dissicant type used in IGU panes?


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Old 12-11-21, 04:44 PM
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dissicant type used in IGU panes?

I been reading that molecular sieve type 3A is used but Silica beads are what is mentioned most often as the dissicant type. These are two different materials. The molecular sieve stuff is potassium and silica is not potassium. Potassium would dissolve into a paste when exposed to water, which is what I've seen gooing-up my windows most likely is, looks like gobs of white tooth-paste (they're 30 years old) and silica beads are re-usable and don't look like paste. You can take them(silica beads) out, bake them at 200f for a couple hours and put them back in.
I haven't taken my windows apart yet to fix them. I'm just wanting to know ahead of time as to what is the right materials to have on hand prior to doing the work.
Since every single window in the house has a failed seal, and some of the stuff leaking out does not look like silica, I'm guessing the manufacturer went out of business for a reason.
 

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12-12-21, 06:25 AM
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I have never seen an IGU that did not use dessicant of some type.
 
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Old 12-11-21, 04:48 PM
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The only desiccant I have ever seen used in IGU spacer bars is a the beaded product. Ask Oberon he could probably tell you the difference.
 
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Old 12-12-21, 05:07 AM
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Many windows don't have a desiccant. They replace the air inside with an inert, dry gas like nitrogen or argon. When the seal holding the glass degrades it allows air and humidity inside.

If concerned about clay or zeolite turning into paste... use something else. I use ceramic molecular sieve to absorb water in a chemistry setting and it remains in solid bead form and can be reactivated by baking just like silica. Both silica jell and molecular sieve can hold a lot of water. Molecular sieve has the benefit of continuing to absorb in a low humidity environment and at higher temperatures.

The stuff in your windows might be calcium oxide or calcium sulfate which are both on the inexpensive end of the desiccant scale and might have been used.
 
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Old 12-12-21, 06:25 AM
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I have never seen an IGU that did not use dessicant of some type.
 
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Old 12-12-21, 10:53 AM
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I have to say that after something like 20 years of answering questions (and learning so much in the process), that this is absolutely a first. No one has ever asked about specific desiccant that I can remember.

My first question is are you trying to restore 30 year old IGU's by taking them apart, drying the desiccant, and reassembling? If so I would suggest that you are basically wasting your time. is it doable? Yeah, probably, but is it worth the effort? Not in my opinion.

If you really want to repair/upgrade your glass units then I would suggest this as a much better idea:

https://www.crlaurence.com/crlapps/s...3&ModelID=3084

Not so much that I see this as a superior product compared with other spacer systems used today (although huge improvement over 30 year old tech), but this is something that you can do yourself if you are thoroughly careful in your application, and it simply makes more sense to me than trying to reuse the original spacer materials.

Virtually all IGU systems contain a desiccant, for a couple different reasons. First is to absorb residual moisture present in the sealed IGU following manufacture and second to absorb whatever moisture that might migrate into the unit over the span of its life. The less free moisture in the airspace, the lower the temperature before any condensation can form inside the sealed space. Figure a goal of somewhere in the neighborhood of -90F.

Desiccant in an IGU has to absorb moisture (obvious) but also has to absorb any off-gassing from the various materials used in spacer manufacture. What desiccant must not do is absorb oxygen, nitrogen, argon, krypton, anything that is supposed to be in the IGU.

Molecular sieve 3A is great at sucking up moisture and it doesn't absorb argon, or krypton or oxygen, or nitrogen or so on. Unfortunately that "so on" includes out-gassing from IG components. Silica gel on the other hand does absorb the off-gassing and it also doesn't absorb argon or krypton or....moisture. So best option could be a mix of molecular sieve 3A and silica gel to remove the bad stuff but not the good stuff.

And what happens if you do use a desiccant that absorbs the good stuff? The potential for a concave or collapsed IGU when the stuff that's supposed to be keeping the glass panes a certain distance apart ends up getting swallowed by the stuff that is supposed to keep the air space clear and dry.

Really curious to hear what you are planning to do....







