Window glazing recommendations requested

[Forrest Bonner]

I am in the process of repairing some French windows that requires replacing many of the window stops on the outside of the windows. The windows (13 doors) are around 20 years old so dry rot is found now and then.

I am in Southern California so we have much UV but not too much rain.

I would appreciate recommendations of a brand or type of window glazing to use that holds up well in UV.

Forrest

[David Thompson 27577]

I would appreciate recommendations of a brand or type of window glazing to use that holds up well in UV.

Forrest

DAP 33 is the bomb, assuming that you know how to use it.

[Peter Pedisich]

DAP 33 is the bomb, assuming that you know how to use it.

Yes, DAP 33 is good. Get it warm in your hands by kneading it well, and roll it out, keep a light coating of BLO on the putty knife and it goes on smooth. Make sure the wood muntins are not dryed out, if they are then you should wipe them with a little BLO so they don't draw all the oil out of the glazing compound. Clean the glass as soon as you are done.
It takes forever to cure...weeks at least, often more. Then you must paint it, 'cause...UV protection = paint.

[Floyd Mah]

It's important when glazing to prevent water from getting in and damaging the wood. I made the mistake many years ago of not putting a bead of putty between the glass and the wood. The net result was some water damage to the frame. This time around, I made sure to both prime and paint the muntin before glazing, with the intermediate putty. The putty external to the glass may crack, but the bead is less likely to crack with aging.

Also, many years ago I visited a window shop when ordering windows and watched a guy applying putty. He was obviously not the best paid employee and was given the task of puttying the windows. Regardless of his position, he was able to do the most beautiful work. I went on to putty about a dozen windows, almost 100 individual panes. It turned out to be a very difficult job for me. I learned several things. Not all putty are alike. Some are softer and easier to apply. You'll have to decide whether to use the stuff that comes in a container or the stuff from the caulking tube. It turned out that the smooth application by the window shop guy was a skill learned by doing many windows. The main thing that I learned technique-wise was to stroke the putty with the knife in two directions. The first stroke to apply the putty gets it into position, but depending on the consistency of the putty, may lift the putty off the muntin. When you subsequently stroke in the opposite direction, that will set the putty down into the window frame. Try to keep the adjacent glass clean. It might be good to tape some paper or newspaper to the glass. The reason is that it takes a lot of work to clean the window later. For me, the exterior of the windows were hard to reach after they were installed, which of course is when you first notice how messy the left-over streaks of putty are. In your case, you probably can get at the door glass easily, but it's still a laborious task to clean the oily putty off the glass without making dents in the fresh putty.

I also found the task of getting the putty into the strips that I could easily press into the frame was difficult. Hand-rolling, even extrusion from a caulking gun, were not satisfactory techniques. There was also a lot of hand labor in pressing globs of putty into the frame. I am currently faced with glazing many panes (more than the last time) and I think that this time I might get a rolling pin to flatten the putty and use a knife (plastering knife) to slice it into small strips. I would appreciate it if anyone has a better solution.

Since you mentioned dry rot, consider getting one of those penetrating epoxies that restore wood. You just brush it on and it hardens the existing soft wood. It also works as a primer. Bondo makes a product that is similar to the wood replacement putty that the epoxy guys sells, but at a tenth of the price.

Good luck. You are facing a job that is literally painful (pane-full?).

[Neal Clayton]

there is an acrylic glazing putty. it's called glaze ease. i've used it on about 10 sets of double hungs over the past two years, and so far they're holding up fine. the look isn't as nice as traditional putty, since it's water based it shrinks a bit. but it works, and it can be painted the same day.

the best glazing putty (best being defined as most resembling traditional putties that last for decades) seems to be sarco type M. it can be ordered online. absent that, yes, dap 33.

whichever you use, if you use an oil based putty, you need to put a sealer on the rabbets to avoid the wood leeching the oil from the putty. shellac is ok, since it's protected from the sun.

you must let the putty skin over before painting it as well. if you paint it too soon, the paint will fail and you'll have to do it all over again. typically, a week, depending on the weather, is a safe amount of time.

floyd's point about an epoxy to seal up dry rot is correct as well. abatron woodepox is the preferred product for that purpose for window restorers that i've seen.

whichever putty and method you choose, note that you have to paint on to the glass a bit to seal the putty, that is critical to longevity. you either need a sash paintbrush (the bristles are cut at an angle) and hand skills, or tape the glass and pull the tape while the paint is still wet. the second method rules out a fast drying water based paint, obviously.

[David Thompson 27577]

......... I made sure to both prime and paint the muntin before glazing............

Perhaps I learned wrong, when I learned about window glazing about 40 years ago.

I was told that if the wood muntins were dry (and they all are), that I should coat them with boiled linseed oil. Linseed oil, since it is the polymerizing ingredient in the glazing compound, would both nurture the wood, and act as a binder between the wood and the glazing compound.

(On edit -- polymerization is a chemical reaction that happens when linseed oil and oxygen meet. It changes the wood, it changes the oil, and it changes the putty. It makes them all into a polymer -- kinda like a plastic or a cement.)

When the polymerization in the wood was done, then the polymerization in the glazing would also be done, and the 'system' would be complete. Both the wood and the glazing polymerize into a single structure, because of the oil.

Although priming the wood will prevent the dryness from pulling the oil out of the putty, it also prevents the crucial 'oneness' of the wood/oil/putty.

