Casting is the technique of filling open or closed molds with molten glass. Heated to 1250°-1300°C, the glass attains a viscosity which allows it to take the exact shape of the mold down to the slightest detail. In the case of open molds the liquid glass is carried directly from the furnace to the mold with a ladle, or poured directly from a crucible into the mold.

This ancient technique, older than glassblowing, was already practiced as well as a pate de verre technique, in the production of amulets and figurines in Mesopotamia. Usually, the necessary amount of glass would be spread out on a flat surface before being formed or stamped with hand held molds. Some examples of pillar molded bowls from Hellenistic and Roman times were made using the same technique. Rarely used during the Middle Ages, this technique reappears in Venice during the Renaissance and eventually establishes itself in the XIXth century as a mechanized technique for the mass production of tableware. Casting from its very origins has always offered sculptural possibilities, but at a small scale. It was the glass artist Henri Navarre (1885-1971) who first noticed the exceptional artistic interest of casting, creating mysterious hieratic masks. Following his example the artists of the Studio Glass movement will further develop the technique of casting.

The American glass artist Howard Ben Tre has developed a sculptural body of work which approaches the monumental in its scale and volume, and in which great quantities of molten glass, supplied by a glass manufacturer, are ladle poured by a whole team of assistants. The cooling process for these massive pieces requires months of surveillance. His archetypal pieces like “Ring of Knowledge: Ground, Water, Fire, Wind, Void” (1993) are strongly symbolic, connecting them to the civilizations of the past.