# cracking seitz windows



## backaxle (Nov 6, 2006)

I have just picked up my MH from storage and as I opened the blinds I noticed small cracks around the catches on the kitchen window,I then looked at all the other windows and found that they were the same including a sliding window.The windows are seitz and I replaced a large one only last month at a cost of close to £400 for the same reason,only the cracks had spread right along the bottom of the window and actually split it.It now seems that all the others are going to need replacing.Has anybody else had this problem?and what causes it?is it age(they are 8 years old)or are they built to self destruct after a while?
All answers would be appreciated.

Backaxle.


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## Traveller_HA5_3DOM (May 9, 2005)

Have you considered the possibility that during storage someone has had a serious attempt at trying to break in !! If this is the case most insurance companies would cover it subject to a police crime number.


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## backaxle (Nov 6, 2006)

Thanks for the reply.I did consider this when the first one cracked.That one started with small cracks and spread along the bottom until it completely split apart over a matter of weeks, it does not look like the sort of damage that would be done in an attempted break in especially on the sliding window where it starts at the bottom and seems to creep upwards. The strange thing is that all the windows have become like this within weeks of each other.The storage yard have no record of anybody interfering with the MH on cctv either.It has been suggested to me from suppliers of these windows that it could be caused by a cleaning product as they all have started together,but I have only used MH cleaners,unless the damage was done before I bought it I am stuck for an answer. Judging by the replies I have so is everybody else! 
regards.
Backaxle.


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## Boff (May 10, 2005)

Hi Backaxle,

what are you using to clean the windows? Any chemicals?

Best Regards,
Gerhard


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## 101405 (Oct 15, 2006)

Have you used white spirit or turps sometimes effects clear plastics


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## PIEDODGER (Aug 22, 2008)

Hi Backaxle,
I have the same problem with one of my windows, but I found it was with the window that had stuck fast to the rubber, I put it down to the window trying to flex over the storage period and because there was no give at the opener it just created this small crack, all the other windows that opened ok were fine. I maybe wrong.


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## maddie (Jan 4, 2006)

Hi Backaxle,this is probably not what you want to hear but it sounds like the window plastics has had it's lifespan.Plastics can go brittle with age hence the cracking.You will have to live with it or replace  It could be down to a simple thing in manufacture,say moulding machine too hot (or something like that) that did not show up at the time,but after 8 yrs I don't think you will get any joy from makers so try a nice letter to the Seitz people explaining your problem,they may supply new ones at cost or something  if you do not ask you will not get :lol: They may even send you new window bits to fit,much simpler than whole windows. 
terry


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## Boff (May 10, 2005)

maddie said:


> Plastics can go brittle with age hence the cracking.


Not all plastics.

And the Seitz windows are made from "Acrylic Glass", or PMMA, which does not go brittle with age.

PMMA is however quite susceptible to stress corrosion cracking, if it has contact with certain organic solvents, like acetone or alcohol. And especially the latter one is rather problematic, as it can be found in many household cleaning agents, especially window cleaning!

That is why I was asking for chemicals you have used to clean the windows. PMMA windows should only be cleaned with clear water, maybe with a little drop of dishwashing liquid. Or with special PMMA cleaning agents.

It is quite typical that the cracks appear weeks if not months _after_ the windows has been in contact with the solvent. I have learned that the hard way, when two of my van's windows had been exposed to a small spray of midge deterrent (guess where... :? ).

Best Regards,
Gerhard


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## maddie (Jan 4, 2006)

Hi Gerhard,you may well be correct, :lol: but after many yrs of working with plastics etc, and getting fobbed off with "what are you cleaning it with" type answers blaming allsorts ,I asked a boffin type and I liked the answer he gave me better saying that if the mouldig machine was too hot it could cause it to happen or discolour with age,more-so than chemicals that are wiped on/off after a few seconds.They have had lots off problems with white windows going yellow, cream or pink, put down to incorrect mix of basic plastic etc, so Backaxle will have nothing to loose by asking about his windows being replaced :lol: 
terry


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## backaxle (Nov 6, 2006)

Hi all,Thanks for the replies.My wife tells me the only chemical she has used for cleaning the windows has been vinegar desolved in water,I wouldn't think that would crack plastic but I don't know.I bought the MH from Brownhills in june last year and it is possible that they used chemicals to clean the van (they do still use high pressure washers on them once a week which is a no no ) and the problem is just appearing.I know I shouldn't knock Brownhills but they are the source of every other problem I have had since I bought the van,and there have been a few.
May try sending a letter to seitz to see if they have any idea,but I don't think they would do much after 8 years.Think I will just have to replace them one at a time when they get worse. 

