Glazing Compounds
Putty, glazing compound, rubber, or plastic strips and metal or wood molds are used for holding glass in place in sash. Metal clips for metal sash (Fig. 11.35e) and glazing points for wood sash also are employed for this purpose.
Putty and glazing compounds are generally classified in relation to the sash material and should be used accordingly for best results.
Bedding of glass in glazing compound is desirable, because it furnishes a smooth bearing surface for the glass, prevents rattling, and eliminates voids where moisture can collect (Commercial Standards, U.S. Department of Commerce). Glazing terminology relative to putty follows:
Face Puttying (Fig. 11.35a). Glass is inserted in the glass rabbet and securely wedged where necessary to prevent shifting. Glazing points are also driven into the wood to keep the glass firmly seated. The rabbet then is filled with putty, the putty being beveled back against the sash and muntins with a putty knife.
Back Puttying (Fig. 11.35b). After the sash has been face-puttied, it is turned over, and putty is run around the glass opening with a putty knife, thus forcing putty into any voids that may exist between the glass and the wood parts.
Bedding (Fig. 11.35c). A thin layer of putty or bedding compound is placed in the rabbet of the sash, and the glass is pressed onto this bed. Glazing points are then driven into the wood, and the sash is face-puttied. The sash then is turned over, and the excess putty or glazing compound that emerged on the other side is removed.
Wood-Stop or Channel Glazing (Fig. 11.35d). A thin layer of putty or bedding compound is placed in the rabbet of the sash, and the glass is pressed onto this bed. Glazing points are not required. Wood stops are securely nailed in place. The sash then is turned over, and the excess putty or glazing compound that emerged on the other side is removed.
Glazing Beads (Fig. 11.35Æ’). These are designed to cover exterior glazing compound and improve appearance.
Continuous Glazing Angles (Fig. 11.35g). These angles or similar supports for glass usually are required for labeled windows by the National Board of Fire Underwriters.
Table 11.17 lists some commonly used glazing compounds and indicates the form and method in which they usually are used. Other compounds used for special service include silicone rubber, butadiene-styrene (GR-S) rubber, polyethylene, nitrile rubbers, polyurethane rubbers, acrylics, and epoxy.
