Bisque Firing:       All painted pieces are subjected to a meticulous quality control inspection. Acceptable ware is carefully loaded into one of our kilns - a large oven designed to cook pottery to very high temperatures. Using a combination of shelving and support posts, the pottery is loaded in a series of layers. Once filled, the kiln is sealed and fired, over a 4-6 hour period, to a temperature of 1950 degrees Fahrenheit. This first firing of our two-firing process is referred to as a "bisque" firing. It serves to burn off all organic materials from the clay body, harden the body, cure the cobalt blue decorations and remove all but a minute percentage of any remaining moisture content in the greenware. Loaded as buff colored greenware, the clay body emerges from the bisque firing bright white. The very porous, unglazed, fired clay body is referred to as "bisqueware".   
     Glazing:      Each of our paints and glazes is carefully formulated in-house to insure maximum control of paint and glaze quality. Our glazes are lead-free to guarantee the safety of our products for use as food-bearing surfaces. Our glazes are primarily comprised of frits (finely ground glass "powder"). We combine the frits with several trace elements and water to produce a liquid having the consistency of heavy cream. Each piece of bisqueware is hand dipped in a tank filled with the glaze. The porous surface of the bisque readily absorbs a thin coating of the glaze.
     Glazing is the most critical step of our production process. The glaze, itself, has to be carefully monitored for various factors that determine its coating quality. Our glazers need to be familiar with the firing history of the bisqueware, the qualities of the particular glaze with which they are working and they constantly need to adjust their dipping rhythm to maximize the surface quality of the finished products.
     The dried, unfired glaze coating is an opaque white color obscuring the cobalt blue detailing. Glazed product is carefully checked to ensure acceptable quality and then loaded back into the kilns for the second firing of our production process.
    Glaze Firing:       The glazed products are carefully checked to insure acceptable quality and then very carefully loaded back into the kilns for the second firing of our production process. Each piece is set on top of a small three pronged "stilt" which eliminates any contact between the pottery and the kiln shelf. The glaze firing heats the glaze coated ware to 1750 degrees Fahrenheit, turning the glaze into a molten coating on each piece. Without stilts, the pieces would fuse to the kiln shelves during firing. Small telltale marks (usually three) on the bottom of the ware are evidence of the stilting process also utilized by many other potteries.
     As the glaze firing nears completion, the opaque glaze coating starts to cure - transforming into a translucent gloss coating of glass over the surface of each piece.  
The Potting Shed's Production Process