Tony Ferguson on mon 9 jun 03
Actually, John, it is not strange that a single fire glaze yields a richer
glaze and body interface, making for more interesting glaze surfaces. In
terms of ceramic history, the practice of bisquing pots is a relatively new
practice.
I just bisqued a number of the pots (I usually single fire) for the last
firing and although my glazes still turned out quite well, there wasn't some
of the surface interactions from the organics burning out and interacting
with the glaze. Very noticeable with my tenmoku and one of my shinos.
Thank you.
Tony Ferguson
On Lake Superior, where the sky meets the Lake
Stoneware, Porcelain, Raku and more
by Coleman, Ferguson, Winchester...
www.aquariusartgallery.com
218-727-6339
315 N. Lake Ave
Apt 312
Duluth, MN 55806
----- Original Message -----
From: "John Post"
To:
Sent: Monday, June 09, 2003 4:12 PM
Subject: Re: Bisque --Better Bisque Better Glaze??
> Hi Joe,
> The point of bisque firing is to make the pot more durable for handling
when
> glazing and to burn out the organic stuff so it doesn't bubble up through
> the glaze while it is firing.
>
> So if you fire your bisque higher than cone 04, it gets more closed and
less
> absorbent...it will not be able to soak up the glaze...imagine trying to
> glaze a drinking glass. That is what it will be like when you try to get
> glaze to stick to an unglazed cone 6 pot.
>
> (When I first started working with clay 15 years ago, I was teaching some
> kids and decided to make my own cone 2 glaze to save some money. I made
the
> mistake of thinking that when you bisque you always fire the ware to one
> cone lower than the glaze....WRONG....it's was near impossible to get any
of
> our cone 2 glaze to stick on cone 1 unglazed pots... That little incident
> got me reading about how to do it the right way.)
>
> As strange as it may seem, single firing the ware with no bisque firing
> often yields a richer glaze and body interface, making for more
interesting
> glaze surfaces...but that's another whole issue...
>
> Cheers,
> John Post
>
>
>
>
> Joe asked...
>
> GOAL: Cone 10 Glazed Stoneware
>
> Question: ...okay...
>
> An average bisque fire is 04.
>
> Drives the water out, firms up the pot.
>
> ---
>
> WHAT IF
>
> The pot went through a second bisque? Cone 6 Or Cone 10?
>
>
> WHEN IT CAME TIME TO GLAZE
>
> Would the glaze on a vitrified Cone 6 or 10 glaze free high fire bisquw
(say
> --2nd bisque or call it glaze free glaze firing) "be better, look better,
> etc that a glaze application on a spongy 04 bisque fired pot?
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Catherine White on mon 9 jun 03
Last week I had a ^10 fired piece. The glaze was too thin. I placed it out
in our hot Yuma sun. When it was very very warm, I sprayed it with hair
spray, then promptly reglazed it while still warm. The glaze adhered
beautifully. I recalled that tip from the dim distant past. Haven't fired
it yet. Will let you know if interested.
Catherine in Yuma, AZ
Forget the losses; exaggerate the wins.
Remember: forget. Remember: forget.
(T. Jefferson Parker)
----- snip-----
>There is a real problem getting the glaze to initially adhere to a
> vitrified pot. No quick dip and pour, brush or spray.
Joe Coniglio on mon 9 jun 03
GOAL: Cone 10 Glazed Stoneware
Question: ...okay...
An average bisque fire is 04.
Drives the water out, firms up the pot.
---
WHAT IF
The pot went through a second bisque? Cone 6 Or Cone 10?
WHEN IT CAME TIME TO GLAZE
Would the glaze on a vitrified Cone 6 or 10 glaze free high fire bisquw (say
--2nd bisque or call it glaze free glaze firing) "be better, look better,
etc that a glaze application on a spongy 04 bisque fired pot?
Bruce Girrell on mon 9 jun 03
Joe Coniglio asked:
> WHAT IF The pot went through a second bisque? Cone 6 Or Cone 10?
> WHEN IT CAME TIME TO GLAZE
...the glaze would run off the pot and back into the bucket.
The ability of the pot to soak up water after the bisque firing is vital to
even glaze application.
