Alberta Slip - A potential substitute for the discontinued Albany Slip. Works as a direct substitute sometimes, but testing is highly recommended

Alumina - Calcined - Al₂O₃ - Aluminum Oxide. Used as a high temperature kiln wash. Also used in small quantities to harden a glaze. Very refractory. In larger quantities, will make a glaze stiff and matte.

Alumina Hydrate - Al₂O₃-5H₂O - Aluminum Oxide with water attached. Same usage as above.

Barium Carbonate - BaCO₃ - Powder is TOXIC. Low solubility in water. Used as a nominal flux to create a matte glaze. Also added to red clay bodies to help prevent soluble salt scum on the surface after firing.

Bentonite B (Milwhite) - A very fine clay, used in small quantities (0.5% to 2%) in a glaze to keep it in suspension. Also a candidate in a porcelain body to improve plasticity. A small amount goes a long way.

Bone Ash - Ca(PO₄)₂ Calcium Phosphate. Made of ground calcined animal bones. A flux and opacifier in glazes. Imparts translucency to a bone china clay body.

Borax Anhydrous - Na₂B₄O₇ - A water soluble low temperature flux. A source of boron and sodium in glazes, improving glaze flow and fit, and aids in the development of bright colors.

Boric Acid - B(OH)₃ - A water soluble flux used to improve glaze fit. Use sparingly.
not stocking

Calcium Zirconium Silicate - A unique opacifier providing a brighter, closer grained texture with high opacity at high temperatures.

Chromium Oxide (Green) - Cr₂O₃ - A potent colorant. Small amounts will produce strong greens in glazes and clay bodies. Used with tin oxide to produce pinks or with zinc to produce browns. Will volatilize in the kiln and potentially affect adjacent ware.

Cobalt Carbonate - CoCO₃ - A fine lavender powder used to achieve various shades of blue glaze, depending on concentration. A less potent colorant, easier to use than cobalt oxide. Approximate substitute ratio is two parts cobalt oxide to three parts cobalt carbonate. Can produce purples when blended with manganese.

Cobalt Oxide - Co₃O₄ - A black powdered oxide. An extremely strong, stable blue colorant in small quantities. See cobalt carbonate substitution ration above.

Copper Carbonate - CuCO₃ - A fine, fluffy light green powder, used as a light green glaze colorant. Capable of producing greens, blue-greens and reds, depending on glaze constituents and firing conditions.

Copper Oxide (Black) - CuO - A black powder, producing greens at low concentrations, up to dark metallic colors at higher concentrations. Under reduction firing, will produce copper red. Use this copper oxide if the recipe does not specify red or black.

Copper Oxide (Red) - Cu₃O - The concentrated form of copper oxide. More difficult to use. Changes to CuO in oxidation.

Copper Sulfate - CuSO₄ - A water soluble blue crystal which gives greens and reds in a glaze depending on atmosphere and other glaze constituents.

Cornwall Stone - An imported mineral similar to a feldspar, primarily used as a flux in glazes. It introduces several alkalis: potash, soda, calcia and magnesia. Very low iron content.

Cryolite - Na₃AlF₆ - A source of sodium and alumina, this strong fluxing agent has a very low melting point.

Dolomite - CaMg(CO₃) - An inexpensive source of calcium and magnesium in a glaze. A high temperature flux which produces a matte to buttery finish to a glaze.

Feldspar - Custer - A potash feldspar used in clay bodies and glazes as a flux. Used in porcelain and white clay bodies due to its white firing characteristics. Generally the flux to use if the recipe just calls for a "feldspar". Mined in Custer, SD.

Feldspar - Kona F4 - A soda feldspar; lower melting than a potash spar. Used in a glaze recipe for intensifying colors. Mined in NC.

Feldspar - G-200 - A potash feldspar, very similar to Custer feldspar. Is interchangeable in most formulations. Mined in NC.

Flint #250 - SiO₂ - Ottawa Silica Sil-co-Sil # 250 is a source of a coarser silica for use in a clay body to minimize expansion/contraction during the silica inversion phase. This improves thermal shock resistance and glaze fit.

Flint #295 - SiO₂ - Ottawa Silica Sil-Co-Sil #90. Used as a source of silica in a clay body recipe. Slightly coarser than Flint #395, discussed below. Used in a high fire glaze to control running during its fluid state, due to its slightly larger particle size.

