Fifty years ago almost every porcelain factory had its own department for the preparation of the clay. This process is quite complex, yet important for the quality. Quartz and feldspar are broken into small pieces and crushed in pug mills. Then the material is grinded to dust in rotary mills running 25 to 30 hours. Kaolin, quartz and feldspar are put together and mixed in a big water tub, resulting in liquid-smooth clay. The clay is then pumped onto a filter press which is made of fabric stretched around frames. The water can drip off through the fabric, the cells itself keep the humid clay, the filter cake.

In a next step the clay has to be remixed and the little air bubbles have to be removed. A vacuum extrusion press is used for this process. After this the clay is homogenous and can be kneaded.

For further processing the clay is passed on to the throwing and turning shop (4a). As for casting (4b), liquid clay called slip is required.

Working conditions are hard. There is a lot of quartz powder in the air, causing the dangerous silicosis. It is also hard to bear up the noise from the rotary mills.

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3. Modelling and mould making