If you want to fire glassware, in fact, the raw materials and the kiln can be overcome.

The real difficulty lies in the three key processes – temperature, blowing and annealing.

The temperature determines the brightness and clarity of the glassware, the blowing determines the appearance of the glass, and the annealing determines the practicality of the glassware after it is made.

All three are indispensable.

The temperature can be tested, but the big deal is to use the exhaustive method, as long as it takes time and manpower and material resources, it can always be tried.

But there is no place to learn the technique of blowing.

It's not that there are no people who know how to blow, but there are too few to find.

Because at present, there are almost no people in Datang who blow glass.

Glass products were actually available in China as early as the Han Dynasty, however, later the Han Dynasty pacified the Xiongnu and strengthened the exchanges with the Western Regions, and during the Wei, Jin, Southern and Northern Dynasties, due to frequent regime changes, long-term feudal secession and continuous wars, the development of Chinese culture in this period was particularly seriously affected, and Persia, Greece and other Central Asian and European cultures also had the first large-scale invasion of China during this period. With the introduction of these foreign cultures, a large number of Western glassware was imported into China, this kind of glass is more transparent and smooth, can be made large and thin, the key is that the hardness is much higher than the glass made by the local process, so the local glass was replaced.

Later, in the Song Dynasty, there was a man named Cheng Dachang, who wrote a book "Yan Fanlu", which mentioned - "However, what China casts is different from the Western Regions, and the cast China is very bright in color and light and crisp in quality. As for its origin in the sea, the difference is blunt, and the color is also slightly dark, and it can be different, although it is poured into a hundred boiling soups, it is no different from magnetic silver, and it is not damaged, and it is a famous glaze.

It shows that the local glass is bright in color, but it is extremely fragile, "wo with hot wine, break with your hand", pour a glass of hot wine will break, and you can hold it with a hand, this strength is not practical at all.

Western glass, although the color and appearance are not as bright and beautiful as the local glass, but "although the boiling soup is injected, it is no different from magnetic silver, and it is not damaged", but the practicality is far beyond the local glass, so the local glass is eliminated.

The local glaze can't be used, and the glaze brought by Hu Shang can't be made, so naturally no one uses the technology of local firing glaze.

This is the result of the Song people's sophistication, but before that, the local glass-firing technology has been lost, and there are naturally very few people who know how to blow, or even none.

However, although the Tang Dynasty did not have the people who blew the glass, there were those in Persia before. Because most of the glazed ware was produced by Great Qin and Persia, and then brought into the Tang Dynasty by Hu Shang. Although Persia has been destroyed, the Great Food has possessed Persia, and the Arabs will not give up this violent business.

Therefore, among the Hu merchants who wandered in the Tang Dynasty, Dashi, and even the Great Qin, especially among those who sold glazed ware, there must be people who know the blowing technology, or know where there are people who know the blowing technology.

These businessmen, as long as the interests are sufficient, can do anything. Therefore, from the hands of these Hu merchants, you must be able to get people who know how to blow.

Naturally, this is the purpose of Wei Renshi coming to Li Chun.

With Wei Renshi himself, he has not been able to find a person who knows how to blow for the time being. But if Li Chun puts some thought into this matter—not even a thought, just a matter to explain in one sentence—then he will definitely be able to find it.

As for annealing, the reason why the local glazed ware could not be practical in ancient times was that there was no annealing process.

In the process of forming glass, due to the characteristics of molten glass, there is always a certain temperature difference between its inner and outer layers. This temperature difference creates a corresponding stress in the glass.

Due to the existence of local, uneven stress, the strength of the product is weakened.

The purpose of annealing is to reduce the stress in the product to a tolerable extent, which can greatly improve the strength of the glass.

The blown glassware is placed in an annealing kiln for a long enough time to cool down through the annealing temperature range or at a slow rate. After this process, the glassware will not have this situation of "wo with hot wine, break with your hands".

If the glass made can have both the color and luster of local glass, and the practicality of Western glass, it will not be sold.

In addition, the raw material used in the West to fire glazed ware is natural quartz, which itself is not easy to find, and it is not easy to mine, so the cost of glazed ware from Dashi itself is very high, and it is also very expensive in its own country.

However, Wei Renshi knows that the silica content in river sand is very rich, so river sand can be used as a raw material. The cost of river sand is low, and after the glassware is made, the price will naturally be lower.

It is practical, bright and beautiful, and it is sold cheaply, so it is not worried that it cannot be sold to the Western Regions, Dashi, and Daqin.

No matter how you calculate this business, you will make sure that you will not lose money.

Wei Renshi didn't hide it from Li Chun, and told him what he knew.

Wei Renshi knew that Li Chun would definitely report back to Li Shi, and after Li Shi learned about this, if he understood the huge profits, he would definitely let Wei Renshi handle this matter. In this way, Wei Renshi will no longer be placed in the five prisons.

If you want Li Shi to be sure that he can really do this, of course, you have to make things clearer. It was only through Li Chun that he passed this information to Li Shi and made Li Shi change his mind.

"River sand?" Li Chun looked at the glazed ware inside the wooden box in surprise, and the expression on his face was very strange. It seems that there is no way to connect the translucent and beautiful glazed ware in front of you with the fine sand at the bottom of the river.

Wei Renshi nodded: "Yes, the raw material is river sand." My fiefdom is on the edge of the Wei River, and the number of river sand in the Wei River is not clear. The more Prince Chun can find someone who knows how to blow, we can set up a kiln by the Wei River, dig sand directly from the Wei River, and then fire the glazed ware in the kiln. The most important thing at the moment is that Prince Chun can find someone who knows how to blow as soon as possible. ”

Li Chun licked his lips and asked again: "Then if it is according to Brother Renshi'er's method, how much will it cost to make this set of ordinary glazed ware?" ”

Wei Renshi glanced at the set of glazed ware in the wooden box and said with a smile: "I can't have a specific number at the moment." However, in the past, it will not exceed 500 at most - in fact, I think that if we get on the right track, the cost will drop further, and I am afraid that it will only be a few dozen times. ”

Li Chun's throat moved visibly.

"Someone who knows how to blow!" Li Chun's hand clenched into a fist and let go, and said in a deep voice: "Brother Renshi, don't worry, give me half a year...... No, three or four months! I'm sure I'm going to find it! ”