In the previous article we saw how Clay can be shaped into a ceramic article of desired shape from liquid slip or plastic slip. Now we will study the drying behaviour of clay to fully understand the process.
When the ceramic article (made from clay) is dried, it retains the shape, gains mechanical strength and increased rigidity BUT in the process it shrinks and decreases in volume. In the first stage of drying, this decrease in volume is equal to the volume of water lost in drying. However in the later stages of drying, the ceramic clay article becomes porous.
Differential Shrinkage And Cracks:
If the rate of evaporation is not uniform, it will lead to differential shrinkage of the ceramic article resulting in warping or CRACKS. This is common in Clay with high drying shrinkage. However thankfully there are so many technical methods to control these problems. You can modify the drying behaviour of clay by adding suitable additives or by changing the manufacturing shop environment by adjusting the humidity levels.
For the common man, this entire phenomenon may appear to be a very simple operation. However ceramists know how complicated the process is and how important it is deeply understand the CLAY-WATER relationship to become an expert in the ceramic manufacturing process.
The drying process is so complicated and unless we have enough understanding to take suitable corrective action, we have to suffer huge loss in the making of Ceramic articles out of clay.
