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Pottery/Duncan EA-820 Switch - Overglaze, Ceramics, Highfire


Hello,  I read your recent response to someones question and I too have a question.  I am having a hard time understanding this kiln.  If I place it on "ceramic" is this to make the greenware bisque or is it assuming I glazed it?  I am fairly new to this so you help is appreciated.  There are "highfire" and "overglaze" other options. Help - this is way different than the Evenheat I used before. :)

Dear Ruthevelynn,

Thank you for your recent question. The switches on your kiln refer to the cone range in which your kiln will fire. This turns the settings of the kiln elements off and on, maintaining the kilns temperature rise as it fires. Therefore, each of the three settings are for a range of cones.

The first setting, Over glaze, refers to luster, gold and decals. It is for extremely low firing in the witness cone range of 022 to 016 or cooler.

The second setting, Ceramics, refers to the witness cone range 07 to 01. In this instance, it would be for bisque.

The third setting, High Fire, refers to the witness cone range 1 or hotter. In this instance, it would be for stoneware and porcelain.

So as you can see, if you follow the witness cone ranges listed here, you can set the knob for the witness cone you are going to fire to. So if you are doing a bisque firing, you would set the knob to Ceramics. However, if you were doing a Cone 5 Glaze, you would set the knob to High Fire.

I hope this helps you. If you have further questions, please feel free to contact me at any time. I am always at your service. Much luck to you.

Ms. Ti Phillips
Earth Stoke 'N Fire Pottery Studio and Artist Retreat


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Ti Phillips


Will answer any questions on hand building, wheel, glaze, firing. Speciality questions to include those in glaze calculation and development, firing techniques. Please do not send questions on identifying pottery. Although I would love to add this to my question topics, I have a retreat to run as well as the studio and volunteering on AllExperts, and therefore do not have the available time to research indentification and marks. Thank you for understanding.


Experience includes 30 years in pottery design and education. Have taught online and studio classes worldwide for the last 20 years. Own a pottery retreat specializing in firing techniques. Have 12 years solid experience in glaze calculation and formulation as well as problem solving in glaze chemistry. I am the first potter in the United States to have developed a complete package of pottery equipment blueprints for a studio. The blueprints include wheels, kilns, studio furniture, wedgeboards, raku kilns, slab rollers, ball mills and studio tools.

Alliance of Pottery Artists Worldwide Association

Ceramic Industry - PPP Wyndstryder Press - Pottery Journal

University of Sciences and Art's of Oklahoma, studied under Professor Jaymes Dudding.

Awards and Honors
Potter of the year with APAWA, various awards for showmanship and design.

Past/Present Clients
Available upon request.

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