jonathan edward byler on mon 11 dec 06
Hi all,
I am looking for some more info about designing and building a small
wood kiln. A friend of mine introduced me to the phoenix fast fire
design, but I have yet to find extensive information about these
kilns. I am most interested in building a smaller (max 30-40 cu ft
total space - not stacking space) kiln that can be fired in under 12
hours. We are not allowed beer at work here, on the clock or off, so
it is going to be hard to talk me into sitting around and tossing
wood on the fire for longerd periods of time... I have some design
ideas of my own, but having never put a wood kiln into service, let
alone fired one, my practical knowledge is a bit limited.
I am interested in building from softbrick where I can, both for
energy savings and ease of construction (i don't have a big wet saw
to cut hardbrick). I have been told that if the firebox is built of
hardbrick, the rest of the kiln can be built with soft bricks
successfully. anyone have experience with this? We would probably
fire this once or twice a semester, but I would like it to be
durable. Does the ash and smoke tend to tear up the regular Thermal
ceramics K-26 bricks? Also Bailey Cermaics reccommends not using
their cheaper high alumina shelves in a wood kiln. is this because
of the high temps reached? or more because of some reaction between
the ash and the shelves? Also, I am wondering about stack design and
firebox area needed. Are there any good books to be recommended?
Many thanks,
jon byler
jon byler
3-D Building Technician
Art Department
Auburn University
Auburn, AL 36849
andrew casto on wed 13 dec 06
Jon,
I fire a 55 cu ft Bourry, which I have had for about 3 years now. What
others have said about the benefits of the Bourry Box design is true. The results can be wonderfull, and it is possible for the kiln to fire in a
very manageable amount of time. Our quickest firing was in 8
hours...usually it takes about 14-16 hrs, depending on the wood we are
using and how the kiln is loaded.
I would caution you though that this style of kiln, while having it's
advantages, can be very tricky to get right. I have rebuilt my firebox 3
times, and made numerous modifications to the entrance and exit flues, bag wall (which I no longer use) etc. It has been a constant learing process (it should be though right?). I also have a website that mentions the phrase "bourry box" several times and, due to this, I frequently get calls and emails asking for trouble shooting advice from others who have a Bourry. From this experience I gather that there are many poorly functioning Bourries out there that folks are having trouble with. It should also be mentioned that I don't get calls from people who own kilns that are working well though, so likely there are plenty of Bourries in good working order out there. I went to Earlham College in Richmond, In, and there is a Bourry there that has been firing very well, and very consistantly for 15 years or so by my guess.
Several on the list have mentioned "Layed Back Woodfiring" by Steve
Harrison. I used his design in our construction, and did not find it to
work well for me. I imagine that in being a novice, I likely did not
understand his formula for proportions, as well as some of the other
nuances of the design. I imagine with his experience, he is able to build
and fire his style of firebox quite well. For me, what we built was really
a nightmare to use.
If you decide to build the bourry I would advise building in lots of
options. I would make more primary and secondary air ports than you think you will need. You can always brick them up later. I would also advise adding either bars in the middle of the firebox at hob level, or a dividing wall in the center of the box to support the wood in the middle (this could be an arch as well so you would not loose space for coals). One problem that can occur with this design is that the accumulation of ash and coals during the firing (especially if you are using hardwoods) can block the entrance flues, or throat arch, into the kiln. If you add some sort of middle support to the hob area, the wood stays on the hobs longer.
Our kiln works well now. I recieved some great advise from Mel in the
process too, which was to add some burners as a safety net that can be used to finish off a poor firing. I have 2 home made venturi style burners on high pressure hoses that can be moved to differant areas of the kiln as needed. They have really saved us in a couple of occasions.
If you build this design and have questions, feel free to contact me on or off list.
Andy Casto
www.redbridgepottery.com
-----Clayart wrote: -----
To: CLAYART@LSV.CERAMICS.ORG
From: jonathan edward byler
Sent by: Clayart
Date: 12/11/2006 01:04PM
Subject: woodkiln construction... need help.
