Gold Plates and Silver Plates

Big Mouth and Monkey worked all day and got hundreds of white poles that could be used for Long Spears, but the adults who cut down trees had it rough.

They toiled all day and only cut down less than ten fir trees, and not all of them were even dragged back; a few were still lying in the forest. Three of the Stone Axes used for cutting trees also broke.

But Luo Chong told them mercilessly that they had to continue tomorrow, though whoever did well would get new equipment.

New equipment? Everyone was a bit puzzled. Stone Axe was the best tool they had ever seen, so what could be better than Stone Axe?

After dinner, everyone started their post-dinner entertainment time, while Luo Chong began boiling wax by the fire pit, melting the collected wax chunks in a pot, then using a Spoon to skim off impurities and pouring it into prepared large clay molds to solidify into a whole new block of white wax.

Then he cut it into small pieces and used a bone knife to carve it into the shape of tools, such as axe heads, small hammer heads, planes, various sizes of chisels, and clamping tongs.

He carefully polished the wax blocks to a 1:1 scale of the actual object, then wrapped these wax block models with clay, leaving only a small opening, pressing tightly to ensure complete contact between the clay and the wax block without any gaps.

Then he let it sit and dry. After the clay was completely dry, he heated it over the fire to melt the wax blocks inside again, and then poured out the wax liquid, thus obtaining a hollow clay mold.

Whatever shape the wax block wrapped inside the mold had, that shape of space would be left inside. For example, if it contained an axe head made of white wax, then after melting the wax block into liquid wax and pouring it out, an axe-head shaped space would be left inside.

Moreover, a thin layer of wax would remain on the inner wall of the mold, making it easier to demold after casting was completed.

Although Lost-Wax Casting molds are a bit troublesome, they are more precise and don't waste material. The poured-out wax liquid can also be re-solidified into large blocks and reused repeatedly.

The women who collected insect wax didn't understand after watching, but they knew the Chieftain really needed this, so they would continue collecting tomorrow.

Dashu and Lame were a bit different. Dashu saw that this should be a weapon, but didn't understand how such a soft thing could be used as an axe.

Lame's focus was on the clay mold. He himself did Pottery Making, so he thought the mold should also be fired in the fire. Was the Chieftain going to make weapons out of clay?

Any explanation to them was futile; it was better to let them see the real thing.

Early the next morning, the tribesmen led the Blue Antelopes away. Under Luo Chong's unremitting indoctrination of ideas, they finally understood that wild beasts could not only be eaten but also help humans work, and all you had to pay was some grass that was everywhere.

Big Mouth, Monkey, Big Fur, and Second Fur stayed behind. Their task today was to operate the bellows for Luo Chong.

The charcoal was ready; the heavy wood burned into black charcoal was very light. Lame's Pottery from yesterday was also fired and he was specifically assisting Luo Chong today.

Lame was very smart, otherwise he wouldn't have invented the rake himself, so Luo Chong planned to teach him the method of copper smelting. Luo Chong couldn't do this kind of work alone forever, it was better to find an apprentice, and Lame, being disabled, was the best candidate because doing these things didn't require running around.

The four furnaces were dry. This time, two were lit at once. Big Fur and Second Fur pressed the bellows, and Big Mouth and Monkey loaded the charcoal.

Under the action of the bellows, flames shot high out of the furnace mouth. A layer of crushed copper ore, a layer of charcoal, and so on were stacked three layers high. The cylindrical furnace chamber had good heat retention, and after a while, the ore in the furnace chamber began to glow a dazzling red, then slowly melted. The molten copper flowed through the gaps to the bottom of the furnace chamber, gathering together into a lump of copper mixed with slag.

Tin Ore was also being processed simultaneously next to it; that was even faster. Tin Ore has a very low melting point and can melt in a few minutes under intense heat.

Using branches from the ashes at the bottom of the furnace, Luo Chong pulled out two pieces of metal mixed with many impurities. It was inconvenient without a blast furnace; he couldn't directly obtain pure molten copper.

