How to Install Glass in a Steel Window Frame

Glass that is properly installed and sealed within a steel window frame ensures a home stays safe and cuts down on energy costs. However, installing window glass the right way can be an intimidating task for some without the proper know-how so that no damage is done to the steel window frame, the glass, or you.

Let’s take a look at the proper steps to take to install window glass in a steel frame.

Take measurements

You can’t install the right window glass without first knowing what size glass you need to cut. You can do this easily by measuring the interior area of the frame. To prevent expansion cracking in the future, make the cut ⅛ smaller than the measurement you took. Make sure you buy the same type of glass as the one you’re removing.

Prepare to install window glass

Once your glass is measured and cut, it’s time to install. 

Gather all the materials you’ll need, including:

• Thick safety gloves
• Glazing putty
• Putty knife
• Hammer or rubber mallet
• Painters tape/masking tape/duct tape
• Protective eyewear
• New spring clips
• Cut glass 
• Chisel
• Abrasives or sandpaper
• Pliers
• Heat gun

Keep in mind that it can be dangerous to install window glass. Breaking and removing glass from the window can cause cuts and can get into your eyes without the proper protective eyewear. So wear those goggles or glasses and heavy-duty gloves to avoid injuries throughout this process.

Remove putty

Next, you’ll need to remove the old glazing putty. Take a chisel and remove as much as possible to make installing window glass easier. If the putty is being a bit stubborn and you’re having a hard time getting it off, use a heat gun to warm the putty and scrape it off. 

Glazing putty can be rock hard, so keep heating it and trying again if it’s still not coming off. You don’t want to be too rough with the putty because it can damage the steel window frame. Just keep repeating the heating technique, and it’ll eventually be easy to remove.

When you’re done, sand down the area to make it smooth.

Take out spring clips

Once everything is sanded down, and all the putty is removed, take out the spring clips. You should have 2 to 4 spring clips, depending on the type and brand of glass. 

Use the chisel to pry out the spring clips and then set them aside. Do not put these back in once you’ve installed your new glass. You should have new spring clips to install for the new glass. Spring clips are available for purchase at any home improvement store. 

Remove the glass

You really need to ensure you1’re wearing those heavy-duty gloves for this one. 

First, grab the duct or painter’s tape and make a criss-cross pattern across both sides of the glass. If you don’t have tape, have a friend hold a piece of plywood against one side of the glass instead to catch any broken glass.

Next, take a hammer or rubber mallet and tap the outer edges of the glass. This should break the glass enough to remove it. Tap the glass to break it until no more glass remains. In most cases, the glass won’t come out in just a few big pieces; you’ll see that there are jagged shards of glass remaining around the edges. Take your pliers to manually pull these pieces out. If you’ve opted for the plywood option, have your friend tilt the plank back slowly to catch the broken glass.

Install window glass

First, grab some of your glazing putty. Make sure the glazing putty you choose is safe to use with steel window frames. Then, roll it into a rope that is about ¼ inch thick and use this putty rope to line the entire steel window frame. Finally, use the putty knife to press the putty down and smooth it out. 

Next, firmly bed the glass in the glazing putty you just lined the steel window frame with. Insert the glass from the bottom and slowly tilt it up. If your friend is assisting you with your home window installation, bedding the glass is a bit easier. 

Once you see that most of the putty has been squeezed out from the inside, the glass has been properly bedded. Then, take the new spring clips and put them in the same place as the old ones. They should be at least six inches apart. 

Completing Your New Window Installation in a Steel Window Frame

The last step for installing window glass is to clean up any excess putty around the steel window frame. This process ensures that the glass looks neat and tidy. However, you must clean the window carefully without messing up the glazing putty. 

Clean up any mess around the window and make sure the frame is smooth and looks clean. Spray a glass cleaner if the glass has smudges or is dirty to make it stand out and be crystal clear. Then, take a step back and admire your luxurious new glass window encased in a steel window frame.