How Do You Glaze a Window?

Glaze a WindowIf you have an old home, you more than likely have windows in desperate need of re-glazing. Glazing is the stuff that makes up the weathertight seal keeping the elements from wreaking havoc on your window’s wood and glass, but over time, it can dry out, crack, and wear down, necessitating a need for a re-glazing. For newer double-glazed windows, this means a trip to a glass shop, but older single pane windows can be done by hand with a little bit of know-how and a decent amount of elbow grease.

The Materials
First things first, you’ll need some supplies. For this particular project, you’ll need:

  • Oil-based primer
  • Sandpaper
  • Painter’s tool
  • Putty knife
  • Glazing putty
  • Paintbrush
  • Paint
  • Heat gun (optional)
  • Razor knife (optional)

For chipping away old glazing, a painter’s tool works well, but if you don’t have one, Family Handyman says using the putty knife works just fine. A heat gun could make the job easier, according to This Old House, but some people feel it doesn’t do enough good to justify the time expended. Popular Mechanics recommends a razor knife on hand to pry stubborn, painted-on glazing free.

The Procedure

Step 1: Take down the window sash. While it’s entirely possible to do this while the window is still up, it’s an added layer of difficulty that’s entirely unnecessary. Spare yourself the hassle, remove the sash, and find a flat surface to get to work on.

Step 2: If you want to reprime the window, you’ll want to scrape and sand off any old, chipped paint now. Doing this before the glazing process will help prevent any flakes getting into your glaze. You more than likely will want to do a new coat of primer, to help seal the glass and putty and provide more weatherproofing.

Step 3: Remove the old putty. With the painter’s tool (or putty knife), begin chipping away the old putty. Some spots will practically fall away at the lightest touch, but other areas may be more difficult to pry loose. The razor knife may come in handy for those, but remember to use caution and a delicate touch to avoid damaging the glass. If you find it impossible to remove some of the old glazing compound, this is where your heat gun will come in handy. Take appropriate precautions to protect your glass– covering it with aluminum foil and being cautious will do– and heat the putty. Adding heat should make the putty soft enough to enable removing any problem areas.

At this point, if you’re replacing a broken pane, you should be aware of the glazier’s points: small metal clips embedded into the glazing to hold the pane in place. If you need to remove the pane, take these out with pliers now. You’ll need to put in new ones or recycle these old ones when you replace the pane.
This is also when you’ll want to prime the frame, if you so choose. No need to be overly cautious; excess primer on the glass can easily be scraped away, and uneven coating on the wood can be smoothed with the brush.

Step 4: Reglaze. Time for the main event! Get your putty and scoop out a golf ball sized glob, then work it in your hands to warm it up and get it pliable, for about a minute. Next, roll it into a snake and press it into the edge between the pane and the muntin with your fingers. Be sure to get the putty deep into the corners. Take your putty knife and work the putty into the seam, first going perpendicular to the muntin, then running at an angle along the glazing to smooth it and remove the excess. To get rid of the excess, simply scoop it up with your putty knife. Ensure a professional, finished look by ending with one long smoothing pass. The glazing should be flush with the muntin on the opposite side of the window, so that it’s not visible when looking out. You might also choose to run your finger along the glazing to make sure the putty and glass form a tight seal. Repeat this process around the whole pane, and for each subsequent pane.

Step 5: Repaint. After the glazing has cured according to the specific brand’s instructions, probably about a week, it’s time to reprime and repaint your window. When painting, be sure the lap the paint about 1/16th of an inch onto the glass pane. This will help create a seal, protect your glazing, and increase the longevity of its life.

Step 6: Replace the window. You’re done! Put the sash back in to its opening and give yourself a well-deserved pat on the back.

Now you’ll want to clean the glass to get it looking its best, but if you use denatured alcohol, keep it away from the putty. Kick back and enjoy your newly weatherproofed view!

Related Resource: Aluminum Window