Advice needed: window repair

[Pat Evans]

I just removed the old glass from the first of 14 casement windows that need new glass. The wood stop, I believe called glazing bead, was stapled in as well as being set in a caulk bed. It did not survive.

The glass is double pane which has an internal frame and sealant around the edge. To conceal that the wood glazing bead is about 3/4" wide. Rather than a square profile and glazing to fill the corner, the profile of the glazing bead has a beveled edge that mimics glazing and the whole bead is well seated in a bed of caulk.

What would be the best wood from which to make new glazing bead?

[Neal Clayton]

cypress, spanish cedar, mahogany, white oak. anything naturally moisture resistant would work.

alternatively you could use actual glazing putty (like dap33) if you're so inclined.

[Forrest Bonner]

1+ with Neal's comment. I have had to replace the wood stops - real wood - on several panes of French door/windows. I used white oak that I had but needed to rout a profile to match the existing wood. I used a string of DAP33 (based on advice from this Forum) under the wood to help seal the stop to the glass. I primed all surfaces before installing.
Forrest

[Neal Clayton]

i was talking about glazing with the putty in lieu of the strips, actually.

the reason the window manufacturers use the wooden strips is speed, it's inconvenient for them to use putty because you have to wait a few days for the putty to skin over before you paint it so it's not conducive to mass production.

putty is better, though. it's more flexible, so it won't lose its seal and trap moisture, it lasts for decades as long as you keep the paint touched up, and it can be spot repaired rather than having to pull/mill new strips when it needs maintenance. and since it's oil based it bonds to the wood like paint does, there won't be any joint failure because there's no joint.

considering you'll have to mill the strips yourself the time difference wouldn't be that much and it would certainly be cheaper, you'd just spend the time on tooling the putty instead of cutting the strips.

if you go that route, generally...

a) knead/roll the putty into rope like lengths like playing with play doh when you were a kid
b) press it into place by hand
c) tool it to shape with a putty knife leaving the putty 1/16 shy of the interior profile
d) let the putty dry for about a week
e) tape off the glass even with the inside profile (so you have 1/16 of glass showing beyond the putty edge)
f) paint, pull the tape while the paint is wet so it flows to a clean line (no need to prime)
g) clean any residue/paint spots on the glass with a razor scraper, and you're done

you'll typically wanna take a look at the putty/paint every 10-12 years thereafter to touch up a bit. as long as the paint is maintained the putty should outlive you.

[Peter Quinn]

I have never seen double glazed insulated glass actually held in with putty. The one thing I didn't see in Neal's description was the installation of the glazing points that hold in the actual panes of glass. The putty does NOT hold in the glass initially, this is done with some type of glazing points or triangles, and these don't really work with typical insulated glass panels. You could actually breach the seal if you nicked it hard and that will lead to fogging and early failure. Plus you would be looking at a HUGE bead of putty that would take forever to set at that thickness. I am a strong proponent of old single glazed windows on classic buildings, with storms for the second layer. But that doesn't sound at all like what you are looking at.

We usually make the glass stops out of the same material as the window frame, and we usually make the window frames out of mahogany, mostly african these days. Spanish cedar would work well too. White oak doesn't take nails well and wouldn't be high on my list. You could certainly give the stops more legs by priming with an epoxy sealer like Smiths CPES or a thin coat of west systems.

Another possibility might be polyurethane trim. you can get it in 5/4, which would be thick enough to split on a bevel for two stops and maintain the smooth factory face out. I have never used the plastic trim as a glass stop, but i have used it in lots of other trim applications around windows and it works very well. It holds paint like rice holds white, it never rots, its impervious to water, might be a good option.

[Floyd Mah]

Here's a hint for using glazing putty. I recently completed five windows (after making 11 windows ten years ago and with 14 more to make). My technique for applying the putty has evolved over this time. Each window had 6 to 8 panes, so there was a lot of putty to apply. Most people advise making a roll of the putty by hand, putting it in place by hand and then pressing and tooling by hand (after bedding the glass in a thin layer of putty and placing the points). I found it messy to handle the putty by hand and got unreliable rolls, perhaps because I hated using my hands. The other part of applying the putty is that you can develop a greasy mess on the pane itself from any stray bits of putty. This creates a problem later when you are trying to wipe the smudges off and disturbing the nice bevel that you created. I developed a technique which I have not seen done by others, but possibly has been discovered independently. Visualize this technique as an artist with a palette in one hand and a paint brush or knife in the other.

The most important part of glazing is to make sure that the putty that you have is not too stiff in consistency. Too stiff and it's hard to shape easily. Use two joint knives to do your work. One should be a large plastering joint knife. I used one with a 10" blade, but 6' or 8" would also work well. The other had a 4", slanted blade. I would basically use the 4" knife to scoop out a ball of the putty from the bucket and place it on the larger blade. The ball is about 2-3" in diameter, whatever you can handle easily. Lay the larger knife along the window frame, leaving an appropriate gap for the putty, about 5/8". Then I would use the smaller blade to cut from the ball enough putty to press against the window frame and the glass. As I formed the bevel, I would cut more putty, move the larger knife if needed along the frame and press more putty into the frame. In this way, I could progress down the edge of the frame. The advantage was that I didn't have to handle the putty, I could control the amount of putty deposited fairly precisely and I could move rapidly, especially with so many windows to do. No putty was deposited on the glass except where I wanted it. After the initial bevel is formed, then I would go back to form the bevel to its' final dimensions. Normally when you draw the blade along the bevel, you create a curl of excess putty which falls back on the glass and creates part of the mess that you have to clean up. This is hard to do without denting the nice bevel that you just made. There are two ways to avoid this. The less convenient method is to prop the window upright and the curl goes wherever gravity directs it. The second is to take the large blade, lay it next to the bevel, and it picks up the curl as you shape the bevel. I also use the larger blade at this time to help control the smaller blade, to get a straight edge, running the tip of the smaller knife against the larger knife. Slide the larger blade along to keep up with the smaller blade. This technique reduced my time from almost 45 minutes to do a multi-paned window to a third of the time. Also I saved a lot of time with the clean-up afterwards, since the windows had fewer smudges.

One last tip is that when you draw the knife along the putty for the last bit of tooling, the putty might lift slightly from the glass. The way to correct this is to smooth down the putty with your finger, but in the Opposite direction from the previous stroke. This last motion lays the putty back down.

I have to apologize for posting all this if you are experienced with glazing with putty, but when I read the part above about rolling the putty, it triggered this response. Hopefully it will help others, especially novices, to think about the process of glazing in a new light.

[Peter Quinn]

Just for clarity, the op said he is using insulated glass units, which are usually at least 1/2" thick and have up to a 5/8" frame and seal around them whichnis either metal exposed or bituminous in nature, and they require a gap of maybe 1/8" light for sealer and expansion. So as the op noted the wood glass stop is almost 3/4" to cover the unsightly and tender parts of the insulated units. Are you telling him to put a bead of putty that large on his windows? It just doesn't work for modern sash of this type. Maybe with laminated glass panels but not insulated.

[Neal Clayton]

whoops, i completely missed the fact that this was insulated glass.

in that case, yeah, putty can't span that big of a gap, traditional glazing rabbets wind up leaving 3/8 x 3/8 or 1/2 x 1/2 at most.

on the topic of cleaning the smudges, get some chalk or whiting or whatever you wanna call it. just dust the glass with it using one of those barber's brushes and it will soak up the oil, then wash away.