There are three main reasons for the drying of ceramic body before firing
1、 Drying in advance can reduce the damage rate during firing
Ceramic firing is a professional and scientific process, in which the key link is to gradually increase the temperature to remove the moisture in the ceramic body. In addition to moisture, the internal structure of ceramic body will be changed, so the bearing capacity of ceramic body should be considered.
The moisture content of the green body is large. If it is not dried and directly fired into the kiln, a large amount of moisture will be quickly eliminated in a short time, the ceramic body will shrink rapidly, and the internal structure will change rapidly, which will easily damage the ceramic body itself and cause the work to burn out.
Volume comparison after firing and before firing
Even if it is a dry ceramic body, it still needs a long baking stage when it is fired in the kiln. In the three stages of baking, heating and burning, the baking time is the longest, which is more than 60% of the whole process.
For traditional Longyao, it takes 15-20 hours to bake and 5-8 hours to heat up. The time of electric kiln and gas kiln is relatively short, but the baking stage is also the longest. It can be seen that drying before firing is very important for the success of firing.
2、 Remove some unqualified ceramic body
If a piece of pottery is not qualified in the production process before firing, clues will be found in the drying process, the most common is cracking.
If these unqualified ceramic blocks are removed in advance, it can not only waste fuel, but also make room for other good ceramic blocks. The space of modern electric kiln and gas kiln is very limited, so each location is very precious.
3、 Make full use of the limited space in the kiln
In the wet state with more moisture, the ceramic blocks can not be overlapped with each other, but after drying, some low-cost ceramic slabs can be overlapped together and fired in the kiln, so that the limited space in the kiln can be utilized to the maximum extent.
Generally, some low-cost tea cups or steam pots will overlap with each other. Even if they will be burnt out, the cost can be balanced by the quantity of tea cups or steam pots. In fact, after a kiln mouth is mature and stable, combined with experienced kiln master, there will be little damage due to overlapping.
However, the author will not risk overlapping them, but sacrifice some firing quantity in exchange for a better firing success rate.