Bruce "guess how I know this" Girrell
L. P. Skeen on mon 9 jun 03
----- Original Message -----
From: "Joe Coniglio"
> An average bisque fire is 04.
> WHAT IF
>
> The pot went through a second bisque? Cone 6 Or Cone 10?
> Would the glaze on a vitrified Cone 6 or 10 glaze free high fire bisquw
(say -2nd bisque or call it glaze free glaze firing) "be better, look
better, etc that a glaze application on a spongy 04 bisque fired pot?
Joe,
There are two ways one might read what you wrote above. First way is: "If
I'm firing to ^10, can I bisque at ^6, and if so, will the finished piece
look better than a piece that was glazed at ^04?"
My answer to this is, I don't think so. There's not a huge difference in
temperature between cone 6 and ^10, so if you bisqued to ^6, your ware would
be too close to vitrification for the glaze to adhere when applied,
ESPECIALLY if you're using a really tight body like Bmix.
The other way I'm reading what you wrote is "What if the piece was bisqued
first to ^04, then a second time to ^6 or ^10?"
If you fire at ^10, your glaze isn't going to stick, because your clay will
be vitrified if you're using a high-fire body.
Now, if you were asking "If I bisque to ^04, then glaze and re-fire to ^6
before final firing to ^10, what will happen?", the answer is, Sintering.
That doesn't mean the ware will look better, it just means that you could
travel somewhere with your glazed pots and the glaze will be less likely to
get knocked off the pots than if you travelled with them glazed but unfired.
If you're not travelling with glazed pots, sintering is (IN MY OPINION) a
waste of time and $, UNLESS you want to be able to paint designs over the
glaze or something like that.
HTH
L
Dannon Rhudy on mon 9 jun 03
Joe asked:
<<<<<,An average bisque fire is 04.
The pot went through a second bisque? Cone 6 Or Cone 10?
> > Would the glaze on a vitrified Cone 6 or 10 glaze free high fire bisquw
(say
> --2nd bisque or call it glaze free glaze firing) "be better, look better,
> etc that a glaze application on a spongy 04 bisque fired pot?>>>>>>
No, it wouldn't. You would find significant difficulty in getting the
glaze to adhere to the piece, for starts. Getting it on evenly would
be even more difficult. There is no advantage to doing that unless
a) you are a commercial producer of tableware, in which case you
would be using low-fire glazes on high-fire clay; or b) you want
to put low-fire glazes on YOUR high-fired clay. You'd still need
special techniques to adhere your glaze, and I think on the whole
you would be annoyed, irritated and generally out of sorts.
regards
Dannon Rhudy
Craig Dunn Clark on mon 9 jun 03
There is a real problem getting the glaze to initially adhere to a
vitrified pot. No quick dip and pour, brush or spray. You'd probably have to
use something like sodium silicate as an adhesive medium to get the glaze to
stick. There may also be unforseen crawling, mottling, etc. faults that
result from improper or poor glaze adhesion..
The idea of a second bisque does not make any sense. You are not
bisquing the pot if you are firing it to a temperature at which the clay
body vitrifies anyway.
Craig Dunn Clark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
----- Original Message -----
From: "Joe Coniglio"
To:
Sent: Monday, June 09, 2003 2:08 PM
Subject: Bisque --Better Bisque Better Glaze??
> GOAL: Cone 10 Glazed Stoneware
>
> Question: ...okay...
>
> An average bisque fire is 04.
>
> Drives the water out, firms up the pot.
>
> ---
>
> WHAT IF
>
> The pot went through a second bisque? Cone 6 Or Cone 10?
>
>
> WHEN IT CAME TIME TO GLAZE
>
> Would the glaze on a vitrified Cone 6 or 10 glaze free high fire bisquw
(say
> --2nd bisque or call it glaze free glaze firing) "be better, look better,
> etc that a glaze application on a spongy 04 bisque fired pot?
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
John Post on mon 9 jun 03
Hi Joe,
The point of bisque firing is to make the pot more durable for handling when
glazing and to burn out the organic stuff so it doesn't bubble up through
the glaze while it is firing.
