There are tradeoffs with every type of glazing. Stay away from DAP in a can. Aquaglaze is a good compromise if you're in a hurry, but it gets hard and is really better painted next day. There are some really good ones used on high rise buildings, but not only are they expensive, but they stick too good, which makes it likely to break something else when replacing one broken pane years later.
My favorite is DAP in caulking tubes, which is entirely different than what comes in a can. It stays soft forever, sticks plenty good enough to primed wood and glass, but has one problem. They say it doesn't shrink but it does. A Lot. I put almost double of what it needs on, and let it do what shrinking it will. Put on thick, the shrinking doesn't make it pull away from wood or glass.
Since I always have other jobs going on with the old houses I work on, I put it on thick, let it cure for several months, and then shave it to finished size with a super sharp chisel. It never cracks and makes it really easy to replace a pane 20 years later with no worry about damage to anything else.
I did a test window that I intended to leave for a year, and go back an trim it, but it ended up being a bit over 2 years, and it trimmed as easily as a few months cure, and hadn't cracked a bit.
They say you don't have to paint it, but it will mildew if left for years like that test window.
With my system, the total time actually working on the window is much shorter than putty knife methods, but only if you leave out the curing months. It takes me 45 seconds to put it on a large sash, and a few minutes to trim it.
If it's an old house where we don't want it to look perfect, I do the trimming by hand. If it has to look perfect, I use a narrow board with the angle on one side to use to guide the chisel.
I think I have pictures on my Glazing page.
I wish there was something ideal I could recommend, but this is the best I've come up with for my work. I can't remember when I first used the caulking tube stuff, but the windows I did on my Grandfather's house in the late '90's still look good from the road. I haven't examined them up close since the family sold that house.
You can see all the trimmings on the floor in the easel picture, and if you zoom in you can see those trimmed and those not yet. I turn the sash between trimming one way, and also when painting. I do both pretty fast, so I have a helper to do the sash turning for both trimming and painting, so I don't have to put tools down.
These are sash in the 1850 house with the green shutters. They were never touched with a putty knife. The diamond windows surrounding the entry doors were done the same way, but in place. Replacement glass was hand blown cylinder glass from Bendheim in Germany. We needed a whole "case" (sent on a pallet in odd shaped sheets) for that job. It was an almost exact match to the 18 original panes we had left.
Single pane glass will get solid water condensing on the inside in some conditions. You need to seal the inside of the glass too, so water can't run down behind the wood. It doesn't need to be anything fancy, so I use the cheapest grade of latex caulking. It's going to be sealed up between the glass and wood with paint, and allows easy replacement of glass when the time comes. It's easy to clean off too. The glass is bedded into it before shooting points to hold the pane in place. Go for the minimum squeezout, but you want complete seating of the glass into the caulking.
I trim it with a razor blade that's easier to get into the corners than a chisel and also the bevel on a chisel can lift the cured caulking out from behind the glass, but trimming off the glass is done with a chisel because it's easier to handle, after it's been sliced free from the sash with the razor blade .
The inside needs to be painted with exterior paint. Interior paint won't last with water from the condensation on it.
The easel is just cobbled up with 2x4's, and has two positions to make whatever part of the window I'm working on easy to get to with comfortable positioning.
Last edited by Tom M King; 04-25-2023 at 12:04 PM.
I stripped a 1974 (probably) single pane window unit today in a rental house garage. The bars had never been primed where the glazing has to bond, so it never had a lasting bond. It all popped right out. I primed it today, but forgot to take another picture.
The Bronco All Terrain scaffolding stands allowed me to set up over, and partially in the ditch left open to run a big subpanel feeder wire.
Wow, this info is awesome Tom. Thanks so much for information and pics which help me understand lot better. I was not looking forward to using that glazing compound, so I am going to give your method try. I do remember as kid we had condensation on inside of our windows cause I would make drawing on panes. No ac in those days but didn't know any different either. This weekend going to buy that dried treated 1/6's that's 5/4 thick and its all #1 lumber so I can make frame. But I didn't ask how much for 2-10' pieces so may be shock.
One more question Tom, I am not doing a 100% cleaning of the windows removing all the paint. I want these windows to show their age, so I was wondering about some kind of clear finish that would help protect the sashes. Any ideas on clear finish that is not shiny, maybe clear epoxy sanded little? Or does this sound crazy?
