Window Glazing -- what am I doing wrong

DrRod · Oct 20, 2015

We have an old building where I noticed that the putty was virtually all gone from the window panes. So I tried to used traditional window putty but found it way too hard to work with. So I got some DAP in a tube and tried applying that. I've had some success but have to admit its a pretty sloppy job -- especially in the corners. So my first question is: do I push it or drag it along the seam? Second, is there a trick to this or is it just a matter of practice.

Thanks

KennyG · Oct 20, 2015

The traditional putty is easy to use as long as it isn't too old. The key is to take a hunk of it and knead it and roll it in your hands until it becomes very soft and pliable. Then put it into place and use the glazing tool to drag over the putty and leave a smooth surface. If it cracks and separates as you drag and doesn't have a smooth surface, you didn't work it and mix it enough before placing it. I've never used the stuff in a tube but I assume you still have to use the glazing tool to finish it.

JRobyn · Oct 20, 2015

I think that the "binder" in old-school glazing putty is linseed oil that will separate out over time in the can. So like Kenny says, you have to knead it to redistribute the oil and soften the rest (clay?) until it is smooth and pliable. Then it should be MUCH easier to work.

- Jay

JamesHW · Oct 21, 2015

I have been working on re-glazing some very old windows where the wood has dried out and have had some success brushing on some boiled linseed oil* into the muntins where the glass sits so it can soak in and renew the wood. Then I push a bed of Dap 33 glazing putty into the frame with my fingers for the window pane to rest in prior to placing the glass and pushing in the glazing points. As KennyG & JRobyn correctly point out working the putty to get it warm and pliable makes the job easier. The boiled linseed oil (dries faster than plain linseed oil) will renew the wood and prevent the dry wood from drawing the oil out of the glazing putty which can lead to cracking. Some people just go ahead and paint the muntin with alkyd primer, but I find the traditional putty sticks better to the oiled bare wood on old windows. I just go ahead and apply the putty immediately after brushing on the BLO. I let the finished glazing putty dry for a couple of days or longer prior to painting with a coat or two of alkyd primer.

The DAP in a tube is I believe a latex product as opposed to the more traditional glazing compound so may not work well with my method described above.

*Care must be taken when working with linseed oil and rags as they rags can spontaneously combust if left in a pile or dropped into a garbage can as the oily rags will generate heat while drying. Additionally, boiled linseed oil contains additives that can be toxic, so care should be taken while handling it

Bengineer · Oct 21, 2015

KennyG & JamesHW have it. Oil the bare wood when you have everything out, points, Dap 33, a glazing tool & a little patience and you'll have new looking windows in no time. I let the glazing age a week before priming & painting. I leave a little line of paint past the glazing onto the glass to seal the glazing in when cleaning up.

Now what I'd like to know is how to get the old glazing out efficiently. A heat gun or infrared heater works, but it seems like I always crack a pane. Too impatient, I guess.

KennyG · Oct 21, 2015

Bengineer said:
Now what I'd like to know is how to get the old glazing out efficiently. A heat gun or infrared heater works, but it seems like I always crack a pane. Too impatient, I guess.

I usually seem to just wait until it falls out. :confused3:

square1 · Oct 21, 2015

Now what I'd like to know is how to get the old glazing out efficiently. A heat gun or infrared heater works, but it seems like I always crack a pane. Too impatient, I guess.

Glazing used to be one of my tasks at the mom & pop hardware store where I worked after school. always used a propane torch to soften the glazing for removal. The pointed flame is easier to direct the heat away from the glass. Helps avoid cracking.

A little linseed oil on the putty knife used to smooth out the new glazing compound will help the knife glide smoothly across, rather than pull, the compound.

japody · Oct 21, 2015

There are several good videos on YouTube that show how to lay down the putty.

Coyote machine · Oct 21, 2015

When done. put the oil soaked rags in a 5 gallon pail of water to let the oil separate out from the rags. This greatly reduces the chances of fire from the Linseed oil.