Bourry Firebox Throat

[Micahel Banyai]

We have fired our latest redesigned kiln twice in the last few weeks,
each time we failed to get to cone ten. This was a profound surprize
as the new box is basicly a fiber kiln and should require signficantly
less BTU's then the hardbrick train kiln that it replaced. This was
useing the same firebox and chimney with new warekiln. After refection
and analysis I believe the cause was relative obstruction of the
firebox throat. This was caused by both structural as well as human
operator issues. The kiln never really seemed to draw as well as it
should have. It turns out that inside the ware kiln at about 6 inches
back from the throat I created a hearth step that was four inchs
high. This was done to place four inchs of fiber on the floor which
was covered with a kiln shelf. The structural effect that was not
anticipated was that the coals tended to back up behind this into the
throat to the effect of 4-5 inchs high. I had never done the
calculations but afterwards I determined that if you take out the
bottom four inches of a 17 inch high throat you have obstructed 40% or
so of the total area. Also, if you are able to look through the top 6
inches of the throat and think that this is a big enough space, in
reality you are only seeing 15% of the toal area. On the last fireing
we climbed to 1850 degrees F in a little more then 4 hours for a 36
cubic foot kiln but then got little more then 2100 over the next
twelve hrs. It turns out that the first 4 hrs were done by a senior
teacher who was meticulos in keeping the throat clear but then the
next crew did not know, and we did not emphsize, so that the throat
was largely obstructed. It will be spring before I can prove this, so
for now it is a hypothesis, but I believe it will turn out to be the
case. Sometime small changes can have large effects. I had never read
about the math of throat arches so this took me by surprize. In
retrospect it was a DUH moment of revelation.

[John Boyd]

I'm sorry Mike, are you discussing the so-called "triangle-of-death" in the pyrophysics of firing trains (ie, flame path on the stack side of the throat arch) or are you referring to a lack of height on the throat arch, or are you only referring to the lack of adequate floor area prior to the throat arch because your last brick steps intrude on this, hanging up the coals?  I have occasionally run into this problem too, so I am curious about what your observations suggest.
Thank you for the report!
JB

[Mike Banyai]

I found that as the height of the coalpile grew in the firebox throat
the air passage obstrction was greater then one would suspect just
looking at the opening. I believe that this choaking off of flow in
the throat was the reason we were not able to fire as hot as we
wanted . In the future we will work very hard to keep it open as much
as possible, warmest regards , Michael

On Nov 15, 2009, at 3:45 PM, John Boyd

[gary navarre]

Hay Mike, Crew,

Control of the coal pile is obtained with a properly designed and functioning mousehole. In "Pioneer Pottery" Cardew explains why on p.210 after discussing firing Stage 4: 1000ºC to 1250ºC. Full Fire, reducing. 7 hours. Average temperature rise 36ºC/hr. I won't go into the details of why smoke in the stack is not a sign of good reduction and how to eliminate it once it develops however the last few sentences are more relevant... "Black smoke is thus the enemy of reduction, not a means to it. A continuous emission of smoke means not only that a large part of the calorific value of the fuel is being wasted but also that the temperature will not rise until it is cleared. Careful control of the secondary air shutter is necessary throughout the reducing stage. The mouseholes also require continual attention, to ensure that the bank of embers does not begin to block the throat arch." After ^8 you can open the air because reduction is complete. That was of
course before slow cooling and downfiring came along but you need to get to ^10 first. My Hobalectric stalled out once and Jeff Cline had me fire off the ember pile for a while and it unlocked the heat and there was more room for the primary combustion gasses to burn with enough secondary air and it got to ^11.

When I built my mouseholes I made the air in hole (approximately) 1½"x4½" and the air exit under the coal pile 2½"x16" to allow for heat expanding the air through the tunnel...

http://public.fotki.com/GindaUP/ca/kpap/uphea07/moreonmousehole045resize.html

... and there is one for the Bourry and the pignose...

http://public.fotki.com/GindaUP/ca/kpap/uphea07/pnmh.html

You might want to discuss over stoking with your helpers too.

