- Ceramic Arts Daily - http://ceramicartsdaily.org -

Ceramic Art Lesson Plan: High School Anagama

Posted By Clay Cunningham On April 13, 2010 @ 4:07 pm In Education,Lesson Plans 9-12 | No Comments

Two layers of concrete block form the foundation and raise the kiln to a workable height. Students build the walls and begin the stack.

Since this is a high school, the students and faculty need to be in classes six straight hours a day, everyday. To avoid conflicts, I decided to direct the project in the form of a summer workshop in June. With a healthy mix of eight adult potters from the community and ten students from the high school, we had plenty of able hands, as well as a safe and constant adult/student firing team. I planned a single-chamber kiln that would have great atmospheric potential, yet would fire over a weekend during the school year. Instructed as a three-week course, we spent the first week building the kiln, the second week making pots and sculptures, and the third week loading, firing and cooling the kiln.

 

 

Building the Kiln

 

We began by laying out a 15-inch high foundation of concrete blocks, on which we placed 9 inches of K23 hard brick in an alternating header and stretcher fashion to create a total interior floor plan that measured 45×96 inches (figure 1). The first three feet of the interior was reserved for the firebox with the remaining five feet, tiered up 6 inches, for the ceramic ware. The flooring in the firebox area was constructed with K26 hard brick to better withstand the cone 10 temperatures we would be reaching. Similarly, the walls were constructed 9 inches thick by alternating courses of stretchers and headers to a height of 15 inches.

 


Download a printer-friendly version of this assignment here:

High School Anagama


A concrete block wall helps bear some of the weight of the roof and is placed 4 inches from the sides. The gap is later filled with pea gravel.

Fig.2 A concrete block wall helps bear some of the weight of the roof and is placed 4 inches from the sides. The gap is later filled with pea gravel.

Before adding the arch, we lined the outer walls of the kiln with cinder blocks to a height of 37 inches, then filled the blocks with rebar and mortar mix. The small 4-inch gap between the concrete blocks and the hard brick was then filled with pea gravel to support the force of the dome on the kiln wall and to increase insulation and to allow for thermal expansion (figure 2). The exit flue to the chimney was created slightly oversized at a total of 22½×22½ inches with the chimney interior at 13½×13½ inches. The chimney was built with hard brick to a height of 15 feet and finished with a 4-foot stack anchored with cables into the ground on three sides. A removable spanner brick was placed above the damper to act as a passive damper.

 

Using a technique from Fred Olsen’s, The Kiln Book, mound and contour dirt to create the domed roof, then cover with plastic. Apply castable refractory over this form.

Fig.3 Using a technique from Fred Olsen’s, The Kiln Book, mound and contour dirt to create the domed roof, then cover with plastic. Apply castable refractory over this form.

The Roof

 

Instead of making a wooden frame for the arched roof, we used excess dirt from the construction site of a nearby middle school to make a solid mound inside the kiln. With a couple shovels and a lot of muscle we piled on two truckloads of dirt to form a smooth curved dome. Once shaped to our liking, we then mixed high refractory castable to form the dome. Since we were on a budget, we mixed all 2400 pounds of castable by hand with a hoe and mortar tray to a consistency of thick concrete. Next, we lined the dirt with plastic bags and added one ball right on top of the other until the entire dome was completed to a thickness of 9 inches (figure 3). Using two plastic buckets, we added the balls around the buckets so that when the buckets were removed, we had negative spaces for side stoking (figure 4). After the last ball, we covered the entire dome with plastic bags to let it cure overnight. The next day we lined the dome with fiber blanket and an adobe mix of mortar, dirt and straw. This not only further insulated the kiln, but also protected the castable from the snow and rain.

 

Plastic buckets were used as forms to create side stoke holes in the roof. A fiber blanket was added then the roof topped with an adobe mix of concrete, mud and straw.

Fig.4 Plastic buckets were used as forms to create side stoke holes in the roof. A fiber blanket was added then the roof topped with an adobe mix of concrete, mud and straw.

