search  current discussion  categories  kilns & firing - wood 

wood firing, wood smoke, and all that kinda' stuff once again

updated thu 30 sep 04


John Baymore on tue 28 sep 04

Hi all.

In light of the current rearing of the "woodfire debate" once again..... =
wanted to repost something that I had said a long time ago here on
CLAYART......... from October 1999. I feel that it is still VERY



-------------Forwarded Message-----------------

From: John Baymore, =

To: Ceramic Arts Discussion List, INTERNET:CLAYART@LSV.UKY.EDU

Date: 10/9/1999 12:48 AM

RE: Wood fire conf. / big anagama

First of all...... Mel...... Thanks for the updates on the conference.

I personally find it sad that the trend should be towards ever larger
kilns, especially at colleges where they should be teaching their
students how to build affordable kilns that one person can, at a pinch,
fire on their own.

The American "bigger is better" phenomona is apparently alive and well an=
seems to be infecting others .

In 1979 when I started doing the planning for my noborigama here in NH, o=
of the main design criteria was that it be of a scale that was fireable b=
one For that is who/what I am. One person studio. So wit=
that as a design goal, I am still able to a more "mature person"=

.......... fire it by myself. With two people working, firing it is a
breeze. =

Being a wood firer that fires mostly glazed wares, I tend to be a bit
outside the current " woodfire trend" . I wanted to be able to fire
varying atmospheres, temperatures, and effects (glazed and unglazed) in a=

single firing. The nobori does that pretty well. Anagama tend to be a=

little more of a "one trick pony"..... although certainly huge variations=

in the same types of effects happen in the single chamber...and you can
fire glazed in certain locations and in saggers. But it is not as
efficient, nor as flexible.

It is interesting to watch the 30 year woodkiln trend since when I first=

started woodfiring to BIG kilns. "Mine's bigger than yours". Oops...let=
not go there . Is bigger better? One of the old Japanese potters I
visited has a two chamber noborigama that helped him produce killer
unglazed wares.... and his kiln was smaller than mine. It isn't the's what you do with it. (God... I'm starting to sound like
Tony!!!!! )

There is also the "anagama uber alles" trend (talk about mixing languages=

). Mel is spot-on about us overlooking the possible beauty of woodfir=
on red earthenware clay and the like. It is such a simple
thing........wood fire makes nice markings as it plays across the wares n=
matter what the temperature or what size the pieces of wood.

I have friend that has a large anagama which was completed recently. It =
a beautiful kiln built with wonderful workmanship. I have helped fire it=
. =

At one level, I am envious of the is a REAL beauty (is this a=

case of kiln-envy? ). He did his homework. But I wouldn't really wan=
to own it as "my" kiln.

The problem with such kilns in private studio situations is that they are=

generally pretty impractical. He fires it about once a year. So all the=

eggs are in one basket, and the cash flow from selling the pots is highly=

intermittent. Then the firing is dependent on getting a bunch of people =
help fire, ..........and of course trading away a good piece of that larg=
kiln space (you paid to build) to get the firing help. So when the kiln
owner is not there, HIS work is subject to the whims of whomever is in
charge of the stoking for that shift. Hard way to assure your work comes=

out OK . =

I once watched the above kiln owner give careful instructions to a team
(potter friends) about how he wanted things done. As soon as he left the=

area to go to sleep, the debates started..... about how the stoking shoul=
actually be done. So the 8 hour stoking shift got done.... but the stoki=
was NOT what the kiln owner thought was being done to his instructions. =

The multiple "experts" on duty all had different theories about what was
"correct"........ and seemed not to value that they were instructed to fi=
a certain way. So they eventually tried periods of every persons pet
theory. So that blew any "cause and effect" ideas that the kiln owner ma=
about the results coming out of that kiln load.......... but he didn't kn=
it . I've seen this many times on "communal firings" in this countr=
We are an independent lot..... and following specific instructions from
"authority" is not our strong suit .

I think there is a place for such big wood kilns (and of course for certa=
rare individuals it IS the right kiln). In a teaching/learning situation=
a huge kiln can help build a sense of community and interaction within th=
department/program. I found that when I built the noborigama at Massart
way back in the mid 70' was a great thing for the majors to
experience. The energy level in a large group firing is fun. The teamwo=
to bring such a firing to completion is a wonderful thing to experience. =

Builds friendships. Inspires lots of good work. A big kiln in full fire=

is an awe inspiring sight. All positive aspects of such a situation. =

But it DOES seem that this type of monster kiln is being promoted as THE
way to wood fire. If nothing else, anagama are terribly inefficient in u=
of fuel, and also produce a lot of smoke (PM10 anyone ). These days =
the ceramic show press, woodfired alternatives to "anagama style pots" ar=
not as easily found. That huge anagama should be sitting right next to t=
50 cubic foot crossdraft caternary (or whatever) wood kiln, and that next=

to the 25 cubic foot downdraft fastfire. That way students/learners get =
see the breadth of possibilites of not only kilns, but wood fire effects.=