Do you mean clear on the inside for exterior windows? I have some museum houses I work on, 1798 and 1828, that the interior woodwork was never painted. I put Bona Naturale floor finish on the inside of the sash. 7 and 16 years later it's still holding up great. Sorry, but that stuff is expensive, and I don't know of any other kind of clear finish that will last and not look like there is anything on the wood.
Maybe one of the waterborne finishes would last okay, but I've never used them for this purpose. I make no claim to be a finishing expert. Others here will know more than I do about this question.
I glazed that window today, and took some pictures. You want to buy fresh stuff. I'm not sure what the numbers mean, but I expect the first four are the use by date. I have bought some before that was set up too hard in the tube from Home Depot. This came from Ace Hardware today.
You want to puncture the seal with something small. Open it up too much, and what's already hard to control becomes Really difficult. I use a cheap screwdriver-1/4 or 3/16 tip, and barely push the end through the seal.
I hold the long part of the tip against the glass, and push a bulge out in front of the heal of the tip held off the wood. It looks terrible for a while, but we'll make it perfect easily later. I'll give these a couple of days, and slice offthe part overhanging the front of the sash, leaving the rest to cure for a couple of weeks. This is on the North end of this house. On the South side would only require a few days to cure in the Sun. It's more important to get plenty on than it is to look good at this point.
I found pictures of the 2 year old test window. As I probably said earlier, I intended to leave this for a year to see how it was after that much time, but forgot about it, and it was a bit over two years before I got back to it. On the vertical bar, I had made a first test pass without going all the way in-the reason it's still too proud. The glazing was left for two years without being painted, so that's the reason it's so gray and dirty looking on the outside. It was still as soft as if it was just a month old.
Chisel is a Stanley no. 40 with an 18 degree bevel and sharpened as sharp as possible. These chisels have my favorite steel. Most woodworkers would turn their noses up because of the black plastic handles with metal cap, but those who know buy them for real money off ebay. It holds that low bevel just fine.
On the featured window in this thread, I sliced off the part of the glazing sticking out past the front today. It was a little softer than ideal, but the to-do list is long, so I want to get this one out of the way. The chisel is so sharp that you can't help but take a little wood here and there. I have never worried about going back and priming these little snips, and never regretted it. The paint will take care of them.
Doing this allows you to see what's going on at that edge during the final trim. Skipping this couple of minute job ends up taking too much wood later because I can't see a clean corner. If you zoom in, you can see the glazing is still piled up above the corner. It might shrink back a little, but it will stay attached to that corner.
I found a picture of one of the windows in place using the sash seen on the easel in an earlier picture. This is all original 1850 window. All the panes but the middle two in the bottom sash are modern made handblown cylinder glass. The middle bottom two are original 1850 glass panes. This was before I made the holdbacks for the big replacement shutters we made, and I think when we were installing and fitting the shutters.
Tom that is fantastic, those windows are the real deal. Dap glazing caulking is on my list along with good sharp chisel, which I have couple but not sharp. No where near as sharp as yours. These pics with chisel in action sure helps me understand the process on how to remove excess caulking so thanks for taking the time posting. I have to say that before the chisel work it looks like mess, but afterwards its a nice historic window.
Quick Question: One of the muntins using the penetrating epoxy to hold in place moved on me before I notice. Is it possible to use the heat gun to break it loose so that I can straighten it?
Yes, heat will soften epoxy. Depending on the type of epoxy, the amount of heat required will vary. That heat gun will easily do it. Just soften it and see if you can move it. Use thick leather gloves because it's going to take 250 degrees and up, so easy to get burned.
My only experience in softening epoxy is pulling golf club heads to change shafts. Golf club head epoxy is engineered to break down a hundred degrees below the laminating epoxy used in composite golf shafts, so you have to be careful and it still takes a lot of force to pull the head.
Carroll, this method won't work without the Really sharp chisel. Since you're so far into this, and sharpening is another topic entirely, requiring more gear, send me a chisel, and I'll send it back sharp to you. The only thing I ask is that if you have any small children that it absolutely has to go somewhere that they can never get close to it.
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