Does anyone have any input on how to remove the accumulation off of the outside of the inner pane of a thermo pane once the outer pane has been removed ?
The windows are on a beach house that is a couple hundred feet from a salt water bay so I assume that the powder I get when I scrape it off with a razor is some kind of a salt residue.
Thanks.
Getting the details right for a wall assembly with the control layers to the exterior and lots of drying potential.
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Replies
If this residue is between panes and is from a blown window seal, you may be SOL. The condensation between insulated glass (when it occurs) almost etches the glass. I don't know how much luck you'll have cleaning it. Then you'll need to evacuate and reseal the outer pane. Best of luck.
__________________________________________
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
20+ years of customers bringing in IG window panels wanting one side replaced or the "fog" removed,etc,etc...............to put it bluntly.........................
IT CAN"T BE DONE...unless you have too much time and not enough good sense to understand the basic economics and physical restaints of IG glass panels.
BITE THE BULLET......order a replacement, put it into the frame, and have a warranty!
Sorry, just had to blow a little steam...........................................Iron Helix
IT CAN"T BE DONE...
Well, it can, and in about 15 minutes more than simple replacement - trouble is, about 90% of inner "fog" is etched, pollishing definitely not worth the effort.
PS Nobody has ever been able to explaint to me the etching mechanism, do you know IH??
The etching comes from the desecant used .
You may be able to clean the widow inside but unless you replace the desecant, get a perfect seal and maintain the total thickness whats the point, it will re-fog or not fit.
Why bother?????? get a new quality unit.
Easy to say the etching comes from the dessicant.
Just BS without the HOW - what physical mechanism or chemical reaction, or even biological/chemical mechanism (my guess, but I don't know) performs the etching?
The desicant is calcium chloride, would this help? Of course you'll replace the desicant when you re-seal the unit.
Tom
And HOW do you replace the desiccant? Drill holes in the spacer bar and try dribble it in, then reseal the holes? For all that you might as well replace the spacer bar- 'course you gotta go to the trouble of finding it. Then reseal the whole unit, not easy to get close to even 90% reliable. Holy cow, how could anyone want to go to all this trouble and still have a questionable unit? There's just not a lot of money to be saved, let alone the time involved!
I was in the glass business for 25 years, seems Iron Helix was in the trade, too. I emphatically second his recommendations. Get a new double sealed factory unit. There's no way you can equal the refined materials and processes that come out of a production facility. Most likely you will also receive a warranty against seal failure (5 years is an industry standard).
OK, I'm done ranting.
Ken Hill
I am sorry if I gave you the impression that I am for re-sealing leaky units. Here is how you do it. Disassemble the glass and the aluminum channels using a utility knife (watch your fingers), the channels will be all wrecked and ready to be thrown away. Then you clean the glass and depending how badly etched it is, it may be next to impossible to get two sheets of clean glass. If you do get two sheets that you think is clean enough, then the assembling process will proceed exactly as doing a new unit. Cut new channels, fill channels with desicant, sandwich channels to glass with sealant. Personally I totally agree with you and Iron Helix, get a factory new unit and the warrantly that comes with it. Save yourself a lot of hassle.
Tom
What Are Molecular Sieves?View Image
Zeolites are crystalline structures not unlike sponges on a molecular scale. They have a solid framework defining large internal cavities where molecules can be adsorbed. These cavities are interconnected by pore openings through which molecules can pass. Because of their crystalline nature, the pores and cavities are all precisely the same size, and depending on the size of the openings, they can adsorb molecules readily, slowly, or not at all, thus functioning as molecular sieves -- adsorbing molecules of certain sizes while rejecting larger ones.
The electrical charge or polarity of the molecules also functions to attract or sort molecules. This ability to selectively adsorb molecules by size and polarity is the key to the unusual efficiency of synthetic zeolites as agents for drying and purifying liquids and gases, and functions as the basis for separation. By tailoring the chemistry and structure of the materials used to create them, synthetic zeolites can be modified to provide a wide range of desired adsorption characteristics or selectivities, and can be used as a separation tool for numerous commercial applications.
Traditional molecular sieves work as desiccants, adsorbents, and ion exchangers. In addition to traditional molecular sieves, UOP's innovative scientists have developed high-silica zeolites resulting in new industry applications, including the removal of organic bodies that can cause odors or affect taste.
