6 Secrets to Glazing Windows

A carefully glazed window can look crisp, professional, and nearly brand new.  Glazing is a technique that comes with steady hands, lots of practice, and patience.  While producing the perfect glazed window feels like a daunting task, especially to someone who doesn’t often participate in the process, the good news is that any mistakes can be redone by scraping off the putty.

Unlike painting and other house projects, glazing is generous in missteps and accidents—there’s no harm nor foul should you need to restart.

a man glazing a new replacement window

1. Use the Right Putty

Setting yourself up for a successful window glazing starts with buying the right product for the job at hand.  There are several different kinds of putty and picking the right one for window glazing will make the task go much more smoothly (and in the same respect, choosing the wrong putty can make for a real mess of it).

There’s a little more to choosing the right kind of putty than simply grabbing one off the shelf that says “good for window glazing” on its label.  You’ll need to take into account the material of the window you’re glazing.  Steel and aluminum windows will require a different type of putty than a wood window.

The putty isle can feel overwhelming if you’re new to glazing, but simply read the labels and you’ll be able to narrow down the right putty for your window.  Manufacturers will clearly indicate on the labeling what type of material the putty is best suited for, so just make sure to take note of your window material before you head to your local home improvement store.

2. Use the Right Tool

Using the right tool for the job is just as important as using the right putty.  You’ll need a good putty knife for this application, like the Lamson ¾” bent putty knife or any professionally-graded putty knife that you can pick up at your local home improvement store or online.

Using a putty knife will make the delicate process of glazing a window go much more smoothly as the tool helps you to be precise with your lines.  Putty knives that are stainless steel will also prevent the tool from rusting.

using a putty knife to seal a replacement window

3. Make Sure Your Putty is Fresh

One of the biggest secrets of professionally glazed windows is that the pros use fresh putty—meaning, your pail of putty should be nearly brand new.  Putty has a relatively short shelf-life, so the pail that’s been sitting around for months will probably have separated oils and won’t make for a good glazing job.

Even fresh putty will have a layer of cured skin on the surface.  Should you open the lid and find that this is the case, don’t mix this layer back in.  You’re going to need to scrape off this layer to avoid undissolved chunks in your putty that will make a mess of your glazing.

4. Whiting Powder

Even the most perfect glazing job will leave behind some oils from the putty onto the window glass.  The oils will need to be cleaned before you paint and the best way to remove them to do so right away by means of a process called whiting.

Whiting powder is chalk dust and can easily be picked up at your local home improvement store or online.  This powder will absorb the oils of the putty quickly which will help clean the glass.  The residual oils from the glazing putty are also absorbed and this helps expediate the curing process.

If you don’t clean the glass right away after glazing, you could be stuck scrubbing off the oils for hours.  Sometimes the dried oil won’t come off unless you use a razor blade.  Skip this headache and use whiting powder to clean the glass up right away and help cure the putty faster.

5. Keep Lines Small and Clean

Professional glazing looks clean because the lines are kept as straight as possible.  It also helps to glaze smaller lines, keeping them 1/16” to 1/8”, leaving room for some imperfections and to prevent paint from showing from the inside when you run a paint line overtop of your putty.

Your goals should be to be able to look through the window from the inside and not see the backside of the glazing putty.  The glazing putty lines should be invisible and the best way to achieve that is to keep the lines small and clean.

6. Keep Your Corners Sharp

The way you glaze your corners will determine if the glazing job is amateur or professional.  Professional window glazing leaves the corners clean and sharp.  Sharp corners means there is a distinctly clear line of glazing that isn’t bubbled or rounded over.  Pointed, sharp corners is the secret to elevating your window glazing.

If you’re in the market for replacement windows in any of our markets across the Midwest, we hope that you’ll consider Feldco for your window replacement project.

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