The last process of Boshan furnace

Boshan furnace is one of the traditional copper casting processes in China, and its last process is "sand making". The specific process flow is as follows:

1. After casting, put the green copper device into the sand box, and then coat a layer of fine sand on the surface of the device.

2. Use a special sand grinder to make its surface smooth and smooth, and at the same time ensure that the lines and patterns of bronze ware are not damaged.

3. Put the polished bronze ware into the sand box again, and cover it with fine gypsum mold.

4. Sinter the gypsum mold at high temperature to harden it, and dry the sand in the sand box at the same time.

5. Cast gypsum mold with liquid copper and wait for it to cool.

6. After cooling, break the plaster mold and take out the copper device.

7. Grind and polish the bronze ware to make its surface smoother and brighter, and further highlight its lines and patterns.

8. Finally, the details of the bronze ware are sorted and corrected with tools such as knives to achieve the final perfect state.