Thixotrophy can be measured by measuring the viscosity before and after standing. Thixotrophy for most of the clays and bodies normally will be very high when we use Na2CO3 and with Sodium Silicate it will be very less. To obtain better casts of the desired thickness and density, the casting process needs very steady conditions like
- Uniform wall thickness
- Uniform porosity in the moulds
- Uniform casting time
- Uniform litre weight
- Uniform viscosity in the slip (It depends upon the temperature of the slip)
Since viscosity changes rapidly with temperature, maintaining uniform temperature is more important. It is also important to use clays which have wide fluidity range and also water low in calcium and magnesium.
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