Connie Christensen on sat 29 mar 03
Craig wrote: After a week with Shino Master Malcolm I have a primary
question: Has anyone out there in Clayartland, been able to get reliable,
black carbon trapping, using natural gas as a fuel?
I use natural gas in a downdraft kiln and get pretty consistent carbon
trapping, starting a moderately heavy reduction about 012 - not smoky - and
a moderate reduction the rest of the way up, ending up a little lighter on
the reduction. The glaze I use is Malcolm's shino and I apply it rather
thin. And I'm jealous, I want a week with the Shino Master.
Connie Christensen
Denver, CO
Donalson on sat 29 mar 03
After a week with Shino Master Malcolm I have a primary question: Has =
anyone out there in Clayartland, been able to get reliable, black carbon =
trapping, using natural gas as a fuel? Malcom uses propane, and the =
kiln at Nottingham also was propane fired. I just recently did a firing =
in Flagstaff, with a natural gas fired updraft, that resulted in just =
one piece that actually trapped much carbon, despite following a =
"tight" firing schedule and extremely smokey, carbon producing body =
reduction at ^010 ^012.
Professor Finkelnburg emails me that the carbon/hydrogen ratio of =
natural gas is 1:4 and that of propane is 1:3. So there is a =
significantly higher concentration of the soot former in propane vs. =
natural gas. Dave's thinking, is that we likely burned off the carbon, =
with even a momentary period of oxidation, at some time prior to the =
glaze "sealing" it in.
Wood sure appreciate hearing from anyone out there with real world =
experience.
Peace,
Craig AZ
Dannon Rhudy on sat 29 mar 03
.........have a primary question: Has anyone out there in Clayartland,
been able to get reliable, black carbon trapping, using natural gas as a
fuel? .....
Yes. I always use natural gas, and have no problems carbon trapping
with shino. I don't really beleive it has much to do with the fuel type.
regards
Dannon Rhudy
Donald G. Goldsobel on sat 29 mar 03
Dannon,
Since you seem to have success at carbon trap shinos, would it be rude
to ask if you share the firing schedule?
-----
Thanks in advance,
Donald Goldsobel in the Sunny
San Fernando Valley
Original Message -----
From: "Dannon Rhudy"
To:
Sent: Saturday, March 29, 2003 2:20 PM
Subject: Re: Carbon Trappers: FUEL
> .........have a primary question: Has anyone out there in Clayartland,
> been able to get reliable, black carbon trapping, using natural gas as a
> fuel? .....
>
> Yes. I always use natural gas, and have no problems carbon trapping
> with shino. I don't really beleive it has much to do with the fuel type.
>
> regards
>
> Dannon Rhudy
>
>
____________________________________________________________________________
__
> 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.
terry sullivan on sat 29 mar 03
In reference to Craig Donalsons speculating on the possible advantage of
propane vs. natural gas to get higher concentration of elemental carbon
for carbon trapping: I've heard that some folks inject propane
directly into a natural gas kiln to get the extra carbon needed for the
trapping.
Anyone know about this ?
Terry Sullivan
Nottingham Arts
San Marcos, CA
www.nottinghamarts.org
terry sullivan on sun 30 mar 03
Ingeborge,
As I understand it from having Malcolm Davis here for a week; the main
trick is t hat the high concentration of soda salts in the shino
glaze results in the sodium migrating the surface during the drying time
after glaze aplication and the drying time before loading into the
kiln. This sodium liquafies at a fairly low temperature and seals
off the clay body from further carbon trapping. What this means is
that one has to introduce a heavy elemetal carbon atmosphere into the
kiln before the sodium melts and prevents further oxidation of same
carbon after the initial melt. Then one continues t he firing in normal
reduction to cone 10. The main thing is that one must get elemental
carbon into the atmosphere and then seal it into the further shino
glaze by preventing re oxidation by keeping the kiln in reduction
while continuing temperature increase. A main point here is that
elemental carbon is far more heavy than just a strong smooking
reduction. There has to be so little oxigen that little or no CO is in
the atmosphere and only elemental C. It is a bit tricky to then keep
the kiln advancing in temperature while maintaining a normal reducing
atmosphere past that point where the lower temp. sodium glaze effect
seals off the carbon trapped stuff from any oxygen.
