James Freeman on sat 7 apr 12
I am hoping to find time this summer to finally build the experimental wood
kiln that has been bouncing around in my head for several years now. About
30 or so acres of my land are forest, and I think I could fire a couple of
times per year just on all the deadfall. Before proceeding further with my
planning, I intend to reread Nils' Art of Firing as well as Frederick
Olsen's The Kiln Book, and will order Mel's book in the next couple of
days. In the mean time, I wanted to ask a few preliminary questions, and
also run a few of my ideas past the ClayArt brain trust to see if I am way
off base.
My general idea is to make the kiln sort of like the front part of an
anagama; the fire box right in the ware chamber (with perhaps a short,
checkered bag wall just to keep cinders and errant logs from piling against
the pots), and in place of the long tail, just a short flue and a standard
stack. The ware chamber would be shaped roughly like an elongated
cross-vault, like the central section of a gothic cathedral between the
nave and the apse, only stretched on one end where the fire would be. I
don't want the standard "train kiln" sort of layout with a firebox chamber
connected to a ware chamber, because I don't want the dead areas where the
ash and flash tend not to reach. To my mind, there seems little point in
going through all of the work of firing with wood unless all of the pots
get absolutely nailed with fire and ash. Any thoughts?
I have already acquired 20 new silicon carbide kiln shelves, 14" x 16", so
my stacking footprint will be 28" x 32". My first question is, how much
room should I leave around the sides and back? I was thinking perhaps 4"
or so, especially on the sides so as to stay with multiples of standard
fire bricks (28" + 4" + 4" =3D 36", which would be 8 fire bricks wide).
For the base of the kiln, I am thinking 4" concrete slab, 8" concrete
blocks laid holes up, one or two layers, perhaps filling the holes with
sand, then a layer of 1/2" concrete backer board. Atop this, I am planning
a floor of one layer of K23 IFB laid flat, one layer of K26 IFB laid flat,
then two layers of High Alumina hard brick, also laid flat, with seams
staggered every layer. I already have 280 brand new 3" thick K23 IFB that
I picked up for $10 per box of 20! Is this base and floor idea overkill?
Other thoughts?
I am planning to build the entire kiln monolithically of castable. I am
thinking a layer of hard castable such as Mizzou laid over the form, then a
layer of fiber blanket, then a layer of lightweight castable or home-made
castable. My main reason for employing castable is to be able to obtain
the cross-vault shape I am after (which I think will result in fewer dead
spots in the kiln) without having to make a bazillion compound cuts in hard
brick. A few questions here: Does this seem reasonable? Will Mizzou (or
other hard castable) hold up to wood? Any thoughts or preferences on
brands of lightweight castable, or home-made? Also, does anyone have any
experience with or thoughts about ITC in a wood kiln?
Several questions regarding the exit flue:
I was planning to employ a simple floor level hole in the back wall of the
kiln rather than going to the trouble of building a channel under the floor
with an exit hole in the center of the floor. Thoughts?
How large should the exit flue be? I was planning to leave a 9x9" hole,
then plug it with hard brick down to the desired size. My thought here was
that the larger hole would leave me with lots of room to make adjustments,
whereas if I made a small exit hole, it would be very difficult to make it
bigger should such be required. The wood kiln at the local college has
three exit flue holes, a central 9x9", flanked by two 4 1/2x9". Whenever I
fire the thing by myself, I plug both side holes completely with hard
bricks, and close off about half of the central hole. The school fires it
with all three holes open, but my firings seem to go much easier and use
less fuel.
How large should the stack be (caliber, not height)? I'm thinking a 9x9"
hole, just to make construction easy.
Since I may be firing this kiln solo at times, my thought is to build in
two burner ports, and to stuff in a couple of atmospheric burners at night
just to maintain temperature should I wish to get some sleep. Any
thoughts? I know the Unzicker brothers just clam up their kiln at night
and let it cool as they sleep, then start things up again in the morning,
but I thought the gas burners would save me a bunch of time.
I will have many more questions as this project gets fleshed out. I
appreciate any insight you care to provide.
Thanks.
...James
James Freeman
"Talk sense to a fool, and he calls you foolish."
