Clay

Richard Boyt, June 2003

Dear Ken Goyer, Rogerio Cameiro de Miranda, and others:

The following material is the third part of a condensation from the booklet "Practical Tips For Potters Making Improved Cooking Stoves. Prepared by Tim Jones, Illustrated by Debbie Riviere. Published by Hofman Systems Engineering b.v., PO Box 642, 3100 AP Schiedam, The Netherlands (1993).

Richard Boyt, June 2003

Again, greetings from Pottershop Holler, where the sky gets smaller as the trees grow taller.

Before I continue with ideas on primitive kiln and stove designs, I want to backtrack to fill a few holes
I've left in earlier writings. Sometimes I have called for equipment or materials that are not likely

Ron Larson and Richard Boyt, June 2003

Stovers: Richard Boyt and I are having a discussion on making charcoal-making stoves out of clay. Richard has sent me a new paper design below. This note is only on my own progress - which Richard has been kind enough to continue.

Initial Design Concepts:

  1. Wide bottom for stability
  2. Main body, grate, skirt, lid, cast lightweight ceramic.
  3. Preheat and control primary and secondary air.
  4. Remove pot, skirt, skirt top, chimney adapter, chimney for grilling, frying roast, etc.
  5. Fuel holder, chimney and adapter metal(?)

Richard Boyt, May 2003

Hello stovers.

Greetings from Pottershop Hollow in the SW Missouri Ozarks where last week tornadoes did their damndest.
Sunday's blow just missed us by a few miles as did the storms of the rest of the week. Two years ago the
farm got hit by several small tornadoes that uprooted over a thousand of our larger trees.

How to Build a Kiln - Various Kiln Building Links
Tom Miles, July 3, 2007

Following are various links to making kilns for bricks, stoves and pottery.

Manny Hernandez, Potters for Peace, http://www.pottersforpeace.org/
Presentations to ETHOS Conferences, 2006 and 2007
How to Build a Kiln (5MB pdf) ETHOS 2006
Kiln Building in Africa and Honduras (4 MB pdf), Presentation to ETHOS 2007

Ken Goyer AID AFRICA
Kilns and Brick Making, A rough Draft March 2006

Building a Small Flat-Top Kiln
Mel Jacobson and Kurt Wild, Pottery Making Illustrated March/April 2005
Kurt Wild's kiln 22.6 ft3

Nils Lou The Art of Firing
Linfield College, Oregon
Building a Minnesota Flat Top Kiln

Frederick L. Olsen, The Kiln Book : Materials, Specifications, And Construction, 2001, Third Edition, Krause Publications, Iola, WI. www.krausebooks.com

Joe Finch, 2006. Kiln Construction: A Brick by Brick Approach. www.upenn.edu/pennpress
www.joefinchkilns.co.uk

Pyrometric Cone Chart Evenheat Kiln, Inc.

Kilns for stoves
Construction of a kiln for firing clay stoves IFSP Malawi on HEDON

Various wood Fired Kilns for Ceramics
The Kiln Book, Materials, Specifications and Construction by Frederick Olsen
- My Olsen Fast Fire Wood Kiln

Firing Guide: Wood Firing Claystation.com

Woodfiring www.woodfiring.com

Sidestoke Gasifier Kiln
Bourry Box or Hob firebox downdraft gasifier side stoker
Double Bourry Box Kiln
Fastfire Wood kiln vs Bourry Box
120 ft3 Bourry Box Kiln

A modification of the Bourry kiln can be found in:
Wood-fired Ceramics, Contemporary Practices, Coll Minogue and Robert Sanderson, 160 pages | 8.5 x 11 | 101 color, 118 b/w illus. Cloth 2000 | ISBN 978-0-8122-3514-2

First test of the Maputo Ceramic Stove
Crispin Pemberton-Pigott, New Dawn Engineering, August 20, 2006

MCS200MCS200

Note: click image to enlarge.

Dear Friends

I have completed a test of the first fully formed Maputo Ceramic Stove (MCS) with 3 litres of water and initially a bit more than 300 gm of charcoal. The unit in the pictures is the final version.

The test was done without any skirt or under-tray to improve efficiency, just a pot and lid sitting on a simple stove.

The water boiled in exactly 30 minutes even though the stove body was wet from being washed (oops).

The specific fuel consumption calculated on the basis of water remaining at the time of boiling (good idea) and water remaining at the end of the simmer (something I think is weird) is:

48 gm per litre of water boiled
16.5 gm per litre simmered at 1 degree below the local boiling point for 45 minutes.

This translates into about 324 gm to boil and simmer 5 litres of water, depending on how you calculate it.

The stove was easy to use. I closed the air hole when it boiled and otherwise did not touch anything at any time.

There was more than 140 gm of charcoal left in the stove at the end of the test. This means it had too much in it to begin with. I was unable to get the temperature to drop below almost the boiling point so I think if it was done again with perhaps 200 or 250 gm of fuel it would come out with a better figure.

The stove in the photos will cost about $3 to manufacture profitably. The material is very low thermal expansion PK11 clay mix fired at 1150 degrees. The whole stove weighs 2230 grammes. The material cost about US$0.40. The grate is removable. The two parts can be formed in a manual press like the Ring Maker.

Maputo Ceramic Stove - 2 samples fired differently
Crispin Pemberton-Pigott, New Dawn Engineering, Swaziland, August 18, 2006

Dear Clay Stove Makers

I am forwarding a photo of two Maputo Ceramic Stoves (MCS) without a grate. One was fired by a thumb-suck method and the other was fired in an oven with a temperature controller.

One of the things I have found is that there is more confidence in the ceramic industry than knowledge.

The two stoves are exactly the same, made from PK11 which is a high feldspar clay, the greater portion being black plastic clay.

You will notice that the darker of the two has a shiny appearance. This is from the melting of the minerals. Looking closely you can see small pock-marks which is where the powdered charcoal burned out (about 10% by weight).

The lighter one is powdery when touched, much lower tone when struck and significantly weaker. The only difference between the two is the firing temperature.

Sample Ring From the Ring Maker
Crispin Pemberton-Pigott, New dawn Engineering, July 30, 2006

Sample Ring From the Ring MakerSample Ring From the Ring Maker

Crispin Pemberton-Pigott, New Dawn Engineering, Swaziland, June 12, 2006

3 Laterit and Charcoal Dust3 Laterit and Charcoal Dust

Dear Friends

I fired two of the rings today for a brief time, perhaps 3 hours at temperature. No particular care was taken regarding the slow initial temperature rise.

Pages

Subscribe to Clay