This is, I think, easier with a downdraft kiln, but we got some good
results from a Halveron updraft car kiln during our workshop with
Malcolm. The point is that one has to do several firings with ones
own kiln to find how to do this. The carbon trap stage and firing
scheduals are very presise. One has to stay on top of the firing all
the time and stay focused. We certainly found that out with our
"vanilla" firing.
terry sullivan
nottingham arts
Vince Pitelka on sun 30 mar 03
> reduce with black smoke for 10 minutes at the end of the firing, this will
> pump carbon into the glaze.
Donn -
You have it right concerning the soad ash in the glaze, but I cannot imagine
that reducing with black smoke at the end of the firing would have any
effect on carbon trapping. The effect requires reduction very early in the
firing (cone 012) to impact carbon into the clay, and partial reduction on
the way up to keep it there. The soda ash in the glaze ensures the early
onset of vitrification in the glaze and the clay surface. That is what
traps the carbon within the glaze.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Office - wpitelka@tntech.edu
615/597-6801 x111, FAX 615/597-6803
http://iweb.tntech.edu/wpitelka/
Dannon Rhudy on sun 30 mar 03
Donald Goldsobel asked:
> Since you seem to have success at carbon trap shinos, would it be rude
> to ask if you share the firing schedule?......
I don't mind in the least. You will find just about a
bazillion carbon-trap firing schedules in the archives, but
here is mine:
Start reduction EARLY - cone 012 is where I begin, give
or take a couple degrees. Then I stay in light reduction for
the remainder of the firing. I never do really heavy reduction,
never have smoke coming out of the kiln. I get good carbon
trapping where the glaze is not too thick. Where it is very
thick, white. Where it is very thin, orange/red. Medium-
carbon trap. Shino is just one of those glazes that needs
practice and attention. Keep notes of what works, and it
is likely to work again. Watch the weather. Heavy wind
affects my kiln atmosphere. Soft rainy days are the best firing
days for ANYthing, in my experience.
regards
Dannon Rhudy
Donald G. Goldsobel on sun 30 mar 03
Thank you for generosity. It is difficult for potters with limited time to
devote to multiple firings to get the degree of experimentation and exposure
that professional potters have. ----- Original Message -----
From: "Dannon Rhudy"
To:
Sent: Sunday, March 30, 2003 5:37 AM
Subject: Re: Carbon Trappers: FUEL
> Donald Goldsobel asked:
> > Since you seem to have success at carbon trap shinos, would it be
rude
> > to ask if you share the firing schedule?......
>
> I don't mind in the least. You will find just about a
> bazillion carbon-trap firing schedules in the archives, but
> here is mine:
>
> Start reduction EARLY - cone 012 is where I begin, give
> or take a couple degrees. Then I stay in light reduction for
> the remainder of the firing. I never do really heavy reduction,
> never have smoke coming out of the kiln. I get good carbon
> trapping where the glaze is not too thick. Where it is very
> thick, white. Where it is very thin, orange/red. Medium-
> carbon trap. Shino is just one of those glazes that needs
> practice and attention. Keep notes of what works, and it
> is likely to work again. Watch the weather. Heavy wind
> affects my kiln atmosphere. Soft rainy days are the best firing
> days for ANYthing, in my experience.
>
> regards
>
> Dannon Rhudy
>
>
____________________________________________________________________________
__
> 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.
Rikki Gill on sun 30 mar 03
I have only been working with Shino glaze [Malcolm 3] for a comparatively
short time [about a year] but I do get a gold luster effect, wirh carbon
trapping that I am very happy with. I fire an Olsen kiln, natural gas, and
start moderate reduction at 012, then comtinue reduction, backing off where
necessary, to cone 11.
