Monthly Tech-Tip | No tracking! No ads! |
The 80:20 base GA6-A Alberta slip base becomes oatmeal when over saturated with rutile or titanium (left: 6% rutile, 3% titanium; right: 4% rutile, 2% titanium). That oatmeal effect is actually the excess titanium crystallizing out of solution into the melt as the kiln cools. Although the visual effects can be interesting, the micro-crystalline surface is unpleasant to touch and susceptible to cutlery marking and leaching (not as stable or durable as in glazes which are pure amorphous glass). For functional ware, rutile glazes are among the most troublesome to keep consistent, one way of avoiding problems is keeping the percentage as low as possible while still getting the desired variegation (of course that will vary depending on the melt fluidity of the glaze, more highly fluid ones can handle more rutile or titanium).
Recipes |
GA6-F - Alberta Slip Cone 6 Oatmeal
Plainsman Cone 6 Alberta Slip based glaze. It can be found among others at http://albertaslip.com. |
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Glossary |
Leaching
Ceramic glazes can leach heavy metals into food and drink. This subject is not complex, there are many things anyone can do to deal with this issue |
Glossary |
Crystallization
Ceramic glazes form crystals on cooling if the chemistry is right and the rate of cool is slow enough to permit molecular movement to the preferred orientation. |
Glossary |
Food Safe
Be skeptical of claims of food safety from potters who cannot explain or demonstrate why. Investigate the basis of manufacturer claims and labelling and the actual use to which their products are put. |
Glossary |
Rutile Blue Glazes
A type of ceramic glaze in which the surface variegates and crystallizes on cooling in the presence of titanium and iron (usually sourced by rutile) |
Materials |
Ceramic Rutile
Rutile mineral ground to a very fine particle size (e.g. 325 mesh) contributes titanium and iron that colors and variegates ceramic glazes. |
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