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Pottery/Identifying Glaze Materials and Their Toxicity


I have just started working in a school pottery where I have inherited a large quantity of chemicals.  I have not done much glaze-making of my own, but I expect a few students to be interested in mixing glaze formulae in the future.  I think I have some illegal toxins from the olden days among the useful containers.  I have recently begun to inventory my stash.

Can you tell me where to find information on low fire glazes that I could use with high school students and an inexperienced teacher?  Is there a place to discover what each chemical will do for me at earthenware temps?
Thank you for your time and knowledge on this!

Dear Julia,

    Thank you for your recent questions. Discovering your raw glaze materials is exciting and prompts one to want to start making glazes. However, as you stated, some materials may no longer be used in the glaze studio because of their toxicity. As for being illegal, I know of no raw glaze materials that are illegal. What I do know from 30 years of expertise is that there are several raw glaze materials that are regulated by the FDA and although they can still be used in glazes, they can be very dangerous to handle if in their oxide form.

    In my opinion, since you are working with high school students, I suggest you not allow students to work with the raw glaze materials until you have a full grasp on handling the materials yourself. Knowledge is the key to safety, especially when working with children. All raw glaze materials have some form of toxicity, depending on whether they are inhaled, consumed or otherwise used in a glaze and fired. So proper handling of the materials is essentially the goal.

    To begin with, when identifying the materials in the glaze room, begin by putting all raw materials in containers that will prevent unnecessary dust in the studio. Be sure and wear a mask during any and all handling of the materials. Label each material with its complete name. It is best to use the original printed label for each material, if available.

    If you wish, you can make a list of every material you have on hand and send it to me. Because there are literally thousands of materials available for glaze manufacturing, it would be easier if you provided a list of the materials you have on hand. I will identify each material with a safety sheet that you can add to your collection of glaze notes.

    As for glazes for low fire, you can search the Internet for many low fire glazes. However, I recommend the following books on low fire glazes so that you have a good source of workable glazes, and not test glazes that came out of a student glaze studio.

    The Glaze Book by Stephen Murfitt - an excellent source of low, medium and high fire glazes with photos of each glaze.

    The Potter's Book of Glaze Recipes by Emmanuel Cooper - another excellent source of low, medium and high fire glazes with photos of each glaze.

    These two books should give you a good pallet of colors, textures and other characteristics you will need in the studio.

    Finally, if you would like to identify the materials toxicity and usefulness on your own, go to the following website for more information.

    I hope this information is of help to you. If you have further questions, or need further assistance, please feel free to contact me at any time. I am always at your service.

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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