# Acrylic Window Cracks



## lordbournheath

I have had a Chausson Allegro 96 from new (March 2010) and after 12 months it started to develop cracks around the Dometic (Seitz) window catches. The dealer has informed us that Chausson will not replace these under the warranty because they are due to chemical cleaning. We have only ever used warm water and a chamois leather to clean as we are well aware of the crazing/misting problems with the use of inappropriate cleaning products.
Has anyone else had a similar problem and was it recified by the dealer..or am I being blagged?


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## trek

I have always washed my windows with the same water as the rest of the van - normal car shampoo & water

never had a problem with windows & my previous van I had for 7 years from new 

ask them what they mean exactly by chemical cleaning ? 

I guess this is Danum's in Weston Super Mare - sounds to me as though they are being totally unreasonable what on earth are they suggesting you used that would damage the plastic ( something like acetone ???)


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## mikebeaches

trek said:


> I have always washed my windows with the same water as the rest of the van - normal car shampoo & water
> 
> never had a problem with windows & my previous van I had for 7 years from new
> 
> ask them what they mean exactly by chemical cleaning ?
> 
> I guess this is Danum's in Weston Super Mare - sounds to me as though they are being totally unreasonable what on earth are they suggesting you used that would damage the plastic ( something like acetone ???)


Wouldn't imagine it's Davan (Danum's?) because they are not a Chausson dealer. Highbridge Caravans, down the road at - guess where - 'Highbridge', are. But no idea if that is the dealer being referred to.

I'm interested in the thread because I believe our Chausson, also a 2010-build, has the same windows. Must scrutinise them closely for any problems.


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## trek

Ooophs 

Yes Mike your right bit too hasty typing & got the two confused 

so appologies to all


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## plasticplumber

The fine crazing on acrylic/perspex windows will only occur under chemical attack and will propagate from stress points example hinges and fastenings, giving a clear indications that this is indeed the cause. Enviromental or stress cracking will also be accelerated with the addition of heat after application and before dilution or removal of the chemical. This may well be just from sun on a hot day and a tinted window absorbing the heat and possibly drying the chemical onto and into the surface of the window. 
This fine type of crazing is not known to occur for any other reason than the contact with various chemicals. It will not have been due to a manufacturing fault in the manufacture of the window or a fault in the material. I can therefore understand why the window will not be replaced free of charge. 
Because the properties of this plastic are known it is not up to the manufacturer to prove what has or has not been used on the window besides which all remnants of it will in all probability have been removed by rainwater or additional cleaning. 
Therefore the rules for cleaning and maintaining acrylic/perspex windows are :-
No Stickers
No vinegar containing cleaners.
No domestic washing up liquid as van cleaner.
Certain surfactants may cause problems.
Always thourghly rinse after cleaning and do not allow cleaning agents to dry out on the window.
If removing scratches and cleaning this type of window use only products specifically designed and tested for use on this material

I know this is not what you wanted to hear but unfortunately the only cause of this type of stress crazing is contact with chemicals and possibly the addition of heat to accelerate the problem.


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## lordbournheath

*ACRYLIC WINDOW CRACKS*

Thank you to the previous three members who have replied to my post
My response to plastic plumber is that as I have stated in my query WE HAVE NEVER CLEANED THE ACRYLIC WITH ANY SOLVENT OR CHEMICALS WHICH COULD CAUSE THIS PROBLEM.


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## pomme1

The OP never mentioned stress crazing, he talked about cracks! Cracks around catches and fixing points could have a multitude of causes, most probably misalignment of the fixings or the window being out of square.

I think the dealer is being disingenuous here. Again, it's the old, old story. The manufacturer's warranty is almost irrelevant, responsibility lies with whoever sold you the'van, i.e. the dealer, which is no doubt why he may be fobbing you off.


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## robrace

*cracks*

I have had two of my Seitz windows crack around the hinges although to be fair the van is nearly ten years old.They are very expensive to replace.in one of the corners there is a code.This is what you need to order a replacement.I have onlt ever washed mine with soapy water and have never used anything else.I think the cracks are probably stress ones.


