Slip Casting
The Plaster mould is made by solidifying the plaster of paris around the original mould and then cut in half to leave a hollow section of the required shape. These two halves are then held together with rubber bands or tensioned string etc. These plaster moulds can last only for fifty casting cycles. Certain industries prefer Clay moulds to plaster moulds as they have a better life time when compared to the plaster moulds.
Slip (mixture of blended clay and water) is poured into the mould from the rim. A percentage of the water is absorbed by the plaster or clay mould itself, thus depositing a layer of clay on the inside. This process length depends on how thick the body of the vessel is required to be. The shorter the time, the thinner and more delicate the body. The thin translucent china vases only need three or four minutes. Heavier bodies may take up to ten minutes or so. It is important to ensure that the mould is kept topped up during this time or there will be uneven thickness from top to bottom.
To be Contd….
