The Most Noble Pottery That Needs Commitment
Porcelain is the most noble ceramic material.
It is originated from China, and its invention dates back to the Tang Dynasty (618-907). It first reached Europe through traders, where all kinds of myths spread about the origin of its material: animal bones, shells, fish scales... In fact, its main raw material is kaolin, which is mixed with feldspar, quartz and other materials to achieve the desired properties. In Europe, production only started in the late Middle Ages, but in larger quantities even later, in the 18th century.
I wouldn't go deeper into history. It is more important what qualities it has.
Porcelain is the strongest ceramic material. It is no coincidence that we find its industrial products everywhere: tableware, faucets, toilets, even dental crowns are made from it, but they can also be found in industrial turbines or laboratories due to their heat tolerance and strong chemical resistance. However, all the outstanding features are only true for the final product.
Porcelain is the most difficult of all ceramic materials to process.
Raw porcelain must be handled delicately. It has very low plasticity, hence cannot be shaped as easily as clay or stoneware. With a tiny little more water it becomes too soft and even “muddy”, the formed piece does not keep its shape, collapses, distorts, does not separate from the hand, sticks. Yet, a few minutes of drying more than necessary, and it cracks and breaks with every little bend, its surfaces have to be constantly reworked, which leaves marks and pressures on it, and air pockets can form inside.
The dried piece is as fragile as compacted powdered sugar or a piece of dried mud. It breaks at the slightest pressure, and it can hardly – or not at all – be repaired.
Then it goes into the kiln for the first firing and finally becomes a ceramic material, but it is still extremely fragile. Did the first firing happen at the right temperature? It only turns out during the glazing. If the glaze is too thick, the temperature was too low, if it is too thin, the temperature was too high, the material has already compacted.
And finally comes the second firing when I must really cross my fingers. I've never had a glaze firing during which I was completely calm. I always think about what I might have messed up before I started the kiln. Is the thickness of the glaze good? What kind of dirt could have gotten on the pieces? But most importantly: which piece did I distort when I processed the raw porcelain?
Porcelain loses a lot of its volume during the glazed firing, about 15%. As the material melts towards the end of the second firing, it starts to compact, and if the raw porcelain was distorted when being shaped – at the very beginning of the process – then I repaired it in vain. The distortion returns at the end of the second firing. Porcelain has a "memory".
However, final distortion not only can be caused by mistakes made during processing, but by almost anything. A drafty kiln, uneven heat distribution during firing, an uneven bottom of the pottery that does not sit stably on the oven shelf, or if the ceramic wall is somewhere too thick or just too thin, or an added part (handle, animal figure) is too heavy compared to the wall it is attached to. These all distort the pot during the final firing.
The work starts when I haven't even touched the porcelain.
When I design the pieces so that their shapes can withstand the difficulties of the second firing. There is awareness in this, but even more experimentation. Handmade porcelain is a challenge. Despite the many annoyances, one should not give up. You have to draw conclusions, do it again, from the very beginning, until finally beautiful pieces are born. The greater the joy and satisfaction.