Zeolites were formed in prehistoric times, when mildly alkaline waters at the bottom of seas or lakes slowly reacted with volcanic ash to form crystals. In 1756, Swedish mineralogist Baron Cronstedt identified natural mineral crystals that seemed to froth or boil when heated in a blowpipe in flame. Cronstedt called his new mineral zeolite, derived from the Greek words zeo (to boil) and lithos (stone).
This causes acid etching when more water is introduced then the zeolites can absorb.
>>This causes acid etching when more water is introduced then the zeolites can absorb.
I am sure Junkhound has the same question in his mind. Where does the acid come from? Specifically, the chemical reaction involved, and if you can get the reaction formula...
Tom
Tom, Thanks for the backup for wanting good data.
Nothing personal is meant by any to the following comments:
Even though the practial advice to replace is good, responses to technical type detailed queries are a good indication as to how much is BS and how much actual knowledge when discussions depart from simple practical experience.
As an example of the type explanation I've found in the past (but that does not answer all the questions or fit all observations), consider the following scenario:
1. Si2O + H20 = 2 SiOH
2. SiOH is hydroscopic, forms a microscopic gel on the surface of glass. Rain or cleaning a single pane occasionally removes this gel, but it remains inside insulated glass assemblies for the life of the unit.
3. Fungus spores are not preventable, they will be inside all assembled windows at assembly - typical fungus A.Pullulans will find the water in the SiOH and grow, releasing various complex enzymes capable of etching glass, while concurrently applying localized stress due to its own growth.
4. Etched glass is the result.
The above however does not explain why heat tempered glass shows a different granularity pebbly etch pattern than does non-tempered glass (unless soley related to localized stresses due to growth). Also, the above phenomenon as seen in camera lenses is usually a radial pattern, rather than the more even pattern seen on insulated glass.
You may ask, why bother - well, an understanding of the exact process could contribute to technological processes. Refer to http://www.ccmr.cornell.edu/IRG-GLASS/umbach033002.pdf
for a typical application of micromaching glass etch process uses.
From the Handbook of Chemistry & Physics, tables of Physical Constants Of Inorganic Compounds..........................
Silica Oxide has a formula of SiO2, not Si2O.
Its solubility in water is ZERO.......hence no chemical reaction as you derived/wrote.
There is no listing for the compound Silicon Hydroxide (SiOH), nor any hydroxide forms of Silica. Glass is of a low chemical reactivity, hence a good storage container for most chemicals produced. But the crystalline structure of glass lends itself to interlocking with other crystalline compounds.
Your concept is on target, but what is missing is the actual formula for the compound commonly used as a dessicant in window production. It will be a micro-sieve type product, but without its physical constants there is no way to derive the reaction products. The proposal that a hygoscopic calcium mineral is the answer is not on target either, because the resulting reaction with moisture in the enviroment results in liquid accumulation on the surface of the calcium crystals, not absorption as needed.
To be a dessicant it must absorb and hold water molecules that may leak through the edge seal of the IG unit in order to retard "fogging".
The dessicant can absorb and hold only so much water when the seal fails, after that point the twin glass acts as a bellows and with each hot/cool solar cycle, pumps more humidity into the IG chamber. This captured water cycles from liquid to vapor on a daily cycle to fog the window. What chemicals are dissolved in this captured water will be dependent on the dessicant used, will generate the white film.
I would venture the trapped water is alkaline in nature as you proposed, but after that we are still missing the formula for the dessicant.
Does anyone know where to find out? .........................Iron Helix
While you guys are figuring this out, see if the same book tells us how to put the smoke back in motors.
I sure don't know a thing about the science of it but from a practical view, definitely replace with a factory unit.Excellence is its own reward!
Sorry it took so long to reply, I have been thinking of doing more research before I tackle the problem. Did you create the following to get a point across or was it an explanation that somebody was trying to pass on to you?
>>consider the following scenario:
1. Si2O + H20 = 2 SiOH
2. SiOH is hydroscopic, forms a microscopic gel on the surface of glass. Rain or
cleaning a single pane occasionally removes this gel, but it remains inside
insulated glass assemblies for the life of the unit.
3. Fungus spores are not preventable, they will be inside all assembled
windows at assembly - typical fungus A.Pullulans will find the water in the SiOH
and grow, releasing various complex enzymes capable of etching glass, while
concurrently applying localized stress due to its own growth.
