Glassblowing

Glassblowing is the process of forming glass into useful shapes while the glass is in a molten, semi-liquid state. While the first evidence of man-made glass occurs in Mesopotamia in the Late-Third/Early-Second Millennium BCE, the actual "blowing" of glass using a tube did not occur until the First Century BCE. This advancement transformed the material's usefulness from a time-consuming process in which the medium was hot-formed around rough cores of mud and dung into a mass-producible material which could be quickly inflated into large, leakproof vessels.

Traditionally, the glass was melted in furnaces from the raw ingredients of sand, limestone, soda, pot ash and other compounds. The transformation of raw materials into glass takes place well above 2000F; the glass is then left to "fine out" (allowing the bubbles to rise out of the mass), and then the working temerature is reduced in the furnace to around 2000F. "Soda-lime" glass remains somewhat plastic and workable, however, as low as 1000F.

A lampworker, usually operating on a much smaller scale, historically used alcohol lamps and breath or bellows-driven air to create a hot flame at a workbench to manipulate preformed glass rods and tubes. These stock materials took form as laboratory glass, beads, and durable scientific "specimens" - miniature glass sculpture. Still practiced today, the lampworker uses a flame of oxygen and propane. The modern torch permits working both the soft glass from the furnace worker and the borosilicate (low-expansion) glass of the scientific glassblower who may have multiple headed torches and special lathes to help form the glass or quartz used for special projects.




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