From Rikki in Berkeley
rikigil@cwnet.com
www.berkeleypotters.com
www.goldengateceramics.com
----- Original Message -----
From: "Donalson"
To:
Sent: Saturday, March 29, 2003 11:32 AM
Subject: Carbon Trappers: FUEL
After a week with Shino Master Malcolm I have a primary question: Has
anyone out there in Clayartland, been able to get reliable, black carbon
trapping, using natural gas as a fuel? Malcom uses propane, and the kiln at
Nottingham also was propane fired. I just recently did a firing in
Flagstaff, with a natural gas fired updraft, that resulted in just one
piece that actually trapped much carbon, despite following a "tight" firing
schedule and extremely smokey, carbon producing body reduction at ^010
^012.
Professor Finkelnburg emails me that the carbon/hydrogen ratio of natural
gas is 1:4 and that of propane is 1:3. So there is a significantly higher
concentration of the soot former in propane vs. natural gas. Dave's
thinking, is that we likely burned off the carbon, with even a momentary
period of oxidation, at some time prior to the glaze "sealing" it in.
Wood sure appreciate hearing from anyone out there with real world
experience.
Peace,
Craig AZ
____________________________________________________________________________
__
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.
Ingeborg Foco on sun 30 mar 03
Craig wrote: After a week with Shino Master Malcolm I have a primary
> question: Has anyone out there in Clayartland, been able to get reliable,
> black carbon trapping, using natural gas as a fuel?
>
I've tried all of the mentioned methods including the sticks and voodoo
stuff that Mel suggests. My results so far have been really nice orange
pots. No carbon trapping whatsoever. I'd be happy with an occasional carbon
trapped pot never mind reliable carbon trapping.
I fire with propane in a downdraft kiln. So what is the real secret to
getting carbon trapped pots?
Ingeborg
the Potter's Workshop & Gallery
P.O. Box 510
3058 Stringfellow Road
St. James City, Florida 33956
239-283-2775
Donn Buchfinck on sun 30 mar 03
carbon trapping
when I was in school and I was firing shino
I got great carbon trapping a couple of ways,
first, make shure your glaze has soda ash in it, this is what traps the
carbon
then glaze the pot and let it sit for a couple of days
this allows the pot to dry and the soda ash to come to the surface of the pot
and deposit there.
reduce with black smoke for 10 minutes at the end of the firing, this will
pump carbon into the glaze.
but the soda ash trick is great,
studio potter had an issue on it last year I think.
Donn Buchfinck
there are some carbon trapped pots on my webpage, and I was able to get them
consistantly
pottery_thumbnail
clennell on sun 30 mar 03
Sour Cherry Pottery
> After a week with Shino Master Malcolm I have a primary question: Has
> anyone out there in Clayartland, been able to get reliable, black carbon
> trapping, using natural gas as a fuel? Malcom uses propane, and the kiln at
> Nottingham also was propane fired. I just recently did a firing in Flagstaff,
> with a natural gas fired updraft, that resulted in just one piece that
> actually trapped much carbon, despite following a "tight" firing schedule and
> extremely smokey, carbon producing body reduction at ^010 ^012.
>
> Professor Finkelnburg emails me that the carbon/hydrogen ratio of natural gas
> is 1:4 and that of propane is 1:3. So there is a significantly higher
> concentration of the soot former in propane vs. natural gas. Dave's thinking,
> is that we likely burned off the carbon, with even a momentary period of
> oxidation, at some time prior to the glaze "sealing" it in.
>
> Wood sure appreciate hearing from anyone out there with real world experience.
>
>
> Peace,
>
>
> Craig AZ
Craig: We fire with natural gas and get soot coming out our ying yangs.
Don't know anything about ratios but i do know that I get black everytime I
fire. go to our website and have a peek. A lot has been said on this list
about carbon trapping. I'm not sure that a whole lot of smokey is that
important. Glaze thickness is a big one!
Here's soot in your eye.
Cheers,
Tony
Tony and Sheila Clennell
Sour Cherry Pottery
4545 King Street
Beamsville, Ontario
CANADA L0R 1B1
http://www.sourcherrypottery.com
clennell@vaxxine.com
http://www.sheridanc.on.ca/academic/arts/craftsdesign/workshops
| |
|