Flint #395 - SiO₂ - Ottawa Silica Sil-Co-Sil #53. Primarily used in glazes as a source of silica to harden a glaze surface and reduce crazing.

Flourspar - CaF₂ - Primarily used as an opacifier in frit formulations. Not recommended for direct use in a glaze. Will outgas fluorine gas, which is toxic. The outgassing in a glaze is gradual, leaving severe pinholing and cratering, which may or may not be desirable.

Gillespie Borate - A fairly successful substitute for the discontinued Gerstley Borate, which was a powerful flux, increasing glaze color and gloss. As with all Gerstley Borate substitutes, testing, testing, testing is the order of the day.

Grogs: See separate section

Gum - CMC - Carboxylmetholcellulose - One hundred percent organic and 100% water soluble. Used as suspending agent in glazes, and to improve brushability. Slows the absorption of the water in a glaze on to the bisque piece. Will reduce its effectiveness with time and temperature as the naturally occurring microorganisms in the glaze degrade the CMC. Adding a couple drops of household bleach will help. Same concept as chlorine in a swimming pool.

Ilmenite Granular - FeTiO₃ - An ore of iron and titanium, primarily used to impart brown specks to a glaze. Start at 2% by dry weight.

Iron Chromate - FeCr0₃ - A complex glaze colorant, giving grayish tones when added up to 6%. Combine with manganese and cobalt to attain blacks. The edges of brushed underglaze will bleed with other colors.

Iron Oxide - A common, versatile, and economical glaze colorant, imparting browns, yellows, blacks, grays and greens depending on recipe and firing conditions. In oxidation firing, all iron oxide forms revert to red iron oxide; while in reduction, black iron oxide is formed. In a clay body, iron oxide, depending on concentration, is an active flux, darkening the clay body from pink to red to brown to almost black near its fusion point.

Iron Oxide - Black - FeO - A flux in glazes, giving a pale green at 1%, green-grey at 3%, and black at 8%.

Iron Oxide - Red Spanish - Fe₂O₃ - This bright red iron oxide is the most common and economical form. If a recipe calls for iron oxide, use this product. It gives yellows at 2% and browns at 8%.

Iron Oxide - Red/Precipitate - Fe₂O₃ - A highly concentrated, pigment grade of iron oxide. More expensive than Red Spanish, but due to its higher concentration, will impart more intense colors, especially catsup reds.

Kiln Wash - Brush a slurry on kiln shelves to protect from glaze drippings.

Kiln Cement - Mortar - A refractory mortar with a sodium silicate binder for repairing kiln brick or building a new kiln. Sold as a dry powder. Add water to achieve the desired consistency, allow to rest -covered-over night to dissolve the binder, then apply.

Kyanite - See Grog Section

Lithium Carbonate - LiO₂ - A strong alkaline flux resembling soda. Although more expensive than other fluxes, less is required because there are more active molecules per given weight. Has excellent glaze response, and is known as a blue enhancer. Is often substituted for soda to reduce crazing.

Macaloid - A clay-like suspension agent for glazes. Use in very small amounts, about one-half percent to 2% by dry weight. May effect the glaze chemistry if the glaze is on the edge. Also used in porcelain bodies to improve plasticity.

Magnesium Carbonate -MgCO₃ - A very light, fluffy white powder, mixing well in a glaze. Acts as an opacifier to glazes, giving a range of satin matt surfaces depending on percentages used.

Magnesium Zirconium Silicate - Another opacifier used to control texture in low temperature matte glazes.

Manganese Carbonate - MnCO₃ - A weak colorant, attaining purples with certain base glazes. Gives a more uniform coloring action than the oxide form.

Manganese Dioxide 325M - MnO₂ - The common form of manganese dioxide, used as a glaze colorant, giving blacks, browns and purples, depending on the other constituents. Will give a glaze a metallic finish in large percentages.

Manganese Dioxide 60M - MnO₂ - Primarily used to impart a speckle to a glaze, engobe or clay body. This product contains all particles through a 60M sieve, including very fine particles.

Molochite 30M, 50x80M, 120M - See Grog Section

Mullite - 35M, 48M, 200M - See Grog Section

Nepheline Syenite - K₂O.3Na₂O.4Al₂O₃.9SiO₂ A consistent feldspar, used to reduce the melting point in a clay, and to introduce soda in a glaze.

Nickel Carbonate - NiCO₃ - Green in color, this glaze colorant is less concentrated than nickel oxide, giving a variety of grays, greens, and browns.

