[Clayart] Glass in pots

[Joseph Herbert via Clayart]

Hello,

Not exactly sure why this occurred but a pot, maybe porcelain, with some
amount of glass nuggets in the bottom, melted in a cone ten firing at a
nearby college. The glass seemed to have melted the bottom out of it. So,
another reason to not use random glass in your ceramics activity is the
unknown composition of the glass. Some are sodium heavy, some are iron
containing, some have boron, and you mostly don’t know which.

Joe
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[David Woof via Clayart]

.......and some glass contains Lead. The glass being a Frit for these materials until melt temps are reached.
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Subject: [Clayart] Glass in pots

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[Rick Mahaffey via Clayart]

In the 1950’s ash trays were made with contrasting color glass in the bottom.
At the age of 5, I hated that look. I discouraged my students for putting glass in Their pots for aesthetic and safety reasons as well as protecting our kiln shelves. Our budget in the community college was not generous enough to replace a number of shelves each year.

Between the chance of bits of glass coming off the pots and issues with questions about proper annealing of the glass it’s just not the best idea in this country where folks often don’t have the slightest idea of proper use and care of ceramic items.


Your glaze choices may vary.

Rick Mahaffey