Glazes of P – series are transparent leadless colourless glossy glazes, based on frits, free of lead oxide (except P 011 91 – 1% PbO). They are fired in temperature range of 980 – 1150 °C; on the stoneware body some of them can be fired up to 1200 °C. They show a high chemical resistance and therefore they are food safe and suitable for the dinnerware, tiles and as an additional flux in raw feldspar transparent glazes for the temperatures of 1180 – 1250 °C. Some of them may be used for regulation of CTE, for example P001 91 or P 016 91. They are suitable for white as well as coloured bodies with CTE alfa (20-500 °C) = 52 – 70 x 10-7 (K-1).
In case of lower firing temperatures or for heavy coat of the glaze or during very slow cooling during firing, the fired glaze may lose its transparency and cloud, more or less.
The glazes can be coloured with ceramic stains by addition of 5 – 10% of stain. They can be used for the covering of underglaze designs under condition of min. firing temperature 1060 °C. Recommended glazing techniques: dipping, spraying.
