The so-called sand mold casting is to put the product to be cast into the sand box, bury it with special fine sand, compact the sand, and then divide the compacted sand into two through the sand box, take out the product inside, form a cavity with the same shape as the product, take out the product, and then close the sand box, and then pour copper or molten iron through the specially reserved inlet, the molten iron will flow in the cavity in the sand box to form the shape of the desired product, and after cooling, you can get the desired product.

The advantage of sand mold casting is that it has good air permeability and avoids defects such as pores in castings, and its disadvantage is that every time you take out the product, you have to open the sandbox and destroy the mold, and every time you recast the previous process, you have to restart the previous process, and the strength of the sand mold is not enough, and you can't cast something too big and too heavy.

Sand casting, on the other hand, can retain the advantages of sand casting while avoiding its disadvantages.

The so-called sand mold is actually made of sand, but the process of making it is a little different.

To make a sand mold, the first step is the same as the sand mold, first put the shape of the product made of wood into the sand box, but the sand box needs to be iron, and then fill the sand box with a filler mixed with fine sand and clay in a certain proportion, and after compaction, put the iron sand box into the furnace together and heat it at high temperature, after firing, the clay and sand filled into the sand box are fired into a brick-like whole.

In this way, the sand mold can be used again and again, and it is strong enough to cast large products, such as cannons.

Compared with the iron mold, the sand mold has poor thermal conductivity, good air permeability, slower cooling rate of the workpiece, relatively less internal stress of the workpiece, and fewer internal defects.

From the point of view of casting iron cannon, the yield of sand mold is much higher than that of iron mold, and in terms of convenience, sand mold is not worse than iron mold.

After Chen Xian personally guided the experiment, his foundry workers soon succeeded in trial-producing sand molds, which are not complicated, the key is the ratio of sand and clay.

In Chen Xian's memory and the information at hand, there is no proportion of sand and clay in the sand mold, but Chen Xian knows that the clay in the sand mold is actually a kind of binder, and its function is to bond the sand together into a whole during firing.

Therefore, Chen Xian conducted many experiments with the proportion of clay from small to many until he was able to fire a strong enough sand mold.

With sand molds that can be used repeatedly, the efficiency of casting is faster, and when Chen Xian asked workers to copy dozens of sets of sand molds for casting three-eyed musket barrels, his foundry produced nearly 10,000 barrels in just over a month.

The reason why Chen Xian wanted to use the sand mold method to cast the barrel was also to accumulate technology for casting iron cannons in the future.

If you want to cast a usable iron cannon, you need to cast the iron cannon wall super thick, which greatly increases the weight of the cannon that is already overweight, and although the sand mold method cannot solve this problem, it can reduce this problem to a certain extent.

The reason why he wanted to cast iron cannons was because the copper cannons were too expensive, and Chen Xian had robbed the things Zhuangzi had accumulated over the years, and he had cast these cannons now, and the new cannons were far away, because he didn't have so much copper.

Chen Xian planned that in the future, only the field artillery would be cast in bronze, and the city defense cannon and the naval gun would be cast in iron.

In addition to changing the barrel to casting, Chen Xian did not cut too many corners on the three-eyed musket, which is after all one of his main export products for a period of time in the future.

In order to install the three barrels together, Chen Xian asked the factory to create a slender gun head for the three-eyed musket, creating three grooves at the back of the gun head as a bed for installing the barrel, and then using an iron hoop to fix the finished font shape of the three barrels on the gun head, the slender triangular tip of the gun head will stick out from between the three barrels for more than half a foot, so that this gun can be pierced and smashed, because the barrel is hard cast iron, this three-eyed gun is better than the three-eyed gun with wrought iron barrel produced by Chen Xian before when used as a two-handed hammer.

At the rear end of the head of the three-eyed gun, there is a half-foot-deep installation sleeve, which is installed in the handle of the hardwood gun more than six feet long produced by the mechanical processing method in Chen Xian's woodworking factory, and then nailed to death.

It is said that Yang Anguo was very satisfied after getting this batch of three-eyed guns.

In the casting of the three-eyed god musket barrel, after the trial production of the sand mold was successful, Chen Xian immediately led the workers of the foundry to try to cast the iron cannon with the sand mold.

After more than two months of repeated trial production and test guns, Chen Xian finally figured out the cast iron version of the one-catty, three-catty, and five-catty cannons.

In order to ensure that the cannon does not explode, the final cast iron version of these cannons is more than twice as heavy as the copper cannon of the same caliber, which is obviously unqualified as a field gun, but it is enough if it is used to defend the city.

Of course, Chen Xian could not give away the real cannon, he finally cast a batch of short-barreled small cannons similar to the Ming Dynasty Huzun cannon, this kind of small cannon is about equivalent to the appearance of a half-catty cannon, and the range power is much smaller, but the weight is not large, two people can move, can be hung on a horse through a special saddle, or can be pulled on an ordinary cart, when needed, through a simple iron support, and then dig a soil pit, it can be arranged quickly.

Chen Xian named this small cannon the Flying Sand Cannon, because he suggested that users (currently only Yang Anguo) use this small cannon to fire fine pieces of sand and stones to inflict large-scale damage on the enemy.

Yang Yongwu, who gave the bridal gift, told Chen Xian with his eyebrows dancing after coming back that after watching the test firing of the flying sand cannon, Yang Anguo was very satisfied.

A few days after the dowry, the Yidu Yang family's family sent the family to the East Zhuangzi, the family sent the family team to stay in Yang Yuanwai's house for one night, the next day Yang Miaozhen sat in a sedan chair, in a long line, blowing and beating under the farewell, came to the West Zhuangzi.

Chen Xian now lives in the Bai Mansion of Xizhuangzi, but he does not monopolize the Bai Mansion, but only occupies a small courtyard in the Bai Mansion, and the entire Bai Mansion is used as the Yiyuan Central School.

In the elation of the people of Xizhuangzi, Yang Miaozhen's sedan chair was staged into the Bai family's compound and sent to the courtyard where Chen Xian lived.

After some tossing, Chen Xian and Yang Miaozhen were sent into the cave room.

I can't forget the long ...... for most of the year. finally fell into his own hands, Chen Xian naturally refused to give up, so he slept the next day.

Because of the blockade from the direction of Laiwu again, Chen Xian did not dare to be careless, even on the wedding day, he did not dare to rest completely, although he held a banquet in the three Zhuangzi, let the people of the village eat, but never provided wine, the soldiers under his command still waited for the day, except for an extra meat dish at lunch, there was no extra celebration.

Listening to Chen Xian's explanation of the current situation, Yang Miaozhen also understood very well and got busy with him.