Bisque firing temp?
 

Is there a general rule about what temp (cone) to fire to the bisque stage? For
example, is it usually one cone under what you would use for glaze? I have some
clay that is Cone 5 and it seems I read that you fire at a lower cone for
bisque than when you glaze.
Thanks for answering all my ultra newbie questions.

Most folks bisque at Cone 06-04. If you bisque your cone 5 clay at cone 4,
you will not be able to easily glaze the pieces. 06/04 is a good temp that
drives out a lot of the moisture but still leaves your pieces porous enough
to accept the glazes. Good luck. Steve in Tampa, FL

"GaSeku" wrote in message
...
Is there a general rule about what temp (cone) to fire to the bisque
stage? For
example, is it usually one cone under what you would use for glaze? I have
some
clay that is Cone 5 and it seems I read that you fire at a lower cone for
bisque than when you glaze.
Thanks for answering all my ultra newbie questions.

i agree with Steve. note too that you don't always bisque at a lower
temperature than a glaze firing. the one example of this i can think of is that
a lot of commercial low-fire glazes are fired at about 06-05 but are best
applied to bisqueware that's been fired to 04.

As a point of interest; UK bisque temperatures are much the same with
the exception of our white earthenware clays. At 06-04 these are
severely underfired and have not completed their *primary* shrinkage, so
much so, that if you bisque at that temperature and then glaze fire 04
plus the body will shrink more than the glaze, and the latter will
*shiver* off, especially on the rims. The right bisque temperature for
these clays is more usually in the regions of cone 1 (1150 C. ish)!

Steve
Bath
UK


In article , SpunMud
writes
i agree with Steve. note too that you don't always bisque at a lower
temperature than a glaze firing. the one example of this i can think of is that
a lot of commercial low-fire glazes are fired at about 06-05 but are best
applied to bisqueware that's been fired to 04.

--
Steve Mills
Bath
UK

"Steve Mills" wrote in message
...
As a point of interest; UK bisque temperatures are much the same with
the exception of our white earthenware clays. At 06-04 these are
severely underfired and have not completed their *primary* shrinkage, so
much so, that if you bisque at that temperature and then glaze fire 04
plus the body will shrink more than the glaze, and the latter will
*shiver* off, especially on the rims. The right bisque temperature for
these clays is more usually in the regions of cone 1 (1150 C. ish)!

Steve
Bath
UK


In article , SpunMud
writes
i agree with Steve. note too that you don't always bisque at a lower
temperature than a glaze firing. the one example of this i can think of
is that
a lot of commercial low-fire glazes are fired at about 06-05 but are best
applied to bisqueware that's been fired to 04.

--
Steve Mills
Bath
UK

I use a lot of different formulas of stoneware clays, and fire to 600-650
degrees farenheit to bisque.
It's never been necessary for me to go much higher than the conversion
temperature of the clay.
Of course, this is going to vary, depending on the formula, the amount of
grog, etc.
Your altitude and your humidity level are going to make a difference too,
but here at sea level,
it works for me. Saves on energy ($), and cooling time, both important
considerations for production work.

Wayne
Key West

It's never been necessary for me to go much higher than the conversion
temperature of the clay.
Of course, this is going to vary, depending on the formula, the amount
of grog, etc.
Your altitude and your humidity level are going to make a difference
too, but here at sea level,
it works for me. Saves on energy ($), and cooling time, both
important considerations for production work.

Wayne
Key West



Hello Wayne

Your answer is worth heaps. We trend to take what is written down as
gospel without testing it ourselves. I am working with a white stoneware
clay that matures at cone 6. Possibly has a frit of some sort in it. When
you think about it there probably isn't a great deal to burn out after it
reaches the conversion temperature. I have been firing bisque to 1000c
because that is what I was told I had to do

The only question is What adjustments have you made to your glazes?

Regards

John Webb

Just found out my school fires Cone 10 clay to bisque at 08.

holy cow! bisquing at 600-700 F? that's not even on my "orton" notes. (cone
022 shows at 1087F). i might have to try that someday. if it works, what a
tremendous savings in time and energy!