4. Etched glass is the result.
When I first read it I knew from my memory there were a few things that didn't make sense there. You know how memory goes, you think you know it and yet you are not sure if you know it, especially after almost 30 years. Then I read IronHelix' reply, did a little research, this is what I come up with. I am not saying this is exactly what's happening, give me some feedback and we'll toss it around again.
This is what IronHelix wrote, he has done his homework for sure.
>>From the Handbook of Chemistry & Physics, tables of Physical Constants Of Inorganic Compounds..........................
Silica Oxide has a formula of SiO2, not Si2O.
Its solubility in water is ZERO.......hence no chemical reaction as you
derived/wrote.
There is no listing for the compound Silicon Hydroxide (SiOH), nor any hydroxide
forms of Silica. Glass is of a low chemical reactivity, hence a good storage
container for most chemicals produced. But the crystalline structure of glass
lends itself to interlocking with other crystalline compounds.
Here are the facts that I know:
Sand is an impure form of silicon dioxide, which has a chemical formula SiO2 (see the site that you referred me to). Si being in the same column as carbon, C, has the same oxidation number of +4 which means it would prefer to take in 4 -ve charges to complete its outer electron orbit. Each oxygen, O, provides 2 e- so the compounds CO2 and SiO2 are formed. There is no way you can form Si2O and the hydrolysed product SiOH is just not possible because the OH group only contributes one e-. That's why IronHelix couldn't find either in the handbook. As for the structure of glass, I am not quite sure what IronHelix was trying to say when he wrote
>> But the crystalline structure of glass lends itself to interlocking with other crystalline compounds.
May be he can fill me in on this one.
Glass is actually an amorphus substance, that mean it doesn't have an organized structure such as the crystalline structure that is found in table salt. So glass is more like water. It is actually a liquid, not a solid, if you can believe that. So your heirloom antique glass vase will one day become a blob of glass, flattening as time goes on. Glass, as IronHelix said has a low reactivity. That's why all chemical reagents, be it organic or inorganic, are stored in glass bottles with glass or plastic stoppers. The exceptions being metallic potassium and sodium which are so reactive that they have to be stored under oil in metal containers. It is not that they will react with glass but it is a safety precaution in case the metals cause an explosion. Glass has no nutritional values to fungi so they don't grow on glass, besides, glass is not porous so those fungi cannot send out those little things (forget what they are called) to attach themselves to the substrate and propagate. Why do you see fungi growth on the lens? It's the coating of the lens that they feed on, and you have to have a pretty moist environment for that to happen.
There are two common desicants used in the things that we come across daily. Calcium chloride as I mentioned earlier in this thread, which has the formula CaCl2 and silica gel, which is a colloidal form of silica. Silica gel is usually found in packaging of electronic goods to keep the goods dry in a storage environment. Silica gel works on the molecular sieve concept and you can reuse silca gel by drying it in the oven. CaCl2 is what's used in window units and I don't know if it works as a sieve or other mechanism. The water sorption is not reversable in CaCl2 and that's why it is kept in an air tight container. I do know that CaCl2 is slightly soluble in water. If IronHelix can look it up in the Handbook, he should be able to find the solubility or dissociation constant of CaCl2 which would be a very small number. I also know that because of its small dissociation constant a weak base is formed when it dissolves in water. When enough water gets into a broken sealed unit, the excess water dissolves the CaCl2, forming a weak base, etching the glass. A base can actually etch more effectively than an acid.
Junkhound, there is still a piece of the puzzle that I need you to clarify. When you wrote
>>The above however does not explain why heat tempered glass shows a
different granularity pebbly etch pattern than does non-tempered glass (unless
soley related to localized stresses due to growth)
Care to explain the difference in the observed etched patterns in different kinds of glass?
One more thing, I went to the site that you suggested about ion etching, very interesting stuff. Now I have a better understanding of what you are getting at.
Tom
Edited 8/5/2002 1:03:30 AM ET by TOMCHARK
Calcium chloride is soluable in water at the rate of 60 grams in 100 ml at freezing and 159 g at boiling temp. (100ml water = 100 g) It's the antifreez in the tires of my Allis Chambers D15. It is very deliquescent. They used to use it on dirt roads to absorb moisture and lay the dust.
A dissociation constant is a function of a partially ionized solution. I believe that a calcium chloride solution is completley ionized.