-Euripides
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources
gary navarre on sat 7 apr 12
Almost lost track of what you were saying there James, my attention span ai=
=3D
n't what it usat be so ...=3D0A=3D0A=3DA0The only disadvantage I see to usi=
ng a c=3D
astable instead of brick is if you don't like the shape of the kiln you are=
=3D
stuck with a bunch of hard to recycle castable. I used castable with lag m=
=3D
ix to fill in the spaces where cutting a brick to fit would take more work =
=3D
so I could make a curved shape.=3D0A=3D0A=3DA0=3D0AGary Navarre=3D0ANavarre=
Pottery=3D
=3D0ANavarre Enterprises=3D0ANorway, Michigan, USA=3D0Ahttp://www.NavarrePo=
ttery.=3D
etsy.com=3DA0=3DA0=3DA0=3DA0=3DA0 <...... New Pots=3D0Ahttp://www.youtube.c=
om/GindaUP=3D
=3D0Ahttp://public.fotki.com/GindaUP/
Paul Herman on sat 7 apr 12
Hello James,
Here are a couple of more books you should get that are much more in
tune with what you are trying to do. Buy or borrow Jack Troy's book on
wood firing, and the one by Robert Sanderson and Coll Minogue. I
recommend buying, because they are the kind of book you keep wanting
to go back to. Both of them can give you a good illustration of what
is out there, and more importantly, what works. Also, you should
subscribe to "The Log Book" which is a great little quarterly magazine
from Ireland about wood firing, also published by Minogue and
Sanderson. It is my favorite magazine. Here's the link to their website.
http://homepage.eircom.net/~thelogbook/
Maximum ash and flashing is great if that's what you want, but many
lovely pieces come from wood firings with just a little blush of ash.
I certainly don't want all my stuff heavily coated with ash. The kiln
should be designed to encourage the effects you want to see in your
work.
Good Luck! Wood firing is one of the major joys of my life, and not an
easy undertaking at all. Just today we finished loading the kiln here
at my place, for it's 25th firing, and commence stoking tomorrow
evening. It's been a long twelve years, and a lot of blood, sweat and
tears have gone into this kiln. I wouldn't change it for love or money.
Don't let anyone try to convince you that wood firing is going away,
that is just not true. We wood burner potters were here long before
gas fired kilns, and we will be here after gas firing has ceased.
best wishes,
Paul Herman
Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/
On Apr 7, 2012, at 3:51 PM, James Freeman wrote:
> I am hoping to find time this summer to finally build the
> experimental wood
> kiln that has been bouncing around in my head for several years
> now. About
> 30 or so acres of my land are forest, and I think I could fire a
> couple of
> times per year just on all the deadfall. Before proceeding further
> with my
> planning, I intend to reread Nils' Art of Firing as well as Frederick
> Olsen's The Kiln Book, and will order Mel's book in the next couple of
> days. In the mean time, I wanted to ask a few preliminary
> questions, and
> also run a few of my ideas past the ClayArt brain trust to see if I
> am way
> off base.
jonathan byler on mon 9 apr 12
what he said regarding the bricks. I think they are cheaper than
castable anyway... I'm not sure why you need high alumina bricks. my
impression is that regular old "empire s" or equivalent will be more
than adequate. also, I can see plenty of reasons to fire with wood
that don't involve ash, etc. it being independent, sustainable and
renewable fuel source for one.
Woodfiring is kind of an underdeveloped art, because of the large
sizes of kilns, I don't see a whole lot of real experimenting with
them. it's a lot of effort to fill a 100 cubic foot or larger kiln,
and a lot on the line if your experiment fails. Think about flame
length (affected somewhat by your fuel source and how it is split),
and how it travels through the kiln. thiknk about whether even
temperature is imporatant to you front to back, top to bottom. are
you firing this by yourself? think about bourrey fireboxes, they are
supposed to save a lot of effort on your part. www.sidestoke.com is a
good place to start with them. think about whether you are interested
in efficiency, and whatever else comes to mind.
Good pots/sculptures/etc, are the main goal, but how you get there is
not unimportant.
-jon
On Apr 7, 2012, at 9:14 PM, gary navarre wrote:
> Almost lost track of what you were saying there James, my attention
> span ain't what it usat be so ...
>
> The only disadvantage I see to using a castable instead of brick is
> if you don't like the shape of the kiln you are stuck with a bunch
> of hard to recycle castable. I used castable with lag mix to fill in
> the spaces where cutting a brick to fit would take more work so I
> could make a curved shape.
>
>
> Gary Navarre
> Navarre Pottery
> Navarre Enterprises
> Norway, Michigan, USA
> http://www.NavarrePottery.etsy.com <...... New Pots
> http://www.youtube.com/GindaUP
> http://public.fotki.com/GindaUP/
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