 

Last edited by Oberon; 12-12-21 at 11:08 AM. Reason: spelling
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Old 12-14-21, 06:25 AM
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I don't know yet what I'm going to do. Here's what I have done: I contacted the only glass business left in town who reps the company who bought out the company that made my windows. I asked them what they're going to do for me as the windows I have were sold with a "lifetime" warranty. I've always suspected that "lifetime" warranty's refer to the lifetime of the tail-lights on the salesman's vehicle, that is in how long you can see them. And here's what I've found out so far: The warranty probably will not cover labor which is $85 per company employee per hour and the job will require 2 employees. Each IGU window will require approximately 2 hours to replace, there are 11 failed windows. So first guestimate is an approximate total of $3740. For me that is a non-starter, but I'm not the main person making the decision. If the window company is not going to cover the "IGU" replacements then I'm looking at $300 or more per window, so minimum would be $7,000. That cost is a total non-starter, ain't going to happen.
Interestingly, the only window that didn't fail is the bathroom window and it was made by a different manufacturer.
My personal opinion of these "IGU" windows is they are a scam foisted upon home-owners. They're designed to fail and cost an insane amount of money. Here's why: 1:The inside of the low-e pane is coated with a Tin oxide. Tin reacts to moisture and after 30 years of exposure, is probably not there anymore. 2:The windows look like they were sealed with silicone adhesive. In my experience, silicone adhesive never lasts beyond a couple seasons. When applied to cleanly-scrubbed glass it will loosen and release itself after a few temperature cycles. I've observed this happen many times. One can grab with your fingers and remove the entire section of glue simply by tugging on it with your finger, it's just laying there on top. 3:The "IGU" is inflated with "Argon"! Doubtful there is any "Argon" left in the IGU past a few weeks, for one the seal glue and seal design is not a gas-tight seal and we already know that silicone glue fails. 4:Argon is 1.4 times denser than air, the only purpose for it's use is to displace the air to keep the moisture out while assembling the IGU window, plus being denser than air it will transfer heat more effectively than air defeating the whole purpose of buying and installing an IGU window. The other thing I know is butyl rubber is probably a better choice for sealant.
I'm going to buy a bottle of silica desiccant, a tube of butyl caulking, a caulking gun, a bottle of windex, a box of razor-blades, a razor holder-tool and a roll of double-sided butyl-tape, oh, and a roll of paper-towels. I'm thinking for about $50 I can buy what I'll need to fix these windows myself. Might take me 3-4 hours per window, doesn't matter, I'm old and can go as slow as I want to, I'm retired. I'm also looking for where I can by a heat-mirror reflective film. I'm thinking that since the tin coating is blitzed, I could try putting a heat-reflective film myself there. I had a west-facing window years ago that used to heat the room to unbearable levels in the summer afternoons. Just placing a $10 film on that glass made a huge difference. I can't find a source for these films anymore, at least large enough to cover a large window.
Perhaps someone who has attempted to do their own IGU windows could post?
And while we're talking about it: where can I get the extruded frames material? I have a small kitchen sink window I want to make into a bay window for plants. I want it to look like the IGU window I put over the stove on same wall. What's stopping me is finding a source for the frames.
And many thanks for the crlaurance.com link
 
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Old 12-14-21, 06:33 AM
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You're really going off your rocker there. I replace igu's all the time for people with no warranty. They don't take 2 hours a piece. More like 15 minutes once you get going. And I give a volume discount anytime there is more than 2 panes.

And you should not attempt to make or "repair" an IGU yourself. Yes this is a diy site, but this is the sort of thing that a commercial glass companies does best for less than it would cost you to buy the components seperately.
 
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Old 12-14-21, 10:07 PM
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You are welcome on the CRL link. Although I really don't recommend trying to build you own IGU's, it's still a much better idea that trying to repair the existing ones, but only in comparison.

All that said, I 100% agree with XSleeper that you would be much better served by buying the IGU's from a glass shop, assuming that the window company doesn't supply them under warranty, which is certainly best case (I wasn't sure if that was a possible option or not based on what you said). Also, like XSleeper I can't imagine two tech's per window taking two hours each to replace the IGU's. If you do choose to buy IGU's, there is always the option that you don't have to buy them all at one time, you could always space out the replacements.









 
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Old 12-15-21, 06:03 AM
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Having been in the window and glass business, I totally agree with XSleeper and Oberon , and you should take their advice.
 
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Old 12-15-21, 03:23 PM
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Did you ever buy a service manual for your car so you could read about that one tricky part on adjusting the valves or on how to get that leaky heater core out of the dash only to have that $50 book tell you to see your authorized service dealer? I think the whole USA has gone to the idiot farm.

I had a quote for a 22x28 inch window, a bay style so my wife could put flowers and starters for the garden there and they wanted $3k for it. On top of that, they said it was too small to bother with doing.
Somebody must make and sell the extrusions for these windows, where can I get them?
 
 

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