Dave Finkelnburg on mon 24 may 04
Paul,
The firing part is pretty simple. Just do it! :-)
The challenges, I feel, are all in the glazing. How you make your
glazes and how you apply them may be different than with twice-firing.
Otherwise, you are just in for a longer firing cycle because you are firing
slowly at the start as you burn out the organics and calcine the clay.
If you are not getting the fired result you want with your iron-rich
body, it's either the kiln atmosphere, the glaze recipe, or the glaze
application, not the process of single firing itself that is the cause.
Single-firing, like any other firing program, takes some study and
experience.
Good firing!
Dave Finkelnburg in Idaho
----- Original Message -----
From: "Paul Raymond"
Sent: Monday, May 24, 2004 8:01 PM
> Does anyone out there single fire at cone 6 and if so what are your
> results/advice? I have done some preliminary tests and it works fine
> with the white body I am using but the iron-rich red body is
> inconclusive. Thanks.
Paul Raymond on mon 24 may 04
Does anyone out there single fire at cone 6 and if so what are your
results/advice? I have done some preliminary tests and it works fine
with the white body I am using but the iron-rich red body is
inconclusive. Thanks.
Paul Raymond
Franklin, Tennessee
Snail Scott on tue 25 may 04
>Snail Scott wrote:
>>Inconclusive how? I have single-fired red bodies
>>(and white)...
>>Never saw any difference between the behavior...
At 09:52 AM 5/26/04 +0900, Lee L. wrote:
> I have....I singled fired a new shino glaze: on a light clay
>body and on an iron bearing clay body. The iron body bloated and
>cracked...it look black
>cored. I am guessing that the soda ash created a barrier, at
>relatively low temperature, that did not allow the organic material to
>burn out...
I wouldn't be surprised if you're right about
that. Most of the times I've single-fired red
clay, it's been without glaze, or with not-
quite-vitreous engobes. Although I've never
had glaze-related bloating, I have had effects
that I attributed to a glaze skinning over early
in the process and blocking the outgassing. It
seems reasonable to assume that it could block
the removal of materials that cause black-core,
too.
-Snail Scott
Reno, Nevada, USA, Earth
Darnie Sizemore on tue 25 may 04
Paul,
I have found that it works well. I have fired quite a few pots this way. My only advice is to take it slow through the first 1000 degrees. After that it is smooth sailing. However I have only used this method in a electric kiln.
Darnie
Paul Raymond wrote:
Does anyone out there single fire at cone 6 and if so what are your
results/advice? I have done some preliminary tests and it works fine
with the white body I am using but the iron-rich red body is
inconclusive. Thanks.
Paul Raymond
Franklin, Tennessee
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Snail Scott on tue 25 may 04
At 09:01 PM 5/24/04 -0500, you wrote:
>Does anyone out there single fire at cone 6...it works fine
>with the white body I am using but the iron-rich red body is
>inconclusive...
Inconclusive how? I have single-fired red bodies
(and white) in the ^4-6 range often, in both
oxidation and reduction, and liked the result.
Never saw any difference between the behavior of
the red and white bodies when I did it, except
those differences that would exist in any other
firing (iron-fluxing issues, etc).
Iron-bearing bodies may be more in need of a
nice, slow 'bisque' phase to remove carbon, as
the effects of black-coring are more prevalent
otherwise, but I generally give all my clays a
nice slow rise through that range anyway.
Ironically (so to speak), the best firing results
I ever got were in a little gas-fired catenary
kiln that I let get ahead of itself, and fired to
^5 in about 5 hours, not counting candling - oops.
The firing slab was a bit black-cored, so I assume
the sculpture is, too, but what a fabulous result!
The amazing subtlety of that bare clay surface was
the best ever, and there were strange (but perfect)
'frosted' effects on the high textures. Haven't
had the guts to do that on purpose again, yet...
-Snail Scott
Reno, Nevada, USA, Earth
Ron Roy on tue 25 may 04
Or - perhaps the most important of all - the cooling.
We used to think - all that wonderful interaction between clay and glazes
must be the reduction. Well a good part of it was simply that the bigger
kilns cooled slower and gave the glazes a chance to change in a variety of
ways.
I can remember John telling me - when he showed someone some of the test
tiles from our reseach on our book - they simply could not believe they
were not fired in reduction at cone 10.
Hi Boron glazes have the potential to trap organics in single firing by the
way. I have no experience here - only theory. I would like to hear from
anyone either way on the subject.
RR
>Paul,
> The firing part is pretty simple. Just do it! :-)
> The challenges, I feel, are all in the glazing. How you make your
>glazes and how you apply them may be different than with twice-firing.
>Otherwise, you are just in for a longer firing cycle because you are firing
>slowly at the start as you burn out the organics and calcine the clay.
> If you are not getting the fired result you want with your iron-rich
>body, it's either the kiln atmosphere, the glaze recipe, or the glaze
>application, not the process of single firing itself that is the cause.
>Single-firing, like any other firing program, takes some study and
>experience.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Gary Harvey on wed 26 may 04
I use to regularly once fire at ^6. When you do so make sure you cook
slowly! So the water will be gone during the later stages and so the pots
wont explode! My kiln is an electric with two stages. Low low for at least
4 hrs. then low med for 2-3 hrs, med med for 2 hrs, med high for 1 hr, then
high high until the cone sitter click off. then reset and fire at high
high at least 30 minutes (on my kiln ) to get the backup inside witness
cones to temp. and to soak the pottery. then soak for 4 hrs on med med.
then turn off the kiln. YOU MUST MONITOR THE KILN AT ALL TIMES. I have
pottery that is definately been over fired and the glaze evaporated for the
lack of a better way of saying it. I nearly burnt up the kiln and my studio
because I didn't use the witness cones and because the kiln sitter jammed!
One of the commercial glazes that I was using bubbled when I was once firing
so I did a bisquik fire once with it. After that, since it was so much
eazier to glaze that way I have done it ever since. When glazing dry
greenware, glaze the inside first. Pour the glaze into it and the turn the
pot till the inside is covered. Then let it set awhile to dry. Then glaze
the outside. If dipping, don't let it soak in the glaze long or the pot
will get too wet and it will break when lifting it. You may have to adjust
the content of your glazes for this type of firing. I am sorry, I used
commercial glazes then so I can't help you there. Good luck, Gary Harvey
Palestine TX
Lee Love on wed 26 may 04
Snail Scott wrote:
>Inconclusive how? I have single-fired red bodies
>(and white) in the ^4-6 range often, in both
>oxidation and reduction, and liked the result.
>Never saw any difference between the behavior
>
I have. I think I wrote about it last week (could have been
another list.) I singled fired a new shino glaze: on a light clay
body and on an iron bearing clay body. The iron body bloated and
cracked. The light body look very nice.
Looking at the inside of the the iron body, it look black
cored. I am guessing that the soda ash created a barrier, at
relatively low temperature, that did not allow the organic material to
burn out. Will do some more tests, on ash glazes too. I am
guessing that washed ash would not cause problems but unwashed might.
--
Lee in Mashiko, Japan http://mashiko.org
http://journals.fotki.com/togeika/Mashiko/ Commentary On Pottery
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