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.


https://www.youtube.com/watch?v=WlrqpL0LtNE

[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.

[Peter Aeschliman]

Gary, to reinforce your SARCO purchase, I can definitely recommend against DAP 33. As part of my basement renovation (I'm moving my shop in there), I restored all of the old wood windows. I used DAP 33, and it took about 2 months before the glazing was relatively firm (meaning, it didn't dent when I touched it with light pressure).

I used whiting (chalk powder) to remove excess oils on the surface probably every other day, and kept fans running on them nearly constantly. 65 degrees in the basement were they were drying (curing?). Super frustrating, but they eventually dried enough for paint.

Also, I recommend the small-diamond shaped glazing points. The ones you find at the big box stores (like the ones linked below, which I used) are too long. I found that when I tried to get the glazing putting to line up with the edge of the rabbet on the other side of the glass, I'd hit the glazing points... so I ended up putting on more glazing than necessary just to cover the points. It doesn't look all that great from the inside, and this might be part of the reason why it took so long for for the DAP 33 to harden.

I'm glad I learned these lessons for a project that I never intend to do again!!

Don't use these:
http://www.homedepot.com/p/Glazier-s-Steel-Push-Points-50-Pack-GP1HD/202284230

[Mel Fulks]

Charles,thanks. I had misinterpreted a couple of things by watching only one clip. And they do bed the glass using the popular latex caulk. Still think they are slow, but old guys are dying off and a lot of us have to find our own methods. The best glaziers I've seen were self employed and worked on job sites and on new stuff in mill shops when needed. They would typically take a long time to set up; endlessly kneading the putty etc. , then do the glazing quickly!

[Rich Engelhardt]

this might be part of the reason why it took so long for for the DAP 33 to harden.Actually - - no, Dap 33 is formulated for exterior application and it has an extended open time.
For inside - in shop - work, you want a Type "M" - which is what Sarco Multi Glaze is.
Sarco also makes a glaze for exterior application - the Sarco Dual glaze. Dual is the one to use when doing sashes that are already in place outside.
Dual is more "well behaved" than Dap 33 - meaning it's much easier for a novice to work with.

Dap 33 is a great product - - it's just not made for just anyone to apply it.


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.
The only thing I've ever seen applied to wood sash before setting the glass is linseed oil or Penetrol.
That's only done so the dry wood won't pull too much oil out of the glazing compound causing it to fail prematurely.

I don't know how "old timey" you consider this. I learned how to glaze back in the late 1960's and early 1970's. A lot of the painters that shared the info were well into their 60's at the time and most were 2nd and 3rd generation, having learned the trade form that father and grandfather.

[Wayne Lomman]

Definitely caulk both sides of the glass. Just because some old windows were done without caulk under the glass doesn't make it right. Cutting corners/laziness is not a new thing. Cheers

[Mel Fulks]

We have had a post or two giving details about sale of company and downgrade in Dap 33. In the last few years I ve seen failures. Not from perhaps an unskilled homeowner but from a skilled guy who runs a pretty prominate mill work company.
He was astounded by the short time before calls on failures. He would have been glad to blame an employee but,alas, he did his own glazing. I seriously doubt he still uses it.

[Paul Girouard]

My Granddad ,born 1894, long since dead, could glaze glass in like no one I've ever met. He was not a professional glazer , but he was a Dough Boy ,(Dough Boy = WW1 era solder / dog face , ) who was shipped to France near the end of WW1 , and he told me that's where he learned to glaze, repairing glass as they "worked" their way to the front. He said the war ended before he GOT to the front , so apperantly a lot of Dough Boy's where used as part of the rebuild , repair France / Europe effort.

He used Dap 33 , he didn't bed the glass in the dap , but he did prime the rabbit before he set the glass in , then the glazing points , then BAM , the glazing part was DONE, smooth as silk , a few quick , really quick, strokes of the putty knife and the glazing was done!

