In Poyang, a private backyard, Li Li used various tools to simulate the process of making bronze mirrors, analyzed the cost of making bronze mirrors to Du, and introduced his own suggestions for improvement.

Comments on cost reduction.

This is the result that Li Li spent several months to figure out, and he also conducted a lot of experiments for this.

Du Shi disagreed with this: the craftsmanship of making mirrors is inherited from her mother's family, and other stores also make mirrors like this. Why does Li Li say that it can reduce costs?

"Do you think I'm fooling people?" Li Li saw Du's thoughts, and Du quickly concealed: "No, I just can't figure it out. Since ancient times, the only way to make mirrors has been to this. How can we improve it?"

"So, the mirror shops are in a dilemma of 'not enough to eat, not starve to death'."

After Li Li finished speaking, he continued to explain.

The production of bronze mirrors in this era was for the casting method. After Li Li carefully understood it, he felt that it was not complicated.

The first step is to make the mold and make the model. First, make the shape of the mirror on the pottery car (turning wheel), and then design patterns on the mud mirror and process them into a mirror mold.

Then, a mud pattern is tamped on the mirror mold, and the mud pattern is divided into two halves. When combined, the internal cavity is the shape of the mirror.

The second step is roasting the mud pan.

After a period of natural shade drying, the mud film can be roasted in the kiln. After a specific temperature and time-consuming roasting, the mud film will be sintered into a ceramic film and placed in a dry place to cool naturally.

After the pottery film is completely cooled, you can combine the film and prepare for casting.

The third step is melting and casting of the mirror material.

After melting a certain proportion of copper and tin, pour it directly into the ceramic mold and mold it in one go.

The fourth step is finishing.

After the pottery film is cooled, the molded copper mirror can be removed, but this is just a blank, and it needs to be ground and flattened to make it have the ability to reflect.

The lines need to be refined to make them more refined.

The costs involved are: first, the mirror material is mainly copper, but the cost of tin accounts for the majority, because tin is very expensive, which is much more expensive than copper.

The second is to roast the mud sheet and the fuel needed to melt the mirror material, namely wood or charcoal; the third is to make the sheet.

Among them, the cost of making a model is the highest.

The key to determining the quality of the bronze mirror is the ceramic model. The ceramic model is well made. The cast copper mirror has a flat front and exquisite back patterns, which are convenient for subsequent processing, so that the finished product will be more product-like.

The bronze mirror without patterns on the back is called "primitive mirror". The price of various places fluctuates between one thousand and two thousand documents. If there are patterns (mainly sun patterns), the price will be at least hundreds of documents more expensive than the plain mirror of the same size.

The more complex the pattern, the higher the price. The reason is that the more complex the pattern, the higher the cost of making bronze mirror pottery style.

The service life of the pottery film is not long. Sometimes it will be scrapped after being cast once or twice and needs to be remade.

Only by using good clay patterns can the best pottery patterns be burned, and such pottery patterns can be cast into copper mirrors without bubbles and fine patterns.

Therefore, the cost of making a bronze mirror accounts for a large proportion, and this is a characteristic of the process and cannot be effectively improved at all.

Therefore, there is actually not much difference in the cost of copper mirrors in different places, and the mirror materials are basically copper-tin ‘alloy’, and there is no obvious difference in the brightness of the mirror surface.

In addition, ordinary people cannot afford bronze mirrors, so the market's "capacity" is not very large. Taking Poyang City as an example, many mirror stores are old stores handed down from generation to generation, attracting customers by relying on reputation, and basically no "newcomers" have entered this industry.

The mirror shop run by Du Shi completely relies on the reputation of Du Shi’s mother’s family to open up the situation, because the Du family has been famous for making mirrors for generations.

The secret of the mirror formula for Du’s mirror is not complicated, that is, nearly 75% copper, 25% tin, and a little lead, that is, copper-tin alloy with a 25% tin content.

The bronze mirror must be made with tin to maintain grinding. The mirror surface after the mirror is shiny. This is common knowledge in the industry today. The difference between each company is nothing more than how much tin content is.

Li Li has carefully compared the bronze mirrors from other companies over the past few months. There is no obvious difference in terms of brightness, which means that the tin ratio of other companies' mirror materials is actually similar.

With less tin, the brightness of the copper mirror will decrease, and with more tin, the copper mirror will become brittle.

Therefore, the content of tin is mostly between 20% and 30%, which can not only ensure that the mirror surface can last long, but also ensure that the bronze mirror is not so brittle, but the bronze mirror is still prone to falling.

This is common sense, and Du specially emphasized this to Li Li.

Therefore, after thousands of years of development, the ratio of copper mirror materials to be determined as copper and tin is stable between 20% and 30%, and no one can innovate.

"Tin is very expensive, more expensive than copper. I have also tried to replace tin with other materials, such as using lead. However, although the copper mirror made is not easy to break, the mirror surface remains bright for a short time and needs to be wiped frequently, which is very troublesome."

"Is that right?" Li Li picked up a bronze mirror and looked at it carefully, "Then, Master Du knows why this is?"

