The capillary suctional forces are directly proportional to the surface tension of the liquid. A clay slip exhibits the effect of surface tension the more manifestly the more time it is given to develop them. The surface tension of water and its boundary surface tension against clay and plaster are the primary causes of cohesion in the body or the slip and of the formation of the cast in a mould.
Yield point and workability increase nearly with surface tension which provides a measure of workability and its diminution on addition of wetting agents.
Drying contraction also falls with increasing surface tension.
To be contd……………
