to soften the light or provide privacy. It may be obtained
with a pattern on one or both sides.
Patterned glass has the same composition as
window and plate glass. It is semitransparent with
distinctive geometric or linear designs on one or both
sides. The pattern can be impressed during the rolling
process or sandblasted or etched later. Some patterns are
also available as wired glass. pattern glass allows entry
of light while maintaining privacy. It is also used for
decorative screens and windows. Patterned glass must
be installed with the smooth side to the face of the putty.
Laminated glass is composed of two or more layers
of either sheet or polished plate glass with one or more
layers of transparent or pigmented plastic sandwiched
between the layers. A vinyl plastic, such as plasticized
polyvinyl resin butyl 0.015 to 0.025 inch thick, is
generally used. Only the highest quality sheet or
polished plate glass is used in making laminated glass.
When this type of glass breaks, the plastic holds the
pieces of glass and prevents the sharp fragments from
shattering. When four or more layers of glass are
laminated with three or more layers of plastic, the
product is known as bullet-resisting glass. Safety glass
has only two layers of glass and one of plastic.
Safety glass is available with clear or pigmented
plastic, and either clear or heat-absorbing and
glare-reducing glass. Safety glass is used where strong
impact may be encountered and the hazard of flying
glass must be avoided. Exterior doors with a pane area
greater than 6 square feet and shower tubs and
enclosures are typical applications.
Glazing compounds must be compatible with the
layers of laminated plastic. Some compounds cause
deterioration of the plastic in safety glass.
Mimers are made with polished plate, window,
sheet, and picture glass. The reflecting surface is a thin
coat of metal, generally silver, gold, copper, bronze, or
chromium, applied to one side of the glass. For special
mirrors, lead, aluminum, platinum, rhodium, or other
metals may be used. The metal film can be semi-
transparent or opaque and can be left unprotected or
protected with a coat of shellac, varnish, paint, or metal
(usually copper). Mirrors used in building construction
are usually either polished plate glass or tempered plate
Proper installation requires that the weight of the
mirror be supported at the bottom. Mastic installation is
not recommended because it may cause silver spoilage.
Sheets made of thermoplastic acrylic resin
(Plexiglas®and Luciteo, both trade names) are available
in flat and corrugated sheets. This material is readily
formed into curved shapes and, therefore, is often used
in place of glass. Compared with glass, its surface is
more readily scratched; hence, it should be installed in
out-of-reach locations. This acrylic plastic is obtainable
in transparent, translucent, or opaque sheets and in a
wide variety of colors.
In this section, well discuss the various types of
sealers youll need to install, hold fast, and seal a
window in its setting.
Wood-sash putty is a cement composed of fine
powdered chalk (whiting) or lead oxide (white lead)
mixed with boiled or raw linseed oil. Putty may contain
other drying oils, such as soybean or perilla. As the oil
oxides, the putty hardens. Litharge (an oxide of lead) or
special driers may be added if rapid hardening is
required. Putty is used in glazing to set sheets of glass
into frames. Special putty mixtures are available for
interior and exterior glazing of aluminum and steel
A good grade of wood-sash putty resists sticking to
the putty knife or glaziers hands, yet it should not be
too dry to apply to the sash. In wood sash, apply a
suitable primer, such as priming paints or boiled linseed
Putty should not be painted until it has thoroughly
set. Painting forms an airtight film, which slows the
drying. This may cause the surface of the paint to crack
All putty should be painted for proper protection.
Metal-sash putty differs from wood putty in that it
is formulated to adhere to nonporous surfaces. It is used