Zero3 G Transparent Glaze


This is our code number G2931G, a low expansion adjustment to the Zero3 K Glaze to make it fit Buffstone and Terrastone (without crazing). By blending this with the K glaze you can fit the thermal expansion of almost any low fire clay body (more of this if it crazes, more of K if it shivers).


To get the best defect-free surface please consider using a hold-rise-drop-hold firing schedule (you can find more information about it on this page).

Terrastone with Zero3 G glaze fired at cone 03.


We recommend decorating ware using underglazes, then overglazing with this and firing to cone 03. You can fire to 04 but ware will not be as strong and the glaze not melt as well.

This recipe employs Ulexite to source the boron (instead of frits). While much better than Gerstley Borate, it still does tend to gel the slurry over time so you may need to add water and tolerate it being thicker than other glazes. The specific gravity can be as low as 1.40. It applies very evenly with little dripping. Ware needs to be absorbent. If your ware is thin it might be necessary to glaze the inside and outside in separate operations (with drying time in between).


As of June 2017 it is not yet available as a premixed product. But you can mix to yourself. For our lab information on the recipe, how to mix and use it click here.

Thermal Expansion

Low fire glazes are much more difficult to match to the body, crazing and shivering are common. That is why we recommend two recipes, G and K, that people can blend to fine tune to their body.

Buffstone with Zero3 glaze at cone 03. Left is Zero3 K glaze, right is the Zero3 G glaze. After a boiling water:ice water thermal shock test, the K has crazed.

Do not use the Zero3 G glaze on Zero3 stoneware or on talc bodies (like Plainsman L215, 212), it shivers. This is intended, it has the very low thermal expansion needed to fit non-talc, non-vitreous low fire bodies (like Plainsman Terrastone, Buffstone).

Safety Data Sheet

Click here for web view.

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702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508