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groundhog kiln

updated wed 13 feb 02

 

Robert J Moore on mon 8 jul 96

Hello fellow potters, I'm new to the group but have had the clay fevor
for a couple of years now.
On to buisness at hand. I started diging a groundhog kiln two days ago
and have made some progress, but it is slow going. The ground is rocky
but seems to have clay deposits throughout. Any experienced advise as to
the slope of the interior, or essential info. would be appriciated. I
read an article in Cer. Monthly about doing one but it was not very
detailed about the constuction and pitfalls to avoid.
Looking forward to your replies..
RJMOORE

John H. Rodgers on mon 9 mar 98

-- [ From: John H. Rodgers * EMC.Ver #2.5.02 ] --

Would someone point me in the direction of a url dealing with Groundhog
kilns, or maybe some other references.

Thanks

John Rodgers
In Alabama

LOWELL BAKER on tue 10 mar 98

John:
I can show one in the flesh, in Alabama..... I am proposing building
one at Tannehill State Park a year from this spring. They aree
pretty neat kilns. I am sure I will get some flack from calling them
the American Anagama, since they are neither, but the firing has some
similarities.

Let me know what you are up to and maybe I can help.

W. Lowell Baker
The University of Alabama
WBAKER@WOODSQUAD.as.ua.edu

Michelle Harris on tue 10 mar 98

> Would someone point me in the direction of a url dealing with Groundhog
> kilns, or maybe some other references.
>
Have you ever read about some of the Southern Folk Pottery families in
Foxfire 8? There are over 300 pages in this volume of foxfire that
describe several families (lots of the Meaders, Burlon and Irene Craig,
Norman and Irene smith, Browns, Hewell, etc.) mostly in their own words.
In this book, a couple of railroad tunnel kilns and a groundhog kiln are
briefly described, with some photos. This is fascinating stuff (oral
history?). Maybe not technical enough for your purposes, but very
interesting background. The book has been around for ages, ISBN
0-385-17741-0
Michelle
heorot@sk.sympatico.ca

Bill Amsterlaw on tue 10 mar 98

Hi John:

There is a detailed description of groundhog kiln construction written by
Vernon Owens (of Jugtown Pottery, Seagrove, NC) which appeared in Studio
Potter (Summer 1974). Vol 3, no. 1, pp 41-44. The article includes
diagrams, dimensions, and notes on construction, stacking, and firing.

- Bill Amsterlaw (wamster@slic.com)
Plattsburgh, NY

Joseph Dallas on wed 11 mar 98

John H. Rodgers wrote:
>
> ----------------------------Original message----------------------------
> -- [ From: John H. Rodgers * EMC.Ver #2.5.02 ] --
>
> Would someone point me in the direction of a url dealing with Groundhog
> kilns, or maybe some other references.
>
> Thanks
>
> John Rodgers
> In AlabamaJohn,
I don't know of a url for ground hog kiln, but I do know where you can
see one. In Lumpkin Ga. there is an 1850's village. D.X. Gordy built
a ground hog kiln when he was the resident potter there. Mr. Gordy
died a few years ago. Stephen Hawks is the potter there now and he
still fires that kiln. I have helped him fire it a few times. If you
need more info e-mail me directly. jedallas@ worldnet.att.net
Joe Dallas
Dallas Pottery
Columbus, GA.

GoodrichDn on wed 11 mar 98

----------------------------Original message----------------------------
>Would someone point me in the direction of a url dealing with Groundhog
>kilns, or maybe some other references.<
>John Rodgers

John, there are photos and plans of groundhog kilns in Foxfire 8, edited by
Wigginton et al, published in 1984 by Anchor Books. ISBN 0-385-17741-0.
Haven't seen any websites yet, though.

