Roxanne Hunnicutt on sat 17 sep 11
What with Steven Hill visiting for a workshop recently, I tried just about
every glaze I ever use on unfired clay in my electric kiln..... Since I had
all these preconceived ideas about what would happen, I was happy with the
third kiln load to finally find ONE glaze that would not work!
All the rest looked just like they did on bisqued clay.
Other than that one glaze, all my glazes work fine in electric at cone six
on B Mix that I made in my pug mill with a little paper content and some
unknown grog.
I just could not believe how easy it was.
Not one of the pots collapsed in my hand or on being sprayed, dipped or
otherwise glazed.
WHY DID WE BISQUE? Isn't that a huge waste of energy?
Have any of you tried single firing with soda? salt? reduction? Any other
ideas for single firing?
What were the results?
Steven is a real gem of a guy to get to do a workshop. He really makes you
think....whether he is doing what you do or not.
And tell me his glazes are not gorgeous! THEY SHINE. They glow. They have
crystals and contrasting shine and matte areas. THEY LOOK LIKE REDUCTION,
yes, but they are interesting in lots of ways besides.
So SINGLE FIRED WORK at lower temps. Who can tell me a better plan for an
energy saving GREEN METHOD IN CLAY?
Roxanne in OR
--
*There is nothing either good or bad, but thinking it makes it so **--
Shakespeare*
William & Susan Schran User on sun 18 sep 11
On 9/18/11 12:39 AM, "Roxanne Hunnicutt" wrote:
> What with Steven Hill visiting for a workshop recently, I tried just abou=
t
> every glaze I ever use on unfired clay in my electric kiln..... Since I h=
ad
> all these preconceived ideas about what would happen, I was happy with th=
e
> third kiln load to finally find ONE glaze that would not work!
> ...I just could not believe how easy it was.
> Not one of the pots collapsed in my hand or on being sprayed, dipped or
> otherwise glazed.
> WHY DID WE BISQUE? Isn't that a huge waste of energy?
We bisque for convenience.
We were taught to bisque fire in school - for very good reasons!
In your own studio, where you control everything, is not an essential part
of the process.
I think if I had a good set up for spraying glazes, I might not bisque my
pots. Steven has introduced his process, layering glazes containing
titanium, that when exposed to a controlled cooling, develop lots of depth
and interesting surfaces from crystal development. None of this is really
new, but he has developed, over the years, his process resulting in some
unique surfaces.
If you have not read it yet, get a copy of "Mastering Cone Six Glazes" by
John Hessleberth and Ron Roy in which they discuss developing stable
functional glazes with depth. It's all in the firing - more specifically,
the cooling. Here's the link: http://www.masteringglazes.com/
We use some of their glazes developed for oxidation firing in our ^6
reduction firings.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Snail Scott on sun 18 sep 11
On Sep 17, 2011, at 11:39 PM, Roxanne Hunnicutt wrote:
> WHY DID WE BISQUE? Isn't that a huge waste of energy?
I often single-fire. Sometimes, I bisque. Why? When
do I choose to bisque?
I bisque when I have a multi-part project that must be
fired in multiple kiln loads, and I can't have the whole
thing sitting around as fragile greenware in order to
true up the sections when it's all complete. By bisque-
firing each phase when complete, I can stack the parts
in a corner, and then lay it all out together for final fitting
before surfacing and high-firing it all.
I bisque when I want to do wiped-back finishes, such
as oxide or engobe washes, and you can't get the same
effect when scrubbing back on greenware.
I bisque when I am doing multi-stage surfaces, and I
want to 'lock in' the bottom layers before proceeding
to the top ones.
Some glazes simply behave better on bisqued clay.
There are also some that prefer green clay, and a whole
lot that just don't care. If you are deeply attached to a
'special needs' glaze, then give it what it requires. If
not, forget it.
When I am teaching, I require my students to bisque-
fire their work. I tell them it's not a 'real-world' requirement,
or a law of nature, just a studio regulation imposed by me.
I do this for a few reasons: first, greenware is fragile, and
in a crowded studio, getting things bisqued as soon as they
are complete reduces accidents and hard feelings. Second,
novices often 'mess up' their early glaze efforts, and knowing
they can wash it off and try again is a big confidence-builder.