Personally, I think you'll learn a lot more about clay, glazes, fire,
kilns, wood, ash, and pots by firing a 20 cubic foot wood kiln by yoursel=
100 times than firing a 2000 cubic foot wood kiln (along with dozens of
others) once. The one big kiln firing is an experience you should try to=

have at least once..... but you might want it for dessert....not the main=


More power to Mel and Kurt and company on the mini-train. And to they an=
others building more realistic, "main-stream" potter studio sized wood
kilns. And to those not totally on the anagama bandwagon as the only tra=
to take. There are other ways to fire with wood, and we'll find more and=

more twists to try as time goes by.

Just my two yen worth .



"not happy about not being able to get out to the woodfire conference"

John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA


John Baymore on tue 28 sep 04

This is another reposting of a posting I did to CLAYART in October of 200=
It too is very pertinent to the current discussion and I feel that it is=

worth reposting.



-------------Forwarded Message-----------------

From: John Baymore, =


Date: 10/11/2001 9:30 AM

RE: RE: Woodkiln in an Urban Area

I am in the very ealry stages of building a woodkiln (anagama, but others=

also) in an urban setting. Possibilities include but are not limited to a=

downtown setting, or on the edge of town in a lose residential area. I'll=

be the first to acknowledge that these might not be the first choices for=

many of us for all sorts of reasons and challenges, but I am looking for =
responses to a particular question/concern. That concern is emission

Hi Josh.

Been there, done that, bought the T shirt . Years ago. (see below) =

Been wood firing since 1969. Currently fire a four chamber noborigama in=
distinctly NON-urban setting.

Got yourself a project..... you do .

Wood kilns and urban settings are, as a broad generality, a VERY large
mismatch. Of the types of wood kilns one can build, an anagama is probab=
the most mismatched of the possible wood kiln types to build in an urban
setting due to its primitive firebox and direct-to-chimney circulation
path. Can be done......... but likely will require great care, solid kil=
design knowledge, careful fire management, alteration of usual firing
cycles, possible alteration to the "usual" design, and sometimes lots of
MONEY. Probably BIG money if you need to go fully "legal".

Oh... and very good relationships with your immediate neighbors. VERY
good. Work those relationships .

Right off the top, one thing I hope you'll give GOOD due consideration
before you go ahead with this project, is the impact YOUR proposed kiln(s=
might have on all the OTHER wood kilns in your town, state, and your
country in general. Not sure where you are located, since some countries=

may be more concerned about emmissions than others. The USA certainly is=

Here in the USA, the EPA's PM10 emissions standard along with the Emissio=
Opacity rule pretty much makes ALL typical potter's wood kilns in the
country in violation of emission standards.......... unless the effluent =
somehow "scrubbed". Period....done deal. The only reason we don't all g=
shut right down is because we are very much "small potatoes" and don't ge=
actively looked at UNLESS there is a specific complaint. The EPA and stat=
DEQ's are used to looking at emissions by multiple tons....... in that
regard, most potters don't even show up on their radar screen. With a
complaint however....... they do have jurisdiction....... and will becom=

(As an aside here...... in many locales a potter does need an
emissions/operating permit even for a gas kiln. The potters don't know
it, and the regulators don't even know the potters exist. They're too bu=
looking at "industry". So no one really does it....and no one enforces t=
law. So things just go on as if there were no laws that apply. Again...=
situation waiting for a complaint to pop to the surface and surprise the
poor potter. BTW...the PM 10 regs apply to
gas/oil/charcoal/bellybuttonlint kilns too. If you fire REALLY dirty (ba=
firing practices....unnecessary) you can exceed the regs too.)

The more rural the setting, the more UNLIKELY that a complaint will be
filed....since rural folks are used to more agricultural and "close to
nature" operations than those in the city. Wood fires are pretty much a
normal aspect of life in the country. In the city.... the
fire department . Plus, in cities the impact of the automobile is
horrendous on air quality to start with........ so any additional insult =
the air really can BE an issue.

The more "NIMBY" the neighborhood... the more likely you will have a
problem. Also, you don't say if you are an individual or an institution.=

Sometimes institutions of higher learning can get away with stuff an
individual would have problems with....... because people assume that tha=
are doing stuff legally and/or know what they are doing. "That smoke mus=
be OK Martha, .... it's coming from the University of Pyromania" . =

Sometimes however.... institutions have administrations that go STRICTLY =
every letter of the law....... and such things are actually HARDER to do =
those places.

