Glass Bedding Methods

Before putting the glass in place the workman spreads glass putty along the ledge on which it is to rest; this is called bedding the glass, which is then pressed firmly into place and fastened there with little triangular bits of sheet zinc, called glaziers' points; these are put in from nine to twelve inches apart, and are laid flat on the glass and driven into the wood of the sash, the implement used for driving being a two-inch chisel which is held with its flat side on the glass and the edge away from the glass; that is, with the back of the chisel down, so as not to scratch the glass.

If the pane is smaller than the opening, it is so set that when the sash is in its proper position the pane will rest on the sash-bar below it; then there will be a crack between the pane and the sash on one or two sides, and the chisel is held vertically over this crack, and with its edge a crimp is made in the triangular zinc point (which has already been driven), so as to prevent the glass from sliding about. Zinc will readily bend, while steel will not, and this is the reason zinc is used for the purpose. These points are of various sizes: No. 1 are used for double-thick glass, No. 2 for the lighter glass. Fire-proof wooden sash are covered with thin sheet metal, and for use with such sash steel slugs are made; these are triangular, 7/8 inch long, 7/16 wide at the wide end, and 1/20 inch thick; these are also used for plate glass. It is of importance to use enough points.

When the glass is thus held in place, the rest of the putty is applied. This may be done while the sash is in a horizontal position; but the professional sets the sash upon a sort of easel, putties the right-hand side and across the bottom with one motion of the arm, then reverses the sash and putties the other side and end.

Sometimes, with soft-wood sash, bedding the glass is omitted, though wrongly so; but it is imperative for hard-wood and metal-lined sash, and for all plate and crystal-plate glass. But in case the glass has not been bedded in putty, we crowd some putty into the crack between the glass and the sash on the indoors side; this is called backing the glass. Large panes of plate glass are not puttied, but are held in place with strips of molding nailed to the sash, and the crack between the glass and the molding is backed with putty.

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