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 Bristol Studio
Noborigama 250

 2005-Present

This kiln has a total volume of 570 cubic feet, when factoring in bag walls, and fireboxes. Robert refers to it as a 250 because that is the actual shelving area in the chambers.

Photo by Tom Pollack

Noborigama

Robert stoking the Salt Chamber (secondary firebox). Stoking door of main firebox in January 2007.

Noborigama

Christine, Robert & "wonder dog" Shino
 with a fully loaded kiln prior to firing.

Six Week Firing Cycle

Glazing a kiln load takes about 14 days and another 12 days to wad and load the pots.

The actual firing time is 42 hours with 4 days of cooling before unloading.

Unloading, cleaning wad debris, grading and pricing pots adds another 20 days.

This kiln is fired twice a year, usually in June and September.

Noborigama

The Noborigama 250

Firings take about 42 hours and burns
6 cords of wood.
The main firebox can take wood up to
6 ft long and burns both hard and softwood, depending on the cycle.

The pots have been bisque fired
"first" in a gas kiln,
 allowing for a faster start during the wood firing.

The kiln was designed so there is plenty of room to maneuver
 in the chambers when loading.

Each firing holds about 1500 pots,
including a dozen or more large planters and urns.
One of the reasons Robert built this kiln was to enable him to fire
 large pots.

 

2005
 First Chamber half loaded
  2005
 Starting to load the First Chamber

Noborigama

"Before" "After"
2006
 Salt (second) Chamber -Before Firing
 
2006
Salt ( second) Chamber -After Firing
 

Noborigama

Watching the chimney & blow holes,
helps determine the proper sequence of stoking.
A section of the roof is taken off before each firing.
 This allows smoke and heat to exit the building.

Noborigama

Stoker's wear a clear protective face shield.
The main firebox consumes 80% of the wood in each firing,
 the secondary firebox of the salt chamber takes the remainder.
Feed doors were built at eye level,
allowing stokers to stand upright when feeding wood.
Keeping good "back pressure" in the salt chamber
 for even heat distribution and nice salt effects. Robert adds one pound of salt for every cubic foot of loading space in the salt chamber.

Noborigama


The chambers are fired to cone 10,
and have about a one and a half cone variation, from top to bottom.

The majority of the work in the first chamber is glazed ware, a small number of pots in the bag wall area are left unglazed
for full ash effect.

Most pots in the salt chamber
are left entirely unglazed, for the full salt glaze effect,  pieces that are glazed have mostly celadon glazes, which are enhanced by the sodium vapor.

 

Flames entering the salt chamber are seem coming in thru the flues from the first (glost) chamber.   Sodium vapors

Noborigama

The July 2005 Stoking Crew
Starting on Left
Lorin Alder, Christine & Robert, Debbie Altschwager, Gregg Galinski,
Josh Baisinger & Kim O'Connell.
The firebox of the salt chamber
  was designed with a waist high stoking port,
allowing Robert to add wood, while in an upright position.

Noborigama

Toward the end of the firing
when stoking the back chamber (salt),
a dragon trail rises from the chimney.
 

This Kiln is fired twice a year, in June and September.

The process and resulting wares were everything
that Robert had hoped to achieve.

 Detailed Construction Photos

 

Noborigama

Design Considerations

This Kiln was designed with ergonomic considerations.  The doors were made tall enough for Robert to walk in without hitting his head.

It's 6.5 ft tall interior makes loading convenient and comfortable.  Feed holes were placed at chest height, so there is no back strain when stoking.

The loading area was designed around our 2ft x 2ft kiln shelves, making a stacking pattern of two shelves wide by three shelves deep.
There is a 4 ft x 6 ft x 6ft loading area in each chamber.

 

We refer to the kiln as having 250 cu ft, this is just the loading area of the chambers, not the total volume, which is significantly larger.

 

 

 

 

Robert Compton Pottery
2662 North 116 Road, Bristol, Vermont 05443, U.S.A.
Phone: 802-453-3778
E-mail: Robert & Christine

 

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