Sodium Silicate is commonly referred to as Waterglass, and can be described as a clear, colourless to light brown solution.

Sodium Silicate is used as a deflocculant for mixing powdered clay into casting slip. A deflocculate acts to reduce the amount of water required to maintain the liquid, pourable state of clay slip and to keep the clay particles suspended in the water.

This means less water is required in your slip which results in far less shrinkage, greater strength and less wetting of the plaster molds.