MOLINA, RAFAEL on tue 23 jul 02
I attended the wood-fire conference at The University of North Texas =
last October and I was quite impressed with Mike Weber's "Rocketman" =
anagama ( more info on this kiln design at =
http://members.fortunecity.com/rubberbands/ ) For a variety of reasons =
I've chosen to build this design at our college.
The only problem is I will be building it on a flat concrete floor. My =
initial thought was to build a concrete slope on top of the level =
concrete floor, but I would still have to put a layer of cinder block or =
more than the two courses of fire brick I usually lay for the floor on =
the concrete slope. Recently, I thought I could build the slope out of =
"Sairset", but the cost would be prohibitive and although I'm confident =
of the heat resistant qualities of the material, I'm not sure of it's =
ability to bear the weight. Now I'm thinking of building the slope of =
concrete and a 2" - 4" layer of Sairset over that for protecting the =
concrete from the extreme heat.
Any thoughts from list members on this project? TIA.
Chao,
Rafael Enrique
=20
Rafael Molina, MFA
Assistant Professor of Art
Department of Music, Art, and Dance
Tarrant County College-Southeast Campus
2100 Southeast Parkway
Arlington, TX 76018-3144
(817) 515-3711
(817) 515-3189 fax
Tony Ferguson on wed 24 jul 02
Rafael,
Mike Weber was my teacher. I built my version of the rocketman in 1996
before graduate school. It is a superior design for many reasons and
continually teaches me that every firing is different.
Flat concrete floor. Oh, boy. Build a false pit within a brick U shaped
outline to contain the soil on top of your slab and line it with dirt. If
you are concerned about the heat, then lay fiber blanket on top of the slab
and covered it with dirt. With the dirt you will be able to carve out the
right degree of slope that you want. The blanket will protect the brick as
you will have brick on top of soil ontop of the fiber. It should be ok but
ask your fiber sales person to do a heat transference estimation. Give them
square footage, rate of heat increase and duration of peak temperature, etc,
etc. I would think 8# density 2 inch fiber out to cover you.
Thank you.
Tony Ferguson
Stoneware, Porcelain, Raku
www.aquariusartgallery.com
218-727-6339
315 N. Lake Ave
Apt 312
Duluth, MN 55806
----- Original Message -----
From: "MOLINA, RAFAEL"
To:
Sent: Tuesday, July 23, 2002 4:02 PM
Subject: Weber's Rocketman Anagama on level concrete floor?
I attended the wood-fire conference at The University of North Texas last
October and I was quite impressed with Mike Weber's "Rocketman" anagama (
more info on this kiln design at
http://members.fortunecity.com/rubberbands/ ) For a variety of reasons I've
chosen to build this design at our college.
The only problem is I will be building it on a flat concrete floor. My
initial thought was to build a concrete slope on top of the level concrete
floor, but I would still have to put a layer of cinder block or more than
the two courses of fire brick I usually lay for the floor on the concrete
slope. Recently, I thought I could build the slope out of "Sairset", but
the cost would be prohibitive and although I'm confident of the heat
resistant qualities of the material, I'm not sure of it's ability to bear
the weight. Now I'm thinking of building the slope of concrete and a 2" -
4" layer of Sairset over that for protecting the concrete from the extreme
heat.
Any thoughts from list members on this project? TIA.
Chao,
Rafael Enrique
Rafael Molina, MFA
Assistant Professor of Art
Department of Music, Art, and Dance
Tarrant County College-Southeast Campus
2100 Southeast Parkway
Arlington, TX 76018-3144
(817) 515-3711
(817) 515-3189 fax
____________________________________________________________________________
__
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Harold Miller on mon 21 jun 04
It's unlikely that "Rocketman"--or any other kiln--needs to be built on
a slope. I have spent some time touring kilns in the Tokoname and
Shigaraki areas and have yet to see any modern anagama built on a slope.
"The Gnarly Boys" seem to credit one of their own with this amazing
discovery:
> Recent research by Svend has shown that it is not essential for the
> chamber of the [anagama] kiln to slope upwards towards the chimney, so
> long as the height of the chimney opening forms the correct angle with
> the fire.
(see http://www.studiopottery.com/potteries/gnarlydudes.html)
Building "Rocketman" on a slope does nothing except add the problems of
having to 1) buttress the front, and 2) chink the angular gap created
between chamber and chimney.
