RJones7582@AOL.COM on mon 27 oct 03
This is addressed anyone who has experience firing a train kiln. I recently
helped with firing a train kiln which had a Bourry box firing chamber with
multiple air ports in the usual primary air positions above the stoking port and
several mousehole air ports into the ash pit area of the kiln. As the firing
progressed the ash pit began to fill and eventually filled almost to the point
of obstructing the arch into the ware area of the kiln. My view was that the
mousehole ports had not been opened enough to reduce the glowing coals into
ash removing the carbon and the volume of the obstructing coals. My impression
from reading about the Bourry box was that the volume of ash was such that
raking out coals was usually not necessary in an average firing. I guess my
question is whether there should be a lot of air going into the ash pit area via
the mouseholes of the Bourry box or not, particularly during the latter part
of the firing?
Robert Jones
dennis jones on mon 27 oct 03
Steve,
I lloked at your web site and I am curious as to the dimensions of the
Bourry box kiln plans in your book.
----- Original Message -----
From: "steve harrison"
To:
Sent: Monday, October 27, 2003 3:43 PM
Subject: Re: Train Kiln firing question
> > This is addressed anyone who has experience firing a train kiln.
>
> > I guess my question is whether there should be a lot of air going
> > into the ash pit area via
> > the mouseholes of the Bourry box or not, particularly during the
> > latter part
> > of the firing?
> >
> > Robert Jones
> >
> Hi Robert,
> I have written a book specifically about Bourry box fired wood kilns,
> called "Laid Back Wood Firing" I think that it will answer all of your
> questions about Bourry box fired train kilns.
>
> Laid Back Wood Firing has been continuously in print for over 25 years
> and is now in its 3rd edition. I have recently revised and enlarged it,
> so that it now comes with a CD of extra images.
>
> Best wishes
> Steve Harrison
>
> Hot & Sticky Pty Ltd
> 5 Railway Pde
> Balmoral Village
> NSW 2571
> Australia
>
> http://ian.currie.to/sh/Steve_Harrisons_books.html
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
neelyjc on mon 27 oct 03
You certainly shouldn't have to rake coals - that's what the mouse holes through the
the stepped floor of the firebox are for - but they also shouldn't be wide open
throughout the firing. They are opened ONLY when you need to burn up coals. If both
the primary air above the fuel and the mouse holes are wide open, the kiln will burn
backwards, drawing air through the mouse holes and exhausting through what should
be primary air holes, which obviously means that no heat is drawn into the ware
chamber. If you reach a point where coals build up to the degree that the draft of the
chimney is inufficient to draw air into the coal bed, you've waited too long to use the
mouse holes, and some drastic action (like opening a hole through the coal bed from
the mouse holes with a 2x4) is called for, but you shouldn't have to rake coals.
It's ideally a situation where you find an equilibrium - allowing a little air to leak into
the coal bed by keeping soaps in the mouseholes at such an angle as to block most,
but not all, of each opening.
John Neely
--- In clayart@yahoogroups.com, RJones7582@A... wrote:
> This is addressed anyone who has experience firing a train kiln. I recently
> helped with firing a train kiln which had a Bourry box firing chamber with
> multiple air ports in the usual primary air positions above the stoking port and
> several mousehole air ports into the ash pit area of the kiln. As the firing
> progressed the ash pit began to fill and eventually filled almost to the point
> of obstructing the arch into the ware area of the kiln. My view was that the
> mousehole ports had not been opened enough to reduce the glowing coals into
> ash removing the carbon and the volume of the obstructing coals. My impression
> from reading about the Bourry box was that the volume of ash was such that
> raking out coals was usually not necessary in an average firing. I guess my
> question is whether there should be a lot of air going into the ash pit area via
> the mouseholes of the Bourry box or not, particularly during the latter part
> of the firing?
>
> Robert Jones
steve harrison on tue 28 oct 03
Hi Denis,
There are a dozen different kiln plans in the book, of various sizes,
from small to medium size kilns. from 6 cu. ft. to 36. cu.ft.
Best wishes
Steve Harrison
Hot & Sticky Pty Ltd
5 Railway Pde
Balmoral Village
NSW 2571
Australia
http://ian.currie.to/sh/Steve_Harrisons_books.html
On Tuesday, October 28, 2003, at 09:36 AM, dennis jones wrote:
> Steve,
> I lloked at your web site and I am curious as to the dimensions of the
> Bourry box kiln plans in your book.
> ----- Original Message -----
> From: "steve harrison"
> To:
> Sent: Monday, October 27, 2003 3:43 PM
> Subject: Re: Train Kiln firing question
>
>
>>> This is addressed anyone who has experience firing a train kiln.
>>
>>> I guess my question is whether there should be a lot of air going
>>> into the ash pit area via
>>> the mouseholes of the Bourry box or not, particularly during the
>>> latter part
>>> of the firing?
>>>
>>> Robert Jones
>>>
>> Hi Robert,
>> I have written a book specifically about Bourry box fired wood kilns,
>> called "Laid Back Wood Firing" I think that it will answer all of your
>> questions about Bourry box fired train kilns.
>>
>> Laid Back Wood Firing has been continuously in print for over 25 years
>> and is now in its 3rd edition. I have recently revised and enlarged
>> it,
>> so that it now comes with a CD of extra images.
