As the largest producer of clay in the Pacific Northwest, Seattle Pottery Supply/Northwest is able to fit your every clay need, whether through our list of stock clays or custom bodies made to your specifications. All of our clays are available de-aired moist and most are also available dry. SPS is dedicated to ongoing safety research and awareness. Our moist clays have been evaluated by a toxicologist and are properly labeled for safe use according to the guidelines established by the The Art and Craft Materials Institute, Inc. In addition, SPS moist clays have been certified Non-toxic and authorized to bear the AP Seal (see description below). Finish-color and precise shrinkage and absortion ratings in clays are best determined by viewing the results of your unique firing methods. As the clay is fired closer to its indicated firing limit*, it becomes richer in color and less porous. An approximate shrinkage chart follows the clay descriptions. * Firing cone temperature (in the titles) indicate recommended firing ranges. Generally, bisque temperature are around cone 04 and final firings are near the upper end of the firing range for best color and durability. Raku firing temperatures, however, using many of our SPS Clays, require lower temperature ranges - - from cone 018-04