The texture of the "rib" can be clearly seen on the surface of this crack, which means that the crack stretches slowly from left to right. It emerges during the drying process and is further expanded during the biscuit firing process.
For cracking, one of the most basic understandings should be: its appearance is by no means accidental, and there must be reasons for it. It is usually caused by some defects or local excessive force.
The edges and appearance of a crack will give us clues as to why it is cracking. The edges and overall appearance of the crack are rough (indicating that the ceramic body has been dragged). This crack may have been caused by dragging while the body was drying, but it may also have Then comes the forming phase.
In addition, it is also possible to understand the cause of the crack by examining the shape and line shape of the crack. The widest part of the end of the crack may be the starting point of its cracking. When a crack continues to extend along the outer surface of the ceramic body, the widest part at the end of the crack is the starting point of the crack.
Uneven drying is also one of the most common causes of cracking in ceramic bodies. In any case, the green body cannot be allowed to blow. The body with thinner walls and the thinner parts on the body have the fastest drying speed. The parts of the green body that dry first are also the first to shrink, which creates tension on the undried areas adjacent to it. If the undried area is soft enough, this tension will be temporarily counteracted. But when it dries and begins to shrink, the tension it experienced earlier returns. This is why drying must be done slowly and with caution.
The uneven thickness of the ceramic body and the unreasonable needle setting are another important reason for the pressure. Thick base, thin wall, too thin wall, not enough muddy net, and too fine mud used will cause the body to crack; on the contrary, coarser mud with reasonable, uniform thickness The design is less prone to problems.
When cracks appear repeatedly somewhere in the body of the ceramic water cup, they can be deeply detected with the help of paraffin. Some cracks are difficult to see with the naked eye, in which case a brush can be dipped in paraffin and applied to the cracked area. It only takes a few seconds for the cracks to appear clearly on the surface of the green body, and then the gaps can be filled by tapping. The paraffin will burn off later in the firing process.
After cutting or trimming the body of the ceramic water cup, be sure to wipe the outer surface of the body with a wet sponge (similar tools are also acceptable). While trimming the green body with tools, it is inevitable that force will be formed on the green body, which will easily cause tiny cracks invisible to the naked eye, and these small cracks will further deepen and become longer during the later firing process.