Historical Note
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Wax Casts Candles, cosmetics, and carbon paper; industrial dies and death masks; statues and sorcery: These are just some of the ways people have found to put wax to use over the centuries. Its ubiquity can be attributed to the fact that it fills a void in the materials world: It is one substance that can easily be worked in both its solid and liquid forms. In early human history, metals smelted from ores could be formed by forging, but not into any intricate shapes; clays could be molded and fired into pottery, but further shaping was difficult after that point. A plastic material that could be worked and reworked at ambient or moderately elevated temperatures was essential to the progress of people’s attempt to shape the objects in their environment into useful and beautiful forms. Natural waxes occur as the result of biological processes in animals or plants. The honey bee (Apis mellifica) constructs the honeycomb cells of its hive by secreting flakes of wax from eight glands on the underside of its abdomen. When harvested, the honeycomb is melted and filtered to produce pure beeswax. The Chinese insect Ceroplastes ceriferus deposits its hard, crystalline wax on the branches of certain trees, then suffers the indignity of being boiled in water to extract the wax still inside its body. In the plant kingdom, cuticle waxes secreted as protective coatings on the leaves help to retain moisture in arid regions. Carnauba wax from the carnauba palm in Brazil, and candelilla wax found on the candelilla shrubs of Mexico and Texas are just two examples of this type. The natural waxes, whether animal or vegetable in origin, share similar properties: They melt at moderate temperatures of 35–100°C, and cool into hard, glossy finishes. Chemically they are composed mostly of high molecular weight fatty acids, straight-chain alcohols containing an even number of carbon atoms greater than 12, and saturated hydrocarbons. While the discovery and use of wax materials is necessarily lost in the obscuring clouds of history, it is generally agreed that either beeswax or Chinese insect wax was first used for practical purposes. Predictably, the Egyptians played a large role in the early development of wax materials. Beeswax was used to seal openings in the body during the mummification process, and the emergence of written hieroglyphic forms for communication was carried out largely on wax tablets poured into shallow wooden molds. These could be erased by rubbing or renewed by pouring fresh molten wax, 54
and were infinitely easier to use than stone tablets. The earliest attempts at oil painting involved the “encaustic” method developed by the Egyptians, in which pigments were ground into beeswax and applied to a surface by a heated spatula. But the most important development in wax technology occurred in the third millennium BC during the Bronze Age: the simultaneous development on several continents of the Cire Perdue, or “lost wax” casting process. With small refinements in technique to control the quality and sizing of the finished
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