Ceramic Foundation
P.O. Box 2760 • Westerville, OH 43086-2760
(614) 895-2663 • (614) 895-5610 fax
email: info@ortonceramic.com

Cone Placement

• Cones can be mounted in a straight line (a), turned to an angle (b) or spaced diagonally (c). Diagonal placement is handy when viewing SSB cones through a peephole.

• It is suggested to place cones at least 6” from the kiln’s inner wall to protect the cones from the effects of drafts. 

• Use of the proper safety glasses when viewing cones is recommended.

Measuring Template

• The bending angle is determined by measuring the large or SSB cone against the scale.

• This angle can be converted into a temperature.

• The difference between 60° and 90° bending angles is usually a small amount in equivalent temperature.

• If your firing cone deforms to a lesser bending angle than desired, you may need to increase the firing time.

  • Manual Kilns: place small cone in kiln sitter in offset position with large end toward center or place next higher cone in kiln sitter if witness cone has hardly moved. (You cannot adjust a pyrometric bar by moving it.)

  • Controller Kilns: add small amounts of “hold” or “soak” time or raise your end setpoint temperature in custom programs.

• If your firing cone is deformed to a greater bending angle than desired, you may need to decrease the firing time.

  • Manual Kilns: place small cone in kiln sitter in offset position with small end toward center or place next lower cone in kiln sitter.

  • Controller Kilns: decrease small amounts of “hold” or “soak” time if this has been set or lower your end set point temperature in custom programs.

• This chart shows the effect of “soak” time at a certain temperature. As shown in the chart, it takes a significant amount of “soak” or hold time to cause the next cone to deform. 

• Soak time can be used to equalize the temperature distribution within the kiln and ware.