Understanding Cone 6 Glazes

Sue McLeod's "Understanding Cone 6" part of the Glazes Without Borders presentation at NCECA in Pittsburgh, 2018.
This presentation explains how glaze chemistry works at cone 6 with regards to the UMF (Unity Molecular Formula). Each glaze can be plotted on the Stull chart which can predict whether a glaze will be matte, glossy, underfired, crazed, etc. The concepts in this presentation are applicable to all temps but my research was conducted at cone 6.
The full presentation also includes:
Copper as a Flux - Kiara Matos
Copper Leaching and Toxicity - Peter Berg
Our research was collaborated with and our discussion panel was moderated by Matthew Katz of Ceramic Materials Workshop.
You can watch the full, hour long presentation here: • Glazes without borders

[@BasilWallace]

My mind was blown by this!! I've just gone ahead and adjusted a glaze I've created to get away from the crazing of another glaze from John's book. Based on your research I predict I would not have solved my problem with my new glaze from how it was previously and I would have been only more confused.

[@FunnyWisdomShorts]

Fantastic. Every ceramic artist (beginner) should see this excellent tutorial. Thank you so much for sharing!

[@suemcleodceramics]

Thank you so much for the feedback :) Feel free to share the video with anyone you think might find it useful.

[@gojec29]

It's the same for me in Belgium , 7 years of working whith the clay at school but nothing on the enamels ... The first time I've seen a Seger formulation I say in my mind: how can I heat that ??? Fortunately whist the time I can now understand what is it . Sorry fgor my bad English but it isn't my mother langage ...

[@zehrabayazit7369]

💖thx for detailed knowledge about glaze

[@mosephina]

Once you settle on a glaze that fits the body well, and gives the desired surface of matte, semi-matte, or glossy would adding colorants, within leaching limits, affect the glaze characteristics of matte, semi-matte, or gloss; materially? Would you have to adjust the base glaze formula to account for the colorants, and/or rutile?

[@suemcleodceramics]

Hi, I just noticed your comment. Colourants can act as a flux, which can shift the flux ratio, especially in higher percentages. But colourants shouldn't affect the matte/glossy-ness of the surface.

[@JohnSmith-fw2et]

! have cone 6 commercially made glazes tat craze, its very frustrating. Is there a way i could fix them so they don't craze?

[@suemcleodceramics]

There isn't really a way to adjust commercial glazes because we don't know what we're starting with. You could try a different clay body. Crazing depends on the relationship between a specific glaze and a specific clay body. If you're glaze is crazing on porcelain, it might not craze on stoneware.

[@tommurphy2850]

"...science, very very cool..." Thank You

[@suemcleodceramics]

Thanks for watching! You quoted my favourite part 😀 Hope you found it useful.

[@lindabloomfield9773]

Very interesting and well presented research! Thank you.

[@suemcleodceramics]

Thanks Linda!

[@nikkithiduong6134]

Great you talk allot like writing a novel