An anagama in "full belch"....looking sort of like like a coal fired choo=

choo train going right thru town, would give a US EPA emissions inspector=
coronary on the spot .

In the "keeping things in perspective" department relative to wood kilns
emissions........ I'd bet one engine of a 747 taking off is putting out=

FAR more "junk" in a few minutes that any handcraft potter's kiln probabl=
will in a year . Stand at a street corner in a city and count the car=
for a half hour......... you want to talk about emissions and their impac=
on the environment? Even with the scrubbing in place... the "leftovers"
from many industrial process stacks STILL put out more junk than a craft
potter will. Our potential problem with any of our kilns is that we are
not looked at as an important "cog" in the wheel of industry and the
pursuit of money and votes,........... not that we are such huge pollutio=
sources. We would be "easy" to shut down.

A "high profile" case involving a wood kiln could draw the attention of t=
governmental agencies (either local, state, or country) down on ALL
woodkilns. This could result in a woodkiln "witch hunt". This would
happen even though 18 wheelers will still go merrily along belching diese=
smoke, gazillions of cars will commute into the city with single
passengers, mass transit will continue to be non-existant, home fireplace=
and wood stoves will continue on unhindered, town municipalities will bur=
brush piles, and so on. This is because potters have NO real political
clout as a group. Potters are not seen as a necessity. Potters don't
number enough to represent a voting bloc. The aesthetics of woodfire are=

"lost" on the masses. And so on. See the archives for a LOT more on thi=
whole concept...... been discussed a bunch....and I don't have time to go=

into all of it again right now. If I remember correctly you might look
under the topic of "Tozan Kiln Shut Down" or something like that..... I
think a bunch of this discussion ran off that topic.

A goodly number of years ago here in New Hampshire, USA, there was a salt=

firing potter who located into an urban setting thinking nothing of what
might happen. Vehement complaints from neighbors about that particular
installation brought the "wrath of the State" down on ALL salt kilns in t=
whole state. It did start a "witch hunt". The "powers that be" knew
nothing about potter's salt kilns before it was thrust to their full
attention by this situation. The State didn't know...and didn't care. =

Probably didn't WANT to care...... more important issues to take care of.=

But once the city neighborhood was "up in arms"...... they HAD to care. =

Even after it came to their attention, they still really knew little abou=
them or their emissions, but they still attempted to shut all salt kilns
down in the state UNLESS the potter installed industrial type emissions
controls (read that as EXPENSIVE). A couple of them did this....... =

including the original "offender". The rest "hid" their firing practices=

or stopped completely. Most stopped. This pretty much eliminated salt
firers here in NH to this day. A couple have crept silently back
in.....but one complaint and "zap".

Rural New Hampshire.... land of the "stealth" salt kiln .

I have not heard of an anagama in a downtowncenter.. so if there is one o=
there what are you doing?

There might be a reason .

A pretty long time ago...... late 70's (?).......... for some very concre=
reasons having nothing to do with simply WANTING to have a wood
kiln......... I constructed a 3 chamber woodfired noborigama right betwee=
Children's Hospital and Beth Israel Hospital in Boston. This was done wh=
I was the FT technician at Massachusetts College of Art. It was done whe=
the State (Massart's a state school), in all it's infinite wisdom, shut
down our entire fuel fired kiln facility for renovations which would last=
full year..... suddenly....without more than a few weeks warning, just
before the beginning of the fall semester!!!!! That wood kiln did ALL th=
fuel firing for the entire department for a year. It was a SURVIVAL
measure to begin with....but became a very positive feature of the school=
facilities later. Massart's program at that time was HUGE. Lots of ware=

to process. Undergrads and grads depending on the opertion. Tons of
elective students. Only 5 small electrics.

Had we not done that wood kiln.... we would have been pretty much focusin=
on "conceptual ceramics" for a year .

I selected a noborigma for efficiency of output volume relative to amount=

of labor and wood processed. Aesthetic issues were secondary (but NICE

That noborigama remained in use after our gas facility was restored.... a=
was utilized for many, many years after that. It is long gone now that
Massart has relocated to the old Boston State campus. That kiln started =
lot of people off woodfirng, and the team building and learning that went=

on was tremendous. I have very fond memories from that time. Have some
great pictures of the Massart parking lot with cords and cords of wood
being split by students. Still remember the subtle scent of wood smok=
during the end of the all night preheat phase, as dawn broke over a still=

quiet Boston and we sat talking quitely and sipping tea. It brought such=
nice "country feel" to the city, and gave the students a pretty unique
experience for an urban school. Oops... I digress .