BJGardening, cooking and woodworking in Southern Maryland
>>A dissociation constant is a function of a partially ionized solution. I believe that a calcium chloride solution is completley ionized.
If your solubility data are correct and I don't have any reason to believe otherwise, then please accept my apology. Calcium chloride is not what's used in IG units. I might have mixed it up with the solubility of calcium hydroxide, calcium carbonate or calcium sulphate. But then even when Ca(OH)2, CaCO3 and CaSO4 are only sparingly soluble, they are 100% ionized. Now, wait a minute, if you hydrolyse CaCl2, you get a Ca(OH)2 ppt + calcium and hydroxyl ions resulting in a weak base. Comment?
O.K., NEXT, we'll get the BBQ ready.
Tom
Sorry about the "crystalline" structure................my last chem class was 30+ years ago and memory is not always concise.
At any rate............I'm still not convinced that CaCl2 is the dessicant of choice for two reasons.....
(a.)CaCl2 is hygroscopic, but not absorptive (it drips with water if left to the open air), which would make it a difficult product to use in manufacture.
(b.)From the failed and fogged IG units I have had to break apart to remove from the sash before installing the new IG panel, I have found the white dessicant pellets still intact in the metal frame.
At this point I need to pull some books for more data before I can step out on another limb.
Keep the saw handy, TomChark......................................Iron Helix
>>(a.)CaCl2 is hygroscopic, but not absorptive (it drips with water if left to the
open air), which would make it a difficult product to use in manufacture.
(b.)From the failed and fogged IG units I have had to break apart to remove
from the sash before installing the new IG panel, I have found the white
dessicant pellets still intact in the metal frame.
Good points, Iron. Is it poosible that there is such a thing as stablized CaCl2 in something like a ceramic matrix? You know what, I'll check with PPG and see if they can help.
Tom
a. The formula, etc are not mine, they were plagarized from comments on camera lens fogging discussion web sites and also on discussions a few years ago when I first started asking about this.
b. Another data point - the first time I noticed the etching was replacing/cleaning my own windows about 12 years ago. They were mfg by Fentron in Seattle (1971) and did NOT have any desicant, so there is also a phenomenon that does not need that chemical in the reaction.
c. Tempered vs. plain glass query. Wish I had a home Scanning Elec. microscope for this. Visualize the surface of a basketball - the pattern on both types glass is much smaller and finer but similar, totally different than sandblasted or Hydroflouric etched glass. The tempered glass pattern is more coarse but smoother than regular glass.
PS - related topic - did find some good web sites debunking the myth that glass flows appreciably over cneturies (eg.cathedral stainded glass thicker at bottom) - it aint so.
>>
a. The formula, etc are not mine, they were plagarized from comments on
camera lens fogging discussion web sites and also on discussions a few years
ago when I first started asking about this.
You mean you have been working on this for a few years? May be I shouldn't have got into this at all :)
>> b. Another data point - the first time I noticed the etching was
replacing/cleaning my own windows about 12 years ago. They were mfg by
Fentron in Seattle (1971) and did NOT have any desicant, so there is also a
phenomenon that does not need that chemical in the reaction.
Did you mean these were IG units? No desicant? Did they vacuum sealed it or something? So shall we just rule out the desicant? Seems logical. What about the aluminum?
>> c. Tempered vs. plain glass query. Wish I had a home Scanning Elec. microscope
for this. Visualize the surface of a basketball - the pattern on both types glass is
much smaller and finer but similar, totally different than sandblasted or
Hydroflouric etched glass. The tempered glass pattern is more coarse but
smoother than regular glass.
I don't think I'll ever in my life could figure this one out (I mean the difference in the patterns between plain and tempered glass). Have you ever observed any difference in the pattern when there were so much water that you could see water streaking down the glass? Have you ever seen any streaking pattern at all in addition to the classical pattern that you described?
>> PS - related topic - did find some good web sites debunking the myth that glass
flows appreciably over cneturies (eg.cathedral stainded glass thicker at bottom)
- it aint so.
Yeah they say antique glass vases have thick bottom because glass flows due to gravity. Now how do thay know how thick was the bottom when it was made? They were just made with thick bottoms. For that or the cathedral stained glass to flow, it would take a lot longer than a few centuries. Does anybody know the flow rate of glass under normal temperature and pressure? Would be another subject to research into.
