alternative for Kona F-4 (no longer available) and NC-4 Feldspar
Soda Feldspar is generally a clean white mineral which sources sodium, alumina and silica along with some potassium and calcium. Albite mineral from which soda feldspar is derived is often tends to be white in appearance compared with the pinkish hue of orthoclase mineral from which potash feldspar is ground. It begins melting around 800C. In many cases soda and potash feldspar are interchangeable in glaze recipes. However, some differences will be apparent. For example, slightly different color responses will be encountered (i.e. cobalt tends toward purple and copper toward blue with soda spar). Sometimes colors will be brighter with soda feldspar. Because soda feldspar is high in sodium, glazes with a lot of soda spar tend to craze. Thus, if any glaze recipe has more than 30% soda feldspar, it is wise to test carefully to assure the glaze is not in tension. - Digital Fire ceramic materials database
Soda Feldspar is generally a clean white mineral which sources sodium, alumina and silica along with some potassium and calcium. Albite mineral from which soda feldspar is derived is often tends to be white in appearance compared with the pinkish hue of orthoclase mineral from which potash feldspar is ground. It begins melting around 800C. In many cases soda and potash feldspar are interchangeable in glaze recipes. However, some differences will be apparent. For example, slightly different color responses will be encountered (i.e. cobalt tends toward purple and copper toward blue with soda spar). Sometimes colors will be brighter with soda feldspar. Because soda feldspar is high in sodium, glazes with a lot of soda spar tend to craze. Thus, if any glaze recipe has more than 30% soda feldspar, it is wise to test carefully to assure the glaze is not in tension. - Digital Fire ceramic materials database
50# bag, white bag, red text "Minspar 200" and "K-T Feldspar Corp"
