Glass Technology:

1
Glass Technology an outline of processes and
applications
Harvard Graduate School of Design
2
Design concerns for base material of glass

• transparency
• reflectivity
• color
• texture
• strength
• Design concerns for assembly
• structural system
• thermal performance
• acoustical seal

3
Base material specified by fabrication process

• Float glass most common, relies on continuous
  production cycle
• Rolled glass used primarily for specialty glass
  such as wired safety glass
• Cast glass for special forms, textures glass
  block
• Wired glass is required by fire code in
  critical locations to prevent catastrophic
  breakage during high heat conditions -- the
  integral wire restrains glass shards from flying
  out. Wired glass may soon be replaced in general
  usage as borosilicate safety glass becomes more
  affordable to produce.

4
Base material specified by color

• Green glass
• ordinary float glass has slight green tint
• Museum grade or "water-white" glass
• green tint is eliminated by removing iron oxide
  from the glass chemical mix
• Body-tinted glass
• integrally colored glass rarely used in
  construction today due to improvements in surface
  tinting technology

5
Secondary processes

• Tempering after formation glass is reheated and
  quickly cooled to reduce normal surface tension
  result is a glass 5x stronger than ordinary float
  glass breakage, when it occurs, results in less
  dangerous, rounded shards
• Curving modifying formed glass through reheating
• Laminating transparent acrylic polymer used to
  fill cavity between two panes of glass polymer
  adds strength and has adhesive function in
  failure (prevents glass shards from scattering)

6
Tertiary processes

• Sandblasting produces an irregular surface for a
  frosted or diffuse effect, transparency
  controllable by degrees should be sealed
  afterwards in areas where people are likely to
  touch the glass.
• Etching creates similar diffusing effect on
  surface using hydrofluoric acid to scar the
  surface of glass self-sealing.
• Sputtering microscopic spray coatings of various
  metals to vary the degree of light and heat
  transmission across the EM spectrum mirror glass
  and low-e(missivity) glass are typical
  products sputtering technology is also used for
  coloring and holographic effects.
• Fritting a silk-screen printing of ceramic
  material is baked on to the glass surface nearly
  infinite variability of patterns, transparency.