Third (the biggie for me) is that virtually all clay explosions
happen in the first few hundred degrees of firing greenware.
They are almost unknown when firing bisqued work. If
some over-thick semi-damp 'bomb' goes into the kiln, I
want it to blow up in a kiln full of bare clay, not a kiln full
of glazes about to become molten, when all those shards
will get glued to everyone else's work and to the kiln itself.
Bisquing is not mandatory due to anything fundamental in
the process of ceramics. It's just another one of those useful
processes that has gotten blindly handed down as the only
right way to work by people who also learned their craft by
rote and never stopped to think WHY? Ceramics is full of
that sort of crappy teaching, carried on by people who were
trained the same way. Good, useful methods get codified
into sacred, unquestioned ritual as the only 'Right Way' to
work. Stupid.
Not every method is suitable for every circumstance, just
as not every tool is right for every job. Pliers are great, but
sometimes you need a wrench. And vice-versa. Sometimes
bisque is really handy, and sometimes it's a total waste.
Evaluate YOUR needs, and make YOUR decisions! If you
aren't sure why you are doing something, stop and think
about it for a while.
Bisque, it appears to me, became ubiquitous in industrial
settings, historically, when craft potters essentially ceased
to exist. The present studio ceramics world is not a lineal
descendent of craft pottery from antiquity. It had to be
re-invented, spliced together, with parts from industry, from
surviving folk potters in unindustrialized areas, and a fair
amount of invention on the spot. Bisque makes a lot of
sense in an industrial setting where things get done in
large batches. It has many uses in a studio workshop, too,
but if it doesn't serve the intentions at hand, then chuck it.
> Have any of you tried single firing with soda? salt? reduction? Any other
> ideas for single firing?
Anything can be single-fired; it's not specific to any
process. Single-firing was probably the norm in much
of ceramics history. Bisque firing is not a magic charm. It
serves several specific purposes, including hardening
the clay so that delicate details can be glazed with less
breakage, burnout of gasses that might affect the glaze,
increased compatibility with certain glazes, reduced
fragility while being stored before finishing, ability to
transport the ware to a distant final firing, and so on.
If none of these needs are your needs, then skip it.
>
> And tell me his glazes are not gorgeous! THEY SHINE. They glow. They have
> crystals and contrasting shine and matte areas. THEY LOOK LIKE REDUCTION,
> yes, but they are interesting in lots of ways besides...
Once and for all, it AIN'T the REDUCTION the makes
glazes seem rich and nuanced. Reduction changes the
colors; that's about it. It does also reduce the serendipity
effect - no waiting for happy accidents; you gotta make
your own. The big difference, I think (and I know that
other think so, too) is that most electric kilns are thin-
walled critters that heat, and especially COOL, quickly.
Most people using an electric kiln run it up to temperature,
then let it crash-cool however fast its skimpy insulation
will allow. Conversely, most fuel kilns are thick-walled
beefy beasts that even when intentionally crash-cooled,
take a much longer time to cool off, creating a built-in
soak cycle with no effort from the artist. More time for
glazes to melt, for materials to combine and to separate,
to run and blend, and to do whatever they are capable
of. Steven builds on this by layering multiple glazes,
and not at random, either. So do most of the folks who
get really rich glaze effects, whether in an electric or
fuel-fired kiln. It just takes more forethought and awareness
to do it electrically, because the kiln won't do anything
but what you tell it to. It's like the difference between
buying software and writing code. Like using those fancy
filters in Photoshop instead of making actual art photos.
Too many people use their fuel kiln (gas, wood, raku,
whatever) as a crutch, to add 'interest' to some otherwise
really boring work. Then they try electric and the 'mojo'
ain't there unless they put it there themselves. The
emperor's clothes didn't come back from the cleaners.
What many people think is the look of 'reduction glazes'
is simply the look of _long-fired_ glazes, with a dash of
randomness from the flame. You won't get the nuances
caused by flame when firing electrically. You have to create
your own surface variety and interest instead. But if you
treat your electric kiln as tool instead of a magical push-
button box, you will find it can be quite versatile.
Lots of bad work made in all sorts of kilns, by all sorts of
methods. Some methods don't hide it as well as others.
