Double glazing misting problem - but not all the time.....

[ladylola]

Like a lot of people I suspect I've been following this thread with interest.
Bowie77 , you say you made your own because you say (tongue in cheek hopefully) that you couldn't trust the morons that work for you. I always assumed a machine was involved rather than some hairy ar,sed yts lad with a silicon gun and you've said the units are put together with machine. I'm interested therefore to know what the operatives could do wrong to make one unit worse or better than the next.
Wheather this is a repair or not when or if my dg units fail I'm prepared to give your idea a go. You have mentioned a sealant of some kind to increase their lifespan. I had a badly misted unit on the bathroom window when I moved in and someone at some point had applied a mastic around the unit rendering it impossible to remove without breaking it. Still as has been pointed out they are cheap to buy.
I would think that there may be some form of market for the repair of decorative units , it's not uncommon for glass designs to be discontinued but for a business I wouldn't think anywhere near as large enough.

 

[slpj]

freddymercurystwin wrote:

Yes my post is a repeat, the thread is indeed just going round in circles as you do not seem to understand what we're saying. We appear fixated with the word fix as you use it in every post be-it within inverted commas or not. Why not refer to it as a temporary repair as that is what it is until proved otherwise? Your last comments are highly typical of a poster unsatisfied with the responses of the professionals and regulars on here.

1)I do understand. 2)The thread is not going round in circles, its in fact changed direction somewhat. 3)A Temporary something, is just that, Temporary. It is intended to only be whatever it is, for a set period of time. My "FIX" is intended to be permanent. I am evaluating it. 5) Are you suggesting that I shouldn't question the views of certain posters on here because they are proffessional and or regulars? Does that make them infallable and all knowing then? Surely not? 6)I am not dissatisified or otherwise with anyone, I merely made an observation. I'll let you have the last word on this side issue FM'sTwin, it not really relevant with respect.

Bowies77. Well its new to me too, but that never stopped me with anything before. And the worst that can happen is that I have to buy a replacement unit(s) anyway. . Besides, I like an interesting challenge, and it turns out that the technicalities of Sealed Double glazed units are way more interesting than I thought.

You read my mind on my next question too. I was wondering about how dessicant is handled/stored prior to installation, with regard to soaking up moisture. I guess this, apart from any other issue could be one reason why sealed units fail prematurely without any obvious cause.

 

[slpj]

ladylola,you wrote

Wheather this is a repair or not when or if my dg units fail I'm prepared to give your idea a go. You have mentioned a sealant of some kind to increase their lifespan.

Sorry ladylola, I wasn't sure if this was directed at me.

Anyway, yes I am looking at sealants to see if I can find one that could be easily applied to the unit, that will not degrade or damage the existing sealant. Assuming that I find one, and I think I can, it will then be possible seal "leaks", and thus extend the life of a unit, that has acceptable small amounts of misting and no water damage. This would be in the eye of the beholder of course. For some people no amount of misting would be acceptable, whilst others are less bothered by a degree of misting if it ceases to get worse.

In addition, a suitable and easily applied sealant will also add to the integrity of the existing sealant applied when the unit was first made. Thus preventing the misting in the first place, and therefore extending the life of unmisted units.

Of course in the case of the unit you describe, where it has been fixed in such a way that it can't be removed, as you say a replacement is the only option anyway. If the mastic sealed the unit so as to prevent drainage, that probably contributed to it's failure. But if installed properly, most units are easily removed (with a little care)for a preventative inspection. That is the point that a suitable could be applied.

Feel free to research sealants, maybe somebody already knows of a suitable post manufacture sealant that can be applied.

When I identify a suitable sealant and method, I'll post it on this forum, on this thread if it is still going, which from the level of interest judging by the number of views, it deserves to be (in my oppinion).

Irrespective of it being commercially viable, for any DIYer (I hate the term as it implies not properly all too often, when in fact many who DIY are as good or better than someone in the trade), with time interest and ability, I see no reason not to persue this, including looking at splitting. Since the cost of a proffessional is not being bourne, it ultimately will be less costly, and perhaps even almost free.

 

[bowie77]

lady lola:- it was tongue in cheek.
when manufacturing dgu's the whole process is done by machine hardly any man involvement, thats the very big firms anyway.
the small local firms all do it pretty much the same way as each other where 1 or 2 men cut the glass by hand cut the spacer bar by hand, fill it with dessicant and put it together. they then put the 2 panes of glass through a glass washer place 1 pane down then the spacer bar then the other pane. then they would clamp the glass together using a clamping bench. with 1 long edge hanging out about 2 or 3 inches. they then seal this first edge with a hand held hotmelt machine. ( see thermoseal they may have a website and pics). they then turn the unit around and seal the next edge. then where the 2 edges meet at the corner they push and mould the hotmelt to make a nice tight corner (very important). continue this process untill unit is completely sealed. (we make about 100 dgu's a day) so if this is not done correctly it could lead to dgu's breaking down.
you need competent people to do this.

as for after market sealant i dont think such a product exists, to my knowledge anyway

 

[slpj]

Thanks, thats a great description of the manufacturing process Bowie77 Do you know of any firms that do guarantee replacement dgus for longer than 5 years? How long is the guarantee from your own co?

I think you might well be right about an aftermarket sealant not existing. At least I haven't found one yet.

Thanks very much for the lead to Thermoseal, just what I needed. They do indeed have a website, and great descriptions of all the components required for the manufacture of sealed insulated units, as well as information on standards of quality etc. Fantastic. There is also plenty of information on Sealants of all types, including hotmelt and silicone.

Understanding the process and components used, gives me a much clearer picture of what's possible in the prevention and repair of misted units, and why they fail prematurely. Thanks again Bowie77.