Gary Navarre
Navarre Pottery
Navarre Enterprises
Norway, Michigan, USA
http://www.youtube.com/GindaUP
http://public.fotki.com/GindaUP/

--- On Sun, 11/15/09, Mike Banyai <mikeb...@gmail.com> wrote:

[Micahel Banyai]

We have 13 different air adjustment ports includeing three mouse holes
that are 2x4.5 inches, the problem is that if there is not enough draw
then the mouse holes will not help burn down the coal pile. I think I
stated pretty plainly that overstaokeing by an inexperianced crew was
a major element of our problem. What I was trying to alert folks to is
the fact that the math shows that that a barrel arch 17 inches high
has a cross sectional area for air to flow of 454 square inches. If
you fill up the bottom half and decrease the height to 8.5 inches you
do not decrease the area of flow so that there is half as much flow
but rather you decrease it to a quarter of the flow area(113 square
inches). Thus the magnitude of the obstruction is much larger then you
would think, just looking at it. I had never seen this noted in
either books or internet. It is simple and plain but was easy to
overlook, at least by me. Takeaway is keep the throat open, a lot,
even if you have to rake out coals to do it. If you can do it with the
mousehole adjustments, all the better but if the draw seems anemic,
look hard at the firebox throat.

[Lee]

I like Dick Lehman's idea of stepdown grates. Never had any
experience with them, but I find them interesting.

--
Lee Love in Minneapolis
http://mingeisota.blogspot.com/
"The intuitive mind is a sacred gift and the rational mind is a
faithful servant. We have created a society that honors the servant
and has forgotten the gift." -- Albert Einstein

[gary navarre]

Oh I think I see what you are saying Michal, although pictures would help, so next firing hopefully the now more experienced stokers will not over stoke. I know some folks think it is OK to pull coals from the fire make it behave but I deduct points for that trick. When ya go to all the trouble to make the fuel all the heat should go into the chamber, one of the reasons I designed the pignose for pre-heating the firebox, chamber, and stack.

So if your stokers slow down and don't choke the throat arch and your draft is still anemic either your stack could use another foot or so of brick and there is not enough brick around the stack to give you a good heat sink. Sure would be nice to see some good drawings or photos so until then stay in there eh!

Gary Navarre
Navarre Pottery
Navarre Enterprises
Norway, Michigan, USA
http://www.youtube.com/GindaUP
http://public.fotki.com/GindaUP/

--- On Mon, 11/16/09, Micahel Banyai <mikeb...@gmail.com> wrote:

> From: Micahel Banyai <mikeb...@gmail.com>
> Subject: *WoodKiln* Re: Bourry Firebox Throat

[gary navarre]

So step to the plate and build one to see who's idea is better. Of course it depends on what comparative ash results take place and fuel consumption over firing time, and smoke alerts to consider but I know my design works just as good if not better, especially for beginners to fire alone, and it can be built for less than 5 grand, maybe half that if you already have shelves and other stuff, pretty cheap for 65cu.ft of stacking space. I wouldn't recommend much larger because it is taking a long time for this old coot to fill it but I'm sure a youngen or two could fire a couple three times a year and maybe make some money. Since I've had the Internet though I've been quite pleased with all the enthusiasm for new designs in wood kilns, some of which I wish I could have built, and firing styles, so if they work I guess they work. More students taking up wood firing was my particular spell so it doesn't matter whose design you use, just get to work and make
it happen. If you like that step-down idea see how you could adapt it to the kiln you had in Japan or redesign what you had in mind and test it. Point the mind and the body will follow, might take 40 years to get there but you will get there.

Gary Navarre
Navarre Pottery
Navarre Enterprises
Norway, Michigan, USA
http://www.youtube.com/GindaUP
http://public.fotki.com/GindaUP/

--- On Mon, 11/16/09, Lee <l...@mashiko.org> wrote:

> From: Lee <l...@mashiko.org>
> Subject: *WoodKiln* Re: Bourry Firebox Throat

[Des & Jan Howard]