That kiln had a main firebox (dogima) design that was very clean burning
(unlike most anagamas), and the dual stacks had an afterburner system
(powered off a pair of 40 lb propane trailer cylinders) to clean up VISIB=
emissions (not fine particulate). While there WAS some smoke leaking off=

the stoke holes, blow holes, and spy ports...... the kiln chimneys burned=

visually "clean" outside the building. At the peak of the firing they
looked like the afterburner on a fighter jet.......... 4 feet of nicely
shaped blue flame. No smoke. The smoke leaking into the kiln room was
picked up by the excellent general dilution ventilation and was SO dilute=
with fresh air that it was not visible where it exited the building.

The focus I put into the kiln design was on controlling visible emissions=
. =

No complaints....... no inspectors. No inspectors....... no check for
particulates. No visible smoke......... no complaints. Simple, but stil=
not strictly legal.

I've considered some industries have faced similar what have=

they done? That said they might have had some system inside there stacks
but, I would think something in your stack could mess with your draft and=

fire. I would welcome any and all suggestions to my querries.

Industry does address the particulate emmissions problem relative to the =
10 regs. And it can be solved. Coal fired plants do. There are also
plenty of wood fired electric generation plants that solve it. Problem i=
that it is ABSURDLY expensive to do when compared to the idea of producin=
handcraft pottery. Maybe in Japan where the valuation of wood fired
handcrafted pots is SO much greater, it makes some form of sense. But in=

the USA it is pretty much "out of balance". You'll need an industrial
engineering firm to do it correctly, and for a typical anagama I would be=

surprised if you can do it for less than $20-30 K for the emissions
controls alone. Then there is the ongoing operational costs and upkeep.

Yes, as you mention, the emissions controls will affect the draft flow in=

the kiln. The impact has to be engineered into the kiln design. That is=

one of the reasons you'll likely need an industrial kiln firm to assist o=
the project.

Going for a completely "scrubbed" effluent is not really practical for th=
handcraft potter. Getting the "worst of it" and eliminating the
"attention" the kiln gets is another matter. A system that will cut only=

the visible smoke is easier to build at more of a "potter budget". =

I've tried things like a fine water mist located over the chimney exit
point....... which certainly works to decrease the smoke a bit....... but=

seems to create a lot of wet ground and drainage issues and sometimes mak=
a lot of steam.....which itself is attention getting. In an urban
setting.... the drainage issue can be a real problem if the ground is
paved, or there is no place for runoff. The most effective system I've
built to eliminate smoke on a wood kiln is an afterburner system.

Bascically, in a nut shell, you need to raise the chimney temperature wel=
above ignition temperature of the effluent gases, supply fresh air (or O2=
well in excess of that needed for the combustion of the afterburner's fue=
itself, induce enough turbulence so that the excess air you supply mixes
well with the unburned gases in the kiln effluent stream, provide enough
space/time to complete the combustion, and bingo....... minimal smoke and=

lower particulates.

Practical considerations include that the chimney will now effectively be=
firebox with VERY high temperatures. The refractory selection for the
chimney lining will be VERY important, as will insulating the chimney
itself to maintain the high temperature. The roof penetration point
becomes more problematic.......... the chimney is now one of the HOTTEST
points in the kiln, not the lowest. And the volume of air that you
introduce into the chimney will impact the draft flow and therefore the
sizing of the cross section of the chimney(s).

Also...... you will likely have the "jet afterburner look" at the top of
the chimney. This visible flame can be shielded by a layer of metal that=

is bigger in diameter than the end point of the stack, added above the
termination of the stack, and stood off the actual chimney so that it let=
dilution air into the bottom area. Sort of like a venturi burner primary=

air inlet. You've probably seen this approach on some
commercial/industrial stacks and not realized what it was. This plume of=

blue flame at the top of the stack(s), if left visible, MAY still get you=

complaints from "fire-ly challenged" neighbors .

You can relocate the afterburner input point to work in the "smoke chambe=
that is often present in anagama and noborigama designs. This moves the
high heat point down to where it may be more easily managable and may
eliminate the plume of flame at the chimney exit point.

The afterburner concept WILL decrease the particulate emissions along wit=
the visible qualities.... but still will not bring them down to EPA PM 10=


So...... hope something here is of use to you. Check the archives...... =
would be surprised if you don't find lots.



John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA

603-654-2752 (s)
800-900-1110 (s)

"Earth, Water, and Fire Noborigama Woodfiring Workshop 2002 Dates TBA"

Chris Ostrowski on wed 29 sep 04

you liken anagamas to a "one-trick-pony." kind of like saying our verbal language has only one word. And considering that the art of firing anagamas has been practiced basically forever, relegating it to "band-wagon" status seems a bit naive. I understand that you don't appreciate the communal aspect of firing anagamas since you are a one-man show, but not all firing crews are as selfish as the one you described. Some actually work as a team. You should see the results.

Chris Ostrowski

ps if any band wagon ever shows up at one of my firings, I believe that I'll disassemble it and stoke it.