As we power on through the extremely time consuming and ridiculously intricate project that is The Front Vestibule, we occasionally run into situations where a little bit of time and patience go a long way towards making the project much better. Sometimes the need to work slower and more deliberately is difficult when all you want to do is finish the friggen project. For me, the little angel on my shoulder saying "take your time and restore this the right way!" usually beats out the devil that says, "just hurry up and finish the damn thing already!" Such is the case with the work we've been doing on the new front doors. Wait, was that the little devil on my shoulder saying that or was it Wendy standing behind me?

When we purchased the french doors, which were actually old sidelites, many of the panes of glass were either broken, or had been replaced with newer glass that didn't seem correct.

This week I've been spending quite a bit of time working on the salvaged french door lites (panes of glass). After I finished removing all of the broken and unbroken panes of glass from the two doors, scraped out all of the glazing putty, and give it a quick sanding, the doors were almost ready to receive new glass. 

I won't actually install any glass until after we've added the additional wood to the doors, mortised the hinges, and made sure the doors are hung in their correct location. Otherwise I'm sure I would end up breaking a pane in the process. But that didn't stop me from getting the glass ready for the doors this week.

One of the things I absolutely love about old houses and antiques is the minor but striking detail and character that wavy glass brings. It's one of those little things that screams "I came from a simpler time, where things were still hand made, imperfect, and unique!" We are lucky enough to have much of the original glass in many of the windows in our house, including the transom windows inside. Whenever I've added glass elements to the house, or replaced newer glass, I've been sure to use salvaged or reproduction wavy glass in every situation. What can I say, I'm obsessed.

Wendy's parents own an older home in Lakewood, Ohio that is a duplex rental. Recently, they replaced some of the windows in the house for more energy efficient models. They know all about my love of old wavy and imperfect glass, so they gave me the window sashes that were removed from the house the last time they visited us.

Lucky for me, the two windows were quite large and in really good shape. Best of all, the large panes of glass were wavy enough to work perfectly in our salvaged french doors. But to make them work for our project, I would need to carefully remove the glass from the window sash, clean it up a bit, then cut it to the correct size for our french doors. This is where the level of patience I mentioned would come into play. I couldn't  make a mistake and end up breaking the glass.

The first step to this process is the most important. It involves removal of the old glazing putty and glazing points so that I could remove the glass from the sash. Old putty that has been in a window sash for a long time is often rock hard and brittle. Some suggest using a heat gun to warm the putty and make it more pliable, which allows you to scrape it away easier, but that is too risky when you care so much about the glass. The heat from the heat gun can easily fracture the glass without warning.

The technique I like to use for putty removal is a simple and methodical process of a utility knife and 5-in-1 tools. I use the utility knife to break the seal between the back of the putty, then I use the 5-in-1 tool to scrape it away as I can. With each tool I make sure I do not put any significant pressure on the glass, only on the putty and wood of the window sash. Here's a quick video showing my technique. 

Though the rest of the glazing came out in larger chunks, the portion Wendy recorded the video on was far more stubborn. For this part I really had to get the knife into the wood behind the glazing to free it. This worked fine since we aren't using the sash. If we planned on using the sash, I would have simply taken more time to get between the glazing and putty.

Once all of the glazing was out, I inspected the entire perimeter of the glass for glazing points. Glazing points are the little metal triangles or diamonds that hold the glass in places before the putty sets up. They are tiny, but if you don't take them all out, your glass will surely break when you are trying to free it. If you look closely, you can see a tiny point in the photo below at the tip of the tool.

To remove the glazing points, I use the 5-in-1 tool to slightly get under the point and bend it up a little. Then I use the edge of the tool to rotate the glazing point out of it's position and away from the glass.

With all of the points removed, I begin working to free the glass from the sash. Glass bends a little, so you have some give to it, but if you force it too much, it will easily break. So I start in the corner and just start pushing up and down on the glass until it gives a little bit. Once it starts to give, I continue to work around the sash until the whole thing is free. If there is a point that isn't letting go, I look very closely to be sure I didn't miss a glazing point, and then I use the utility knife to cut between the glass and the wood. 

I then repeat this process all the way around the glass until the pane of glass is free from the sash. I was very patient with this pane of glass, probably because it was so large. Have I mentioned I REALLY didn't want to break it? My patience paid off and the end result was a break-free and huge piece of glass just waiting to be cut.

The new french doors take six lites of 10-1/4" x 11-9/16" in each side. Cutting glass is actually very easy if you have the right tool for it. The key is the small glass cutter with a fresh and sharp cutting wheel and a straight edge that you can run the tool along.

You don't need a lot of pressure, just a straight edge and a sharp wheel will score the glass in one pass. Don't make multiple cuts, that won't help. Just run the cutting wheel along the glass in one direction one time. You should hear the glass getting scored by the cutting wheel. It sounds just like movie special effects sounds when a robber is cutting a circle in a building's glass. Once you are across, you can easily see the scored line.

With the cut mark made, I move the glass so that a portion is unsupported and the scored line area of the glass assumes much of the weight. Then I just apply even pressure on the unsupported side of the glass while holding the other side in place. If all goes well, you will get a sudden and clean snap and a very sharp piece of glass with a good straight line.

Then, if you have any dirt, putty, or paint left on the glass, just use a razor blade and some Windex or a 50/50 of water and vinegar to scrape it away.

Once the glass was cleaned up, I did a test fit of the piece I had just cut.

I then repeated these steps over and over and over until I had all of the pieces of glass cut for the french doors. It is best to cut the glass slightly smaller than the opening it will be going in, that way it will fit easier and will allow for expansion of the wood or glass. 

We have a little ways to go before I put this glass in for good and putty it, but I'm quite happy with the fact that the doors will fit nicely with the age of the house and look quite appropriate with slightly to very wavy glass in true divided lites. It should add to the character and comfort of the new doors and entry of the home in a subtle but significant way. And the real icing on the cake is that we were able to reuse salvaged glass that might have otherwise ended up in the dump.

I know I'll do another post about this once we actually putty the glass into place. That is seriously an art form to do it well, and I'm by no means an artist. 

Have you had much experience in cutting glass? I know there are lots of different ways to cut glass, some even involve WD-40. If you have an interesting technique or practice, we'd love it if you shared it here.

Comments 5


Josh Shaffer
7/22/2011 at 12:54 PM
You need to create a jingle for before your videos. :)
Old Town Home
7/22/2011 at 12:59 PM
We agree, kind of a signature intro like they have on This Old House.
Josh Shaffer
7/22/2011 at 1:09 PM
That is what was in my head when your videos started.
10/23/2012 at 11:28 AM
Hi Alex,

Just found your website while looking for ways to re-purpose some "wavy" glass window sash. I had always heard that old glass cannot be cut because it is too brittle. But you did it? Any problems with cutting it?

thanks for a reply,

Hi Ken,

Yes, you can absolutely cut old glass. It is more fragile than modern glass, and sometimes the cut doesn't go quite where you want it to go, but you just need to take it slowly to get it to work the way you want it to. The key is a sharp and fresh cutting wheel, and apparently to also use cutting oil. I didn't use the oil the last time, but plan to use it on the next project where I need to cut old wavy glass.
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