-Snail
paul gerhold on mon 19 sep 11
Snail,
I have heard this discussion about slow cooling improving glazes many times
and yet no one seems to be able to give a scientific rational as to why thi=
s
should change anything.
My current glaze interest is cone 6 and I havetested about 20 glazes with
slow cooling, fast cooling, and firing abou one half cone higher. Most
improvement in appearance seems to come from firing higher rather than slo=
w
cooling. Slow cooling seems to help in crystlline matts but not in shiny
glazes.
I just wonder what the scientific rational for slow cooling is for most
electric glazes. Maybe one of the more scientific potters out there can
enlighten.
Paul
On Sunday, September 18, 2011, Snail Scott
wrote:
> On Sep 17, 2011, at 11:39 PM, Roxanne Hunnicutt wrote:
>> WHY DID WE BISQUE? Isn't that a huge waste of energy?
>
>
> I often single-fire. Sometimes, I bisque. Why? When
> do I choose to bisque?
>
> I bisque when I have a multi-part project that must be
> fired in multiple kiln loads, and I can't have the whole
> thing sitting around as fragile greenware in order to
> true up the sections when it's all complete. By bisque-
> firing each phase when complete, I can stack the parts
> in a corner, and then lay it all out together for final fitting
> before surfacing and high-firing it all.
>
> I bisque when I want to do wiped-back finishes, such
> as oxide or engobe washes, and you can't get the same
> effect when scrubbing back on greenware.
>
> I bisque when I am doing multi-stage surfaces, and I
> want to 'lock in' the bottom layers before proceeding
> to the top ones.
>
> Some glazes simply behave better on bisqued clay.
> There are also some that prefer green clay, and a whole
> lot that just don't care. If you are deeply attached to a
> 'special needs' glaze, then give it what it requires. If
> not, forget it.
>
> When I am teaching, I require my students to bisque-
> fire their work. I tell them it's not a 'real-world' requirement,
> or a law of nature, just a studio regulation imposed by me.
> I do this for a few reasons: first, greenware is fragile, and
> in a crowded studio, getting things bisqued as soon as they
> are complete reduces accidents and hard feelings. Second,
> novices often 'mess up' their early glaze efforts, and knowing
> they can wash it off and try again is a big confidence-builder.
> Third (the biggie for me) is that virtually all clay explosions
> happen in the first few hundred degrees of firing greenware.
> They are almost unknown when firing bisqued work. If
> some over-thick semi-damp 'bomb' goes into the kiln, I
> want it to blow up in a kiln full of bare clay, not a kiln full
> of glazes about to become molten, when all those shards
> will get glued to everyone else's work and to the kiln itself.
>
> Bisquing is not mandatory due to anything fundamental in
> the process of ceramics. It's just another one of those useful
> processes that has gotten blindly handed down as the only
> right way to work by people who also learned their craft by
> rote and never stopped to think WHY? Ceramics is full of
> that sort of crappy teaching, carried on by people who were
> trained the same way. Good, useful methods get codified
> into sacred, unquestioned ritual as the only 'Right Way' to
> work. Stupid.
>
> Not every method is suitable for every circumstance, just
> as not every tool is right for every job. Pliers are great, but
> sometimes you need a wrench. And vice-versa. Sometimes
> bisque is really handy, and sometimes it's a total waste.
> Evaluate YOUR needs, and make YOUR decisions! If you
> aren't sure why you are doing something, stop and think
> about it for a while.
>
> Bisque, it appears to me, became ubiquitous in industrial
> settings, historically, when craft potters essentially ceased
> to exist. The present studio ceramics world is not a lineal
> descendent of craft pottery from antiquity. It had to be
> re-invented, spliced together, with parts from industry, from
> surviving folk potters in unindustrialized areas, and a fair
> amount of invention on the spot. Bisque makes a lot of
> sense in an industrial setting where things get done in
> large batches. It has many uses in a studio workshop, too,
> but if it doesn't serve the intentions at hand, then chuck it.
>
>
>> Have any of you tried single firing with soda? salt? reduction? Any othe=
r
>> ideas for single firing?
>
> Anything can be single-fired; it's not specific to any
> process. Single-firing was probably the norm in much
> of ceramics history. Bisque firing is not a magic charm. It
> serves several specific purposes, including hardening
> the clay so that delicate details can be glazed with less
> breakage, burnout of gasses that might affect the glaze,
> increased compatibility with certain glazes, reduced
> fragility while being stored before finishing, ability to
> transport the ware to a distant final firing, and so on.