Don Goodrich in rewintered Zion, Illinois

Laura FREEDMAN on thu 12 mar 98

Stephen Mills from the UK has a groundhog kiln at :
stevemills@mudslinger.demon.co.uk

GoodrichDn wrote:

> ----------------------------Original message----------------------------
> ----------------------------Original message----------------------------
> >Would someone point me in the direction of a url dealing with Groundhog
> >kilns, or maybe some other references.<
> >John Rodgers
>
> John, there are photos and plans of groundhog kilns in Foxfire 8, edited by
> Wigginton et al, published in 1984 by Anchor Books. ISBN 0-385-17741-0.
> Haven't seen any websites yet, though.
>
> Don Goodrich in rewintered Zion, Illinois

Nathan Hinshaw on sun 14 jun 98

well folks..its everyones favorite (???) silent member of clay art....
i'm setting up to build a ground hog kiln and i was wondering if anyone out
there had any input on this.. it'll be fired wood..maybe gas fire in the
begining then wood. And it will be salted as well.
any stories...do's, dont's, what works, and what doesnt?
how about quartz on the kiln floor?
yeah just let me know
nathan in iowa where the weather is screwy as all get out :)
peace

LOWELL BAKER on mon 15 jun 98

I think it would be worth your while to visit some kilns. There is
one in Hamilton, AL. This one is now fired with gas but Jerry has
all the information you will ever need on wood firing a groundhog.
The stoking cycle he used, very successfully, would not be one I
would choose, but it worked to cone 11.

W. Lowell Baker
The University of Alabama
wbaker@woodsquad.as.ua.edu

MERKLEYS on wed 17 jun 98

Nathan,if your still looking for information on groundhog kilns,try
foxfire 8 . The foxfire books are published by Anchor Press, number 8
deals in depth with folk pottery's of the south and you'l find very
detailed information on kiln building in this volume. Lots of luck on
your endeavour.
>
> --------------------------

McCoy, Jack Eugene on thu 18 jun 98

You might also take a look at "Turners and Burners." Like the Foxfire 8
book, it also has some information on groundhog kilns.

----------
From: Nathan Hinshaw [SMTP:Slacker773@aol.com]
Sent: Sunday, June 14, 1998 11:21 AM
To: Multiple recipients of list CLAYART
Subject: groundhog kiln

----------------------------Original
message----------------------------
well folks..its everyones favorite (???) silent member of clay
art....
i'm setting up to build a ground hog kiln and i was wondering if
anyone out
there had any input on this.. it'll be fired wood..maybe gas
fire in the
begining then wood. And it will be salted as well.
any stories...do's, dont's, what works, and what doesnt?
how about quartz on the kiln floor?
yeah just let me know
nathan in iowa where the weather is screwy as all get out :)
peace

Gary Dexter on tue 16 nov 99

Fall has been beautiful here in the NC Blue Ridge Mtns. I fire in a
groundhog-type kiln using alkaline (ash and sand) glazes. My kiln is 6' w x
15' L x 30'' h. It is made of hard brick. The floor is below grade and the
side walls and most of the arch are bermed with earth. The temperature drops
steadily from firebox to chimney, ^10 to ^3. I set the kiln with ash glaze in
the front, Alberta slip in the middle and earthen ware in the back and
chimney.

I would like to extend the range of ash glaze and wondered how this might
best be accomplished. It sounds like it would benefit to some degree from a
coat of ITC. Would it be practical to put fiber on the hot face and coat it
with ITC? How does one go about spraying in a confined area like this or is
it even possible? What would the life of fiber alone be in a wood-fired kiln?

I find that going beyond the present temp. to mature my glaze further back
causes the glaze in the front rows to run to much. In addition, I would love
to save on fuel. Any thoughts or suggestions? Thanks.

Nikom Chimnok on wed 17 nov 99

Hi!

The kilns we use here are a lot like groundhog kilns, but wider,
longer, and higher. They have the same problem as yours--hot in the front,
cold in the back, tho the temperature variation is about twice as much as
yours. I've tried half a dozen modifications to even things out, and the
only thing that ever worked was using a fan to blast secondary air deep into
the kiln and and start some fires back there. It helps, but it still doesn't
make the temperature even. I think it's impossible. I think it's a primitive
design, and primitive people put up with a lot instead of getting just what
they want. In a state of nature, you go to the water; in civilization, the
water comes to you. And so it is with kilns. As I understand it, there is so
much radiative heat from the fire at the front of the kiln that it's easy to
melt not only the glazes but the pots too; but radiative heat transfer
varies with the square of the distance, so the heat of the fire does very
little to heat the back of the kiln. If you built an electric kiln and
installed elements on one wall only, people would say you're silly, and
they'd be right. If you've ever lived in a cold place and used a wood stove,
you'll understand this easily. When you go home to a cold cabin in the
middle of the night, you build a big fire and stand right next to the stove
to get warm. The far side of the room is cold for hours, and you have to
keep turning around to toast first your front and then your back. You can
burn your calves while the ice still hasn't melted off your shins.

