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.
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
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
<burningcoffinpott...@gmail.com> wrote:
> 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
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...
> From: Mike Banyai <mikeban...@gmail.com> > Subject: *WoodKiln* Re: Bourry Firebox Throat > To: "woodkiln@googlegroups.com" <woodkiln@googlegroups.com> > Cc: "woodkiln@googlegroups.com" <woodkiln@googlegroups.com> > Date: Sunday, November 15, 2009, 8:10 PM
> 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
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.
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
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!
> From: Micahel Banyai <mikeban...@gmail.com>
> Subject: *WoodKiln* Re: Bourry Firebox Throat
> To: "WoodKiln" <woodkiln@googlegroups.com>
> Date: Monday, November 16, 2009, 8:21 AM
> 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.
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.
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
<navarreenterpri...@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 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
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.
> From: Lee <l...@mashiko.org> > Subject: *WoodKiln* Re: Bourry Firebox Throat > To: woodkiln@googlegroups.com > Date: Monday, November 16, 2009, 5:02 PM
> On Mon, Nov 16, 2009 at 4:43 PM, gary navarre > <navarreenterpri...@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 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.
-- Des & Jan Howard Lue Pottery Lue NSW Australia 2850
> 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.
> 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
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.
> 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!
> --- On Mon, 11/16/09, Micahel Banyai <mikeban...@gmail.com> wrote:
>> From: Micahel Banyai <mikeban...@gmail.com>
>> Subject: *WoodKiln* Re: Bourry Firebox Throat
>> To: "WoodKiln" <woodkiln@googlegroups.com>
>> Date: Monday, November 16, 2009, 8:21 AM
>> 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.
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...
> > 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.
"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 <navarreenterpri...@yahoo.com> wrote:
From: gary navarre <navarreenterpri...@yahoo.com>
Subject: *WoodKiln* Re: Bourry Firebox Throat
To: woodkiln@googlegroups.com
Date: Tuesday, November 17, 2009, 12:22 PM
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...
> > 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.
On Tue, Nov 17, 2009 at 11:42 AM, tb <nacla...@yahoo.com> wrote:
> "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 <navarreenterpri...@yahoo.com>* wrote:
> From: gary navarre <navarreenterpri...@yahoo.com>
> Subject: *WoodKiln* Re: Bourry Firebox Throat
> To: woodkiln@googlegroups.com
> Date: Tuesday, November 17, 2009, 12:22 PM
> 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...
> > > 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.
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.
-- Des & Jan Howard Lue Pottery Lue NSW Australia 2850
On Tue, Nov 17, 2009 at 3:08 PM, Des & Jan Howard <djhow...@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 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
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.
-- Des & Jan Howard Lue Pottery Lue NSW Australia 2850
On Tue, Nov 17, 2009 at 4:26 PM, Des & Jan Howard <djhow...@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.
-- 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
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.
> From: Lee <l...@mashiko.org>
> Subject: *WoodKiln* Re: Bourry Firebox Throat
> To: woodkiln@googlegroups.com
> Date: Tuesday, November 17, 2009, 5:03 PM
> On Tue, Nov 17, 2009 at 4:26 PM, Des & Jan Howard
> <djhow...@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.
> --
> 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
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?
> From: CRAIG <craigledwa...@gmail.com> > Subject: *WoodKiln* Re: Bourry Firebox Throat > To: woodkiln@googlegroups.com > Date: Tuesday, November 17, 2009, 12:30 PM > Hey thar G in da UP... whens ya gonna fer > dat ting? > Make Good Pots > ~Craig > New London MN > http://woodfiredpottery.blogspot.com/
<navarreenterpri...@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.
-- 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
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