To repair a broken single pane window you must first scrape away the old window glazing compound around the perimeter of the broken pane. In the process you may or may not have to remove the metal glazier’s points stuck in the wood frame. Next, carefully remove the broken pieces of glass. Once the glass is out, continue scraping the recess area of the frame to ensure that it’s clean, flat and smooth.
If the wood is in bad shape it may be necessary to sand the surface with a sanding sponge. The new glass pane should be cut about one eigth of inch less than the dimensions of the opening. If the wood frame is not coated with paint or stain, apply a light coat of primer to the surface before proceeding. When the primer is dry, carefully set the new pane in place and secure it on all four sides with new glaziers points. Press the pointed end of each point against the frame and gently press it into the wood with a putty knife. Be careful not to break the glass as you press on the glazier’s points.
Next you will apply the glazing compound along the edges where the glass meets the wood. Get the glazing compound that comes in a caulking tube. Now use a putty knife to smooth it out. Turn the knife at a 45 degree angle from the top of the wood molding out about a quarter inch onto the glass and slowly pull it along the molding. The flattened bead of glazing compound should cover the glaziers points completely and have a smooth, even surface. After the compound dries for a day or two it’s ready to paint.