Monthly Tech-Tip | No tracking! No ads! |
These mugs are Plainsman H443. The cone 10R dolomite matte bamboo glaze on the left (A) has 3.5% rutile and 10% Zircopax added to our base G2571A dolomite matte. The one on the right (B) has the same addition but in a base having less CaO/MgO and much more KNaO. This gives it a craze-prone calculated thermal expansion of 7.9 (vs 6.7 for ours). B also stains badly (as can be seen from the felt marker residue that could not be removed using lacquer thinner). Why does A stain only slightly? It has an additional 4% Gerstley Borate, a powerful flux that develops the glass surface better (giving a slightly less matte surface).
Troubles |
Staining of Fired Ceramic Glazes
Ceramic glazes are glass. That means they are always easy to clean, right? Wrong - because the surface is not always glassy. |
Recipes |
GR10-J1 - Ravenscrag Cone 10R Bamboo Matte
Plainsman Cone 10R Ravenscrag Slip based glaze. It can be found among others at http://ravenscrag.com. |
Recipes |
G2571A - Cone 10 Silky Dolomite Matte glaze
A cone 10R dolomite matte having a pleasant silky surface, it does not cutlery mark, stain or craze on common bodies |
Glossary |
Bamboo Glaze
A high temperature reduction glaze made by adding a small amount of iron oxide to a magnesia matte base glaze |
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