DO-IT-YOURSELF : Sharpen Your Skills on Fixing Broken Panes

Replacing a broken pane of window glass is a relatively simple task and, for most homeowners, an inevitable one. However, if it’s performed carelessly, it can result in injury.

To make the job easier, it’s advisable to remove the window sash from the frame and repair it on a workbench. Lay the sash on the bench with the exterior side up. While wearing heavy-duty work gloves and safety goggles, pull free any loose shards of glass from the shattered windowpane.

Next, remove the old putty from around the pane. If the putty hasn’t become too hard, you can pry it off with an old chisel or rigid-blade putty knife. Otherwise, you’ll have to first soften the putty with a heat gun and then scrape it off.

Also remove the glazier’s points that you’ll find under the old putty stuck into the wood sash and muntins. The small metal points secure the window glass to the sash.

After removing the old putty, pull free all of the remaining glass from the broken pane. Now scrape down the sash and muntin rabbets to the bare wood using a chisel held perpendicular to the surface.

Apply a liberal coat of linseed oil to clean the rabbets with a small brush. The linseed oil will prevent the bare wood from absorbing any oil out of the new glazing putty. Oil in the glazing putty helps keep the putty flexible and crack-free longer.

Although glass cutting is very easy, if you’d rather, you can custom-order pre-cut glass from most hardware stores and glass shops.

It you do it yourself, cut the pane from single-strength glass with a standard glass cutter. Measure the opening and subtract one-eighth inch from the overall width and length.

Nail a straightedge board to the workbench and butt the replacement glass against it. Lubricate the cut line with kerosene and, while using a framing square as a guide, score the glass with the cutter.

Wearing gloves and goggles, hold the glass with the cut line on the edge of the bench. Push down firmly and the glass will break cleanly on the line.

After your glass is cut to size, apply a one-eighth-inch-thick bead of glazing compound (not putty) in the rabbets around the opening. Compound is preferred over putty because it doesn’t dry brittle and it resists cracking and shrinking.

Position the pane in the opening and press down gently to eliminate any air pockets that may appear in the compound. Then, using a rigid-blade putty knife, push glazier’s points in the rabbets to secure the glass. Space the points about four inches apart.

Roll glazing compound between your hands to form three-eighths-inch-diameter ropes. Lay the ropes around the edges of the pane and press them into place with your fingers. Be sure to conceal all of the glazier’s points.

Using a flexible-blade putty knife, compress the compound to form a smooth, triangular-shaped bead. Clean off the excess compound from both sides of the glass.

Allow the compound to dry for about a week before repainting it. Then apply the paint so that it extends about one-sixteenth inch onto the glass to form a moisture seal. This little trick will help to protect the compound and seal the glass from excessive moisture.