>>
>> Best wishes
>> Steve Harrison
>>
>> Hot & Sticky Pty Ltd
>> 5 Railway Pde
>> Balmoral Village
>> NSW 2571
>> Australia
>>
>> http://ian.currie.to/sh/Steve_Harrisons_books.html
>>
>>
> _______________________________________________________________________
> _____
> __
>> Send postings to clayart@lsv.ceramics.org
>>
>> You may look at the archives for the list or change your subscription
>> settings from http://www.ceramics.org/clayart/
>>
>> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>>
>
> _______________________________________________________________________
> _______
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>
>
Stephani Stephenson on tue 28 oct 03
ROBERT WROTE
I recently
> helped with firing a train kiln which had a Bourry box
firing chamber with
> multiple air ports in the usual primary air positions
above the stoking port and
> several mouse hole air ports into the ash pit area of the
kiln. As the firing
> progressed the ash pit began to fill and eventually filled
almost to the point
> of obstructing the arch into the ware area of the kiln.
My view was that the
> mousehole ports had not been opened enough to reduce the
glowing coals into
> ash removing the carbon and the volume of the obstructing
coals. My impression
> from reading about the Bourry box was that the volume of
ash was such that
> raking out coals was usually not necessary in an average
firing. I guess my
> question is whether there should be a lot of air going
into the ash pit area via
> the mouseholes of the Bourry box or not, particularly
during the latter part
> of the firing?
Robert
I have seen a similar situation during a group firing of a
train kiln. I do not own a train kiln and in no way an
expert on it's use or construction but I did run into a
similar situation when helping to fire one,
People kept saying 'with a bourry box you shouldn't have to
rake coals..it is supposed to burn itself down.. i.e. you
can just load up the bourry and the kiln will take care of
the rest."
to my view (note: with this kiln and on this particular
firing!,) that approach seemed to bog the kiln down, ash
and coals soon clogged the bottom part of the ashpit, and
the kiln was not able to climb in temperature.
we were using long thin pieces of wood which to my
knowledge were pretty dry... but no matter what the THEORY
was, the REALITY was different in that particular case.
(I still find it odd that potters confronted with reality
will still insist that the reality cannot be real because
the theory says it should be otherwise.)
In this case, the only way we got that kiln to climb was to
feed wood into it a few pieces at a time, so that the wood
pieces could combust almost immediately upon entering the
box.
We also did have to regularly reach down into the coalbed to
'open it up' to get more air into the coals and periodically
had to clear ash and coals from the lower part of the box .
It was pretty much a 2 person operation, with one person
feeding fuel and other person tending to the ash/coal bed.
I am not much use for debating the theory,, and not owning
the kiln, I can't be of much help with ideas on the kiln
itself, but that technique worked in that instance
Stephani Stephenson
steph@alchemiestudio.com
P>S> ha ha ! I must be rummy, spell check turned 'Bourry '
into first 'Blurry', then 'Booby'....
glad I second guessed it
clennell on tue 28 oct 03
Sour Cherry Pottery
> This is addressed anyone who has experience firing a train kiln. I recently
> helped with firing a train kiln which had a Bourry box firing chamber with
> multiple air ports in the usual primary air positions above the stoking port
> and
> several mousehole air ports into the ash pit area of the kiln. As the firing
> progressed the ash pit began to fill and eventually filled almost to the point
> of obstructing the arch into the ware area of the kiln. My view was that the
> mousehole ports had not been opened enough to reduce the glowing coals into
> ash removing the carbon and the volume of the obstructing coals. My
> impression
> from reading about the Bourry box was that the volume of ash was such that
> raking out coals was usually not necessary in an average firing. I guess my
> question is whether there should be a lot of air going into the ash pit area
> via
> the mouseholes of the Bourry box or not, particularly during the latter part
> of the firing?
>
> Robert Jones
Robert: If the box is filling up and blocking the arch it could mean the
wood is green. We rarely ever open the secondary air ports. Maybe just the
top ones to peek to see thru the arch, and if it is high we push the coals
thru with a wet 2x4. Opening these ports is rushing the kiln with cold air.
I like to think of firing the bourry box like operating an airtight wood
stove. Primary air and keep the fire box sealed tight.
cheers,
Tony
p.s there is a chart at the back of Jack Troys Woodfiring book that lists
varieties of wood and there coaling, smoking and heating abilities. Worth a
look.
Tony and Sheila Clennell
Sour Cherry Pottery
4545 King Street
Beamsville, Ontario
CANADA L0R 1B1
http://www.sourcherrypottery.com
clennell@vaxxine.com
steve harrison on tue 28 oct 03
> This is addressed anyone who has experience firing a train kiln.
> I guess my question is whether there should be a lot of air going
> into the ash pit area via
> the mouseholes of the Bourry box or not, particularly during the
> latter part
> of the firing?
>
> Robert Jones
>
Hi Robert,
I have written a book specifically about Bourry box fired wood kilns,
called "Laid Back Wood Firing" I think that it will answer all of your
questions about Bourry box fired train kilns.
Laid Back Wood Firing has been continuously in print for over 25 years
and is now in its 3rd edition. I have recently revised and enlarged it,
so that it now comes with a CD of extra images.
Best wishes
Steve Harrison
Hot & Sticky Pty Ltd
5 Railway Pde
Balmoral Village
NSW 2571
Australia
http://ian.currie.to/sh/Steve_Harrisons_books.html
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