> If none of these needs are your needs, then skip it.
>
>>
>> And tell me his glazes are not gorgeous! THEY SHINE. They glow. They hav=
e
>> crystals and contrasting shine and matte areas. THEY LOOK LIKE REDUCTION=
,
>> yes, but they are interesting in lots of ways besides...
>
>
> Once and for all, it AIN'T the REDUCTION the makes
> glazes seem rich and nuanced. Reduction changes the
> colors; that's about it. It does also reduce the serendipity
> effect - no waiting for happy accidents; you gotta make
> your own. The big difference, I think (and I know that
> other think so, too) is that most electric kilns are thin-
> walled critters that heat, and especially COOL, quickly.
> Most people using an electric kiln run it up to temperature,
> then let it crash-cool however fast its skimpy insulation
> will allow. Conversely, most fuel kilns are thick-walled
> beefy beasts that even when intentionally crash-cooled,
> take a much longer time to cool off, creating a built-in
> soak cycle with no effort from the artist. More time for
> glazes to melt, for materials to combine and to separate,
> to run and blend, and to do whatever they are capable
> of. Steven builds on this by layering multiple glazes,
> and not at random, either. So do most of the folks who
> get really rich glaze effects, whether in an electric or
> fuel-fired kiln. It just takes more forethought and awareness
> to do it electrically, because the kiln won't do anything
> but what you tell it to. It's like the difference between
> buying software and writing code. Like using those fancy
> filters in Photoshop instead of making actual art photos.
> Too many people use their fuel kiln (gas, wood, raku,
> whatever) as a crutch, to add 'interest' to some otherwise
> really boring work. Then they try electric and the 'mojo'
> ain't there unless they put it there themselves. The
> emperor's clothes didn't come back from the cleaners.
>
> What many people think is the look of 'reduction glazes'
> is simply the look of _long-fired_ glazes, with a dash of
> randomness from the flame. You won't get the nuances
> caused by flame when firing electrically. You have to create
> your own surface variety and interest instead. But if you
> treat your electric kiln as tool instead of a magical push-
> button box, you will find it can be quite versatile.
>
> Lots of bad work made in all sorts of kilns, by all sorts of
> methods. Some methods don't hide it as well as others.
>
> -Snail
>
Pam Cresswell on mon 19 sep 11
-----Original Message-----
From: Hank Murrow
Sent: Monday, September 19, 2011 8:37 AM
To: Clayart@LSV.CERAMICS.ORG
Subject: Re: What's new with you? Single firing pottery
On Sep 19, 2011, at 4:43 AM, paul gerhold wrote:
> My current glaze interest is cone 6 and I havetested about 20 glazes with
> slow cooling, fast cooling, and firing abou one half cone higher. Most
> improvement in appearance seems to come from firing higher rather than
> slow
> cooling. Slow cooling seems to help in crystlline matts but not in shiny
> glazes.
Dear Paul;
You have said the answer to the issue. Crystalline matts do improve with
slower cooling, especially around 1900F. The reason for this is that
microcrystalline growth occurs around that temperature, so slowing, or
halting altogether, the cooling allos time for that change to happen. Since
the metallic ions which are producing the color are still susceptible to
atmospheric changes at that temperature, holding the kiln either in
reduction or oxidation, will improve color development. I fire in a gas kil=
n
to C10-11 reduction or oxidation, but my crystalline matts all really pop
with a soak in oxidation around 1900F. I have yet to begin trials with a
soak in reduction to see what will happen under those conditions.
Cheers, Hank in Eugene=3D
Lee on mon 19 sep 11
On Mon, Sep 19, 2011 at 7:57 AM, Paul Herman wr=
=3D
ote:
> Paul,
>
> The rational is that it gives the glaze more time to develop
> crystalline structures. As the glaze cools, minerals sort themselves
> out of the melt and develop crystals, which make some interesting
> colors and textures. That's why big heavy hard brick kilns, which cool
> slowly by their nature, do a good job of finishing the glaze.