Tom
> IT CAN"T BE DONE...unless you have too much time and not enough good sense
These windows are an example of people insisting on doing it the high-tech way, whether it works or not. All over northern and central europe you can see old buildings that have casement windows with two sets of sash in them, one swings in, the other swings out. When both are closed, you have about 4" - 5" between them. That larger air space works as well as or better than the fancy inert gas approach.
-- J.S.
Any performance report to support that? I know the other guys are going to ask anyway.
Tom
John has it right, code weenies and their 'free' lunches have screwed the hell out of us now though!
Was a dumb techno-xgenthen-kid in '71 when we bought the crap IG glass (still is crap IMHO; also>10% the cost of my whole house then!!). Codes have been corrupted by money interests too nowawdays. If I knew then what I know now, I'd'a used storm windows with newspaper seals like granpa and pop built, and 'sh!t' on the insulated glass unless true fused glass hermetic seal.
Auld Deutsch: Too soon old, too late smart.
>>I'd'a used storm windows with newspaper seals like granpa and pop
built, and 'sh!t' on the insulated glass unless true fused glass hermetic seal.
See if I get this right. You would use newspaper to seal the windows and glass to wipe? The first time I heard two things so dissimilar yet so interchangeable. :)
They are already using the true hermetically sealed glass in autos like the Mercedes and the Lexus. Could it be there is no such market in an average home?
Tom
Sorry, just anecdotal evidence. The King of Norway has that kind of window in his palace in Oslo, and I haven't heard him complaining. I had them in my room in the National Hotel in Moscow, back in 1990 before it was renovated. They seemed to work better than the thin IG kind that my wife's relatives in Norway and Sweden have.
With no manufacturer pushing this simple dual sash kind of window, there's nobody who has sufficient incentive to test them.
-- J.S.
>>With no manufacturer pushing this simple dual sash kind of window, there's
nobody who has sufficient incentive to test them.
That's very true with everything else. Also I found that people can use the same set of data to support completely opposing opinions.
Tom
But John, those are on masonry walls over a foot thick with less insulating value than our flimsy wood walls. Their windows probably have more insulating value than the walls so they feel well insulated by comparison.
;)Excellence is its own reward!
Take the windows out and give them to sombody building a green house, you can get them pretty clean by slitting them and spraying about 900 gallons of Lime-Away, but in the end they will still just be clear enough for a greenhouse.
Jason
More info to keep our minds muddled:
Sheet glass is made by mixing Silica Sand with Sodium Carbonate, Sodium Sulfate, and Calcium Carbonate and heated ti 1400 deg F. The heat causes the CO2 and SO3 to offgas from the molten mass, leaving in "solution" Na2SiO2 & CaSiO3 to be drawn into sheet glass.
The interesting fact here is that there is Calcium and Sodium in the "molecular structure"(see TOM ,I did my homework) to serve as bonding sights for the "fogging"chemical reaction that I can't solve.
As far as a zeolite dessicant, I think it has( but am not positive) the following formula. Na2(ALcSi3O10).2H2O. Sodium Aluminum Silicate. I attempted to locate my Standard Inorganic Reactions Handbook...................But Can't..........looks like trip to the University Library in my Spare time.
What would the the zeolite's reaction be after saturation with water?
The salt CaCl2 is a by product of the Solvay process for the production Sodium Carbonate. The salt that can be crystallized from a concentrated solution is a hexahydrate, CaCl2.6H2O which is heated to remove the water of hydration to form CaCl2. If CaCl2 the is mixed with water it produces CaO and 2HCL. The hydrated form is deliquescent and is used for snow and ice melt on roads, or for dust control in mines. The dehydrated form is used as a chemical reaction dessicant.
I hope the PPG man can shed some light in this dark tunnel of a conundrum
More questions than solutions.........................Iron Helix
I'm a chemist, so I'll chime in - but I am not a glassblower or glass chemist. Glass is one of those highly specialized products that are often more art than science - a little of this and a little of that to improve its properties, but the exact mechanism of improvement is unknown.
Regardless, my guess would be one of two things: either the glass is getting etched, or simply appearing to be etched. The latter seems most likely to me. What may actually be happening is salt deposition. Water + Salt gets in, water dissapears into desiccant, salt remains behind. The crystals formed may reflect/refract light so much that even the slightest amount would be noticeable.
When I pry off some of my old windows in the near future, I'll talk to some of the old hands who live for this sort of thing. . .