When it comes to applying glazing putty to wood, it’s important to understand that while glazing putty adheres well to glass, it does not adhere to wood surfaces easily. If you’re repairing old windows, you’ll first need to scrape the wood surface using sandpaper to remove the weathered wood and paint.
Preparing the Wood Surface for Glazing Putty
Before applying glazing putty to a wood surface, it’s crucial to properly prepare the wood to ensure a strong bond. Here are the steps to follow:
Scrape off weathered wood and paint: If you’re working with an old window, use sandpaper to remove any weathered wood and paint from the surface.
Apply a primer: After scraping, apply a good primer to the wood surface. It doesn’t matter whether you use a water-based or oil-based primer, as some professionals prefer the latter while others have successfully used the former.
Sand new wood: If you’re using new wood, you won’t need to scrape, but you should still sand the surface to create a smooth finish for the putty to adhere to.
Proper preparation of the wood surface is the most important step when applying glazing putty, as poorly applied putty can fall apart within weeks if the surface isn’t prepared correctly.
Preparing the Glazing Putty for Application
Once you’ve prepared the wood surface, it’s time to prepare the glazing putty for application. Here’s how to do it:
Warm the putty: Since cold putty doesn’t work well, you need to warm it up to make it malleable. You can do this by working the putty in your hands until it softens and becomes sticky, or by submerging the container of putty halfway in pre-heated warm water.
Knead the putty: If you’re using putty from a tub, remove all of the putty and knead it to achieve a consistent texture. The oil in the putty often rises to the surface, and kneading helps distribute it evenly.
By properly preparing the glazing putty, you’ll ensure that it’s ready to be applied smoothly and effectively to the wood surface.
Applying the Glazing Putty to the Wood
Once you’ve prepared both the wood surface and the glazing putty, it’s time to apply the putty. Here’s how to do it:
Apply putty strings: Start by applying strings of glazing putty, also known as putty beads, along the length of the groove in the wood surface.
Fill in with a putty knife: Use a putty knife to fill in the groove with putty and smooth the edges. Hold the knife at a 45-degree angle to apply only the necessary pressure to the surface.
Smooth with your finger: After applying the putty, smooth the surface with your finger to create a clean, even finish.
Allow time to dry: Glazing putty should be allowed to dry for at least 24 hours before being painted, with some experts recommending letting it sit for a week.
By following these steps and applying the glazing putty correctly, you’ll ensure that it adheres properly to the wood surface and provides a strong, long-lasting seal.
Painting the Glazing Putty
Once the glazing putty has dried, you can paint it to match your window frame. However, it’s important to note that linseed oil putty can only be painted with an oil-based paint. If you try to use a water-based paint, it will likely peel off.
If you really want to use a water-based paint, you’ll need to buy acrylic putty and a sealant gun. However, be aware that the technique needed to use acrylic putty is completely different and can be more difficult than using linseed oil putty.
By choosing the right type of paint and following the manufacturer’s instructions, you can ensure that your painted glazing putty looks great and lasts for years.