This air drying modelling clay is softer to work with than some of the leading brands it contains a small amount of nylon fibres to give it strength if the clay is to be air dried but it can also withstand kiln firings up to stoneware temperatures of 1200c without any detrimental effectas with all clays to be kiln fired ensure that the clay is wedged well to remove air bubbles and dried slowly and thoroughly before going into a kiln softer clays contain more water which means the shrinkage