Built level, the only modification needed is to raise the height of the
exit flue so that the fire doesn't flow strictly along the floor. And
you may need to load some taller pieces, placed close together, along
the back edge of the fire pit, so together they can act as a bagwall of
sorts (also to help raise the fire flowing through the chamber). If
the 'bagwall' pieces are not uniform in height, that's just fine, as
the 'bagwall's' irregular top edge will help to increase the turbulence
(and therefore distribution) of fire and ash in the chamber.
Harold Miller
_____________________________________
The Shigaraki Pottery in Texas
http://www.shigaraki-pottery.com
Lee Love on mon 21 jun 04
Harold Miller wrote:
> It's unlikely that "Rocketman"--or any other kiln--needs to be built on
> a slope. I have spent some time touring kilns in the Tokoname and
> Shigaraki areas and have yet to see any modern anagama built on a slope.
I was talking with Craig Edwards about this
yesterday. He has a cantenary anagama built by Svend at a kiln
building workshop. Amount of slope is a similar situation as with
solubles in glazes we have been talking about: not right or wrong, but
what works for the effect you want to achieve.
Degree of slope you use depends upon the type of
atmosphere you are trying to get. Craig's anagama has only a very
gentle rise from front to back. This is more likely to produce a
reducing atmosphere, all other things being equal.
If you don't have the slope you want, you can always
create it with earth and/or block or brick.
Craig also mentioned that he doesn't use air holes in
conjunction with the side stoke holes. Without the side air ports,
you have to time your stoking with the wave of the flame coming from the
front of the kiln, where the air comes in.
> "The Gnarly Boys" seem to credit
Better "Gnarly Boys" than Gnarly pots I always say. ;-)
--
Lee in Mashiko, Japan http://mashiko.org
woodkiln list: http://groups.yahoo.com/group/WoodKiln/
John Baymore on mon 21 jun 04
We were discussing this with Matsumiya-san here at Kanayama a few days
ago. He said that there are historical anagama that have a NEGATIVE slope
on the chamber itself. The angle formed from the firebox to the top of the
chimney is the critical factor for draft and flame speed.
best,
...............john
John Baymore
Tsugaru Kanayama
Goshogawara-shi, Aomori-ken
Japan
Paul Herman on tue 22 jun 04
Hello Mark,
You asked:
Mark Potter
Rivers of Clay
New Haven CT>
I don't know the best source, but the one we built here works really
beautifully. We've had nine firings so far, and the results, to put it
mildly, are very encouraging. Just like what you described, anagama,
catenary salt chamber, chimney. It does have the "unnecessary" upward
sloping floor.
There are some diagrams and pictures of construction on my website,
below. Look at "About the Kiln", then "Kiln Diagrams".
Regarding the flat vs sloping question, I think whatever works for you
is good. Let us know if you like the performance. But I'd also say,
build one and fire it before you make any sweeping judgements.
The best book I've seen on the subject is 'Anagama: Building Kilns and
Firing' by Furutani Michio. Originally in Japanese, and hard to get a
translation and copy. You could pester Odin at
questions@anagama-west.com
And good luck with your kiln-to-be.
Hot fires,
Paul Herman
Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/
Mark Potter on tue 22 jun 04
John, et al:
I'm about to build a woodfired anagama with a catenary arch chamber
between the anagama and the chimney for taller pieces. Do any of you
know the best source for advice on shaping the anagama chamber?
Mark Potter
Rivers of Clay
New Haven CT
mark@visionage.net
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of John
Baymore
Sent: Monday, June 21, 2004 7:50 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: weber's rocketman anagama on level concrete floor?
We were discussing this with Matsumiya-san here at Kanayama a few days
ago. He said that there are historical anagama that have a NEGATIVE
slope
on the chamber itself. The angle formed from the firebox to the top of
the
chimney is the critical factor for draft and flame speed.
best,
...............john
John Baymore
Tsugaru Kanayama
Goshogawara-shi, Aomori-ken
Japan
________________________________________________________________________
______
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You may look at the archives for the list or change your subscription
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Moderator of the list is Mel Jacobson who may be reached at
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Craig Edwards on wed 23 jun 04
Hello John and All: Just back from Korea and a wonderful stay with Lee
in Mashiko. Much of the trip was centered around celadon production(the
work of heaven) and the historical sites that produced them. All of the
kilns at the historical sites had a healthy rise in the chamber.
I was extremely interested John when you mentioned some historical
kilns had negative slope in the chamber. I would be grateful to find out
where these sites are and what sort of ware that they produced. I will
be traveling again in the orient within the next year and would like to
document these kilns if at all possible.
