subject: Replacing The Glaze On Single-pane Windows [print this page] Many older, single-pane windows contain a glazing compound putty; this putty seals the edges and holds the glass in place. While it will last for years, it will eventually harden and crack or fall off, allowing the elements to slip in. Luckily, you can replace the putty and any broken glass yourself in under an hour.
You can replace the putty and glass while the window is in the wall, but it's easier to do and more effective if you remove the window and clamp it to a flat surface. Get rid of any broken glass first by putting a piece of cloth over the cracked pane and tapping it with a hammer. Remove the shards from the frame by hand, and extract the glazing points with a pair of pliers. Be sure to wear eye protection and thick gloves while you do this. Next, get rid of the putty. If it's in very bad condition, it should be a simple task to take out the chunks. If it's not so old, it will take longer to pull off. Use a heat gun and a putty knife to soften and pry out the putty. Move the heat gun around so you don't crack the glass, and keep leather gloves on so you don't get burned! You can protect the glass with some sheet metal if you're concerned. Once you have the putty out, prime the bare wood inside the frame with a quick-drying primer (shellac-based).
You can get new glass cut at a hardware store. Measure the opening and subtract an eighth of an inch from the dimensions. Take some of the old glass with you to match the thickness. Depending on the size, it will probably cost from five to thirty dollars for the new pane. You'll also want to purchase some glazing points to hold the glass in place and some glazing compound. Oil-based putty is good if you need a smooth result. Latex putty, on the other hand, lasts longer and dries faster, so you can paint it sooner than with oil-based. However, it often dries out before you can make it fully smooth.
If you're using the oil-based putty, put a drop of acrylic latex caulk inside the frame before you set the glass inside. Press it down firmly, then apply the putty. Smooth it out (warm the can in a bowl of hot water to make it soft) and be careful not to touch it for a few days. If you have latex putty, put a drop of compound in the frame first, then set in the glass. You can prime and paint the putty soon after you've applied it.
