Glazing putty is most commonly used in the installation of windows. Glazing is the process of fitting glass window panes into a window frame, and glazing putty is what you will need to ensure that the pane is held in place inside the frame. Glazing putty is important not only because it holds the windowpane but also because it serves as an excellent sealant. Window frames are made from wood, metal, and fiber, and the technique used to apply glazing putty differs depending on the material of the frame. Here’s how you should use glazing putty on wood.
Prep the Wood
When it comes to applying glazing putty to wood, you need to remember that while glazing putty adheres well to glass, it does not adhere to wood surfaces easily. Poorly applied glazing putty can fall apart in weeks, and that is why this step is the most important. If you are repairing old windows, you will first need to scrape the wood surface using sandpaper to remove the weathered wood and paint. Then, apply a good primer. Keep in mind that it does not matter whether you use a water-based or oil-based primer.
While some professionals will vouch for the latter, others have successfully used the former. If you are using new wood, you will not need to do any scraping; simply apply the primer.
Prep the Putty
Before you apply the putty to the wood, you need to prepare it for application. Since cold putty does not work, the main aim of this step is to warm the putty and make it malleable. You can do this by working the putty in your hands until it softens and begins to feel sticky. Alternatively, you can halfway submerge the container of putty in pre-heated warm water.
Apply the Putty
Once your putty is pliable, start applying it to the wood surface by using the putty knife. It is easier to apply strings of glazing putty, also known as putty beads. Place these strings along the length of the groove, and then use a putty knife to fill it in and smooth the edges. If you are setting a window, this is the time to place the glass pane. Use glazing points, or push points, to hold the frame in place.
Now, apply more putty. Always take more than needed, and gently remove the excess during the application process. You should hold the putty knife at a 45-degree angle. This ensures that only adequate pressure is applied to the surface. When you have applied sufficient putty, use the knife to draw a sharp line along the edge that meets the glass. After applying the required amount of putty, smooth the surface with your finger. Glazing putty should be allowed to dry for at least 24 hours before being painted. Some experts recommend letting it sit for a week.