Caution: As a safety precaution, everyone wore face masks and rubber gloves while handling the fiber blanket, as the small particles can irritate the lungs and the skin. Rubber gloves are recommended when handling adobe as wee. Concrete can irritate skin (and it makes your fingers pruney). After the castable set up, the door was disassembled and the dirt was removed. At last, after five days, the Lewis Central Anagama was complete.

 

Making Work

 

The next week was spent making a wide variety of pottery for the kiln. I provided three different clays to use with maturing rates from cone 6 to cone 10. In addition, a variety of tried-and-true high-fire glazes were supplied from copper reds to celadons and shinos. Students were encouraged to keep good notes of which clays and glazes were used for each piece to reflect on successes and learning experiences.

 

Firing steadily for more than 30 hours, the kiln reaches cone 10 and soaked at that temperature for a few hours. It’s then allowed to cool slowly for a few days.

Fig.5 Firing steadily for more than 30 hours, the kiln reaches cone 10 and soaked at that temperature for a few hours. It’s then allowed to cool slowly for a few days.

Getting Ready

 

Over the weekend, we spent one full day loading the pieces into the kiln. Tumble stacked one on top of the other, nearly every nook and cranny of the kiln was used. By Sunday, the front of the kiln was bricked up, leaving a main stoke hole and primary air inlets at the bottom of the door. Using a homemade block of castable, a U-bolt, an eyebolt and some chain, we were able to suspend a movable door from a post and lintel so that wood could be stoked with minimal heat loss. The post and lintel were made by setting two 8-foot 4×4 posts with a 10-foot 4×4 post for the horizontal beam and securing them with metal brackets. With the door in place and the kiln full of work, we were ready to go.

 

Fig.6  View of the kiln interior and the stack of ware, showing some of the 400 pots included in the inaugural firing.

Fig.6 View of the kiln interior and the stack of ware, showing some of the 400 pots included in the inaugural firing.

Firing

 

The kiln was started with a small fire at 5 PM on Sunday. By early Monday morning the kiln was nearing 1800ºF. Working in teams of two or three and stoking several split logs at the end of every reduction cycle, the kiln climbed to 2200ºF by Monday evening. We were at cone 10 by noon on Tuesday (figure 5) and held it at that temperature until 5 PM when we stopped stoking and sealed the kiln. To help ensure a slow cooling, we dipped newspapers into a large barrel of slip and completely coated the entire kiln with the dripping wet sheets to decrease heat loss. This, as you can imagine, was a fun and messy highlight of the entire experience.

 

Porcelain vase, 20 in. (51 cm) in height, by Clay Cunningham (instructor).

Porcelain vase, 20 in. (51 cm) in height, by Clay Cunningham (instructor).

 

 

Porcelain vase, 17 in. (43 cm) in height by Rick Devoss. Click to enlarge!

The Results

 

After three days of cooling, it was time to open the kiln. The old adage of a unloading a kiln unloading feeling like Christmas morning could not be more apropos (figure 6). All of the students, young and old, came early to see their approximately 400 newly finished creations and enjoy a potluck meal with a new family of bonded potters. We had much to celebrate. We were able to load and fire the kiln in the course of a weekend with just under two cords of wood. We proved that an anagama is not only doable at the high school level, but an amazing learning tool that will provide students with a life-long experience. We will be firing it up again this summer and our pottery club is in full swing to fill the quota.

 

 

Stoneware vessel, 6 in. (15 cm) in height, by Deanna Williams. Click to enlarge!

Porcelain bowl, 5 in. (13 cm) in diameter, by Kelly Cox. Click to enlarge!

Clay Cunningham is a ceramic artist and instructor, currently teaching at Lewis Central High School in Council Bluffs, Iowa. To see more of his work, or for contact information, visit www.claycunningham.org.

 

 

 

 


Article printed from Ceramic Arts Daily: http://ceramicartsdaily.org

URL to article: http://ceramicartsdaily.org/education/high-school-anagama/

Copyright © 2008-2012 Ceramic Arts Daily. All rights reserved.