《天工开物·中篇·冶铸》
铸造万斤以上的大朝钟之类的钟和铸鼎的方法是相同的。先挖出一个一丈多深的坑，使坑内保持干燥，并把它构筑得好像房舍一样。将石灰、细砂和黏土塑造调和成的土作为内模的塑型材料，内模要求做得没有丝毫的裂缝。
凡造万钧钟与铸鼎法同，掘坑深丈几尺，燥筑其中如房舍，埏泥作模骨，用石灰、三和土筑，不使有丝毫隙拆。
The method of casting bells, such as the great court bells and cauldrons weighing more than ten thousand catties, is the same. Firstly, dig a pit with a depth of more than 1 meter and keep it dry, and build it as if it were a house. Lime, fine sand and clay are shaped into a mixture of plastic materials as the modeling material for inner mold, and the inner mold is required to be without any cracks.