Maria Elaine Lanza on wed 28 jul 99
What is the logic and/or rule(s) of thought behind choosing a bisque
firing range appropriate for specific clay bodies?
The college I attended years ago used ^010 exclusively for their ^10
reduction ware... the clay body used was somewhat heavily grogged for
teaching purposes... as students progressed in their throwing skills
porcelain was introduced... both clay bodies were bisqued at ^010... the
thinking there was at this temperature the bisqued clay was more receptive
to glaze adherence and uniform application.
I still bisque at ^010 sometimes ^09 for my ^6 white stoneware and
^6 porcelain... have no problems with glazing or final firing that I can
detect
using this bisque temperature range... nonetheless, am curious though if
there is a rule of thumb about bisquing that would possibly encourage an
improvement to the final firing glaze results... any thoughts, advise...
thanks in advance, Marie Elaine
wschran@erols.com on sun 1 aug 99
<000901bed85c$6d9dc6c0$34751ad-@mel> wrote:
original article:http://www.egroups.com/group/clayart/?start=48882
> ----------------------------Original message-------------------------
---
> What is the logic and/or rule(s) of thought behind choosing a bisque
> firing range appropriate for specific clay bodies?
>
> The college I attended years ago used ^010 exclusively for their ^10
> reduction ware... the clay body used was somewhat heavily grogged for
> teaching purposes... as students progressed in their throwing skills
> porcelain was introduced... both clay bodies were bisqued at ^010...
the
> thinking there was at this temperature the bisqued clay was more
receptive
> to glaze adherence and uniform application.
>
> I still bisque at ^010 sometimes ^09 for my ^6 white stoneware and
> ^6 porcelain... have no problems with glazing or final firing that I
can
> detect
> using this bisque temperature range... nonetheless, am curious
though if
> there is a rule of thumb about bisquing that would possibly encourage
an
> improvement to the final firing glaze results... any thoughts,
advise...
> thanks in advance, Marie Elaine
>
>Marie Elaine - When I was in school, we only did high fire reduction &
all bisque firing was done at ^08. Since I've been teaching, I do all
bisque firings at ^06 and considering going to ^04 to create a less
porous body to prevent students from getting too thick a coating of
glaze ( no matter how many time you demonstrate, some never listen). I
guess it's all what you are used to and what works for you. The only
thing is some clays contain larger percentages of organic compounds
which need a higher bisque to be sure all is burned out. If you start
noticing pits or bubbles in glazes, and nothing else has changed, you
may want to bisque at a higher temperature, even the same clay from
another part of the mine can have more organics in it.
Bill
Mike Bailey on sun 1 aug 99
In message , Maria Elaine Lanza writes
Dear Marie,
I suppose it all depends on the clay you are using. Many of the U.K.
clays have to be bisqued at 06 (1000 deg. C.) to avoid the risk of
'pavement' cracking. We'd certainly run into problems at 010 and would
expect cracks at right angles at the rims of pots and long curved cracks
around the sides of pots often with other cracks running at right angles
to these. We have to strike a balance between firing too high (above
1040 deg. C) and losing porosity (that hinders the glazing) and firing
low - which may give us pots that are easier to glaze but tend to dunt
on cooling.
In terms of stoneware generally with low bisque, high glaze, there will
be very little difference in glaze fit or maturation whatever temp. you
bisque to.
I feel sorry for the earthenware potters who have to do a high bisque to
vitrify the clay - and then have to find some way of getting the glaze
to stick and dry on the non-absorbent body.
Cheers,
Mike Bailey.
>----------------------------Original message----------------------------
>What is the logic and/or rule(s) of thought behind choosing a bisque
>firing range appropriate for specific clay bodies?
>
>The college I attended years ago used ^010 exclusively for their ^10
>reduction ware... the clay body used was somewhat heavily grogged for
>teaching purposes... as students progressed in their throwing skills
>porcelain was introduced... both clay bodies were bisqued at ^010... the
>thinking there was at this temperature the bisqued clay was more receptive
>to glaze adherence and uniform application.
>
>I still bisque at ^010 sometimes ^09 for my ^6 white stoneware and
>^6 porcelain... have no problems with glazing or final firing that I can
>detect
>using this bisque temperature range... nonetheless, am curious though if
>there is a rule of thumb about bisquing that would possibly encourage an
>improvement to the final firing glaze results... any thoughts, advise...
>thanks in advance, Marie Elaine
>
--
Mike Bailey
Barney Adams on wed 4 aug 99
Hi,
I first started bisque at 08, but I was getting terrible blistering on my
dark body.
I changed to a slow 04 and everthing cleaned right up.
Barney
wschran@erols.com wrote:
> ----------------------------Original message----------------------------
> <000901bed85c$6d9dc6c0$34751ad-@mel> wrote:
> original article:http://www.egroups.com/group/clayart/?start=48882
> > ----------------------------Original message-------------------------
> ---
> > What is the logic and/or rule(s) of thought behind choosing a bisque
> > firing range appropriate for specific clay bodies?
> >
> > The college I attended years ago used ^010 exclusively for their ^10
> > reduction ware... the clay body used was somewhat heavily grogged for
> > teaching purposes... as students progressed in their throwing skills
> > porcelain was introduced... both clay bodies were bisqued at ^010...
> the
> > thinking there was at this temperature the bisqued clay was more
> receptive
> > to glaze adherence and uniform application.
> >
> > I still bisque at ^010 sometimes ^09 for my ^6 white stoneware and
> > ^6 porcelain... have no problems with glazing or final firing that I
> can
> > detect
> > using this bisque temperature range... nonetheless, am curious
> though if
> > there is a rule of thumb about bisquing that would possibly encourage
> an
> > improvement to the final firing glaze results... any thoughts,
> advise...
> > thanks in advance, Marie Elaine
> >
> >Marie Elaine - When I was in school, we only did high fire reduction &
> all bisque firing was done at ^08. Since I've been teaching, I do all
> bisque firings at ^06 and considering going to ^04 to create a less
> porous body to prevent students from getting too thick a coating of
> glaze ( no matter how many time you demonstrate, some never listen). I
> guess it's all what you are used to and what works for you. The only
> thing is some clays contain larger percentages of organic compounds
> which need a higher bisque to be sure all is burned out. If you start
> noticing pits or bubbles in glazes, and nothing else has changed, you
> may want to bisque at a higher temperature, even the same clay from
> another part of the mine can have more organics in it.
> Bill
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