Any help would be greatly accepted.
Craig Edwards
New London MN
>We were discussing this with Matsumiya-san here at Kanayama a few days
>ago. He said that there are historical anagama that have a NEGATIVE
>slope
>on the chamber itself. The angle formed from the firebox to the top of
>the
>chimney is the critical factor for draft and flame speed.
>
>best,
>
>...............john
>
>John Baymore
>Tsugaru Kanayama
>Goshogawara-shi, Aomori-ken
>Japan
>
>
>
Gary Navarre on wed 23 jun 04
Mark and crew,
Your idea of a smaller second chamber is where I've been heading for some
time. Some years ago I had enough brick to build the prototype second
chamber but not enough to use the hob firebox. That kiln went to a decent
bisque. Then I came into more brick and added the brick from the first to
build the prototype for the larger front chamber. This was all in the
backyard of a rental on Westnedge Ave. in downtown Kalamazoo almost 30 years
ago. And ya I had a gal in Kalamazoo who had my daughter so I bought a house
and moved the brick there. Then in the mid '80s I found more brick and built
a 30cuft. version of the main chamber with the hob and a pignose near
Plainwell, Michigan. Once I got the hang of it she fired like a dream. I
could do 72hr. by myself. Of course I had to climb pine trees and glean wood
for a year or two to fire a bunch of times but the research was worthwhile.
I was rebuilding the floor to increase the volume because the firebox could
have easily handled 50cuft. That lead to the discovery of why to not use
concrete block as filler to save brick under the floor. I wish I had a
scanner since I took photos of the disintegration. I had noticed the floor
sagging a bit. Trust me, over time concrete cannot take the heat.
The second chamber can be rather versatile. Some might use it for taller
pots, or salting, or I've thought of medium tempetures. The excess heat
could be enough to fire with no additional stoking, although I'd design for
that option. For me right now is getting the brick, some of which is still
near Kalamazoo. There is a supplier in Iron Mountain but they don't handle
much fire brick now that foundries have switched to castables so a small
order will probably be dear. Maybe some could help with that mile of coke
oven down in Tennessee if they are still useable. I know I can't afford the
trip yet.
Just a few thoughts after another all nighter "working", looks like
another beautiful day out there and I should be in the woods, oh well. Stay
in there!
Gary Navarre
Navarre Pottery
Norway, Michigan, USA, Earth
John Baymore on wed 23 jun 04
The negative slope anagama is sort of capitalizing on the "train kiln"
idea. Or was it the SOURCE of the idea ? Getting ash UP into the draft
stream is harder then having it go DOWN by gravity. So the negative slope
would promote the coals and the ash getting onto the pots immediately
behind the main firebox.
As to the best shape for the anagama.... a lot depends on what you want to
get OUT of the anagama. Different types of kilns produce different effects
as the kiln chamber shape affects the draft flow rate and such. In the
west there are kilns labeled "anagama" that are straight tubes with
something like a sprung arch...... straight tubes with a catenary type
arch, .... upside down "sea dory" shapes with complex arches.
I'd go look at existing kilns and at the work that comes out of them and
see how it mmatches your aesthetic before commiting to a design.
best,
..............john
John Baymore
Tsugaru Kanayama
Goshogawara-shi, Aomori-ken
Japan
Ivor and Olive Lewis on wed 23 jun 04
Dear Friends,
Without reasonable diagrams to illustrate what is being discussed this
is becoming a very difficult thread to follow.
But I have a shrewd feeling it is related to the thread about Stack
Height we had six months ago. which may mean we have to ask of
"Science" the "Questions"
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
Lee Love on wed 23 jun 04
John Baymore wrote:
>We were discussing this with Matsumiya-san here at Kanayama a few days
>ago. He said that there are historical anagama that have a NEGATIVE slope
>on the chamber itself. The angle formed from the firebox to the top of the
>chimney is the critical factor for draft and flame speed.
>
>
I am wondering if the slope effects the amount of ash work
further back gets? Craig and I looked at the climbing kiln at the
Kasama Ceramic Park. The firebox is pretty long and has a nice size
space to stack ware in. It has a very steep slope up to the first
climbing chamber. Looking at the steps inside the firebox, I think
you can see that having ware on rising steps like this would expose more
work to ash.
--
Lee in Mashiko, Japan http://mashiko.org
http://journals.fotki.com/togeika/Mashiko/ Commentary On Pottery
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