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## plasticplumber

If its fine crazing cracking its due to chemical attack combined with stress and heat - end of. If its a split then its not a crack and is due to a bang or being forced at some time. Neither of which are manufacturing faults and as such the manufacturer is well within their rights to refuse to replace the roof light. Whether you as the current owner have applied cleaner that has caused the damage or wheather something has been applied elsewhere will not be of concern to the manufacturer as it is known that stress cracking will not occur without a catalyst to start the process. Due to the breadth of knowledge on this matter I am afraid its likely to be cut and dry. That is not to say that as a show of good will the supplying agent may choose replace the window. Unfortunately this phenomena is usually a slow process and can take weeks, sometimes months after the chemical causing the problem has been applied for the crazing to become visible. Much will depend on the chemical and the amount of heat and stress over time that is absorbed. I would point out that I do not work in the caravaning or plastic window production industry but have experience in tracing failure within plastic items and I am not trying to attribute blame. I am just stating facts relating to the known propertis of this material.

Add to my previous list in my other post the use of cling film.

.


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## pomme1

Plasticplumber,

Surely stress cracking is just that, cracking due to stress, which can be initiated in any number of ways, not just by chemical attack. As I said earlier, a misaligned fixing could easily induce stresses which would lead to cracking/splitting, call it what you will.

If the window were suffering from crazing, then I agree with your analysis of the likely cause.

Roger


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## plasticplumber

I am not possibly putting this well but I was trying to say what you have interpeted. Crazing = chemical. Crack = bang, stress,misalignment which equates and leads to forcing all of which take the material beyond its limits. Perhaps a photo would clarify but as the claim was rejected as chemical attack I naturaly assume crazing, if its not crazing then this opens it up as you say to all types of causes.


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## pomme1

Plasticplumber

Pleased to say we now agree!!

Roger


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## grandadbaza

lordbournheath said:


> I have had a Chausson Allegro 96 from new (March 2010) and after 12 months it started to develop cracks around the Dometic (Seitz) window catches. The dealer has informed us that Chausson will not replace these under the warranty because they are due to chemical cleaning. We have only ever used warm water and a chamois leather to clean as we are well aware of the crazing/misting problems with the use of inappropriate cleaning products.
> Has anyone else had a similar problem and was it recified by the dealer..or am I being blagged?


Hi your post is practically word for word in describing the problem with our washroom window , like you when I wash the m/h I use a very expensive car cleaner with a brush on a telescopic arm ,but I never use it on the windows I use a sheepskin glove car cleaner just for the windows and finish off with water and chamois , when I noticed the cracking/crazing I emailed Auto Trail direct , they too suggested I may have used some form of chemicals , but assuring them I didnt they asked me to send them close up photos of the window (it only affected one of them ) , they forwarded them to the window manufacturer and after a couple of weeks I got a call from Auto Trail to say they had agreed to replace the window , this was subsequently carried out at the Auto Trail factory


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## sallytrafic

As an aside if you have a crack that you want to stop, you can stop it dead .... by making it bigger or rather wider.

Carefully drill a small hole at the very end of the crack.

Be careful not to press hard and use sharp drill










If you are accurate a 2mm hole will do but some might find a 3mm one easier to do.

This works, for the scientifically minded, by reducing the stress concentration ahead of the propagating crack. The radius of the propagating crack before you add the hole was only about the size of a single atomic bond so even in a relatively unstressed material the concentration of stress at the tip of the crack is so large that bonds are ripped apart and the crack spreads.


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## spykal

Hi

Not a help really with the problem now that it has happened but I am sure that many rooflights and windows get crazing, hazing and stress cracks because they are overheated by the sun. This can happen if the roof light or window is closed and the reflective blind is also closed ...the heat build up between the blind and the rooflight is what causes the damage... I know that the instruction manual and the stickers on the windows tell us not to do it but knowing and doing are two different things :wink: 


Mike


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## teljoy

spykal said:


> Hi
> 
> Not a help really with the problem now that it has happened but I am sure that many rooflights and windows get crazing, hazing and stress cracks because they are overheated by the sun. This can happen if the roof light or window is closed and the reflective blind is also closed ...the heat build up between the blind and the rooflight is what causes the damage... I know that the instruction manual and the stickers on the windows tell us not to do it but knowing and doing are two different things :wink:
> 
> Mike


Thanks Mike , that's interesting. I hadn't realised that heat build up could do that. When our van is stored on the drive the heiki blind is always closed to keep the heat off and this last season the heiki now has a glazed patch some three inches in diameter. But it's six of one and half a dozen of the other as closing the blinds does protect the furnishings and wood from fading. So we'll live with it!