Hi all,
I am looking for some more info about designing and building a small
wood kiln. A friend of mine introduced me to the phoenix fast fire
design, but I have yet to find extensive information about these
kilns. I am most interested in building a smaller (max 30-40 cu ft
total space - not stacking space) kiln that can be fired in under 12
hours. We are not allowed beer at work here, on the clock or off, so
it is going to be hard to talk me into sitting around and tossing
wood on the fire for longerd periods of time... I have some design
ideas of my own, but having never put a wood kiln into service, let
alone fired one, my practical knowledge is a bit limited.
I am interested in building from softbrick where I can, both for
energy savings and ease of construction (i don't have a big wet saw
to cut hardbrick). I have been told that if the firebox is built of
hardbrick, the rest of the kiln can be built with soft bricks
successfully. anyone have experience with this? We would probably
fire this once or twice a semester, but I would like it to be
durable. Does the ash and smoke tend to tear up the regular Thermal
ceramics K-26 bricks? Also Bailey Cermaics reccommends not using
their cheaper high alumina shelves in a wood kiln. is this because
of the high temps reached? or more because of some reaction between
the ash and the shelves? Also, I am wondering about stack design and
firebox area needed. Are there any good books to be recommended?
Many thanks,
jon byler
jon byler
3-D Building Technician
Art Department
Auburn University
Auburn, AL 36849
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David Hendley on wed 13 dec 06
It sounds like the Olsen Fastfire design would be great for your
situation. Get Fred Olsen's "The Kiln Book" for plans.
I have built and fired 2 of them, although each time I have made
the kiln larger than shown in the plans. As shown, it is about
3 feet wide, 2 1/2 feet deep and 4 1/2 feet tall = 34 cu ft total
space. The book will also give you guidelines about firebox and
stack sizes and designs.
Since it has 2 fireboxes, the Olsen design can fire very evenly.
The Phoenix design is a cross draft, so it will produce hot spots
and cool spots. Neither design will result in a lot of ash deposit.
My large Fastfire is built with hard bricks for the fireboxes and
IFBs for the kiln. It will fire to cone 10 (with bisqueware) in
less than 8 hours, but I stretch it out to 10 hours for better
results. A smaller kiln should fire even faster.
K-26 bricks should be fine everywhere except right where the
flame enters the kiln - I would insert a handful of high alumina
hard bricks there. I have always coated my kilns with ITC, and
I think it helps protect the bricks.
High alumina shelves have performed terribly for me - warping
and awful spalling. Silicon carbide is worth the extra cost.
Beer should never be consumed while firing a kiln.
David Hendley
Maydelle, Texas
david(at)farmpots(dot)com
http://www.farmpots.com
----- Original Message -----
> I am looking for some more info about designing and building a small
> wood kiln. A friend of mine introduced me to the phoenix fast fire
> design, but I have yet to find extensive information about these
> kilns. I am most interested in building a smaller (max 30-40 cu ft
> total space - not stacking space) kiln that can be fired in under 12
> hours. We are not allowed beer at work here, on the clock or off, so
> it is going to be hard to talk me into sitting around and tossing
> wood on the fire for longerd periods of time... I have some design
> ideas of my own, but having never put a wood kiln into service, let
> alone fired one, my practical knowledge is a bit limited.
John Dellow on thu 14 dec 06
David ,
you may be able to answer a question about the chimney I intend to use
with my phonex fast fire.It will be 1&1/2 deep and full width and 12 ft
tall.Will I get the same draft as with a standard chimney ,ii.e.1&1/2 X
1&1/2 bricks and say 20 ft even if both had the same cubic capacity ?
Thanks John
John Dellow "the flower pot man"
From the land down under
Home Page http://www.welcome.to/jkdellow
Lee Love on thu 14 dec 06
On 12/12/06, jonathan edward byler wrote:
> I am interested in building from softbrick where I can, both for
> energy savings and ease of construction (i don't have a big wet saw
> to cut hardbrick). I have been told that if the firebox is built of
> hardbrick, the rest of the kiln can be built with soft bricks
> successfully. anyone have experience with this?
John,
My kiln is hardbrick for the firebox and outer walls and
floors with a softbrick liner and arch. I cut the hard brick I
needed to cut with an angle grinder and a diamond blade. It gets
better flashing than an Olsen.
You can see designs and photos of the building process here:
http://public.fotki.com/togeika/my_kiln/
Results here:
http://potters.blogspot.com/
--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone
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