I have stuck test patches of untreated ceramic fiber to the ceiling:
stiff and flaky after one firing, completely disappeared after three. I'd
love to hear that ITC would fix the problem.

Hope for the best,
Nikom
****************************************************************************
******************
At 12:09 16/11/99 EST, you wrote:
>----------------------------Original message----------------------------
> Fall has been beautiful here in the NC Blue Ridge Mtns. I fire in a
>groundhog-type kiln using alkaline (ash and sand) glazes. My kiln is 6' w x
>15' L x 30'' h. It is made of hard brick. The floor is below grade and the
>side walls and most of the arch are bermed with earth. The temperature drops
>steadily from firebox to chimney, ^10 to ^3. I set the kiln with ash glaze in
>the front, Alberta slip in the middle and earthen ware in the back and
>chimney.
>
> I would like to extend the range of ash glaze and wondered how this might
>best be accomplished. It sounds like it would benefit to some degree from a
>coat of ITC. Would it be practical to put fiber on the hot face and coat it
>with ITC? How does one go about spraying in a confined area like this or is
>it even possible? What would the life of fiber alone be in a wood-fired kiln?
>
> I find that going beyond the present temp. to mature my glaze further back
>causes the glaze in the front rows to run to much. In addition, I would love
>to save on fuel. Any thoughts or suggestions? Thanks.
>
>

Steve Dalton on wed 17 nov 99

Gary,
On the ITC, instead of spraying you can brush or roll it on.
For me brushing worked the best as opposed to a roller.
You may though, still get the temp difference. I would think,
even though it would call for a lot of work, to add side stoke
holes. Possibly halfway ( 7.5 feet).
Steve Dalton
----------
> From: Gary Dexter
> To: CLAYART@LSV.UKY.EDU
> Subject: Groundhog Kiln
> Date: Tue, 16 Nov 1999 12:09:06 EST
>
>----------------------------Original message----------------------------
> Fall has been beautiful here in the NC Blue Ridge Mtns. I fire in a
>groundhog-type kiln using alkaline (ash and sand) glazes. My kiln is 6' w x
>15' L x 30'' h. It is made of hard brick. The floor is below grade and the
>side walls and most of the arch are bermed with earth. The temperature
drops
>steadily from firebox to chimney, ^10 to ^3. I set the kiln with ash glaze
in
>the front, Alberta slip in the middle and earthen ware in the back and
>chimney.
>
> I would like to extend the range of ash glaze and wondered how this might
>best be accomplished. It sounds like it would benefit to some degree from a
>coat of ITC. Would it be practical to put fiber on the hot face and coat it
>with ITC? How does one go about spraying in a confined area like this or is
>it even possible? What would the life of fiber alone be in a wood-fired
kiln?
>
> I find that going beyond the present temp. to mature my glaze further
back
>causes the glaze in the front rows to run to much. In addition, I would
love
>to save on fuel. Any thoughts or suggestions? Thanks.

Vince Pitelka on wed 17 nov 99

> Fall has been beautiful here in the NC Blue Ridge Mtns. I fire in a
>groundhog-type kiln using alkaline (ash and sand) glazes. My kiln is 6' w x
>15' L x 30'' h. It is made of hard brick. The floor is below grade and the
>side walls and most of the arch are bermed with earth. The temperature drops
>steadily from firebox to chimney, ^10 to ^3. I set the kiln with ash glaze in
>the front, Alberta slip in the middle and earthen ware in the back and
>chimney.
> I would like to extend the range of ash glaze and wondered how this might
>best be accomplished. It sounds like it would benefit to some degree from a
>coat of ITC. Would it be practical to put fiber on the hot face and coat it
>with ITC? How does one go about spraying in a confined area like this or is
>it even possible? What would the life of fiber alone be in a wood-fired kiln?

