Any experts know why this has just happened?

[Glassman]

J4CKO said:

Club Sport "Waffer thin" glass ?

4/4.5/5mm

[meths]

tank slapper said:

When tempered glass is made, the surface is rapidly cooled by blowing air onto it. This causes it to solidify before the inner part of the glass. As the rest of the glass solidifies and cools it contracts, setting up compression forces in the surface. This makes the glass stronger, but any damage to the surface can lead to the balanced forces being upset causing cracks to propagate instantly across the whole pane. This means you get the small pieces you see there rather than the very sharp shards you get from untoughened glass.

A defect such as a scratch or chip could easily cause failure like that along with a temperature change. It is also possible for it to fail spontaneously without there being external damage, due to impurities in the glass during manufacture.

This is correct.

Another possibility after seeing the age of the car is that a bit of the window surround has rusted and put pressure on the glass, causing it to spontaneously fracture. The insides of window seals can be water traps when they begin to fail.

[cindychops]

Stress,the glass must have been like a very stretched rubber band and got to the point of its limits.(what really happened was there was little porsche pixies living in the boot and went overboard with their riverdance routine and one of the steel reinforced tap shoes hit the glass).

[EddieFelson]

Happens a fair bit on 968s

[Blakewater]

There was an article in my local paper once about a woman walking past a Citroen AX parked on the roadside and the rear window shattered apparently covering her in broken glass.

[RealSquirrels]

Glass is funny stuff

[Stuartggray]

The glass top on my gas cooker did that. Mrs SGG forgot to switch the gas off when she closed the lid. I thought it was meant to cut the gas supply when it was closed.
I doubt there is a gas cooker in the rear of a Porsche though.

[quiraing]

Elephants? Check in the corners of the garage and inside the car.

[Glassman]

Blakewater said:

There was an article in my local paper once about a woman walking past a Citroen AX parked on the roadside and the rear window shattered apparently covering her in broken glass.

The AX tailgate is a weird one - the glass is bonded and bolted to the bottom section and then the struts go through the glass. The earlier 309 hatches were the same.

[pobox205]

Seen this before...but on a Peugeot 106...no idea why it happens.

[rallycross]

it happened on one of my old 944 turbos in the frost and the heating element was on and I was driving along and it suddenly imploded.

hope you find that a 944 rear hatch will fit, you should be able to get one for under £300 from a breaker, a new one will probably cost a fortune (£2.5k?).

[12v3pot]

mrmr96 said:

tank slapper said:

When tempered glass is made, the surface is rapidly cooled by blowing air onto it. This causes it to solidify before the inner part of the glass. As the rest of the glass solidifies and cools it contracts, setting up compression forces in the surface. This makes the glass stronger, but any damage to the surface can lead to the balanced forces being upset causing cracks to propagate instantly across the whole pane. This means you get the small pieces you see there rather than the very sharp shards you get from untoughened glass.

Yup. Have a look on youtube for Prince Rupert Drops on youtube to learn more:
http://www.youtube.com/watch?v=xe-f4gokRBsý
http://en.wikipedia.org/wiki/Prince_Rupert's_Drop

Great clip. Explains something... I bought some fairly cheap and nasty sunglasses last week, and they have some type of lens that reveals compression/tension patterns in all sorts of transparent materials. The Lexus 460H I was following today, for example, had a very odd moire-type pattern in its rear screen (but not its side windows, nor did any other car close by). So perhaps it's the same type of tension-compression pattern?

When I first wore these sunglasses, I thought my Aygo's radio screen was borked, because the glasses showed a very super weird distortion on the screen. Glasses off, and the screen looks just fine with the naked eye. FWIW, with my more spendy Oakleys, these effects do not show up.

[falkster]

Paulm4 said:

Nothing to add other than nice car :-)

Cheers

[A9XXC]

Should be able to get a 944 screen - they are the same - for £50 or so, and then put it into your frame.

Porsche list them at something over £3.5K !

[Glassman]

A9XXC said:

Should be able to get a 944 screen - they are the same -

Spoiler differences, non?

[falkster]

Glassman said:

Spoiler differences, non?

But the frame is the same, not sure how the rear wiper delete works though.

[hornetrider]

Perhaps it rebelled against the cack NI 'private' plate

[falkster]

hornetrider said:

Perhaps it rebelled against the cack NI 'private' plate

I was thinking about the pile of washing in there.
I've had the car 3 years and really want it back on an M plate. Hate those plates.

[carinaman]

J4CKO said:

Club Sport "Waffer thin" glass ?

[GC8]

rallycross said:

it happened on one of my old 944 turbos in the frost and the heating element was on and I was driving along and it suddenly imploded.

hope you find that a 944 rear hatch will fit, you should be able to get one for under £300 from a breaker, a new one will probably cost a fortune (£2.5k?).

Any hatch will fit but it needs to be a bridge spolier type from a late Turbo or very late S2.

My advice to the OP is not to open the hatch under any circumstances. A new glass can be fitted, but the hatch WILL bend if you open it and a good 968 hatch is going to be very expensive to find.

My further advice is to buy a reasonable late 944 hatch (the wiper hole size is different) and then pay an expereinced man to fit this replacement glass into your existing hatch.

A 944 hatch is virtually worthless and can be picked up for next to nowt. New glass is available but itll be extremely expensive and Id prefer to be calling the shots with a job like this.