[David Thompson 27577]

>>"you need to put a sealer on the rabbets to avoid the wood leeching the oil from the putty. shellac is ok,......"<<

See my post above (sorry -- on edit, I find that it's actually below).

IMO, a shellac seal for window glazing is not a good thing. It prevents the oil in the putty from becoming one with the oil in the wood.

The reason that window glazing is so incredibly difficult to remove (after fifty or sixty years, or just one or two) is because it has become part of the wood-glass-putty-BLO polymerization. It's all one piece. Adding any primer or sealer (like paint or shellac) between the layers defeats that process -- it prevents the polymerization from including the wood in the chemical reaction. The wood cannot become one with the putty.

>>"whichever putty and method you choose, note that you have to paint on to the glass a bit to seal the putty, that is critical to longevity....."<<

Absolutely true. A layer of paint that covers the wood, the putty, and about 1/16" of the glass, is critical to the waterproofing and weatherproofing concepts. Without that layer, the putty will dry and shrink, and will allow leaks.

[Rick Gooden]

I make many historic reproduction windows. Myself and all others that I know doing this type of work use a product called Sarco putty and have found it much easier to work with than DAP. I was made aware of it from an historical window restoration and reproduction seminar. We also use BLO as others have mentioned.

[David Prince]

I have done better than 120 windows over the last few years. DAP 33 works fine. Make sure it is fresh out of a new can for best results. BLO should be used if needed.

It takes some practice and a good putty knife. Try a couple of knives to see what feels best for you. I like one that has a bit of flex to it.

Paint after it has formed a skin.

I then used a razor to clean off paint and excess residue on the pane after everything is dry.

A good heat gun works wonders to get old glazing off.

[Neal Clayton]

Perhaps I learned wrong, when I learned about window glazing about 40 years ago.

I was told that if the wood muntins were dry (and they all are), that I should coat them with boiled linseed oil. Linseed oil, since it is the polymerizing ingredient in the glazing compound, would both nurture the wood, and act as a binder between the wood and the glazing compound.

(On edit -- polymerization is a chemical reaction that happens when linseed oil and oxygen meet. It changes the wood, it changes the oil, and it changes the putty. It makes them all into a polymer -- kinda like a plastic or a cement.)

When the polymerization in the wood was done, then the polymerization in the glazing would also be done, and the 'system' would be complete. Both the wood and the glazing polymerize into a single structure, because of the oil.

Although priming the wood will prevent the dryness from pulling the oil out of the putty, it also prevents the crucial 'oneness' of the wood/oil/putty.

i have heard both arguments for and against, and have always opted for sealing the rabbets. to be honest, it probably depends as much on the species of the wood and its age as anything else as well. older, more dry wood will leech more oil from new putty, new wood will not. i have used all 3 common methods (oil sealer, primer, a thinned coat of shellac) and after a few years, i honestly don't remember which were done which way, but they all look the same and seem to be holding up fine.

either way since i use cypress for new sashes primarily, and i have seen oil paint and oil putty struggle to adhere to cypress due to the watery sap in the wood, i do use some sort of sealer to help anything oil based bind to said wood.

as for the technique forrest, here's a video with a pretty good demonstration...

http://www.youtube.com/watch?v=_J5oNMfI5og

it's not rocket science, just a matter of figuring out a method of holding the knife that's comfortable and can be maintained in a single stroke. it's simple enough to practice, just cut a 3/8 x 3/8 dado in the edge of a scrap board and glaze it until you figure out a method that's comfortable for you.

the only thing not in that video that i can think of is don't be too meticulous about drips and putty residue and such. rather than trying to clean up such mistakes when the putty and paint are wet, just let it all dry, and you can easily clean the glass afterward with a razor scraper, it's easier that way and saves on tape ;).

[Forrest Bonner]

I did not make it clear in my original post that I am replacing the wooden stops that hold the glass in. The wooden stops will be tacked to the fixed muntins with narrow crown (22 gauge) staples. I need to seal the stops to keep water out.

Is DAP 33 still the product to use to seal the wood windowstop-to-glass interface? Should I put a narrow bead under the stop-to-muntin and stop-to-glass interfaces when I install the stop? The now-exposed muntin and the replacement stops will all be primed before installation of the new stop. All will be painted later.:mad:

I was told years ago by the manufacturer that it is important to shape the glazing compound next to the glass so that there is no 'gulley' or valley that would catch and hold water.

Forrest

[Neal Clayton]

glazing putty is in every way superior to wooden strips. putty is flexible, wood isn't. putty doesn't trap water, wooden strips do.

why not just glaze the windows and ditch the wooden strips?

[Forrest Bonner]

I am sticking with wood stops because I have 210 individual panes, most of whose wood is in good shape, and I don't think I have the time, or patience, to ship out all the wood stops and reglaze.
But thanks for the thought!:)

Forrest

[David Thompson 27577]

I did not make it clear in my original post that I am replacing the wooden stops that hold the glass in. The wooden stops will be tacked to the fixed muntins with narrow crown (22 gauge) staples. I need to seal the stops to keep water out.

Is DAP 33 still the product to use ..........

Forrest

Well, it seems that we (myself included) have spent the last dozen responses trying to give you the right answer to the wrong question.

In all of the old doors and windows I've repaired that use wood stops, there has been no sealer other than the interior and exterior finishes.

I've often thought that a very thin bead of glazing compound, or even some silicone, would be a good addition to those doors and windows. It would act as a cushion for any imperfections in the wood, and would absolutely seal out the weather.