He continued to add charcoal and ore to these two furnaces to keep them at a high temperature, smelting copper non-stop. Luo Chong personally watched one furnace just now, and only a piece of impure metal the size of a child's fist came out at a time, which was very slow.

After smelting seven or eight furnaces, which took about three to four hours, he finally accumulated a pile of impure gold and silver lumps.

Because all the Chalcopyrite Luo Chong brought back this time had a content exceeding 80%, a lot of crude copper was refined. If it were Malachite and Azurite, the copper yield definitely wouldn't be that high. The tin yield from Tin Ore wasn't high either, but tin doesn't account for a large proportion in Bronze, so it was enough.

He lit two more furnaces. After the temperature rose, he placed crucibles made of refractory clay in the furnaces. He put the crude copper and mixed tin into two separate crucibles. He used the bellows to increase the heat. After the copper and tin melted into liquid, because copper is a heavy metal with high density, the lighter impurities would float on top of the molten metal.

Then he used a clay Spoon to skim off the impurities on the surface, but didn't discard them; he stored them for now. There was still some copper on these impurities, and when enough accumulated, they could be piled together for secondary smelting.

Using a pre-prepared clay rod, he carried the crucible containing the skimmed pure molten copper and poured it into a grid-shaped clay mold. He just let it sit and cool down.

The same process was done for the molten tin, only faster. Tin has a melting point of only over 200 degrees Celsius, which is why it's used as a material for soldering circuit boards. And when copper and tin are mixed together, it also lowers the melting point of the alloy.

Lame, the four buddies, and Luo Chong were all watching the liquid metal in the mold slowly solidify and cool down.

They didn't understand the principle behind it, so they seemed very surprised, wondering why something like water could be burned out of stone, and why this hot water would get harder and harder as the temperature decreased.

Elder had nothing to do today, so he also came to observe. He wanted to draw everything Luo Chong had done to pass down to future generations, but this copper smelting was too complicated. He didn't know how to draw it, so he kept watching with a frown.

He waited until the copper plates and tin plates were no longer hot to the touch. Luo Chong couldn't wait to pour out the metal plates. It was noon at this time, 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 had one side that was flat, and the other side had rows of neat small cubes, which were very beautiful.

Lame, Elder, and the four buddies all opened their mouths and stared at the metal plates. They had never seen anything so beautiful and shiny, and their expressions were no less obsessed than modern people seeing gold bars.

Even Qu Bing, who was playing, was attracted over. He touched this, looked at that; it was still warm.

"Chieftain, what is this?" Qu Bing picked at the bumps on the copper plate and asked Luo Chong, tilting his head back.

Luo Chong rubbed his head, "This is called copper, and this is called tin. You watch here, I'll go get something."

Qu Bing nodded, and whispered the words 'copper, tin' with Lame and the others.

Meanwhile, Luo Chong moved over a pile of tool molds, as well as several large and thin clay plates with very shallow grooves on them, which were used for making rulers, and also board saws.

Luo Chong, who urgently needed metal tools, didn't rest and immediately began the Bronze casting work.

He took out a new crucible, first put in copper blocks, and after they melted into liquid, he added tin blocks. Copper has a much higher melting point than tin; the tin melted within a minute of being put in. He stirred it evenly with a clay rod, and then it was ready for casting.

The first batch cast was axe heads and hammers, but the ratio was slightly adjusted. The copper-tin ratio was 5:1.5, which is 20 copper ingots and 6 tin ingots. This was because Luo Chong was afraid that the 5:1 ratio wouldn't be sharp enough and would be too soft.

The hot alloy liquid poured into the mold, a puff of white smoke came out of the hole left in the mold, then a small flame rose, flickered twice, and went out with a pop.

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I examine myself three times a day: Did you vote? Did you comment? Did you like? Finally, I quietly ask for a tip, give me a red envelope for the New Year (super quietly)