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| Glass and
Glassmaking Terms |
 A
Brief History of Glass and Glassmaking
About 6,000 years ago Egyptian or
Mesopotamian potters are believed to have
manufactured the first glass quite accidentally
while firing their earthenware. The first glass
was in the form of a glaze, a mixture of sand and
minerals fused onto the surface of stone or
ceramic objects. The glaze resulted in a hard and
shiny outer surface. |
 The Chemistry of
Glass Much to the surprise of most people,
glass is actually more of a fluid than it is a
solid. In fact, if you could view a long-term
ultra-high-speed motion picture of a pane of
window glass you would see the glass actually
slowly flowing to the bottom of the pane. |
 Making Glass by
Machine Sand, soda, and lime are the chief raw
materials used in making glass. Cullet is waste
glass or recycled glass that may be added to aid
the melting process. These materials are mixed
together and the resulting batch is sent to a
furnace where it is subjected to extremely high
heat until they literally melt together into
molten glass. |
 Making
Sheet Glass Using the Drawing Method
In the drawing method, a
ribbon of glass is drawn vertically from the
glass furnace up an annealing tower by powered
asbestos rollers which grip the ribbon as soon as
it has cooled enough, a few feet above the
furnace. This process is used primarily for
window glass. |
 Making
Sheet Glass Using the Float Method
In the float process, a
continuous ribbon of glass up to 11 feet wide
moves out of the melting furnace and floats along
the surface of a bath of molten tin. |
 Making Colored
Glass is as easy as adding specific chemical
compounds to the batch of silica, soda and lime. |
