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Seattle Pottery Supply/Northwest Ceramic Supply, offers one of the most complete selectiions of chemicals and raw materials for the entire ceramic spectrum, including pottery, ceramics, glass and enameling. Descriptions are provided for some, but certainly not all of the chemicals on our price list. If you need something and can't find it on our lists or on our price lists, call us. Chances are we have the material or can find it for you.

Many ceramic materials are TOXIC. We at SPS feel that the safest course is to consider all materials worked with as toxic. Before you use any raw material, read up on it. Remember that combining two different items that are perfectly safe may result in an extremely toxic product. Use good common sense and be safe. A good industrial grade respirator and rubber gloves MUST be used. Do not eat or smoke with working with chemicals! Good habits of cleanliness, including frequent changes of contaminated clothing, can keep your studio a safer place.

The companies that supply us with our raw materials are the best in their fields. However, many of the materials we supply are natural products and may vary. We urge you to test each material when purchased. We can't make any warranty concerning these materials since the control of them is out of our hands. Again, test each raw material to make sure it will do what you expect before committing to a large batch.SPS is dedicated to ongoing safety research and awareness.

Raw Materials S-Z
Sand SiO2
Used to replace grog in clay bodies.
Seattle Slip
The definitive replacement for True Albany Slip Clay. Melts around 2260º F. Use in bodies and glazes or as a glaze itself.
Setit A
A colloidal glaze suspending agent.
Silica (Flint) SiO2
Increases thermal expansion in clays, reduces thermal expansion in glazes.
Silicon Carbide SiC
Used primaril in glazes a local reduction agent.
Silver Nitrate AgNO3
Used as a coloring agent in stained glass.
Sodium Bicarbonate Na2HCO2
Used in Egyptian Paste and cobalt sulfate stains. Water soluable.
Sodium Nitrate NaNO3
Used as a soda feldspar. Helps to reduce crazing when added to clay bodies.
Sodium Silicate Na2SiO2
The primary deflocculant for casting slips. Diluted for normal use.
Spodumene Li2O:Al2O34SiO2
Reduces thermal expansion in clay bodies and helps to develop copper blue tones.
Superpax ZrSiO2
The most popular zircon opacifier. Helps to reduce crazing.
Stannous Cloride SnCl2
Used in the fuming process in Raku.
Strontium Carbonate SrCO3
A low solubility glaze flux with a long firing range. Reduces crazing.
Colorants for glazes and clays. A separate price sheet follows the Raw Materials section.
Talc 3MgO:4SiO2:H2O
Used as a flux in low temperature clay bodies. Adds opacity to glazes.
Tin Oxide SnO2
A strong and effective glaze pacifier. Stays in suspension in the glazes.
Titanium Dioxide TiO2
An opacifier. Causes a slight matting. May add a cream color to some glazes.
Tricalcium Phosphate Ca3(PO4)2
The primary ingredient in bone china. Used as a flux and opacifier in glazes.
A strong zirconium glaze opacifier. Formulated especially for glazes.
Umber, Burnt
Darkens clay bodies. Also used as a surface decorating agent.
Vanadium Pentoxide V2O5
A glaze colorant producing yellows and other colors used in combination with other materials.
Vee Gum
A suspending agent in glazes. Also used to increase plasticity in clays.
Volcanic Ash (Pumice) SiO2Al2O3
Used in glazes and clays as a flux. Generally similar to feldspar.
Volcanic Ash, Mt. Saint Helens
Volcanic ash from the Mount Saint Helens eruption. Sized and screened.
Wax Resist
Used to keep glaze from areas on bisque. At SPS you get the original MobilCer A wax resist.
(See Calcium Carbonate)
Wollastonite CaSiO2
Reduces shrinkage in clays and glazes. A source of calcium. Can replace silica and whiting.
Zinc Oxide (calcined) ZnO
High temperature glaze flux. Gives some opacity. Extends the maturation point.
Zinc Zirconium Silicate ZnZrSiO3
Used in glazes as an opacifier and as a brightener.
Zircopax SrSiO4
Used in glazes when a semi-opaque nature is desired. Lessens crazing in glazes.
Zirconium Silicate ZrSiO2
Used as a glaze colorant and stabilizing agent.

CAUTION: Many ceramic materials are toxic and should be handled with care. Inhalation and ingestion should be avoided. User should be familiar with proper safety precautions before using. M.S.D.S. are available upon request.

Raw Materials S-Z
Code Name Image Price    

Prices are subject to change, and items may not be in stock.

WARNING: Some of our products can expose you to chemicals including Quartz, which are known to the State of California to cause cancer, and Lithium Carbonate, which is known to the State of California to cause birth defects or other reproductive harm. For more information, go to