View of soda kiln firing at night,
February, 2001.


Used for Soda Vapor Kiln
Built by Greg Stahly, senior.
Marvin Bartel, Consultant, summer, 2000
Goshen College

Materials below are all by Volume - NOT Weight
  1. Dry mix first until all ingredients are totally blended. Careless mixing produces defects in the kiln wall.
  2. When ready to mold it, add just enough water to bind when tamped in place.

  3. Tamp with end of 2x4 or similar tamper.

Mixes used for Cone 10 Soda Vapor Firing Kiln

Interior Solid Refractory
Hot Face - has some shrinkage as it dries, but tends to expand when kiln is fired.*
(1 inch thick)

Ball Clay OM4
Kaolin 6-T

10  parts
1 parts
2  part
3 parts
4  parts

This mix proves to be very resistant to vapor glaze deterioration, but the hot face and insulating layers tend to delaminate in some areas.
It may help to add 1 part portland cement.  See door block mix below.
Interior must be bone dry before firing.  First firing must be very slow to avoid pop outs.
This mix used for 1 inch floor slabs.
They are pre fired to cone 10 and laid on top of 4 inches of insulating castable.

Insulating Refractory Castable
(4 inches thick)
Ball Clay OM4
Portland Cement

4  parts
4  parts
2  part
2  part
5 parts
4  parts

This mix is tamped directly on the hot face mix for the walls and top.  Both layers are built at the same time to attempt bonding of the layers.

Subsequently, the exterior gets an additional 2 inches of mineral block
1900 F insulation, plus 0.5 inch
refractory stucco with wire mesh in it.

*SUGGESTION: Add 1 part Portland cement to the hot face mix. It may prevent drying shrinkage and help bond the hot face to the insulating castable to minimize the crack between them.  CAUTION: Portland cement melts at cone 10.  Too much cement would compromise the refractory.
Mixture for door blocks The inside needs to resist the effects of the soda vapor and the outside needs to provide insulation.
  1. Make both of the above mixtures, but add 1 part portland cement to the hot face recipe to stabilize it and bond it to the insulating castable.
  2. Make the hot face about 1/3 of the thickness and use the insulating mix
  3. Before using, door blocks are fired to cone 10 in the stoneware kiln.
  4. Door blocks are 5 or more inches thick.


Bowl Assignment
Castable for Soda Kiln
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Coil Building Assignment
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Learning to Throw Pots
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Bartel Exhibition Catalog
Ceramics Alumnus, Tom U
Ceramics Alumnus, Dick L
Contact Marvin Bartel

Greg Stahly pours soda in burner blower
at end of firing, February, 2001


All rights reserved. Goshen College students may make one copy for their own use.  Others need to E-mail for permission to publish any part of this document.
photos © Marvin Bartel

Updated 10-10-01