Micahel
As well as overstoking there is the problem of WHAT is
stoked.
We used 2 species of eucalypt, 2 of acacia & one of
native pine.
One eucalypt gave long, hot flames, lotsa flash,
minimal embers, insufficient for good ember pile.
Second eucalypt gave long hot flames, yellow ash glaze
on pots, minimal flash, hard, clean embers, choked throat.
Acacia spp. gave long, medium hot flames, minimal
embers, flash on pots.
Native pine, looong, resinous flames, medium hot,
minimal embers, flash on pots.
So, a blend gave the best ember bed, the be-all/end-all
of a Bourry box kiln.
The throat arch base was the width of the firebox.
The mouseholes, (two fireboxes), were really ratholes,
don't stint on their size.
Raking out excess embers is only for Fast Freddies :)
Des

gary navarre wrote:
> Oh I think I see what you are saying Michal,
although pictures would help, so next firing
hopefully the now more experienced stokers will
not over stoke.

--
Des & Jan Howard
Lue Pottery
Lue NSW
Australia
2850

02 6373 6419
www.luepottery.hwy.com.au
-32.656072 149.840624

[Lee]

On Mon, Nov 16, 2009 at 4:43 PM, gary navarre
<navarreen...@yahoo.com> wrote:

>  it happen. If you like that step-down idea see how you could adapt it to the kiln you
> had in Japan or redesign what you had in mind and test it. Point the mind and the
>body will follow, might take 40 years to get there but you will get there.

Gary, I don't have the property now. I did have the idea of
building stepdown grates in front of the firieboxes of my kiln in
Mashiko and then filling the bottom of the firebox with pots. I
would have made them portable, so I could move them aside to firing
for the main chamber.

Dick's grates allows him to fire with whole logs for a week.
He stokes logs every 6 hours and doesn't have to stoke frequently
until the last 36 hours with small wood.

--
Lee Love in Minneapolis

[gary navarre]

Since I made this kiln bigger I have a larger pignose so I just might be able to stoke every 10 down to six hours over a couple days and get past quartz conversion and maybe up to 1500ºF before switching the fire to the hobs. The Bourry box should hold about a dozen 6-8"x35" sticks for holding the heat built when thinner sticks are added for acceleration of the temperature. Once I figured out how to fire this variation of Cardew's drawings bending the cones in 24 hours became easy, at least I hope that will be the case. It could take longer because I have twice the volume as the old one in Kalamazoo. However, since I read from some of you guys about that old guy in Japan that sets his wood burner so it will only cool down to 1900º and starts it up again in the morning I realized I could could do that and not screw up the firing. I always thought once ya got started ya had to keep going on up till it was done.

Gary Navarre
Navarre Pottery
Navarre Enterprises
Norway, Michigan, USA
http://www.youtube.com/GindaUP
http://public.fotki.com/GindaUP/

--- On Mon, 11/16/09, Lee <l...@mashiko.org> wrote:

> From: Lee <l...@mashiko.org>
> Subject: *WoodKiln* Re: Bourry Firebox Throat
> To: wood...@googlegroups.com

[Des & Jan Howard]

Gary
Hah! Only when yer short on years &/or long on
testosterone.
Or, stokers that will do exactly as you say & not get a
rush of blood to the gonads in the potter's absence &
fire the kiln 'their way'.
Des

gary navarre wrote:
> However, since I read from some of you guys about
> that old guy in Japan that sets his wood burner so
> it will only cool down to 1900º and starts it up
> again in the morning I realized I could could do
> that and not screw up the firing. I always thought
> once ya got started ya had to keep going on up till it was done.

--

[Jeff Guin]

Hey Gary,
Do you have any pictures posted of your kiln?
Jeff
Coon Valley, WI

http://mudwerks.blogspot.com http://www.flickr.com/photos/mudhead99/


 
> Date: Mon, 16 Nov 2009 14:43:37 -0800
> From: navarreen...@yahoo.com

[Mike Banyai]

Yes I agree that this is imprtant, our best sucess was when three
small cedar sticks were with a hardwood stick.

On Nov 16, 2009, at 5:57 PM, Des & Jan Howard <djho...@hwy.com.au>
wrote:

[Mike Banyai]

I used to be adverse to rakeing coals untii I read the Ag report that
indicated that vast majority of the energy of wood is the volital
gases given off, that the coals are really not much of the wood
energy. I agree the design and purpose and fireing plan of a kiln are
determinant. My kiln is never going to go for a week as this is not
realistic in a college setting.

