The lost-butter technique: A possible alternative to beeswax for constructing complex copper-casting moulds in the Late Chalcolithic period of the southern Levant

Late Chalcolithic metallurgy developed in the southern Levant alongside the emergence of new social institutions, the rapid growth of other crafts and technologies, and the introduction of secondary products. While found throughout the southern Levant, most copper items were recovered in the Negev, the Judean Desert, and the Jordan Valley, manifesting two technologies: The casting of pure copper from Feinan or Timmna in open moulds to produce simple objects (e.g. axes, chisels, and awls) and the casting of non-local, polymetallic alloyed copper in closed moulds to produce relatively complex objects (e.g., maceheads, standards, vessels, and crowns). The latter technology is often dubbed the lost-wax technique, and Late Chalcolithic artisans are widely assumed to have used beeswax to construct the moulds. However, while beeswax might have been used, we should also consider other possibilities. We suggest that ash butter is likely to have served this purpose. Unlike beeswax, butter was an everyday, accessible substance during the Late Chalcolithic period, and we demonstrate through a series of experiments that by mixing it with water and fire wood ash, the Late Chalcolithic artisans could produce a cheap and available material highly suitable for making the complex moulds.