Backaxle


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## Hymer_Bay (Feb 6, 2008)

I am a Design Engineer, working with Polycarbonate, Acrylic and many other plastics, and I absolutely agree with all that Boff says. I would bet good money that it is a solvent/cleaner issue. Some plastics virtually disintegrate when exposed to strong hydrocarbon solvents (such as petrol), others are more slowly de-natured. This includes ABS and Styrene, materials commonly used for vacuum formings (shower trays, sinks, door liners etc.) NEVER take a risk with cleaning agents is my advice. 

When looking at secondhand motorhomes it is common to see cracked windows, sinks, shower trays etc. This is not old age, it is either stress cracking because of vibration or mechanical flexing or more likely simply damage from aromatic cleaning chemicals. Some external plastic parts are not adeqately UV stabilised and often whiten and roughen, this is commonly called ageing. 

For what it is worth....
My workshop is full of plastics materials of many different types, some are 30 years old. I have found some Vinyl sheet embrittles slightly with time, as does PEEK and other more exotic materials, Acrylic doesn't seem to change much and Polycarbonate not at all, both of which are common window materials. Polythene and Polypropylene are very stable, impervious to most solvents and quite resistant to bending back and forth, Nylon slightly less so. ABS varies a lot, depending on the blend, Styrene is mostly terrible stuff, brittle with a low melting point and very suceptible to solvents, it flexes very little before snapping. UPVC tends to lose its plasticiser with time and discolours, goes hard, and can damage adjacent materials. PVC is quite stable but rather soft and prone to marking and UV ageing. Many plastics are adversely affected by sticky tapes and paints. Fire-retardent plastics often go brown over time. Hope this is of some interest or use. 

Simon


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## backaxle (Nov 6, 2006)

Thanks Hymer bay,what you say sounds very plausable plus it seems you are well qualified to comment.I have been discussing all the information I have received so far with my wife and now she remembers spraying mosquito repellent on the window nets when we were in the south of france in June,maybe here lies the answer?
Maybe this post will bring the problem to the fore and so help prevent anyone else doing the same, or at least get people thinking about what they use on their plastic windows. 

Backaxle


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## backaxle (Nov 6, 2006)

Back again,what are your thoughts on this?TheMH was in a bodyshop in May after a small accident to the rear,when we went down to see how things were going on, the day before we picked it up, we saw it was covered in about an inch of dust and overspray in places.I am now wondering if when it was cleaned it was cleaned with solvent or paint thinner,but I suppose I will never know.
Backaxle.


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## Boff (May 10, 2005)

backaxle said:


> ...and now she remembers spraying mosquito repellent on the window nets when we were in the south of france in June,maybe here lies the answer?


Most probably that's it! Cause and time do match.

Was exactly the same with my two windows: It was in 2006, we were in Scotland, Glen Affric, and suffered from a severe midge attack. We had all windows closed but those two in the overcab. It only took a few minutes for thousands of them to find their way in through these two windows.

In my panic I sprayed repellant onto the mosquito mesh (which is totally useless against midges). Although I cleaned it up immediately afterwards, three months later, these two windows showed cracks. 

Our van is now almost 7 years old, and all the other Seitz windows are, besides some scratches, in pristine condition. In the Euramobil manual it is clearly written that the windows are sensitive to organic solvents, but in that moment my brain was running in "survival mode", so I just did not think that much. :wink:

Best Regards,
Gerhard

P.S: In fact, I have not yet replaced the two windows. The cracks have not (yet) grown enough to be of any worry.


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## backaxle (Nov 6, 2006)

Thanks everybody for the input,I wil have to replace as and when necessary,but I have now learned(and maybe a few watchers)not to use anything but water on these windows.
best regards.
Backaxle


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## maddie (Jan 4, 2006)

:lol: Already noted, and SWMBO has taken out the spray on fly killer :wink: 
terry


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## Imbiber (May 11, 2007)

My M/H is only 6 months old and I've noticed stress fractures around the fittings on the lounge window (Seitz also).

I wondered if this was due to the fittings been over-tightend?


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## backaxle (Nov 6, 2006)

Imbiber said:


> My M/H is only 6 months old and I've noticed stress fractures around the fittings on the lounge window (Seitz also).
> 
> I wondered if this was due to the fittings been over-tightend?


Sorry to hear that imbiber,but that is how mine started.Maybe you should inform your dealer before it gets worse. Keep me informed.


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