So if you fire your bisque higher than cone 04, it gets more closed and less
absorbent...it will not be able to soak up the glaze...imagine trying to
glaze a drinking glass. That is what it will be like when you try to get
glaze to stick to an unglazed cone 6 pot.
(When I first started working with clay 15 years ago, I was teaching some
kids and decided to make my own cone 2 glaze to save some money. I made the
mistake of thinking that when you bisque you always fire the ware to one
cone lower than the glaze....WRONG....it's was near impossible to get any of
our cone 2 glaze to stick on cone 1 unglazed pots... That little incident
got me reading about how to do it the right way.)
As strange as it may seem, single firing the ware with no bisque firing
often yields a richer glaze and body interface, making for more interesting
glaze surfaces...but that's another whole issue...
Cheers,
John Post
Joe asked...
GOAL: Cone 10 Glazed Stoneware
Question: ...okay...
An average bisque fire is 04.
Drives the water out, firms up the pot.
---
WHAT IF
The pot went through a second bisque? Cone 6 Or Cone 10?
WHEN IT CAME TIME TO GLAZE
Would the glaze on a vitrified Cone 6 or 10 glaze free high fire bisquw (say
--2nd bisque or call it glaze free glaze firing) "be better, look better,
etc that a glaze application on a spongy 04 bisque fired pot?
Dave Finkelnburg on tue 10 jun 03
Joe,
You may want to look for a book, "Single Firing" by Fran Tristram. To
answer your question, it is sufficient to fire as slowly at first as you
would a normal bisque firing. When you reach bisque temperature continue as
if for a glaze firing of bisqued ware.
Good firing!
Dave Finkelnburg
----- Original Message -----
From: "Joe Coniglio"
> You "guys" are very patient and kind. Thank you! I GET IT!!
> NOW towards the end, you've got me wondering about single fire
applications
> on greenware.
> Do you bring the kiln up extra slow for a single fire to drive the water
out
> without the glaze coat going crazy?
Joe Coniglio on tue 10 jun 03
You "guys" are very patient and kind. Thank you! I GET IT!!
---
NOW towards the end, you've got me wondering about single fire applications
on greenware. But like you say that's a whole nother story. I'm going to
look into it sometime.
It saves time and energy and reloading the kiln. The problem? Pinning etc?
Do you bring the kiln up extra slow for a single fire to drive the water out
without the glaze coat going crazy?
Lee Love on tue 10 jun 03
----- Original Message -----
From: "Joe Coniglio"
> WHAT IF
>
> The pot went through a second bisque? Cone 6 Or Cone 10?
I bisque to 012, about 850*C Most potters in Mashiko bisque lower (about
800*C.) In the noborigama, they just bisque to low red heat in the main part
of the chamber. This means some work is bisqued way below cone 012.
At low bisque, it is good to sponge the work with water. This was my
job as an apprentice, I wiped every piece going into a glaze firing before it
was glazed. When I wiped my first bisque out of the noborigama, I broke two
matchawa in a row! These sell for up to 5 to 7 thousand bucks each (when
finished), depending on what part of the kiln they are from! Sensei just sent
another apprentice to fetch another one. Ever since, every new
deshi/apprentice I experienced, too broke at least one piece of bisque from the
Noborigama bisque. Each time, privately, I assure them that they wouldn't be
thrown out of the pottery, but that it is sort of a "right of passage."
--
Lee Love In Mashiko, Japan
"Concerning all acts of initiative (and creation),there is one elementary truth
the ignorance of which kills countless ideas and splendid plans: that the
moment one definitely commits oneself, then providence moves too. A whole stream
of events issues from the decision, raising in one's favor all manner of
unforeseen incidents, meetings and material assistance, which no man could have
dreamt would have come his way." --W.H. Murry
WHC228@AOL.COM on wed 11 jun 03
I have been single firing for many years. I start the kiln slowly. I fire to
200F and hold for an hour. Then I let it go to temperature at 270F/Hr. to its
maturing temperature, and the reduction stuff.
On my crystalline glazes I put in another hold for an hour at 1050F to make
sure that I get rid of any carbon that could be unburned in the body. I do that
so that I do not have any blisters showing up from localized reduction from
any dirt that could be left in the body.
Bill Campbell
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