>
Cristobalite crystals like slow cooling too and make trouble in a high
silica clay body. Mick Casson and Euan Craig crash cool to avoid dunting
and Euan does it to enhance flashing red on porcelainous stoneware. (half
Aussie stoneware and half Shigaraki Nami clay.)
--
Lee Love in Minneapolis
http://mingeisota.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he land
of eternal youth is behind the house, a beautiful land fluent within
itself." -- John O'Donohue
Hank Murrow on mon 19 sep 11
On Sep 19, 2011, at 4:43 AM, paul gerhold wrote:
> My current glaze interest is cone 6 and I havetested about 20 glazes =3D
with
> slow cooling, fast cooling, and firing abou one half cone higher. =3D
Most
> improvement in appearance seems to come from firing higher rather than =
=3D
slow
> cooling. Slow cooling seems to help in crystlline matts but not in =3D
shiny
> glazes.=3D20
Dear Paul;
You have said the answer to the issue. Crystalline matts do improve with =
=3D
slower cooling, especially around 1900F. The reason for this is that =3D
microcrystalline growth occurs around that temperature, so slowing, or =3D
halting altogether, the cooling allos time for that change to happen. =3D
Since the metallic ions which are producing the color are still =3D
susceptible to atmospheric changes at that temperature, holding the kiln =
=3D
either in reduction or oxidation, will improve color development. I fire =
=3D
in a gas kiln to C10-11 reduction or oxidation, but my crystalline matts =
=3D
all really pop with a soak in oxidation around 1900F. I have yet to =3D
begin trials with a soak in reduction to see what will happen under =3D
those conditions.
Cheers, Hank in Eugene=3D
Paul Herman on mon 19 sep 11
Paul,
The rational is that it gives the glaze more time to develop
crystalline structures. As the glaze cools, minerals sort themselves
out of the melt and develop crystals, which make some interesting
colors and textures. That's why big heavy hard brick kilns, which cool
slowly by their nature, do a good job of finishing the glaze.
best wishes,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Sep 19, 2011, at 4:43 AM, paul gerhold wrote:
> I just wonder what the scientific rational for slow cooling is for
> most
> electric glazes. Maybe one of the more scientific potters out there
> can
> enlighten.
>
> Paul
Snail Scott on mon 19 sep 11
On Sep 19, 2011, at 6:43 AM, paul gerhold wrote:
> I have heard this discussion about slow cooling improving glazes many =3D
times and yet no one seems to be able to give a scientific rational as =3D
to why this should change anything.
I won't claim science, but merely personal observation
of the phenomenon. I _speculate_ that more time spent=3D20
at or near peak temperatures allows more thorough melting,=3D20
more 'flow time' for glazes so inclined, a bit of separation=3D20
time for minerals that might crystallize out, and so on.=3D20
Firing higher, as you suggest, also contributes to this,=3D20
as the glaze will spend more time in the critical ranges.
Either way, it's heat-work. If a glaze looks better hotter,=3D20
I'd re-label it.=3D20
I am a fan of less-shiny glazes, too, and a slow cooling is=3D20
halfway to being a 'real' hold, allowing microcrystallization=3D20
in glazes with the right chemistry (which is rather a lot of=3D20
them) creating yet another opportunity for surface variation.=3D20
-Snail=3D
Ron Roy on mon 19 sep 11
Hi Paul,
Go to the masteringglases.com and take a look at the tiles John
Hesse;berth put up to see what happens when a glaze is cooled at
different rates.
No doubt about it that many glazes look much better when cooled more slowly=
.
Not sure exactly why but is does have to do with how different
thicknesses of glaze recrystallize and how glazes react with the clay
under them.
RR
Quoting paul gerhold :
> Snail,
> I have heard this discussion about slow cooling improving glazes many tim=
es
> and yet no one seems to be able to give a scientific rational as to why t=
his
> should change anything.
>
> My current glaze interest is cone 6 and I havetested about 20 glazes with
> slow cooling, fast cooling, and firing abou one half cone higher. Most
> improvement in appearance seems to come from firing higher rather than s=
low
> cooling. Slow cooling seems to help in crystlline matts but not in shiny
> glazes.
>
> I just wonder what the scientific rational for slow cooling is for most
> electric glazes. Maybe one of the more scientific potters out there can
> enlighten.
>
> Paul
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