 

[btb23]

ladylola,you wrote

Wheather this is a repair or not when or if my dg units fail I'm prepared to give your idea a go. You have mentioned a sealant of some kind to increase their lifespan.

Sorry ladylola, I wasn't sure if this was directed at me.

Anyway, yes I am looking at sealants...

...maybe somebody already knows of a suitable post manufacture sealant that can be applied.

Regarding sealants, it was in another context (resealing misting car headlamps), that Sikaflex was recommended to me. Would www.sika.ie/ie-tds-Sikaflex_296.PDF be of any use? Mainly used in the marine industry, seems to have a long life, I've seen 30 years quoted, and good water resistant properties.

 

[slpj]

btb23 wrote

Would www.sika.ie/ie-tds-Sikaflex_296.PDF be of any use?

Thanks for the post. I dont know, maybe.

I read the pdf and it certainly is designed to bond to glass, but as I am looking for sealant that will bind to the existing sealant in the dg unit, I am not sure if this would work. Surface preparation is described as needing to be free from oil and wax. I don't know how that sits with the type of sealant used to seal DG units. It might not stick at all.

But I will ring the makers next week and ask them, and also ask them if there is likely to be any unwanted reaction between the two different types of sealants too.

Otherwise it is described as suitable for manual application, so could be just the ticket.

Thanks btb23.

 

[slpj]

On the subject of replacement sealed units. I now definitely, won't buy a replacement unit that is not guaranteed for at least 10 years.

Here is a summary of just one company I found that is prepared to give a 10 year warranty on the units they make, when they are installed in UPVC frames. How can they do this? They can do this because they test not only the finished product, but also the vital components used.

On a DAILY basis, they do a Desiccant Test, Spacer Bar Test, Dew Point Test, and a Sealant Test.

Weekly Test:Humidity Machine: The humidity machine puts each unit through a 5-week cycle taking the unit through extremely high temperatures to very cold. The temperatures in the humidity machine are hotter and colder than British weather. The units are checked weekly to ensure they have not broken down and the units are dew pointed before entering the cabinet and after removal.

Now that's the kind of quality that I have been looking for, and I'm surprised that it has been relatively difficult to find this kind of information, and would have been even more difficult without help and pointers in the right direction. But now that I know so much more about desiccants, sealants, spacer bars and methods of construction, I am also surprised at some of the posts on this thread with regards to the life expectancy of replacement units. I argued earlier that a unit ought to be capable of a far greater life than 5 years, purely on the basis of logic, since all the components used in the construction are capable of life greater than 5 years. And so now I have my proof.

Here's a quote from another companies document, -- on desiccants.
"A large number of IG(insulated glass) Unit manufactureers in the UK, are under the illusion that if a desiccant is tested by a notified body (for moisture capacity) and the factory where the desiccant is manufactured has a recognised quality system, that the desiccant is of high quality" ------- They go on to discusss the two roles of the dessicant, at manufacture and throught the life of the sealed unit. And they describe amongst other things, how poor quality dessicant is in effect already partially wet (initial moisture content), when it is installed, and how the spacer bar is inadequately filled due to desiccant bead size and bead damage.

These are all quality issues. If I can find all this out, I would find it very surprising if most of those who are actually in the industry, fitters, manufacturers, and suppliers aren't already aware of all this. However judging by some of the almost fatalistic views on the life span of sealed units, perhaps most aren't aware that they could last so much longer if manufactured to a better standard.

So I think the customer is getting pretty poor deal from replacement units that only carry a 5 year warranty, even if they are cheap, when they could easily be offered a superior product that carries double the length guarantee.

Going right back the beginning of this thread (Maxdread can correct me if wrong), perhaps that was the sentiment behind Maxdreads post. Why, if the basic components of a sealed unit are long lived and still intact, does it all have to be discarded sooner than it should be? Can't this be prevented? Can't they be repaired?

Yes it can be. Yes they can. Firstly at the point of manufacture. I am sure most original units are built to a higher quality than the 5 year gauranteed replacements. Secondly prevention, in installation, and during the life of the window system (maintenance). Thirdly repair.

I'm still researching all 3, and in the meantime, I have donned my tin hat, to protect me from the explosive posts coming my way.

 

[masona]

Not sure if you're aware of a de-misting non-return valve design from USA. There a few companies in the UK are doing this but not sure of the outcome, also the problem I see is the wasted heated U-value will escape through the valve? They reckon they can do the repair at a fraction of the cost of unit replacement

 

[slpj]

Hi Masona, i dont know if the one way return valve method works or not. I have emailed several of the companies involved asking for testimonials and details of how exactly they perform the repair, and so far NONE have replied. My thinking is that since the problem begins with the imperfect sealant exposing the interior to the air, then exacerbating the problem by drilling holes, sounds self defeating, as I wonder about the seal around the valves. But without specific details its impossible to evaluate it.

I came across this though, on splitting and re-assembly after drying and cleaning. www.peter-scott.org.uk/glazing.html.

As with Bowie77's method, the unit is dis-assembled, but in this case the unit was put back together by the owner. He used silicone, but admits that it was difficult to get a clean neat seal. So I would it think it better to do as bowie suggest and get it re-sealed by a local company. Very interesting at least though, esp as he describes drying the desiccant with a hair dryer. Desiccant can be dried or regenerated as it is termed, by heating to drive out the moisture. I found out by accident when I left my unit lying in the hot sun. And it is only neccessary to drive out sufficient moisture to restore the dessicant below saturation point, if you are able to ensure an adequate seal to prevent further ingress of moisture laden air.

Anyway, I have emailed for details of longevity. When he made his post he was at 8 months mist free. Pretty good I think. Perhaps he is a viewer of DIYnot and might reply here?