Chapter 39 Gold Plate and Silver Plate (Please collect and recommend)
Big Mouth and Monkey worked for a day and got hundreds of white poles that could be used as spears, but the adults who cut trees were miserable.
After a day of hard work, they only cut down less than ten fir trees, and they haven't pulled them all back yet. Some of them are still lying in the forest. Three stone axes for cutting trees have also broken.
But Luo Chong told them mercilessly that they would continue tomorrow, but whoever did a good job would be given new equipment.
New equipment? Everyone was a little confused. The stone axe was already the best tool they had ever seen. What could be better than the stone axe?
After dinner, everyone started their after-dinner entertainment time again, and Luo Chong started to boil wax by the fire pit. He put the collected wax blocks in the pot to melt, then skimmed off the impurities with a spoon, poured it into the large clay mold prepared in advance, and condensed it into a whole piece of white wax again.
Then cut it into small pieces and use a bone knife to cut it into the shape of tools, such as the axe head of an axe, a small hammer head, a planer, various types of chisels, and clamps.
Carefully polish the wax block to a size ratio of 1:1 with the real object, then wrap these wax block models with clay, leaving only a small opening, and then press them tightly so that the clay and the wax block are in full contact without leaving any gaps.
Then let it stand and dry. After the clay is completely dry, put it on the fire to heat it so that the wax block inside melts again, and then pour out the wax liquid inside, so that you can get a hollow clay mold.
What shape of wax block is wrapped in the mold will leave a space of the same shape inside. For example, if the inside is an axe made of white wax, then melt the wax block into wax liquid and pour it out, and there will be a space in the shape of an axe.
In addition, a thin layer of wax will remain on the inner wall of the mold, so that it will be easy to demold when the casting is completed.
Although the "lost wax method" casting is a little troublesome, it is more accurate and does not waste materials. The poured wax can also be re-condensed into large blocks and reused.
The women who collected insect wax did not understand it, but they knew that the chief really needed it, so they would continue to collect it tomorrow.
Dashu and Lame were a little different. Dashu saw that it should be a weapon, but he didn't understand how such a soft thing could be used as an axe.
Lame's focus was on the clay casting. He was a pottery maker, so he thought the mold should also be burned in the fire. Was the chief going to use clay as a weapon?
All explanations to them were in vain. It would be better to let them see the real thing.
Early the next morning, the tribesmen took all the blue antelopes away. Under the indoctrination of Luo Chong's unremitting efforts, they finally understood that wild animals can not only be used for food, but also for human work, and you only need to pay some grass everywhere.
Dazui, Monkey, Damao, and Ermao all stayed. Their task today was to operate the blower for Luo Chong.
The charcoal was ready. The heavy wood was very light after being burned into black charcoal. The pottery that Lame had made yesterday was also fired. Today, he was specifically helping Luo Chong.
Lame was very smart, otherwise he would not have been able to develop the rake by himself, so Luo Chong planned to teach him the method of copper smelting. It was impossible for Luo Chong to do this kind of work alone in the future. It would be better to find an apprentice, and Lame, a disabled person, was the best candidate because he did not need to run around to do these things.
The four furnaces were already dry. This time, two were lit at the same time. Da Mao and Er Mao pressed the blower, and Da Zui and Monkey loaded the charcoal.
Under the action of the blower, the flames shot out of the furnace mouth very high. A layer of broken copper ore and a layer of charcoal were piled up in three layers. The cylindrical furnace had a good heat-gathering effect. After a while, the ore in the furnace began to become dazzling red, and then slowly melted. The copper liquid flowed along the gap to the bottom of the furnace and gathered together, turning into a lump of copper mixed with slag.
There was also a tin mine working at the same time, which was faster. Tin ore had a very low melting point and could be melted in a few minutes under a fierce fire.
Using a branch, two pieces of metal mixed with a lot of impurities were pulled out from the ashes under the furnace. It was inconvenient without a blast furnace, and pure copper liquid could not be obtained directly.
