Which Trade Portal is leading Indian Wood , Panel & Allied Industries?
The Process of Glassmaking
The processes of glassmaking have remained essentially the same since ancient times. The materials are fused at high temperatures in seasoned fireclay containers, boiled down, skimmed, and cooled several hundred degrees; then the molten glass (called metal) is ladled or poured into molds and pressed, or is blown or is drawn.The shaped glass is annealed to relieve stresses caused by manipulation, then is slowly cooled. The glass, formerly annealed on shelves in a melting furnace, is now usually carried on rollers through annealing ovens (lehrs).
Although today most hollow vessels such as light bulbs or containers are machine blown, fine ornamental hollow ware is still made by gathering a mass of glass at the end of a long, iron blowpipe, blowing it into a pear-shaped bulb, which is rolled on an oiled slab (marver), shaped with tools, and then reblown, often into a mold; the glass is reheated periodically in a small furnace (glory hole). It is finally transferred to an iron rod (punty) attached to the base of the vessel, and the lip is shaped and smoothed. Methods of decoration include cutting, copper-wheel engraving, etching with hydrofluoric acid, enameling, gilding, and painting.
Glass has become invaluable in modern architecture, illumination, electrical transmission, instruments for scientific research, optical instruments, household utensils, and even fabrics. New forms of glass, new applications, and new methods of production have revolutionized the industry. Recently developed forms of glass include safety glass, which is usually constructed of two pieces of plate glass bonded together with a lastic that prevents the glass from scattering when broken; fiberglass, which is made from molten glass formed into continuous filaments and used for fabrics or for electrical insulation; and foam glass, which is made by trapping gas bubbles in glass to yield a spongy material for insulating purposes. Certain uses of glass are now being superseded by newly developed plastics.