There's a few theory's why they where called Dough Boy's:



Doughboy as applied to the infantry of the U.S. Army first appears in accounts of the Mexican-American War (https://en.m.wikipedia.org/wiki/Mexican-American_War) of 1846-48,[5] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-partridge-5)[6] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-6)[7] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-7) without any precedent that can be documented. A number of theories have been put forward to explain this usage:


Cavalrymen used the term to deride foot soldiers, because the brass buttons on their uniforms looked like the flour dumplings or dough cakes called "doughboys",[2] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-brewer-2)[8] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-smithsonian-8) or because of the flour or pipe clay (https://en.m.wikipedia.org/wiki/Pipe_clay) which the soldiers used to polish their white belts.[8] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-smithsonian-8)[9] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-origin-9)
Observers noticed U.S. infantry forces were constantly covered with chalky dust from marching through the dry terrain of northern Mexico (https://en.m.wikipedia.org/wiki/Mexico), giving the men the appearance of unbaked dough (https://en.m.wikipedia.org/wiki/Dough) or the mud bricks of the area known as adobe (https://en.m.wikipedia.org/wiki/Adobe), with "adobe" transformed into "doughboy".[9] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-origin-9)
The soldiers' method of cooking field rations (https://en.m.wikipedia.org/wiki/Field_ration) of the 1840s and 1850s into doughy flour-and-rice concoctions baked in the ashes of a camp fire. This does not explain why only infantryman received the appellation.[9] (https://en.m.wikipedia.org/wiki/Doughboy#cite_note-origin-9)

[Mel Fulks]

Earlier tonight I aluded to a change in Dap 33 glazing putty. I can find no mention of it anywhere and I apoligize for possibly confusing experience with documentation. I stand by my comments about the failures I noted ,but at this point must admit the possibility of simply observing failures due to single bad or out of date product. Would appreciate any new information.

[Gary Viggers]

Before purchasing the Sarco Type M, I spoke to a product specialist at DAP. Mel is correct - it does not contain linseed oil anymore. Check out the MSDS http://www.dap.com/media/52763/00010401001english.pdf

It contains soya oil.

I also spoke with one of the owners of Sarco. According to him, that's what is being used on the window renovation at the White House. He gave me some tips on using their product. He also advised bedding with either the Sarco or caulk. I've got a bunch of DAP Dynaflex 230 that I'm going to use.

Peter, my points' protrusions are just barely in the acceptable range. I may track down some smaller ones.

[Mel Fulks]

Gary,thanks for vindication, I'm ending my self imposed exile on this rocky island! I had been unable to find that information and was starting to doubt my recollection of product change. Wishing you steady hand and smooth glazing!

[Rich Engelhardt]

It's quite possible Dap 33 never did contain linseed oil.
Tall and soya oils go way back - civil war era and before - so it's very possible the Dap formulation was one never based on linseed oil.

[Mel Fulks]

Possible. But SOMETHING is different that is causing early failures.

[Gary Viggers]

It's quite possible Dap 33 never did contain linseed oil.

The rep told me it used to contain linseed oil. I think she said the putty for metal windows still does.

[Steve Schoene]

When energy efficiency becomes an issue on such a house, one reasonably period alternative is to use an wood framed exterior storm window. Some are strictly old fashion but virtually the same look can be a achieved with a moveble lower pane, that allows a screen to be used. Off course the storms can be put in place in fall, and replaced by purely screen windows in the spring. The joys of a 1928 house.

[Rich Engelhardt]

The rep told me it used to contain linseed oil.

Interesting...according to the tech bulletin it still does.

http://www.dap.com/media/73954/33-glazing-tb-2012.pdf

Oh well. Someone is wrong....or someone hasn't updated the web site..

[Sherry Canon]

I would prefer to bed them and use a putty.It will be easier to remove the pane if it is broken, I recently did a casement replacement (http://www.heritagehomedesign.ca/) which I bought from heritage home design windows and doors. It is messy but it is easier to remove smaller pieces from the window frame than one unbroken piece. Sometimes even after you remove the putty and the points the window may not come out. This could be because it could be glued to the place by the old putty that was used to bed the glass.This bedding gives better air seal and allows the air to seat firmly against the frame when you set the points. Heating the glass with a heat gun around the perimeter will soften the old putty allowing you to remove the old glass.If nothing works then you would have to break the glass to remove it.

[Brian Williamson]

About 5 years ago I built 18 sashes of VGDF windows to match those original to the house. The original 1939 glass was bedded and the millwork was painted under the glazing. For the new sash, I pre treated the rabbets with copper green and painted over that. I used Dap 33 to bed and glaze. Everything's fine so far, but I'm in sunny so-cal so no hard weather here..!