. The trick to avoiding
dunting would be to slow the cooling before 573C where the quartz inversion
takes place and which is responsible for the dunting. You would want to
stop any uneven cooling before 5TH but I don't know how accurate our cheap
pyrometers are at that temperature so starting the slow down above 600C
would seem prudent to me.

>----------------------------Original message----------------------------
>I fire to ^06 during our bisque firings... How quickly or slowly would you
>suggest to allow for cooling? ...Marshall

Ron Roy
93 Pegasus Trail
M1G 3N8
Evenings, call 416 439 2621
Fax, 416 438 7849
Studio: 416-752-7862.
Home page