Carbon and ore were added to the two furnaces to keep the furnaces at a high temperature and smelt copper continuously. Luo Chong personally watched one furnace just now, and only one piece of impure metal the size of a child's fist came out at a time. It was very slow.
After smelting for seven or eight furnaces, about three or four hours, a pile of impure gold and silver lumps were finally accumulated.
Because Luo Chong brought back chalcopyrite with a content of more than 80% this time, a lot of crude copper was produced. If it was malachite or azurite, the copper yield would definitely not be that high. The tin yield of tin ore was not high either, but the proportion of tin in bronze was not large, which was enough.
Two more furnaces were lit, and after the temperature rose, crucibles made of refractory clay were placed in the furnace. The crude copper and miscellaneous tin were placed in the two crucibles respectively, and a blower was used to increase the firepower. When the copper and tin were melted into liquid, because copper is a heavy metal with a high density, the lighter impurities would float to the top of the metal liquid.
Then use a clay spoon to skim off the impurities on the surface, but don't throw them away. You can save them first. There is still some copper on these impurities. When there is more, you can pile them together for secondary smelting.
Use the prepared pottery stick to take out the pure copper liquid and the crucible, and then pour it into the grid-shaped clay mold and let it stand to cool down.
The same operation is done for tin liquid, but it is faster. The melting point of tin is only more than 200 degrees, otherwise it will not be used as a material for soldering circuit boards, and when copper and tin are mixed together, it will also lower the melting point of the alloy.
The lame man, his four friends and Luo Chong were all watching the metal liquid in the mold slowly solidify and cool down.
They didn't understand the principle behind it, so they were very surprised. They didn't know why something like water could be burned out of the stone, and this boiling water would become harder and harder as the temperature dropped.
The elder had nothing to do today, so he also came to observe. He wanted to draw everything Luo Chong had done and pass it on to future generations, but this copper smelting was too complicated. He didn't know how to draw it, so he kept frowning and watching.
After waiting until the copper and tin plates were no longer hot, Luo Chong could not wait to pour out all the metal plates. It was noon, and the metal plates, which were still warm to the touch, reflected dazzling light under the sunlight.
The golden copper plates and the silver tin plates were horizontal on one side and neatly arranged in rows of small cubes on the other side, which were very beautiful.
The lame man, the elder, and the four friends all stared at the metal plates with their mouths wide open. They had never seen such beautiful and glittering things. The expressions on their faces were no less than the obsession of modern people when they saw gold bricks.
Even Qubing, who was playing, was attracted to come over. He touched this and looked at that. It was still hot.
"Chief, what is this?" Qubing asked Luo Chong with his head raised, picking at the protrusions on the copper plate.
Luo Chong rubbed his head, "This is called copper, and this is called tin. You watch here, I'll go get something."
Qubing nodded and whispered the words "copper, tin" to the lame man and the others.
Luo Chong brought a bunch of tool molds, as well as several large and thin clay plates with a shallow groove on them, which were used to make rulers, and a plate saw.
Luo Chong, who was in urgent need of metal tools, did not rest and immediately started casting bronze.
He took out a new crucible and put in a copper block first. After it melted into liquid, he added a tin block. Copper has a much higher melting point than tin. Tin melted within a minute after it was put in. Stir it evenly with a pottery stick, and then it can be cast.
The first pot was cast with an axe and a hammer, but the ratio was slightly changed. The ratio of copper to tin was 5 to 1.5, that is, 20 copper ingots and 6 tin ingots. Because Luo Chong was afraid that the ratio of 5 to 1 would not be sharp enough and too soft.
The boiling alloy liquid was poured into the mold, and a puff of white smoke came out of the hole reserved in the mold, and then a small flame rose, shook twice, and went out with a puff.
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I examine myself three times a day. Do you vote? Do you comment? Do you like me? Finally, I will quietly ask for a reward, please send me a red envelope for the New Year (super quiet)
(End of this chapter)
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