I am a Primitive Man
Chapter 132 – Earthen Kiln and Tiles
“Rising from the ground, emitting a bluish smoke, is a round clay pillar, approximately 1.3 meters tall, with an internal diameter of 1.2 meters and an external diameter of 1.6 meters.
This hollow clay pillar is covered on top by two large ceramic plates, each covering half of the pillar. Below the plates are broken pottery pieces, creating a gap of about two centimeters between the plates and the pillar.
The bluish smoke and flames emerge from the edges of these plates and the seams where the two plates connect. This is not a signal beacon used for warnings like a beacon tower; instead, under the guidance of Han Cheng, the master potter of the Green Sparrow Tribe, Hei Wa, after several failed attempts, managed to create this kiln.
Originally, the clay kiln was not built here but about a hundred meters away, closer to the river, for convenient access to water and clay. However, after heavy rain and a rise in river water levels last year, that kiln collapsed and became unusable.
Learning from that experience, Hei Wa spent nearly ten days rebuilding a larger kiln about a hundred meters from the riverbank. This location is farther from the small river and at a higher elevation, so it remains unaffected even during heavy rains, making it a wise choice for the kiln’s construction.
After several experiments and guidance from the shaman, Hei Wa discovered some tricks for building a successful clay kiln. First, he dug a pit about 90 centimeters deep, one meter long, and 90 centimeters wide in the chosen location for the kiln.
He erected a wall about half a meter high in the middle of this pit using previously made clay bricks mixed with well-prepared mud. On top of this wall, he placed three slender and sturdy wooden sticks every ten centimeters. The other ends of these sticks rested on the edges of the pit.
In the past, when the kiln was smaller, there was no need for this wall; the sticks were directly placed on the sides of the pit. Now that the kiln is larger, these sticks would not withstand the weight over time without the middle wall.
There’s no worry about the sticks being burned by the flames because they are covered with a thick layer of clay. Three sticks form a group, and they are coated with mud after bundling them together. The reason for using three sticks is twofold: it increases load-bearing capacity and allows more mud to be applied outside. If there’s only one stick, applying mud on top is challenging.
Once this is done, the construction proceeds to build the walls. Following the same process, when the wall in the pit becomes level with the ground, more sticks coated with thick clay are placed on top. This layer is denser than the one below because it will support the clay embryos to be fired later. The construction of the kiln’s base is complete, and the remaining work involves building the walls with clay.
Similar to building walls within the tribe, the mixture includes crushed straw and some salt. Based on past experiences where kiln walls tended to crack, Hei Wa added some sand collected from downstream using jars.
It’s worth mentioning that adding salt to the wall construction is a deliberate action.”
After some contemplation, Han Cheng found that the previous approach was too salt-consuming. Therefore, he made a change.
Instead of purified salt, he decided to crush the salt from the salt mountain and mix it directly with the clay. This method proved to be more efficient and saved a lot of effort.
Layer by layer, Ha Wa stacked the well-prepared clay. To ensure the kiln’s shape was round, he used two wooden sticks for comparison – one measuring 1.2 meters and the other 1.6 meters.
This technique, taught by Divine Child, was initially applied to resolve the issue of irregularly shaped pottery. It became handy for Hei Wa in building the kiln walls.
As the kiln walls were made purely from soft, well-prepared clay, every thirty centimeters of height required lighting a fire underneath to solidify the walls before continuing to build upwards.
Approaching the clay kiln, which emitted bluish smoke, one could feel a wave of heat even from about ten meters away. With clay-covered hands, Hei Wa busied himself near some large, flat stones.
He pinched some fine dry soil from a pottery jar nearby and evenly sprinkled it on the stones. Then, he placed a wooden frame with a thickness of about half a centimeter on top.
The frame was made by breaking a tree stick in the middle, creating a somewhat flexible structure, and binding it at the joints with twine. The broken side faced inward, while the arched side faced outward to ensure a smooth edge for the pottery.
The frame was not a standard rectangle but a trapezoid with one end larger than the other, creating a 1.5-centimeter difference between the top and bottom. This design allowed for seamless connections when the tiles were laid.
Initially, the frame was a standard rectangle, but Hei Wa successfully fired the first batch of tiles with Divine Child’s help, overcoming the curvature issue.
Seeing the tiles, which Divine Child referred to as “wa,” Hei Wa was pleased. Divine Child said that these tiles could be used to build better houses than the deer enclosures, and everyone in the tribe could eventually move out of their caves and into these houses.
Though Hei Wa didn’t understand why Divine Child wanted to move out of the caves, his hopeful expression made him realize that these houses must be more comfortable than the cave they lived in for generations.
Besides the housing reason, another source of Hei Wa’s joy was that he had completed the task assigned by Divine Child, and Divine Child, looking at the tiles he had fired, showed a delighted expression.
This was undoubtedly the best approval for his craftsmanship, and Hei Wa was naturally delighted.
However, his joy did not last long because Divine Child suddenly put them down, sighed, and slapped his forehead after playing with two pieces of tile for a while.
This made Hei Wa worry whether Divine Child was displeased due to the quality of the tiles he had fired.
Hei Wa’s craftsmanship was indeed outstanding. Although it was his first time firing tiles, with his prior experience in many pottery, the tiles turned out very successful, comparable to the small tiles he had seen in Han Cheng’s later years.
Of course, this overlooked the flaw that the tiles had the same size at both ends. Having tiles of the same size at both ends meant gaps would appear when two tiles were stacked together. Using such tiles for roofing could easily lead to leakage.
After some adjustments, the mold used for making tiles evolved into its current form.