On Nov 16, 2009, at 4:49 PM, gary navarre

[gary navarre]

Ya Jeff, where ya been, I've been posting pretty much brick-by-brick progress reports on 4 clay forums for about 5 years. Here is the Fotki page about my kilns or others I've helped with...

http://public.fotki.com/GindaUP/ca/kpap/

... and the videos are on my YouTube link.

Gary Navarre
Navarre Pottery
Navarre Enterprises
Norway, Michigan, USA
http://www.youtube.com/GindaUP
http://public.fotki.com/GindaUP/

--- On Tue, 11/17/09, Jeff Guin <mudh...@hotmail.com> wrote:

[tb]

"Hey Gary,   Do you have any pictures posted of your kiln? "

sorry jeff , but that one gave me a big laugh! T. E. Brown --- On Tue, 11/17/09, gary navarre <navarreen...@yahoo.com> wrote:

[CRAIG]

Hey thar G in da UP... whens ya gonna fer dat ting?
Make Good Pots
~Craig
New London MN
http://woodfiredpottery.blogspot.com/

[Des & Jan Howard]

Mike
That Ag report & others of it's kind are not lying or
attempting to evade. They just don't cover all of the
facts. The way in which the wood is used is paramount.
A hefty ember bed is essential because a
Bourry firebox doesn't burn the wood, as such.
The ember bed radiation gasifies the wood
& these gases are led into the kiln.
At the same time the ember bed preheats/superheats
the secondary air & this is led into the kiln.
The gases & heated air mix & combust INSIDE the kiln.
Tertiary air that travels through the mouseholes
is not just to knock down the embers but to keep
the ember bed at a cosy white heat essential to
the gasifying/preheating.
One of the beauties of the Bourry box kiln is the
ability to fire pots with wood, no stirring/raking
of embers with consequent ash dumped on pots.
Not every woodfirer wants 'snot' on pots*
If that's yer bag build an "Annie" ;)
Des
* a bit of 'flash' is nice.

Mike Banyai wrote:
> I used to be adverse to rakeing coals untii I read the Ag report that
> indicated that vast majority of the energy of wood is the volital
> gases given off, that the coals are really not much of the wood
> energy. I agree the design and purpose and fireing plan of a kiln are
> determinant. My kiln is never going to go for a week as this is not
> realistic in a college setting.

--

[Lee]

On Tue, Nov 17, 2009 at 3:08 PM, Des & Jan Howard <djho...@hwy.com.au> wrote:

> Not every woodfirer wants 'snot' on pots*
> If that's yer bag build an "Annie" ;)
> Des
> * a bit of 'flash' is nice.

I've never understood wood kilns that require all of the pots
being glazed. Might as well save your effort and soda fire.

Shimaoka's kiln had 5 chambers of various temps and
atmospheres. Hands down, my favorite chamber, the only chamber he
personally loaded, was the Yohen chamber, right being the main firing
chamber. It didn't get the ash deposits of the firebox, and even in
there, I would not say the ash deposit was "snot-like", but the Yohen
(changing chamber) only got light ash, was very hot and flashed nicely
all around. It was heavily reduced at the end of the firing.
Charcoal was poured into the chamber to cover the pots. They all had
a dull oxide surface until they were polished. Polishing revealed mat
suraces that showed color and depth. Those were my favorite pots
and actually, the nicest pots to touch from the noborigama.

--
Lee Love in Minneapolis

[Des & Jan Howard]

Lee
Don't make the basic mistake in thinking every
woodfirer follows a wabi-sabioid aesthetic.
Ivan McMeekin, the introducer of contemporary
wood-firing & Bourry boxes to Oz, complained to me of
the 'fuzz' that happened, to glazes, when the embers
were stirred. He adored historical Chinese work,
loathed Japanese.
We fired with wood for years because we lived out in
the bush & had 5000 acres of timbered country to pick
over.
The flash was nice on our grainy home-made clay body.
Ash specks on temmoku gave an acceptable amber shading.
Ash on shino looked like dandruff on a tuxedo.
Des

Lee wrote:
> I've never understood wood kilns that require all of the pots
> being glazed. Might as well save your effort and soda fire.

