General problems encountered in Casting – Casting Defects:
If the moisture content in the clay is not correct, then the dimensions of the product will vary during drying and hence a correct dimension product will not be available for firing. Hence the clay has to have correct amount of moisture in it for proper forming, and this can be maintained by keeping the clay flocculated. Also Ageing of clay will help maintain better moisture as the moisture content distributes itself during ageing and also elements like sulphates are broken down during ageing and thereby make clay more plastic. De-flocculation of plastic bodies before forming process has to be prevented. Hence if the body has any such element then it is better not to delay the forming process and prevent ageing as the elements tend to de-flocculate during ageing and thereby affect clay plasticity. The Slip casting method requires that the clay slurry be well dispersed and have a uniform size particle distribution. The specific gravity and the slip viscosity are important factors that determine the quality of ceramic ware in the slip casting method.
To be Contd….
