My system is not decent

If you want to make porcelain, you can't avoid the five famous kilns, and if you want to imitate the five famous kilns of the Song Dynasty, you can't avoid nail firing.

Ru Kiln, Guan Kiln, Ge Kiln, etc. are often fired with nails, which are shaped like a mountain with a pointed top and a round bottom. There are different numbers of nails on the round cake, and there is only one nail.

Porcelain fired with nails has small nail burn marks on the bottom.

Ru kiln has the smallest nail marks and is fragrant gray in color;

The official kiln and Ge kiln have slightly larger nail marks, which are iron black.

Therefore, the use of nail firing is to glaze the bottom.

This technique appeared very early, and it was a ceramic firing technique that became popular during the Five Dynasties.

The specific method is to use kaolin to knead "support nails", and stick these nails to the edge of the bowl ring foot, with 9--12 nails in each stack.

Then put the bowl blank on the pad column, and then overlap the bowl blank with the nails to form a column and fire it in the kiln.

Although this method can utilize the space of the kiln chamber to burn more products with the same specifications, it has defects.

Since the flame is not separated from the product, it is easy to cause more waste products due to sticky slag;

At the same time, the nails damaged the glaze of the inner bottom of the container, which affected the appearance of the product.

In addition, the number of stacks does not make enough use of the high altitude of the kiln chamber, which also greatly increases fuel consumption.

This is the kiln firing process. It turned out that Chen Wenzhe was mainly involved in temperature control, and he had never learned other aspects.

Now, through the inspiration of Nail Burning, a lot of knowledge about firing kilns popped up in his mind instantly.

It can be said that when he saw the nail marks, he knew what kiln process was used.

Although time passed by for a moment, he learned a lot, such as overlay burning, overlapping burning, nail burning, and all kinds of burning!

This is analogy, he has only been in contact with single firing, how would he know that there are so many methods of firing kilns?

This time, through firing with nails, it is possible to study the firing process of Yingqing in the Song Dynasty.

In fact, Chen Wenzhe had already seen the necessity of a firewood kiln through the high imitation Yuan blue and white piece last time.

However, whether it is ancient or modern, burning firewood is very expensive.

It turned out that Chen Wenzhe thought that ancient firewood could be obtained for free. Obviously, this idea was wrong.

The more inheritance he received and the more he learned, Chen Wenzhe knew very clearly that the labor and prices in ancient times were relatively cheap.

It seems that ancient firewood is not expensive, but in ancient times, the ancients felt differently.

In their opinion, firing kilns was also very expensive at that time.

Immersive experience is just this good, allowing him to replace others and experience their past.

In this past, I not only experienced their work, but also experienced a part of their life.

This is also the reason why Chen Wenzhe has all kinds of messy life experiences.

Through analogy this time, I learned not only how to burn, but also the characteristics of various kilns.

How to burn, what to use, and how long to burn, all these need to be learned.

Taking the egg-shaped wood kiln in Jingzhen in the Qing Dynasty as an example, it took four days to burn a kiln and consumed 22 tons of firewood.

The 22 tons are not just any dead wood. It must be two feet long and thick pine wood, and it must be half dry and half wet.

Although there were many pine trees in the past, it would cost a lot of money to burn them once.

Although they all burn firewood, there is a big difference between firewood kiln, Cha kiln and wood burning.

The egg-shaped kiln has an area of ​​[-] square meters and a height of more than two meters. A large part of the space in the kiln is wasted by the sagger.

However, the saggers had to be used at that time, because when the firewood was burned, there was a lot of soot and ash, which would blacken the porcelain.

Therefore, it is necessary to seal the porcelain and keep it away from the smoke and dust. This is the function of the sagger.

Saggers became popular in the Tang Dynasty, and there were also kilns dedicated to burning saggers, called sagger kilns.

There are big and small saggers, the big ones are for vases, and the small ones are for cups and bowls.

They are all made of clay. To ensure strength, the walls of the bowls are made thicker, about two centimeters.

From the photos sent by Professor Tao, it can be seen that the outer circle of the fragments excavated from the ruins is the sagger.

This kind of burning method in which only one bowl is placed in a sagger is called single burning.

The advantage of this firing method is that, except for the unglazed bottom circle, the whole body is glazed, so it has been passed down to the present, because modern people are not afraid of high costs.

In some photos, some bowls are stacked on top of each other, and the soil between them is the sagger.

Because it has been rotten for too long, but the general shape can still be seen.

The single-firing kiln installation method is very simple, that is, many saggers filled with bowls are piled up, the top is used as the bottom cover, and the top one is covered with a cover.

The disadvantage of this firing method is that it wastes space. There are only about twenty bowls in a stack of saggers one meter high.

The cost of single firing is high, and it is generally used for fine porcelain, such as official kilns.

The low-grade bowls and dishes used by the people need to reduce the cost of firing kilns. The first thought of ancient porcelain workers is that many bowls share a sagger, which can save a lot of space in the kiln.

Wouldn't it be enough to put it up like we usually collect bowls, and then put it in a high sagger?

It's not that simple, there is also a problem of adhesion.

The glaze on the porcelain is completely molten during the firing process, and it is also fluid, and will stick to any object it touches after cooling.

If you burn a glazed bowl directly, you will get a sticky bowl.

But the porcelain body will not stick. The porcelain we use now has an unglazed part on the bottom (maybe in other places), that is the part that is placed on the kiln board when firing the kiln.

The firing methods that Chen Wenzhe knew were all designed to prevent porcelain from sticking together.

As soon as the bowl is placed, put the sagger with the mouth of the bowl facing upwards, this is stack burning.

How to prevent adhesion?The most common thing is to scrape off the glaze inside the bowl, which is the same size as the bottom foot, and then put another bowl with no glaze on the bottom foot.

The bowls are only in contact with each other, so they will not stick. This is called astringent circle burning.

The porcelain fired in this way was used by Chen Wenzhe when he was a child. It was a large bowl of rough white porcelain. The inner and outer ring bottoms were not glazed, making them extremely rough.

In addition, there is a firing method of adding spacers between bowls, and adding a piece of mud, which is called pad cake stacking.

There are also support nail stack firing, supporting beads stack firing, sand stack firing and so on.

No matter what kind of stack firing, the inside of the bowl has a part that lacks glaze.

Therefore, these technologies will eventually be eliminated by the times.

Later, overlay firing was developed, which is a method of firing bowls upside down, the most famous being the Ding kiln of the Song Dynasty.

The bowl is buckled on a clay ring as big as the mouth of the bowl, called a support ring.

Put another support ring on the support ring, and then buckle a bowl. If it is repeated, you can put more than ten layers, and then put the sagger for firing.

Over-fired bowls and plates have only the rim without glaze, which is called mangkou.

Mangkou is a defect in the firing process. During the firing process of porcelain, the edge of the mouth is unglazed and the fetal bone is exposed, which is called Mangkou.