--

[Lee]

On Tue, Nov 17, 2009 at 4:26 PM, Des & Jan Howard <djho...@hwy.com.au> wrote:
>
> Lee
> Don't make the basic mistake in thinking every
> woodfirer follows a wabi-sabioid aesthetic.

I don't. But if you gotta glaze every pot, it is simply a waste of
good fuel. You can get the same effect in soda.

That isn't limiting to wabi-sabi. Actually, a lot of
unmelted ash buildup isn't wabi. Wabi-sabi is often used by folks
that don't understand it to mean Japanese woodfired pots. Most
woodfired pots in Japan after the noborigama were either fired in
sagars or behind shields to protect the pots from ash.

[gary navarre]

Hay Guys,

Since I'm still not certain what is this wabi-aesthetic, or any other for that matter, and my American glaze effects probably have no Japanese named equivalent, so I really don't care, and my experience with the average customer shows they like holding a glazed cup or bowl more than un-glazed, a few like/understand unglazed/flashed, so that's the amounts I'm making. Either style offers me a lot of opportunities to explore their effects but for a first firing I'm putting most of my eggs in the glaze bucket.

I'm not trying to replicate any particular aesthetic nor do I intend to denigrate them by not doing so. It seems popular in Asia for a student to keep his teachers style alive to preserve the linage. In America we are free to deviate as far as we want to the point of leaving the linage to others. The 30cu.ft. Hobagama had many smaller areas of effects I wanted to develope. In the new larger Hobagama I would expect an equally expanded area of the different effects throughout the chamber. I'll probably leave some pieces unglazed near the front and see if I can get those snotty pots I kinda like a lot too but I can get a lot more information from glazed and ash falling on them than just flashing. After the first firing I'll know for sure what I can get and our Japanese adepts can tell me if any of the pieces fall into one of those wabi or the sabi categories like Waterfall, Deer Rub, or Dragon Skin.

I don't want to do soda or salt in this kiln, yet, because it is all new and I want to keep it clean for a while. Most of all the glazed pots I made way back when sold off within a few years and about 8%-10% were unglazed, some were pretty neat, but it took a couple kiln loads to get there. I had one customer said he collected them and had another of mine from the year before. I'll see if I can make a couple real TB sheet phlegm snotty pots for ya Lee just so'es ya know I can appreciate that aesthetic too but in America we are free to create an individual aesthetic with no lineage to perpetuate. I don't think Gawaine Dart or Jack Foster expected me to make pots like them, just that I use good technique to get where I want.

Gary Navarre
Navarre Pottery
Navarre Enterprises
Norway, Michigan, USA
http://www.youtube.com/GindaUP
http://public.fotki.com/GindaUP/

--- On Tue, 11/17/09, Lee <l...@mashiko.org> wrote:

> From: Lee <l...@mashiko.org>
> Subject: *WoodKiln* Re: Bourry Firebox Throat
> To: wood...@googlegroups.com

[gary navarre]

That's hard to predict Craig, on the one hand I'm thinkin of lighting the pignose to warming it up overnight and glaze a bunch of bowls for loading tomorrow after noon when it would still be warm so the fresh shelf wads, cone packs will dry bowls and they shouldn't freeze if I brick it back up... Right??? I was looking at some old kiln notes and noticed the firing date was in February and the ambient temperature was 0ºF. Or I'm psyching up to get into throwing some more so I can watch clay dry. The chamber is just past half full so I'm thinking of more 6" or taller pieces to open up the front a bit and fill it sooner. I might need to order some clay from somewhere that would stand a bit taller better without being so "stout". I'm guessing the problem is a preponderance of the flabby Rhodes porcelain I'm adding to the mix to get rid of it. I need some more stoneware for that and another porcelain or two that really works. Got any favorite store bought
from within 500 miles of here?

