Apart from its obvious use in the decoration process of ceramic glazes, this is also used as a binder in ceramic bodies.
Related Information
Wax emulsion enables liner glazing and much more
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This technique enables the use of a liner glaze, in this case GA6-B. These are most valuable where the outer glaze is reactive (melt-mobile, crystallizing or heavily pigmented) and therefore potentially leachable. Not only are liner glazes less likely to leach but they are less likely to craze, this assures water tightness and eliminates any potential for bacteria growth in the cracks (especially if the body has porosity). Liner glazes are also less likely to stain and cutlery mark, adding to the durability of pieces. The straightness of the dividing line is affected by the degree to which the two glazes bleed into each other. Liner glazing also adds a decorative element to pieces. This technique is also practical where mug walls are thin and cannot absorb enough water to dry the glaze quickly after dipping or brushing.
Wax resist on a low fire transparent over an underglaze
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Bubbles are appearing on the two sides of the blue where a vertical brushstroke was applied. No wax was used over the transparent at the rounded corner. This transparent, Spectrum 700, is normally ultra-clear and ultra-glossy, but over these stains (Amaco Velvets), that transparency is fragile and the wax is enough to affect it.
One way to avoid drying cracks on handle-joins of engobed mugs
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The foot ring on these leather-hard mugs has already been trimmed. At the stiff-leather-hard stage an engobe was applied to the inside. This rewets the bodies of the mugs, almost to the same point as freshly-thrown. But the handles did not get rewetted. To re-dry these mugs to the point of being able to turn them over will take 4-6 more hours. But by that time the handles will be too dry. To prevent that I wax them after trimming (leaving a just the inside handle-curves bare). That slows their drying down enough to keep them even with the body of the mug. This method works well enough that none of my mugs need covering during drying, even in our desert climate. Keeping all parts of a piece at the same water content throughout the process, that is a key to successful drying.
Drying mugs in front of a fan in 2 hours. No Cracks.
These are Plainsman Coffee clay. They, and the handles, were made on the wheel about half an hour ago, then stiffened enough in front of the fan to enable handle attachment. Coffee clay is plastic and will crack if pieces are not dried evenly. But if they are dried evenly, there is no problem. The handles were waxed after they were attached (leaving only a thin section on the inside where some water could escape). This slowed them down, otherwise they would have dried far ahead of the body. They went in the kiln and were ready for glazing the next morning.
Wax emulsion arrived lumpy and thick
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This is CrystalCer A from PMC Crystal, a manufacturer of waxes, wax emulsions, oils and soaps. In ceramics it is mainly used as a resist during the application of glazes. Using a propeller mixer we were able to thin it and remove the lumps.
Links
Articles
Binders for Ceramic Bodies An overview of the major types of organic and inorganic binders used in various different ceramic industries.
Typecodes
Additives for Ceramic Bodies Materials that are added to bodies to impart physical working properties and usually burn away during firing. Binders enable bodies with very low or zero clay content to have plasticity and dry hardness, they can give powders flow properties during pressing and impart rheological properties to clay slurries. Among potters however, it is common for bodies to have zero additives.
