Making Glazes

Glazes don't just happen. They have been developed over the years. They need a critical, sensitive balance of ingredients to create a certain color, a durable smooth surface, a matte or gloss finish, good adhesion to the clay body and maturation at a specific temperature.
Most of my glazes were acquired in the years that I lived in Boulder, Colorado, worked for Betty Woodman and took classes through Boulder's City Park and Recreation Department in the old fire house. I've modified and changed several of the glazes to create some "new" colors over the years. I've also tried many other glaze recipes but settled on a few that are dependable.

Most of my glazes are made from various ratios of five basic ingredients. They come in 50 pound bags. You will recognize most of them. The first is kaolin, a white clay from Florida or Georgia. It is commonly used to make porcelain or face powder! The next is silica, a finely ground sand. Then talc, just like what

used to be used for babies. Calcium carbonate or whiting is another ingredient and is still

Bags of silica, custer feldspar, redart clay
and calcium carbonate.

used occasionally to mark the lines on football fields. The last of the five ingredients is feldspar, a mineral from North Dakota.
In some combinations the ingredients make the glazes glossy and in others, the same ingredients form a matte finish. Each ingredient adds an important quality to the glaze.

Each glaze has a recipe, just like cookies. A triple-beam balance scale is used to measure out the exact weight needed for each ingredient. The powder is then added to water to make a heavy cream-like consistency. The pots are dipped into the glaze to provide an even coating on the surface of the pots.

After the pots are dipped and the glaze dries, the designs are drawn on the surface of each piece using a Japanese paint brush dipped in the various oxides. The pots are now ready for the kiln. The temperature of the kiln is critical. The materials are fused together and mature at about 2300 degrees Fahrenheit. Even at this high temperature a difference of 20 to 40 degrees can completely change the color of the glaze. It can make a color shiny rather than matte, or the glaze may run off the pot and "glue" it to the shelf. Because of the sensitivity of the glazes, there is often a little variation in color from pot to pot. The glaze color is also affected by the thickness of the glaze application. It is really important to be as consistent as possible in working with the glazes. One needs to make every glaze a friend.