Setting Glass in Wood and Metal Sashes

Figure 4-30.-Types of metal-sash glazing. nonporous surface. Figure 4-30 shows examples of the types of metal-sash putty. Elastic glazing compounds may be used in place of putty. These compounds are produced from processed oils and pigments and will remain plastic and resilient over a longer period than will putty. A skin quickly forms over the outside of the compound after it is placed, while the interior remains soft. This type of glazing compound is used in windows or doors subject to twisting or vibration. It may be painted as soon as the surface has formed. For large panes of glass, setting blocks may be placed between the glass edges and the frame to maintain proper spacing of the glass in the openings. The blocks may be of wood, lead, neoprene, or some flexible material. For large openings, flexible shims must be set between the face of the glass and the glazing channel to allow for movement. Plastics and heat-absorbing or reflective glass require more clearance to allow for greater expansion. The shims may be in the form of a continuous tape of a butyl-rubber-based compound, which has been extruded into soft, tacky, ready-to-use tape that adheres to any clean, dry surface. The tape is applied to the frame and the glass-holding stop before the glass is placed in a frame. Under compression, the tape also serves as a sealant. Glass may be held in place in the frame by spring clips inserted in holes in the metal frame or by continuous angles or stops attached to the frame with screws or snap-on spring clips. The frames of metal windows are shaped either for outside or inside glazing. SETTING GLASS IN WOOD AND METAL SASHES Do not glaze or reglaze exterior sash when the temperature is 40°F or lower unless absolutely necessary. Sash and door members must be thoroughly cleaned of dust with a brush or cloth dampened with turpentine or mineral spirits. Lay a continuous 1/6-inch-thick bed of putty or compound in the putty run (fig. 4-31). The glazed face of the sash can be recognized as the size on which the glass was cut. If the glass has a bowed surface, it should be set with the concave side in. Wire glass is set with the twist vertical. Press the glass firmly into place so that the bed putty will fill all irregularities. When glazing wood sash, insert two glazier’s points per side for small lights and about 8 inches apart on all sides for large lights. When glazing metal sash, use wire clips or metal glazing beads. After the glass has been bedded, lay a continuous bead of putty against the perimeter of the glass-face putty run. Press the putty with a putty knife or glazing tool with sufficient pressure to ensure its complete adhesion to the glass and sash. Finish with full, smooth, accurately formed bevels with clean-cut miters. Trim up 4-26