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| There are four main ingredient categories in functional stable glazes (of course, every rule is made to be broken). |
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Definition
| Glass former, Flux, Stabilizer,and colorant/ opacifier |
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Term
| It is the ________ _________ that gives glaze its glassy look. The_____________ _________ vitrifies the ware, and makes it both attractive, and also food safe and food ‘convenient’. It is usually added to a glaze as clay (EPK, Ball Clay, Grolleg). |
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Term
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Definition
| SiO2 – Also called Flint or Quart: |
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Term
| Silica needs so much heat to melt (c. 28 or 2,950F) that you must |
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Definition
| add Fluxes so that it will melt at a lower temperature. |
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Definition
| Lowers the melting temperature of Silica. |
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| Once the______ is added, the job is essentially done. In fact… many fluxes may act as a glaze by themselves, as they work with the silica in the clay. |
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| Primary: These are ‘alkaline fluxes’: Potassium, Sodium, Lithium Fluxes: |
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| _________ means that the ‘flux’ is combined with alumina and silica.) |
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| If a glaze recipe doesn’t specify… use Custer. |
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Definition
| Soda Spar, with Potassium |
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| Potash. A substitute for Custer. |
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| Soda. The highest fluxing spar. Highest soda spar. |
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Definition
| /a potash spar with high calcium |
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Definition
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Definition
| a lithium source in a potash spar. |
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Term
These are alkaline earth fluxes,
All form crystals and thus different create a variety of matte effects. |
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Definition
| Secondary:sometimes called secondary fluxes. |
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CaO – Calcium Oxide (Whiting)
MgO – Magnesium oxide
BaO – Barium oxide
SrO – Strontium oxide |
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Definition
| secondary fluxes or alkaline earth fluxes |
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Term
Examples of secondary fluxes:
(some of these are not strictly secondary fluxes, but they are worth experimenting with) |
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Definition
Barium carbonate, Bone ash, Strontium carbonate, Whiting, Zinc oxide, Soda ash, Titanium,
Fourspar, Zircopax, Wollastonite, Wood ash. |
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Definition
| we need a stabilizer to keep it from running off the pot. Here we usually add clay which is an excellent source of: Al2O3 - Alumina Oxide “Al is stable…..” |
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Term
| _______ stiffens the melted glaze, and stabilizes and hardens the fired glaze. is a main ingredient in clay, and is often added to a glaze in the form of clay (EPK, Ball Clay, Grolleg). |
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| Copper, Cobalt, Rutile, Manganese, Iron, Chromium– are natural earth oxides, and also have fluxing properties. Mason stains – are another great source of color. Many have a limited ‘cone range’ and some change DRAMATICALLY depending on the other ingredients in the glaze. *note Mason Stain website. |
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Term
| Some opacifiers that may also have fluxing properties: (Opacifiers keep the glaze from being transparent) |
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Definition
| Zircopax, Superpax, Titanium, Tin, Zirconium opacifiers. |
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Definition
| Essentially a frit made of colorant chemicals, compatible fluxes, and possibly glass formers, which has been melted, cooled, and pulverized to a fine powder |
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Term
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Definition
| (Inclusion Pigments)—A new generation of stable stains made by melting metallic colorants with zirconium silicate, cooling the melt, and grinding the result to a fine powder. Because zirconium silicate is refractory, stains containing it can produce brighter colors up to cone 10 using pigments that would otherwise fade at high temperatures. These colors are safe to use in the studio. |
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Term
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Definition
| Unity or Seger Formula—The chemical composition, commonly of a fired glaze, expressed as one mole of total flux to the number of moles of all other ingredients in the glaze. The term ‘unity molecular formula’ does not specify whether the flux, alumina, or glass formers are in unity. Each can be at different times for different purposes, but flux unity is used almost universally by ceramic artists. |
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Term
| cadmium inclusion stains. |
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Definition
| These stains also contain selenium combined with sulfur, and they will produce the full range of colors in the red spectrum from yellow through orange to brilliant red. They work in both translucent and opaque glazes, in oxidation and reduction firings, and at all firing temperatures |
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