Glazing Windows

[Gary Viggers]

I'm replacing all of the louvre windows in my house with casement windows. I've already built the frames (douglas fir, loose tenons, Whiteside sash router bit) and now it is glass installation time. The glass dealer gave me a lesson on glazing (on previous windows I had used shop-made mitered wood moldings), but one of his steps goes against everything I have read or seen online. He does not put the glass on a bed of putty or caulk, just straight in the rabbet, then puts in the points, then does the glazing. He has 30 years of experience and said this is how the old-timers did it (he said look under old panes and you will NOT see putty under the glass). Any old-time glaziers out there? Does this sound right? Any possible problems using his method or should I first bed the pane in putty or caulk?

I'm using DAP 33 unless someone can recommend a different glazing putty.

Thanks,

Gary

[Jerome Stanek]

That is how they did my parents greenhouse and they had an acre and a half under glass.

[Mel Fulks]

Does not sound right. Obvioussly everything that can be done wrong is often done wrong. Architectural specs on custom mill made sash usually say the "bedding" is required. I see it as a common sense thing in that it minimizes glass breakage ,seals against air leakage, and keeps the glass from rattling. Some years ago I took four sash to a local glass shop to be reglazed. I had removed the glass ,scraped all old putty on glass and wood and primed the sash. Told the counter guy I wanted them bedded and glazed. He wrote that on ticket. When I picked them up I tapped on a pane and it rattled! What a pane pain! When I asked him why they were not bedded he said "guy in the back said it wasn't neccessary and we don't do it". I complained bitterly and irately and demanded big discount. Sorry to hear you ran into the same incompetant. Dap 33 is a low grade non lasting product. I'm told it used to be good. Sorry I can't remember name of one of the good ones, please google it .

[Floyd Mah]

I have rebuilt and installed over 25 windows (casement style) in my house over the years. The important step is to paint the frames first. This ensures that the window frame under the glass and putty doesn't rot. Putty under the glass also helps seat and seal the glass in case the frame is not completely in one plane. It takes just a few seconds to do, in fact, the easiest part of the glazing.

If the windows are in a room with a lot of moisture (bathrooms or dining room and kitchen where people may be sitting, talking and eating a long time), moisture can get under the muntins and rot the wood. This would happen especially in climates where the temperature difference between the interior and exterior is significant. (I have single paned windows, so this is an important consideration). For the small investment in time, I think it is a worthwhile measure.

(Here's a hint for cleanup if you use the oily type of glazing putty. The glass can get quite smudged with the oily residue of the putty while you are working unless you can come up with an easy way to protect the surface short of taping most of the window. If you sprinkle talcum powder on the window, you can brush away the powder after it's soaked up the oil. It will leave behind a clean surface. Don't know if this hint puts you at risk for ovarian cancer if you are a woman. Might be a good idea to do this step outdoors or in an area with good ventilation.)

[Adam Herman]

there is no scientific link between talc and cancer. some people got scared because talc and asbestos used to come from the same mines and our system of social justice decided they should get some evil corporate profits for their trouble.

anyway...

i would bed them and use a high quality putty. No reason not too really. are you installing insulated glass or single pane?

[Larry Browning]

I painted houses in the summers when I was in college back in the early 70s. Almost all windows were casement. Part of painting was to always to re-glaze the windows before painting. I never once encountered a bedded pane of glass. It may be that it was a more common practice north of Tulsa, OK where the winters are colder.

May I ask why you decided to do wooden casement windows? Seems rather energy inefficient in these days of double and triple gas filled pane, vinyl clad energy efficient windows.

Just wondering.

[Robert LaPlaca]

Does not sound right. Obvioussly everything that can be done wrong is often done wrong. Architectural specs on custom mill made sash usually say the "bedding" is required. I see it as a common sense thing in that it minimizes glass breakage ,seals against air leakage, and keeps the glass from rattling. Some years ago I took four sash to a local glass shop to be reglazed. I had removed the glass ,scraped all old putty on glass and wood and primed the sash. Told the counter guy I wanted them bedded and glazed. He wrote that on ticket. When I picked them up I tapped on a pane and it rattled! What a pane pain! When I asked him why they were not bedded he said "guy in the back said it wasn't neccessary and we don't do it". I complained bitterly and irately and demanded big discount. Sorry to hear you ran into the same incompetant. Dap 33 is a low grade non lasting product. I'm told it used to be good. Sorry I can't remember name of one of the good ones, please google it .

Mel, is the glazing compound brand you are thinking of Sarco? I understand it is the brand used by window restorers and professional glazers.

[Tyler Trowbridge]

I have a friend that went to North Bennett St. School for Preservation Carpentry. He was taught to bed his glass in glazing compound there. He also recommended Sarco brand putty to me before as the one of the best.

[Mel Fulks]

Robert, I'm not as involved in this stuff as I used to be. I've seen some recommendations on good ones posted on this forum before and am confident you will see more replies.

[Charles Wiggins]

I don't think they mention it specifically in the narration, but when they clean the old glazing off you can see pretty plainly that there is no bed of glaze under the glass.

[Mel Fulks]

That video would be fine as instruction for home owners, IF they bedded the glass. As an ad for that company all I get is the realization that the homeowner better be rich! I've worked with glaziers many times faster ,they could feed the putty out of their hand faster than most could empty a caulking gun into a garbage can. And they didn't use tape. Why should the expensive use of tape be accepted as a substitute for skill and the cheap, practical, often specd.out bedding be rejected?

[Gary Viggers]

May I ask why you decided to do wooden casement windows? Seems rather energy inefficient in these days of double and triple gas filled pane, vinyl clad energy efficient windows.

Just wondering.

I'm restoring the house back to its original 1928 features. There used to be wood casement windows, so that's what is going in. I've used 1/8" laminated glass for some other windows (a little better sound/weather insulation than regular single pane), but it was not available this time. I may look for other sources of lami after I finish the two sashes that I already have glass for.

I had previously heard of Sarco, and after reading more about it ordered some. I think I'm going to scrape off the putty (DAP 33) on the two panes we did at my "lesson" and redo them with bedding once the Sarco arrives.

[Mel Fulks]

Most I've worked with now use latex caulk for the bedding. Fast and easy to trim off later.

[Michael Weber]

+1 on Sarco putty. You'll likely have to buy it online but it is highly recommended by restorers. Among other advantages it's ready to prime and paint much sooner than the Dap product. Another step to do is to paint the bare wood where the putty contacts with linseed oil to keep the wood from absorbing the oil quickly from the putty.

[Charles Wiggins]

Why should the expensive use of tape be accepted as a substitute for skill and the cheap, practical, often specd.out bedding be rejected?

Painting with a spray gun.