Glaze Notes Master sheet

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12 Elements related to Glaze Materials:

1. Al -- Aluminum

2. B -- Boron

3. C -- Carbon

4. Ca -- Calcium

5. Co -- Cobalt

6. Cu -- Copper

7. Fe -- Iron

8. H -- Hydrogen

9. K -- Potassium

10. O -- Oxygen

11. Si -- Silicon

12. Ti -- Titanium


Ceramic Glaze Compounds and Properties:


Flux -- Causes other materials to melt at a lower temperature. Sometimes considered a "Glass Maker"

Lead -- (Pb on periodic table of elements) In the old days was used as a flux in glazes, facilitating the melting of ceramic elements in a glaze. When the pottery is fired at the proper temperature for the proper amount of time, essentially all the lead is bound into the glaze. If any migrates to food, it will be an insignificant amount. However, if not properly fired, the lead may not fuse to the clay and may contaminate food when the pottery is used with food. We NEVER use Lead in Glaze anymore!

Gerstley Borate -- (2CaO·3B2O3·5H2O) -- Clear Flux (thin) Milky Flux (thick)

Frit 3124 -- (no Formula) Soda Ash (Na2CO3) and Silica (SiO2) Melted, crystalized and pulverized. Frit is a ceramic composition formed by fusing inorganic materials into a glass by heating them in smelters and quenching them in water. This process, known as "fritting" was developed to render any soluble and/or toxic components insoluble and/or nontoxic. Clear Flux Many Varieties denoted by number (i.e. 3195, 3234, etc.)

Colorant -- Produces color in a glaze.

Copper Carbonate -- (CuCO3) Green Colorant (Red in reduction).

Cobalt Carbonate -- (CoCO3) Blue Colorant.

Rutile -- (TiO2) Honey Yellow Colorant.

Red Iron Oxide -- (Fe2O3) Rust Brown Colorant. High Temp Flux.

Clay -- Used as an Opacifier in glaze and binder.

Opacifier -- Reduces transparency of a glaze.

Kaolin -- (Al2O3·2SiO2·2H2O) Also known as Edgar Plastic Kaolin (EPK) Clay, Binder, Opacifier

Red Art -- (no formula) Clay and colorant. Rust brown/redbrown

Grog -- The "Sand" in clay. Made by firing selected fire clays to high temperature before grinding and screening to specific particle sizes. Strengthens clay, reduces shrinkage.

Oxidation Fire -- Firing with sufficient oxygen.

Reduction fire -- Firing without enough oxygen. Produces color changes in glaze. In smoke fired pottery causes black pots.