how to replace broken glass in old windows
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How To Replace Broken Glass In Old Windows

Do you have old windows with that lovely old wavy glass but a pane is cracked and so you want to know how to replace broken glass in old windows? This guide will show you how.

Our place has a few old double hung windows and instead of replacing with new, I wanted to restore the windows and replace the broken glass, saving money and living sustainably.


Replacing Broken Panes of Glass in Old Windows

  1. Prepare the New Used Pane of Glass

    First, you will need to find another old window the same size. Try the web or local classifieds for anyone looking to get rid of theirs or second-hand stores. Even if they don’t have one, they might know of someone who does.

  2. Scrape Off the Old Putty

    Next, you will need to carefully scrape off the old putty around the pane using a chisel. Carefully scrape along where the putty meets the glass then along the top where the putty meets the frame. It is best to use many strokes than to put too much pressure on the glass as the glass will crack, especially with downward pressure.

    Removing putty from window with a chisel.

  3. Bend Up the Tacks

    Once the putty is removed, bend up the tacks which are holding the glass in place then carefully remove the pane of glass. 

    Window tacks

  4. Remove the Glass

    Set it in a safe place where it won’t be broken while you work on the other window. You may need to use a rubber mallet to tap open the frame to aid removal, but if there is any putty still left on the window, the pane will break.

    Using a Rubber Mallet to take apart the Window

  5. Removing the Existing Window

    Remove the windows from the wall.  There is usually just a strip of timber along either side of the window which will need to be removed. The window will then come out easily. If old paint is making them stick you will need to carefully wiggle the window until it comes loose or try scraping down the sides where the paint is holding on.

  6. Removing the Broken Glass

    Remove the putty from around the broken pane. You will not need to be as careful with the glass as it is already broken but remember to wear gloves and protective glasses in case a broken shard flies up and lands in your eye.

  7. Sand

    Sand down the window, using a coarse grit sandpaper to get the build-up of paint off. Then switch to a finer grit for the finish and wipe clean. Scape old paint off the replacement window pane with a razor blade.

  8. Glazing

    Use linseed oil-based putty for glazing. Place a small amount along the base where the window pane will sit and use a putty knife to smooth it off. Carefully set the window pane in place then bend down the tacks.

    Apply putty before placing down window.

  9. Apply Top Glazing Putty

    Place putty along the top edges of the pane and smooth off. Use regular putty to fill any holes in the wood frame. Sand off when dry being careful not to touch the linseed putty that will be still drying.

    Applying putty to a glass window.

  10. Dry then Paint

    Allow 2 to 3 days for the putty to skin then paint with an oil-based undercoat before applying the top coat. I used a gloss enamel for the two top coats. Depending on your climate it can take several weeks for the putty to completely harden. However, you can put the window back in place after the painting is finished and dried.

    Painted Window

You can find window putty at Amazon. (Paid link)

To save or print this guide on how to replace broken glass in old windows, here is the  PDF Version

Have you ever tried making doorhandles from scrap materials?  Try this DIY guide How to Make Door Handles.

Looking for more projects around the home? Try making a Bird Bath or Reusing a Broken Cup.

For more information on homesteading, try this free Homesteading guide.

For more information try this guide on DIY Projects around the home.

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