When ancient craftsmen made gold bricks, they first had to select the soil, which must be sticky but not loose, powdery but not sandy. The selected soil would be left out in the open for a whole year to remove its "soil nature." Then, the clay would be soaked in water until it softened, and several cattle would repeatedly trample on it to remove any air bubbles in the clay lump, ultimately refining it into a dense lump. After repeated pounding, the clay lump would be placed in a mold, covered with a flat plate, and two people would step on the plate until it was compacted. Next, the brick molds would be air-dried for more than seven months before entering the kiln for firing. During the firing process, chaff would be used to fumigate for a month to remove moisture, followed by split wood burning for a month, whole wood burning for another month, and finally pine branches burning for 40 days before the bricks could leave the kiln. After leaving the kiln, the bricks would undergo strict inspections. If six gold bricks in a batch did not meet the standard of producing a resonant sound when struck and having no holes when broken, the entire batch would be considered defective and need to be re-fired. Thus, from soil to gold brick, the process took as long as two years. The production of "gold bricks" required several steps: soil selection, brick forming, firing, kiln removal, polishing, and soaking. Although these steps might not seem particularly complicated, each major step actually contained many smaller steps, making the production of "gold bricks" an extravagant affair.
The first step is soil selection. Before selecting the soil, experienced masters would identify locations where the soil not only has stickiness but also contains a higher amount of aluminum that can be ground into powder. After selecting the soil, it would go through seven steps: digging, transporting, drying, pounding, slurry making, grinding, and sieving, taking up to eight months to complete.
The second step is brick forming. The prepared soil would be made into brick molds using semi-handmade and semi-mechanical methods. Ordinary Beijing bricks simply require shaping the soil into blocks according to the needed dimensions and thickness. More complex are the patterned bricks, such as those requiring drawings. To make the patterns vivid after firing, the details must be precisely carved during the molding stage.
The third step is firing. After the bricks enter the kiln, the ignition process is extremely complex: one month of chaff smoking, one month of split wood burning, one month of whole wood burning, and 40 days of pine branch burning. After 130 days of burning with these four different types of fuel, the bricks can be cooled down and removed from the kiln. Cooling involves pouring water into the kiln to reduce the temperature. This water must be carried by workers up steep and high brick ladders to the top of the kiln and then poured inside.
The fourth step is removing the bricks from the kiln. On the day of removal, the small kiln interior is filled with choking dust. Even though water has been poured to cool the kiln for several days before removal, the temperature inside is still very high, and the "gold bricks" after prolonged firing are scorching hot. Workers quickly pass the hot and heavy "gold bricks" among themselves. To encourage their companions to speed up and also to motivate themselves, workers emit a strange hissing sound while moving the "gold bricks."
The fifth step is polishing. The "gold bricks" just removed from the kiln are still semi-finished products like raw jade. To make them shine like polished jade, further meticulous polishing is required. Using extremely simple tools, the polishing is done in a circular water trough, with constant water flushing. Not only does this make the surface of the Beijing bricks smooth, but it also ensures that the longer they are used, the shinier they become, even to the point of being used as mirrors. Unfortunately, the polishing technique that makes "gold bricks" mirror-like has been lost.
The final step is oil soaking. After polishing, the "gold bricks" are individually soaked in tung oil. Tung oil not only gives the "gold bricks" a fresh sheen but also extends their lifespan. At this point, all the procedures from soil to Beijing bricks are completed. Adding up all the time spent on these procedures takes over a year, and each kiln can produce at most 7,000 Beijing bricks per session, with a certain proportion being substandard or defective.
Jianguo Gold Bricks from the Kaiyuan Treasure Shop:
- For the first time, vividly displays the grand demeanor of the founders of New China and completely reproduces the historical grandeur of the founding ceremony.
- Made with 999 pure gold and pure silver, divided into three series and thirteen specifications: gold bricks (6 pieces), silver bricks (6 pieces), and gold bricks (1 piece) + silver bricks (6 pieces).
- Each specification comes with precious gifts: two collector scrolls of "Founding Heroes" and "Hero Handwriting," as well as a Chairman Mao badge.
- Utilizes advanced world techniques such as low relief, mirror finish, sandblasting, and color printing specifically for precious metal coin casting.
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