Du shook his head: "I don't know, no one knows."

Li Li relaxed his hand when he heard this, and the bronze mirror in his hand fell to the ground. With a "bang", it cracked in half and turned into a broken mirror.

That year, the Sui army crossed the river and invaded the capital of Chen State Jiankang. The Northern and Southern Dynasties that lasted for hundreds of years ended, and the world was finally unified.

That day, Xu Deyan, the prince-in-law of Chen, smashed a bronze mirror and took half of it himself, and his wife, Princess Lechang, took half of it. The couple agreed with tears in their eyes that if they were destined in the future, they would use the broken mirror as a token of recognition.

The kings, ministers, royal families, and princesses were taken to Chang'an by the Sui army. According to convention, the princesses of the country were the best quality trophy and distributed to the heroes.

As a result, the beautiful Princess Chen of Lechang became the favorite concubine of Yang Su, an important official of the Sui State.

Although he was favored by the new master in every way, Chen could not forget Xu Deyan, so he handed the half of the broken mirror to his servant and asked the servant to sell it in the Chang'an market.

The miserable Xu Deyan was also in Chang'an. He saw the broken mirror, took out the other half of the broken mirror in his hand, and combined it into one.

When Yang Su learned about this, he helped the miserable couple to let Chen return to Xu Deyan and give him money. The couple then returned to Yanyu Jiangnan.

This is the story of "reunitement of the mirror".

Thousands of years later, some scholars expressed doubts about the authenticity of this story, so they used the ancient mirror they collected and smashed it on the ground, but it couldn't be smashed.

So, is the story of "reunite from a broken mirror" really fake?

Not because the bronze mirror used by scholars to test was a bronze mirror after the Tang Dynasty, and the bronze mirror used by Xu Deyan and his wife was a bronze mirror before the Tang Dynasty.

The bronze mirror has a history of thousands of years, but it is bounded by the middle and late Tang Dynasty and has different materials: the Han and Tang bronze mirrors are made of copper-tin alloys, and the bronze mirrors after the Tang Dynasty are made of copper-lead alloys.

The copper mirror made of copper-tin alloy has a hard texture and can maintain the brightness of the mirror for a long time, but it is very brittle, easy to break, and expensive.

The copper mirror made of copper lead alloy has a soft texture and is difficult to maintain the brightness of the mirror for a long time, but it is very tough and not easy to break, and the price is relatively cheap.

Therefore, after the middle and late Tang Dynasty, a profession that was widely present in various places was born: Mirror Grinding Man.

The bronze mirror of Han and Tang dynasties is polished and consecrated after production. The mirror surface is bright and can be used for a long time. When the mirror surface begins to become blurred, you only need to take a skin, apply some mirror medicine, and gently wipe the mirror surface, and it will be as bright as new.

This kind of work is very simple and you can do it yourself, and you don’t need to hire someone to do it. Of course, some craftsmen also travel around the streets and polish their mirrors for others.

Because various accidents in daily use will cause physical damage to the mirror surface. For example, if scratches appear, tools are needed to smooth the mirror surface. Therefore, there are also people who polish mirrors in this era, but it is not a common profession.

The bronze mirror after the Tang Dynasty was polished and consecrated after the production. The mirror surface was brighter than the Han Tang Dynasty bronze mirror and could not last long and easily become blurred, but it was very troublesome to deal with.

Special tools are needed, such as another extremely flat surface to "grind". Be careful and carefully smooth the mirror surface before you can use the photocopy to wipe it back to let the light return.

This kind of work requires professionals to do, so the profession of "mirror grinding" has become widely known.

With the middle and late Tang Dynasty as the boundary, the state of copper mirrors changed because of the changes in the material of the mirror, the different characteristics of copper-tin alloys and copper-lead alloys, and the prices.

Copper mirrors made of copper and tin are expensive, while copper mirrors made of copper lead are relatively cheap. Therefore, since the Northern Song Dynasty, the popularity of copper mirrors has increased and the demand for grinding mirrors has also increased, which has led to the grinding mirror industry.

Li Li is not an expert in mirror making. This knowledge was talked about by later generations when he heard from a collector who collected ancient mirrors, so he remembered it in his heart.

But he could not explain to Du, after all, the allusion of "reunite mirror" happened decades later, of course, the premise was that there were Sui and Chen countries at that time.

Du saw Li Li breaking a bronze mirror without saying a word, wanting to hear what Li Li is going to say next.

Li Li looked at the broken mirror and said to Du: "The mirror material and technology have not changed for thousands of years. Everyone in the industry cannot break through the technical bottlenecks. The competition between each other is just a struggle in the dilemma."

Du found it ridiculous when she heard this. She thought Li Li, a layman, was so arrogant that she laughed at the craft of mirror making.

She asked, "Since that's the case, what do you think you should do?"

"It's easy to deal with. In a few days, new products will be available for Du Dongzhu's store." Li Li said confidently, "I haven't had a waste of time in the past few months. I have made many bronze mirrors, whether it's good or bad, and how much sales are!"
Chapter completed!