Gary -
Here at the Appalachian Center for Crafts we have a sort of hybrid
groundhog/anagama which we call our "hoggama." It is all hardbrick, and is
about the same size as yours, perhaps a little longer, a little narrower,
and a little taller. Also, the floor steps up twice, although the sprung
arch is level from front to back like a groundhog. But we have a
side-stoking port halfway back. When the front gets to temperature, we
side-stoke to get the back to temperature. The kiln fires like a dream, and
we have been able to achieve fairly even temperatures (^9 to ^12) throughout
the kiln.

As I understand it, ITC does not bond well to refractory surfaces which have
been compromised already. So, if you have a lot of ash slagging on your
walls, you cannot really expect a fiber veneer or a coat of ITC to adhere.
Others will be able to give you better advice in this area.
Good luck -
- Vince

Vince Pitelka
Home - vpitelka@DeKalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166

Louis H.. Katz on thu 18 nov 99

Hi Nik,
Your kiln design I believe needs a steeper slope in the floor like the kilns in
Sukhothai. This will at least help even the temperature from top to bottom at th
back the kiln. A faster narrowing of the width of the kiln may also help but wil
decrease the amount of ware you can squeeze into the kiln.

It is hard to talk about secondary air in your kilns fireboxes, but secondary ai
replacing primary will help move the heat generation back in the kiln.

Louis


Nikom Chimnok wrote:

> ----------------------------Original message----------------------------
> Hi!
>
> The kilns we use here are a lot like groundhog kilns, but wider,
> longer, and higher. They have the same problem as yours--hot in the front,
> cold in the back, tho the temperature variation is about twice as much as
> yours. I've tried half a dozen modifications to even things out, and the
> only thing that ever worked was using a fan to blast secondary air deep into
> the kiln and and start some fires back there. It helps, but it still doesn't
> make the temperature even. I think it's impossible. I think it's a primitive
> design, and primitive people put up with a lot instead of getting just what
> they want. In a state of nature, you go to the water; in civilization, the
> water comes to you. And so it is with kilns. As I understand it, there is so
> much radiative heat from the fire at the front of the kiln that it's easy to
> melt not only the glazes but the pots too; but radiative heat transfer
> varies with the square of the distance, so the heat of the fire does very
> little to heat the back of the kiln. If you built an electric kiln and
> installed elements on one wall only, people would say you're silly, and
> they'd be right. If you've ever lived in a cold place and used a wood stove,
> you'll understand this easily. When you go home to a cold cabin in the
> middle of the night, you build a big fire and stand right next to the stove
> to get warm. The far side of the room is cold for hours, and you have to
> keep turning around to toast first your front and then your back. You can
> burn your calves while the ice still hasn't melted off your shins.
>
> I have stuck test patches of untreated ceramic fiber to the ceiling:
> stiff and flaky after one firing, completely disappeared after three. I'd
> love to hear that ITC would fix the problem.
>
> Hope for the best,
> Nikom
> ****************************************************************************
> ******************
> At 12:09 16/11/99 EST, you wrote:
> >----------------------------Original message----------------------------
> > Fall has been beautiful here in the NC Blue Ridge Mtns. I fire in a
> >groundhog-type kiln using alkaline (ash and sand) glazes. My kiln is 6' w x
> >15' L x 30'' h. It is made of hard brick. The floor is below grade and the
> >side walls and most of the arch are bermed with earth. The temperature drops
> >steadily from firebox to chimney, ^10 to ^3. I set the kiln with ash glaze in
> >the front, Alberta slip in the middle and earthen ware in the back and
> >chimney.
> >
> > I would like to extend the range of ash glaze and wondered how this might
> >best be accomplished. It sounds like it would benefit to some degree from a
> >coat of ITC. Would it be practical to put fiber on the hot face and coat it
> >with ITC? How does one go about spraying in a confined area like this or is
> >it even possible? What would the life of fiber alone be in a wood-fired kiln?
> >
> > I find that going beyond the present temp. to mature my glaze further back
> >causes the glaze in the front rows to run to much. In addition, I would love
> >to save on fuel. Any thoughts or suggestions? Thanks.
> >
> >