Terry


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## Jezport

I was a dispensing manager at a large opticians shop for a number of years. I dealt with lenses in rimless frames so can say from experience that stress cracks can be caused by fitting screws through plastics, and have seen new lenses crack if the screws are fitted too tightly.

Dont put up with it, complain and ask them for a repair.


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## lordbournheath

*ACRYLIC WINDOW CRACKS*

Thanks to everyone who has taken the trouble to reply.

I must admit I was encouraged by the last contributer's post. I had shown the problem to my local garage professional who is a long standing RV owner and classic sports car enthusiast. He had seen this before and it was also his opinion that this was the result of stress where the holes were drilled in the acrylic to secure the catches.

It may well be that sunlight will exacerbate the problem coupled with the vibration when the vehicle is in normal use, or when the windows are opened or closed. Either way if the vehicle is purchased from new then the warranty should cover replacement as obviously they are "not fit for use"


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## sennen523

Hi All,
I realise this reply is a bit late. I have a two year old van and one of the Dometic/Seitz windows is crazing, right next to the centre locking catch on the INSIDE pane.

In my opinion, this explanation that this is caused by harsh chemicals used in washing is absolute nonsense. I have never used ANYTHING on the interior acrylic of my window.

Hope you got this sorted.
sennen523.


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## plasticplumber

Any chance of a photo when it stops raining?


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## sennen523

Hi plasticplumber,
I have got some good photos but are "too big" for this site. I would be very interested in an independent view of this crazing as Dometic/seitz are adamant that it's caused by aggressive washing chemicals. The crazing projects from the screw holes of the centre locking catch on the inner pane.

Kind Regards,
sennen523.


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## plasticplumber

sennen523. you have a PM


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## 96299

Hi

We had a skylight that had 'starring' all over it, but was very hard to see even when underneath it looking up, it had to be in a certain light. I only ever used motorhome cleaner on it and it did not occur on any other skylights or windows. Luckily I got a replacement under warranty and it hasn't happened since, and we still use the same cleaning methods.

Steve


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## lordbournheath

Hi Sennen65
I am afraid I have hit a brick wall with this problem.
My dealer has been no help at all. He did contact Chausson and Dometic but I am not convinced he argued my case with any vigour.
Chausson said "These kind of cracks appear if the customer uses a cleaning product with alcohol. Adding this explanation was given by the supplier Seitz which has done some tests to know why their windows can crack." 
The dealer said <I will send you a copy of the Dometic information sheet that clearly explains their position on the matter of the cracking windows. When you have seen this fact sheet if you still feel you want to take this issue further then our only option is to put you in contact with Dometic.> 
He continued <This problem is becoming quite common. Most manufacturers of motorhomes and caravans are now including information to dealers and customers about it. When we ask what can cause the problem, no other reason is given other than "aggressive cleaning " or "corrosive cleaner. When we ask what is meant by this, the answer comes back "nearly anything" Only use very mild washing up liquid and make sure this is well washed or wiped off. Once cracked the window will not repair and may or may not get any worse. The only option is to replace it.>
I am 100% convinced that we have used nothing but soap flakes and warm water to clean these windows and no one else has used our vehicle. BUT it has been to two different FIAT dealerships for service and clutch replacement, back to the dealer several times for annual service and multitude of repairs under the warranty, to paintseal for exterior protective coating and upholstery protection, to another company to reupholster the interior. 
So any of these companies plus Chausson themselves could have been responsible. I put this to the dealer. He replied
<Our company have been aware of this issue for many years, and as such do not use any chemicals that may cause this issue near the windows. Paintseal too are aware of the potential issue.>

So I think unfortunately we are both screwed.


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