How To Deflocculate Clay Slip?
Clay is commonly used to make casts of various shapes and forms. Liquid clay is poured into the mold and this will set to form the figure, statue or what you will.
But this clay slip that is made by mixing water in dry clay tends to shrink and crack as it dries. The clay may even turn lumpy and fail to flow properly.
This is why a deflocculant is added to keep the clay from coalescing together. In fact, mixing the appropriate deflocculant will make the clay slip smoother and easier to apply as the particles are now suspended properly.
Now, while various deflocculants are available in the market (soda ash, darvan, etc), sodium silicate emerges as the most effective and economical deflocculant for clay slips. Dry sodium silicate (also known as liquid glass or water glass) is mixed with an equal amount of water before adding it to the clay mixture. Liquid water glass is also available.
This deflocculant will work to thin the clay slip and make it flow better. However, you have to be very careful about the amount of water glass that is added to the mixture because after a point, the same water glass starts flocculating the clay slip. This will make the clay thick and mostly unusable.
The same sodium silicate can also render a cracked texture on ceramics. This treatment is generally used to create a lovely antique finish on pots.
Water glass can be easily sourced online through EnvironMolds at www.artmolds.com.