LOWELL BAKER on thu 18 nov 99

I will have to defend the poor groundhog. The one we built in
Mississippi last summer fires fairly evenly and very easily. We
only stoke from the front but we stoke fairly heavily. You cannot
fire a groundhog like other wood kilns. Stoke the firebox full and
then when the flame clears so you can see the pots, stoke it
again. This is one of the easiest wood kilns I have ever fired.

The ash pit is very large and will contain about 50 cubic feet of
coals during the firing.

Hog Chain Merrie who is on this list can send photos of her
wonderful groundhog. Merrie is firing with mostly southern pine
which is very sappy wood.

CM has accepted an article on the kiln in Mississippi so you will
be able to see the details in the near future.

W. Lowell Baker
The University of Alabama

CNW on fri 19 nov 99

There are several groundhog kilns in Catawba county North Carolina where I
live. I will gladly help you find some help on this subject if you call me
directly.

Celia
828-241-9772
cwike@conninc.com

Rose Pinkul on tue 12 feb 02


Hi All
I was at a gathering this evening and heard someone mention that the Hilton
potters in Marion North Carolina, until quite recently used a groundhog kiln to
fire their pots. I have seen some of their work, it was wood fired stoneware and
some of it looked salt glazed. What I would like to know is what is a groundhog
Kiln? The best description I could get was a trench dug in the ground, filled with
pots and covered with combustibles.
Rose

--
Rose Pinkul Originals
Beautifully sculpted dolls
Quality plaster molds
Website http://www.pinkul.com
Phone 828-652-7430
Fax 828-652-2171

Dannon Rhudy on tue 12 feb 02


....What I would like to know is what is a groundhog
>Kiln? The best description I could get was a trench dug in the ground,
filled with pots and covered with combustibles......

A groundhog kiln is a kiln that is dug into the ground, usually
in a long trench-like form, sometimes with a slight tilt/grade upward
from the front to the back. The top of the kiln is generally arched
brick. The kilns are often small (narrow and low ceilinged),
but don't have to be - I've seen
some big/tall ones. The kilns are loaded back-to-front, by crawling
inside to stack the wares. There is a firebox in the front of the
kiln, a chimney/flue in the back. They are fired with wood, in the same
general way that an anagama might be fired (they always seem like
semi-submerged anagamas to me). They were (and still are) often used in the
midwest and south by the potters who settled where the clay was.

regards

Dannon Rhudy

Merrie Boerner on tue 12 feb 02


Hello Rose,
The groundhog kiln was popular in the 18th and 19th century, mainly in
the hills of North Carolina and Georgia. It is loaded and then stoked
through the same opening. Typically "it's form is a long, low rectangle with
a deep firebox spanning one end and a wide chimney at the other end.
Frequently, but not always, it is buried in the ground or against a
hillside, hence the colorful name. " (from "Turners and Burners") The
old-timers usually stacked pots on pots and once fired them mainly because
it was the most efficient way to produce jugs and utilitarian wares. Many of
the old-timers just watched the pots and flame and could tell when "they
were done". With the availability and ease of using gas, groundhog kilns had
become a novelty......but, with the renewed interest in wood firing, they
are springing back up again.
My groundhog has been called a "mini anagama" by some. It is a
rectangle, above ground, supported with metal. Front to back it is 14 feet,
and it is 6 feet wide. The fire box in the front (which you climb through to
stack the pots) is about 3 1/2 feet deep and the pot chamber behind it is
about 6 feet deep...then, the sexy chimney is about 4 1/2 feet (this is not
exact, cause there are some bricks scattered in there that I didn't count
: ) ....The flame goes from the front firebox...through the pots....then,
out the chimney. I fire it for the results the ash and flame give on the
clay. We use about 3 cords of wood over 36+ hours.
That is the short version....if you want more, believe me,......I got it !
Merrie in Mississippi