Tips on How to Repair a Broken Pane of Glass

Repairing a broken pane of glass in a wood window is a task that most home handymen can tackle with a minimum of effort.

The first step is to remove the old glass. Arm yourself with leather gloves, eye protection, and a stiff putty knife. Begin by removing any loose glass that can easily be removed simply by pulling it out. Then use the putty knife to scrape out the old window putty.

Coating the putty with linseed oil will help soften it, or you can use a hot air gun or a light application of heat from the tip of a soldering iron. Beware of propane torches or other high-heat sources, as they can leave behind smoldering paint that can ignite hours later.

With the putty removed, you’ll find that the glass is held in place with several small, flat metal pins, called glazier’s pins. Use one corner of your putty knife and a pair of pliers to remove them one at a time, carefully removing each freed-up section of broken glass as you go.

With the glass removed, use sandpaper to clean and smooth the channel in the window frame. Apply a light coat of linseed oil to the wood in the channel to prevent the dry wood from absorbing the oil from the new glazing compound you will use.

Measure the exact size of the frame opening, and have a glass company cut a new pane of glass for you. They will undersize the new pane slightly to simplify installation and allow room for the glazing compound.

Start with a small ball of glazing compound, and roll it between your palms to form a rope about one-quarter-inch in diameter. Press the rope into the channel to form a bed for the new glass. Add additional lengths of the compound until the entire channel is filled.

Press the new pane of glass into the glazing compound, slowly and firmly, until a small amount of excess compound is forced out around the channel. Using the tip of your putty knife, secure the pane to the frame by pressing new glazier’s points into the wood channel. The points should be spaced four to five inches apart, and avoid placing them too close to the corners of the glass. Scrape off any excess putty.

The final step is to place a top coat of glazing compound over the glazier’s points, forming a seal between the glass and the frame. Roll out ropes of compound as before, and press them into the channel around the entire window frame. Holding the putty knife at an angle, carefully smooth the compound into a bevel from the edge of the window frame onto the glass itself.

Dipping the blade of the putty knife in warm water will help prevent sticking and make smoothing the putty much easier.

Allow the compound to dry for 7 to 10 days, then paint it with a good grade of exterior paint. Lap the paint slightly onto the glass to form a complete weather-tight seal.