Spectrum’s 1050 Underglaze Base is formulated as a base media for preparing your own underglaze colors by mixing with Ceramic Stains like Mason Stains. It contains frit, which acts as a flux to help the stain be a compatible fit with various clay bodies. The underglaze base also contains additives, which keep the frit and stain suspended and allow it to brush on smoothly and easily.
Spectrum recommends that you mix 1 part of dry powder ceramic stain to 2 parts wet underglaze base by weight. Therefore, for example, if you put half a pint (8 oz. or 228 gm.) of 1050 underglaze base in a container you should mix ¼ lb. (114 gm.) of stain in this.
This recommendation is only a general guideline as the strengths of different stains vary, and you should test colors to determine the correct strength for your application.
Lead free, non-toxic and dinnerware safe when covered by a dinnerware safe clear glaze.