Nickel Oxide - Black - NiO - A strong colorant, capable of producing a range of greens and browns. The limit is about 3%. Great for obtaining black glazes combined with other oxides.

Ochre - Yellow - 2Fe₂O₃.3H2O - A weak form of iron oxide, which eventually stabilizes as red iron oxide in the melt.

Petalite - Li₂O.Al₂O₃.8SiO₂ - A feldspar used to introduce lithia to a glaze. Can help reduce thermal expansion in a glaze or clay body. Not as economical as spodumene.

Poly Fiber - A fiber added to a clay body to enhance green strength for large sculptural pieces. Will burn out during firing. Have good ventilation.

Pyrophyllite (Pyrotrol) - Al₂O₃.4SiO₂.H₂O - A fairly refractory non-plastic clay added to clay bodies to reduce thermal expansion. Acts similar to calcined kaolin, but not as white burning.

Rutile 200M - TiO₂ - A stable, natural titanium oxide and iron oxide stain for glazes, imparting a weak tan to brown color. Mostly used to produce a range of mottled textures to a glaze.

Rutile Granular -not stocking - A granular form of rutile; 60M and fines. Will produce a brown speckle in a glaze.

Silicon Carbide 1000M - SiC - Used as a local reducing agent during an oxidation firing. Temperature in the kiln must be reduced below the melt point quickly, or oxidation will take place and reverse the process. Also used to create cratering of the glaze.

Silica - Amorphous - SiO₂ - A microcrystalline silica. Used in glaze to reduce crazing, because the finer particles enter into the melt faster.

Silica Sand - 50M - Used as an inexpensive grog in some clay bodies. The very uniform grain size is about the size of table salt.

Silver Nitrate Crystals - AgNO₃ - A water soluble crystal, used as a wash to impart an opalescence on a glaze. Poisonous, do not allow contact with skin.

Soda Ash, Light - Na₂CO₃ - Sodium Carbonate. Water soluble Used as a deflocculant in clay slips. An active flux producing a variety of effects when applied on a clay surface, then fired.

Sodium Bicarbonate - NaHCO₃ - Baking soda. A ingredient in Egyptian paste.

Sodium Silicate - Dry - Na₂SiO₃ - A dry, water soluble form, used as a deflocculant in clay slips.

Spodumene - Li₂O.Al₂O₃.4SiO₂ - A lithium feldspar which has a lower expansion rate than other feldspars. Introduces thermal shock resistance to a clay body. In glazes, is a blue enhancer.

Strontium Carbonate - SrCO₃ - A insoluble source of stronia (SrO). A mid range flux when introduced into a glaze, working similar to calcia and zinc oxide.

Talc #1 - 3MgO.4SiO₂.H₂O - An economical source of magnesia in clay bodies and glazes. A major constituent in low fire bodies. Added to lower melt temperature and increase thermal shock resistance. In glazes, it is used to produce opaque and matt glazes. Mined in New York State.

Tin Oxide - Ceramic Grade - SnO₂ - Used in a glaze at 5% to 10% to give a wonderful creamy white. Due to its refractoriness, will increase the viscosity of the glaze, which can lead to pinholing.

Titanium Dioxide - TiO₂ - A highly refractory white powder, used as an opacifier at 5% to 10% in glazes, resulting in a soft matt finish.

Umber - Burnt - A hydrated iron oxide used as a reddish brown to brown colorant . Used for brush decorating and to darken clay bodies.

Vanadium Pentoxide - V₂O₅ - A weak yellow colorant in a glaze.

Veeum T - A colloidal magnesium alumina silicate compound used in glazes at about 1% (3% maximum) as a suspender. Will not deteriorate over time as will organic gums. Used in a clay body to increase handling strength.

Volcanic Ash A.F. - Pumice - Can be used as a feldspar in a glaze.

Whiting - CaCO₃ - Calcium carbonate. An economical source of calcia for clay bodies and glazes. An active flux at high temperatures.

Wollastonite - CaSiO₃ - A natural compound combining calcia and silica. Replaces whiting in a glazes when decomposition of the carbonate causes glaze disturbance.

Zinc Oxide - Ceramic Grade - ZnO - A common high temperature flux, used in small amounts to increase the maturing temperature of glazes and produce bright, glossy colors.

Zircopax Plus - ZrSiO₄ - A highly refractory opacifier, more economical that tin oxide, but the "white" is not as white. Use twice as much zircopax plus as tin oxide. Replaces Superpax, which has been discontinued.