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New uses for canned air


homnspector
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I came up with a nice trick today you guys may want to try. I had a dual pane window that I thought may be compromised but the internal streaking was not real obvious and the window was dirty. I took my can of "air" or whatever it is, the stuff from office max for dusting your computer, from the truck and shot it on the window with no results. But, if you turn the can upside down and shoot it on the window, it will freeze a small area. After wiping off the frost, there was clear condensation on the interior. I tried it on a few other windows that looked OK and no condensation formed. Try it and let me know the results. It seems to be a pretty good test.

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Originally posted by homnspector

I came up with a nice trick today you guys may want to try. I had a dual pane window that I thought may be compromised but the internal streaking was not real obvious and the window was dirty. I took my can of "air" or whatever it is, the stuff from office max for dusting your computer, from the truck and shot it on the window with no results. But, if you turn the can upside down and shoot it on the window, it will freeze a small area. After wiping off the frost, there was clear condensation on the interior. I tried it on a few other windows that looked OK and no condensation formed. Try it and let me know the results. It seems to be a pretty good test.

I've been doing that for years. I even thought of patenting the technique. After thousands of windows I have some insights:

The process is harmless. At first I thought the stresses might crack the glass. Haven't cracked one yet.

The test will definitely show every insulated glass panel that has clear visible signs of a failed seal. However, it also causes a reaction in panels that have never shown visible signs of a failed seal. This presents the inspector with a dilemma. Do you test every single insulated panel in the house? If not, why not? If the test shows 30 failed panels, do you recommend replacing them all?

For me, it's a huge can of worms. For a while I tested every single window and was finding anywhere from 4 or 5 up to dozens of failed windows in any given home. When a seller would challenge me, I'd cite the industry standard "cold puck test" which is similar, but not quite the same; the stuff in the can brings the window surface to -50 degrees and the cold puck test only calls for a -40 degree puck. In either case, the seal might be failed, and there might be enough moisture between the panes to condense behind the spray, but there might not be enough moisture to condense during normal conditions for several years. If so, is it really failed?

After all that experimenting, I now only use it to test the occasional window that seems borderline, just as you described. Even then, if a client sees me doing it, he wants me to test all the other windows. And that invariably leads to a bunch of dilemmas.

- Jim Katen, Oregon

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Originally posted by homnspector

Damn, I thought I invented it. Appreciate the feedback, I wondered if some "unfailed" windows might show signs of condensation. Also, it is so dry here (usually 10% humidity), I wonder if it is reliable.

Good point. I hadn't considered that. In AZ, I'll bet you could have a fist-size hole in a window and still show no condensation.

BTW, I always note the temperature and relative humidity at the start of every inspection. During the winter, it's frequently 99% rh up here. If I ever visit AZ, my skin would just dry up and blow away.

- Jim Katen, Oregon

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While we're on this subject, maybe someone can educate me a little.

I had 5 winows yesterday that had a whitish haze between the panes, varying from just near one edge to one that was about 50% covered. No signs of the streaking that I normally see. No doubt the windows needed replacing, but can anyone explain what causes that particular condition? It was fairly cold, about 40F after an overnight frost, and I'm guessing there's a level of trapped humidity that fogs in this way. Weird looking though, almost like a fine overspray rather than fogging. Had me trying to clean the glass inside and out before I was confident it was between the panes.

Also broke my hot water temperature record yesterday...169F. 16 year old gas heater not even turned up to "high". I almost got out my emergency tea-bag!

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Originally posted by Richard Moore

While we're on this subject, maybe someone can educate me a little.

I had 5 winows yesterday that had a whitish haze between the panes, varying from just near one edge to one that was about 50% covered. No signs of the streaking that I normally see. No doubt the windows needed replacing, but can anyone explain what causes that particular condition? It was fairly cold, about 40F after an overnight frost, and I'm guessing there's a level of trapped humidity that fogs in this way. Weird looking though, almost like a fine overspray rather than fogging. Had me trying to clean the glass inside and out before I was confident it was between the panes.

I see that pretty often. Also, sometimes you'll see a coating of tiny, tiny droplets that make me think of Pam cooking spray. It's an easy one to miss. Another version is a collection of tiny crystal-like patterns on the inside surfaces of the glass sort of like snowflakes.

It may be that some of these phenomena are the result of the desiccant that's in the aluminum channel. I suspect that the desiccant absorbs moisture up to a point, then when it becomes saturated, it releases some of it again. When this water is released it may contain impurities that it picked up from the desiccant that make it appear different from plain water.

Also broke my hot water temperature record yesterday...169F. 16 year old gas heater not even turned up to "high". I almost got out my emergency tea-bag!

Tetley or Lipton?

- Jim Katen, Oregon

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Paul,I have a similar disclaimer but use it if I find 2 or more. I also make note if the windows are dirty. As usual, learned the hard way.

Many buyers seem not to care that the electrical system could electrocute them or burn the house down, garage door could kill the kids, furnace has cracks in the heat exchanger, but, by God, you WILL get a call back about that window that fogs up when the morning sun hits it.

"The process is harmless. At first I thought the stresses might crack the glass. Haven't cracked one yet."

Its good to know that freezing the glass won't crack it. I tried it on some of mine first with no problems.

Chris, what you have heard is true, but it is risky to remove their heart ("Indy, cover you haaart").

I do see the compromised seals quite a bit. My theory is that most of the windows we get around here are made in California, near sea level. The combination of heat and elevation (about 4500 ft here) breaks the seal. We have a local window manufacturer (Better-Bilt) and I rarely see problems with those.

As an aside,is there any simple instrument to test for tempered glass? (besides a ball-pien hammer, Chris)

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Originally posted by Jim Katen

...It may be that some of these phenomena are the result of the desiccant that's in the aluminum channel. I suspect that the desiccant absorbs moisture up to a point, then when it becomes saturated, it releases some of it again. When this water is released it may contain impurities that it picked up from the desiccant that make it appear different from plain water.

....

Tetley or Lipton?

Thanks Jim, that makes a lot of sense.

BTW...Red Rose, I also have some Canadian in me! Eh!

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