Gary Navarre
Navarre Pottery
Navarre Enterprises
Norway, Michigan, USA
http://www.youtube.com/GindaUP
http://public.fotki.com/GindaUP/

--- On Tue, 11/17/09, CRAIG <craigl...@gmail.com> wrote:

[Lee]

On Tue, Nov 17, 2009 at 9:27 PM, gary navarre
<navarreen...@yahoo.com> wrote:

>that aesthetic too but in America we are free to create an individual aesthetic
>with no lineage to perpetuate.

Gary, I was responding to Des's mentioning of his dislike of "Snot on
pots." I don't believe we need to denigrate what we don't do.
The success you get in the different styles of wood firiring can be
assessed by their own aesthetic. As I mentioned, my preference is
for the soft surfaced heavily reduced pots. I always like a variety
out of woodfiring. I like a kiln that can do it all.

And not all people in Japan are lock-stepped into a certain
kind of tradition. One of the unique aspects that Hamada brought to
Mashiko, was an innovative approach to traditional clay work. I met
many folks who moved from ancient kiln areas or from Kyoto to Mashiko,
so they could make the pots they wanted to.

Hamada told Shimaoka when he was first on his own, to stop
making Hamada pots. Shimaoka told all his students "Make your own
pots." None of the apprentices in Japan used jomon zogan (rope
inlay.)

Certainly, our lack of our tradition is both our
strength and weakness. But also, there are actual traditions or
schools in American. You just have to look around to see them.

[Des & Jan Howard]

Lee
Hey! Whoa back!
I said,

"Not every woodfirer wants 'snot' on pots*
If that's yer bag build an "Annie" ;)
Des
* a bit of 'flash' is nice."

I have done snot on pots, I don't mind snot on pots,
some snot, some pots, some times.
The method of firing is not the be-all/end-all.
We, (Jan & I), evaluate pots as themselves,
resolving the puzzle of process being part of the fun.

Oz has the liberation or restriction of never having
had a folk tradition. From earliest colonial
settlement, the English industrial model was the go.
A potter was the owner of the factory, a thrower was a
cheap machine & so on. Checking out our very old large
regional potteries I found the wheel placement reminded
me of chicken batteries.
Des

Lee wrote:
> Gary, I was responding to Des's mentioning of his dislike of "Snot on
> pots." I don't believe we need to denigrate what we don't do.
> The success you get in the different styles of wood firiring can be
> assessed by their own aesthetic.
>

> Certainly, our lack of our tradition is both our
> strength and weakness. But also, there are actual traditions or
> schools in American. You just have to look around to see them.

--

[Lee]

On Tue, Nov 17, 2009 at 11:36 PM, Des & Jan Howard <djho...@hwy.com.au> wrote:

> I have done snot on pots, I don't mind snot on pots,
> some snot, some pots, some times.
> The method of firing is not the be-all/end-all.
> We, (Jan & I), evaluate pots as themselves,
> resolving the puzzle of process being part of the fun.

I like ash deposits done aesthetically.

>
> Oz has the liberation or restriction of never having
> had a folk tradition. From earliest colonial
> settlement, the English industrial model was the go.

We all have the traditions from Great Brittan. (I have been
researching old Irish pottery.) I understand the Aboriginals had no
folk tradition in pottery. My friend Euan learned from Scottish
potters in Bendigo. The tradition there is as old as the tradition in
Mashiko, 150 years. I attach a photo, but you can read more at the
link below:

http://www.nma.gov.au/collections/bendigo_pottery_collection/

> A potter was the owner of the factory, a thrower was a
> cheap machine & so on. Checking out our very old large
> regional potteries I found the wheel placement reminded
> me of chicken batteries.

All folk potters were involved in industry. Most made
crockery for daily use of common people.

[Lee]

More Bendigo ware:

http://www.nma.gov.au/collections/bendigo_pottery_collection/bendigo_pottery_objects/

[Luc Foucher]

Anybody could enligthten me on the origins of salt glazing in Germany
and in Japan?

I know Hamada started it in Japan but was there any industrial salt
glazing (ie: sewage pipes) before he did it as a studio potter?

I think I remember reading somewhere that Hamada started his first salt
kiln in 1956 after seeing salt glazing in America during a trip in
1952.

