Glass video introduction video 2

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Glass (video introduction)video 2
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Bunsen Burner Safety

• Tie back or tuck hair!
• Keep flammable materials away from burner!
• Remember-burner and glass stay hot for some time
  even after the burner is shut off

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Glass History

• Glass is one of the oldest manufactured materials
  without a known discovery date. Nature makes
  natural glass.
• Natural glass
• Obsidian is a common natural glass product formed
  by intense volcanic heat and is usually black,
  but can be red, brown, or green.
• Obsidian was used by early peoples to make
  jewelry, weapons, tools.
• 5000 B.C. glass was found around campfires on
  sandy beaches.
• 5000 B.C. First attempts to make glass in region
  of Syria.
• 4000 B.C. Glass beads and bottles found near
  Mesopotamia
• Egyptians used glass products as adornments for
  the rich and powerful because glass production
  was very expensive.
• 200 B.C. Babylonians invented the process of
  glass blowing that changed the production rate
  from a couple of hours to several minutes.
• Romans were first to produce a relatively clear
  glass and flat glass.
• Glassmaking spread throughout the Roman Empire to
  Syria, Egypt, Greece, Italy, Gaul, and Brittany.

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Early Glass Manufacturing

• Glass blowing process
• Glass blowpipe is a hollow iron tube from 4 to 5
  ft long with a knob at one end and a mouthpiece
  at the other end.
• Dip knob end into melted glass, where glass
  sticks to the end of pipe.
• Air is blown gently while rotating pipe which
  produces a hollow bulb of glass, where the
  thickness of the bulb depends on size of bulb.
• The bulb cools and solidifies into a number of
  symmetrical shapes.
• Molds are used to rapidly cool glass and allow
  more many shapes, including, bottles, dishes,
  lamps, and jars.
• Glass slabs
• Early attempts included rolling hot, clear glass
  over stone slabs covered with sand leaving rough
  pockmarks that distorted the light passing
  through it, making it unsuitable for window
  glass.
• 600 C.E., Syrians discovered efficient way to
  manufacturer sheet glass which involved blowing a
  bubble of glass that was spun and produced a
  crown in the center, named crown glass.

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Middle Ages to Modern Glass Manufacturing

• Glass production moves to Venice after Crusades.
• Stain glass became common in churches.
• 4 centuries of Venetian influence elevated
  glassmakers to noble status.
• Production methods and craftsmen were highly
  guarded and were prohibited from emigration upon
  penalty of death.
• Modern Glass Manufacturing
• 16th Century, Venetians perfected first colorless
  and transparent glass.
• Product called cristallo glass and was used to
  make lenses for microscopes, telescopes, and
  early cameras.
• 16th and 17th Centuries marked the beginning of
  the modern period of glass since glass became a
  tool of science.
• In 1675 flint glass (produced with lead oxide)
  developed to give distictive brilliance and
  comparative softness for easy forming.
• In1688 the French perfected making quality flat
  glass by pouring molten glass over flat iron
  tables and rolling out with rolling pins and then
  polished by hand. Similar process is automated
  today.

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Glass Manufacturing in America

• Glass making started in Jamestown Virginia in
  1608.
• Caspar Wistar imported Belgian glass-workers to
  New Jersey in 1739 and set up glass business for
  high quality glass ware.
• Henry Stiegel founded glassworks in Penn. in 1765
  and made finest blown glass and the first flint
  glass. Closed 1774.
• Winstar plant closed in 1781
• Boston and Sandwich Company founded in 1825 and
  was the first large scale production plant.
• Credited with inventing the method of pressing
  glass into iron molds to make less expensive
  glass for the general public.
• Closed in 1887
• Since 1887 many U.S. glass companies have formed
  and failed
• Today glass manufactures are conglomerates, e.g.,
  Owens-Corning Fiberglass, Vetrotex Certaineed,
  Fiberglass Industries