I would welcome all information.
Thank you.
Cordially.
Luc Foucher

[bill geisinger]

Of course this is the romantic story! Probably some truth to it

Once upon a time, a Rhineland potter thought he had enough wood for one last firing before having to head out into the forest, with his wagon and ax, to do all the hard labor of cutting, splitting, and hauling the wood back to his pottery. Besides, his merchant friend wanted his latest pots ready to ship in four days; it would take longer than that just to replenish his woodshed.

He stacked his kiln and started the firing. Dark red, cherry red, red-orange, orange, then yellow glowed the kiln. But, disaster! He was out of wood, with the kiln almost to temperature, but not all the way. If he stopped the firing now, his efforts would be wasted; he would have to start the firing all over again once he chopped more wood. And worse, the pots wouldn't be ready for his friend, and friend or not, merchants dealt first with the potters who could supply them on time.

What to do? Desperate, the potter scraped the woodshed floor and scrounged the last few splinters there. He then charged into the house and flustered his wife greatly. Wildly, he looked about the place. "Wood! I must have wood!" His wife, eyes wide, pointed to the storeroom.

Throwing open the door, the potter rummaged through their household stores. There! In the back! His thrifty wife had saved some old sauerkraut barrels!

The potter and his wife hurriedly hauled the sauerkraut barrels back to the kiln, where the potter promptly broke them apart and began pitching them into the firebox. He saw the salty crust of dried up brine on the inside of the barrels, but thought little of it at the time.

The kiln was fired to temperature, fed on the salt-encrusted staves. When the kiln cooled and he unloaded it for his merchant friend, the pottery within was coated with a magical, glossy frosting of glaze. And thus, German potters discovered salt glazing.

[Lee]

Luc,

Robert Yellin seems to think it was Hamada who brought it to
Japan. There are several doing it in Mashiko but he doesn't mention
them. Check out the article about John Dix.

http://www.e-yakimono.net/html/dix-john-jt.html

Vapor firing is big here in the States, especially soda firing.
Frankly, I never understood firing a whole wood kiln in salt. I can
see a chamber at the end of a noborigama. And I like the French way
of putting in salt cups for localized effect.

[Mike]

Hello Luc,

This is my understanding as well. Locally, there is Kuromuta Yaki, the
patriarch of which is Maruta Masami. He was one of the Hamada mingei
gang way back, and apparently had the first salt kiln on Kyushu. I don't
know if they fire one currently.
Sorry that's all I'm aware of,


Mike

Mike
in Taku, Japan

karatsupots.com
karatsupots.blogspot.com
karatsupots-workshop.blogspot.com/



Luc Foucher ????????:

[Luc Foucher]

Hi Bill,

thank for the story, I read about such a probability.

I wonder if the fact that there is rock salt mines in germany has
anythng to do with it?????

[Luc Foucher]

Hi Lee,

>
>
> Robert Yellin seems to think it was Hamada who brought it to
> Japan. There are several doing it in Mashiko but he doesn't mention
> them. Check out the article about John Dix.
>
> http://www.e-yakimono.net/html/dix-john-jt.html
>
> Vapor firing is big here in the States, especially soda firing.
> Frankly, I never understood firing a whole wood kiln in salt. I can
> see a chamber at the end of a noborigama. And I like the French way
> of putting in salt cups for localized effect.
>

Used to be the only way as wood was the only means of firing at the
time.

I like salt glazing with wood because of the random effects of salt and
wood/ash and reduction and the unpredictability of it.

Salt cups help for the area where the salt is hard to get.

Each firing is different depending on kiln packing and wood and
atmospheric conditions.
Always a wonder at what is going to come out of it.

Cordially.
Luc Foucher

[Luc Foucher]

Hi Mike,
> ,

>
> This is my understanding as well. Locally, there is Kuromuta Yaki, the
> patriarch of which is Maruta Masami. He was one of the Hamada mingei
> gang way back, and apparently had the first salt kiln on Kyushu. I
> don't
> know if they fire one currently.
> Sorry that's all I'm aware of,
>
>

I am aware of these people, yes they are still firing, I came across
their work and also Maruta in Ukiha Ichinose gama.

I am trying to put together a short history of salt from its origins in
Germany and its importing in Japan most probably through Hamada to make
Japanese people a bit more aware of the art.
Thanks to all who can provide information.

Cordially.
Luc Foucher

[bill geisinger]

Luc,

I am sure there are many theories about the development of salt glazing . As I sit and think about firing and choosing new directions for myself, I wonder abot potters from the past and how they thought.
My immediate thoughts abot trying new things develops by thinking about things that are familar to me. I use salt to help glaze materials melt. I use salt to help glaze materials stay in suspension. I know they are part of a glaze. I see woodash melt and make glaze when I throw wood in the kiln. It is natural for me to think if I throw things that make glaze in the kiln they will melt and make glaze. This is how I think salt glaze started.

bill in sebastopol

[Lee]

This is book has interesting information on Bauhaus:

http://www.amazon.com/Marguerite-Wildenhain-Bauhaus-Eyewitness-Anthology/dp/0976138123

One interesting thing, is that what the salt firers in
Germany put in the kiln was a mixture of cobalt, lead and salt.
Looking at church records, they died at about the age 0f 37 and had
symptoms of lead poisoning. This is why folks have the
misconception about salt firing being dangerous. It is similar
to the fallacy that copper glazes are dangerous: The original
problem was that copper was used in lead glazes, and the copper helped
the lead be more soluble

I'd scan you some sections, but I lent the book to Craig and
it is in New London.

[Lee]

On Fri, Nov 20, 2009 at 10:13 AM, Lee <l...@mashiko.org> wrote:

>           One interesting thing, is that what the salt firers in
> Germany put in the kiln was a mixture of cobalt, lead and salt.

Makes you wonder: who developed Salt only firing? Is it
something like American Raku? Or American Shino?

[Paul Herman]

Luc,

I think the origins are lost in obscurity, but that was a good story
from Bill about the barrels. I've also hear the speculation that using
salty driftwood could have happened. No doubt the discovering was a
lot of fun.

I have been mostly relying on various colored slips for use in the
salt. The other potters who fire here use a lot of glazes, but to me
glazes rarely take advantage of the salt firing much. Slips, if they
are the right composition will show nice orange peel texture. Some
clay bodies don't make very good orange peel either.

good firings,

Paul Herman

Great Basin Pottery
Doyle, California US
www.greatbasinpottery.com/

[bill geisinger]

This is a great book about Marguerite and Bauhaus I would recommend it also.

bill in sebastopol which is a few miles from Guerneville where Marguerite had her Pond Farm studio.

[Lee]

I've been using a mixture of soda ash, baking soda and whiting in my
soda firing. I guess the whiting serves the same purpose as the
original lead in salt firing.

[bill geisinger]

you might try to use wood ashnext time instead of whiting it melts better! MHO

bill

[Lee]

On Fri, Nov 20, 2009 at 10:53 AM, bill geisinger <geis...@deanza.edu> wrote:
> you might try to use wood ashnext time instead of whiting it melts better!
> MHO

Does it dissolve as well? I find that spraying works best with
soda. Shimaoka's ash was repeatedly sieved though 200 mesh. I
thought of it as being sort of the terra sig of wood ash.

I use salt cups made of 50/50 alumina/epk for
localized salt. Salt bleaches shino, but soda does not.

[bill geisinger]

I have not had any problems with the wood ash and a soda mixture. I know about the Shimaoka screening and it helps with the ash that's for sure. I have actually ball milled wood ash for several days to make some really fine particles. It never clogs up the sprayer and adds quite a bit of additional color to the soda. If you saw my pieces from the late 90's  you could see an iridescence on the surface because of the wood ash in the salt mix. Maybe the clay I had at that time also had considerable iron to help there also.

My soda mix is generally 8lbs water 3lbs soda and 1 1/2 lbs wood ash. I have never tried to use wood ash alone. I'll have to try it next year the spray technique is very simple and easy in most kilns I've seen. Currently I'm using a 20 cu. ft. gas and a 30 cu. ft. wood similar to Euan's design that was your kiln in Mashiko.

I have also found salt bleaches some shinos and I do like it but soda does not. I wonder why? Na is Na.

bill in sebastopol