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To cold for 30 year old glass


MJLamberson

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So I get home last night and see a huge chunk of my hatch glass had fallen out and into my car... I was furious thinking that somebody had taken a baseball bat or something similar to my car. then I noticed that the edges of the shattered parts seamed to be bent upwards, and that there was no spider web of cracks, rather, EVERY inch of the glass was in pieces hardly staying in place, and you could hear it cracking more and more as you stood there, the glass formed a wave shape then finaly all fell out.

 

grrrrrrrr.

 

And it wasnt even that cold! maybe close to freezing.

 

anybody else have this problem?

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Must be California spec glass. :wink:

 

I've never had glass fail from thermal stress unless it was already cracked and it went from extreme cold to hot very quickly (hot deftroster). Even then, the stress would only propogate a crack line, not detonate the pane.

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Must be California spec glass. :wink:

 

I've never had glass fail from thermal stress unless it was already cracked and it went from extreme cold to hot very quickly (hot deftroster). Even then, the stress would only propogate a crack line, not detonate the pane.

 

Correct

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Sorry to hear that man!

It's 15 degrees out and all of my spare hatch glass is covered in more than foot of snow, but I believe that it's all still intact.

If you're willing to pay shipping, I have some cold tested glass you can have ;)

Well, that is if I can get it out of the hatch without busting it...

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Sorry to hear that man!

It's 15 degrees out and all of my spare hatch glass is covered in more than foot of snow, but I believe that it's all still intact.

If you're willing to pay shipping, I have some cold tested glass you can have ;)

Well, that is if I can get it out of the hatch without busting it...

 

Hey thanks but Ive got a friend with a 280z in town who just finished swapping everything from that car into a 240z and he said I can borrow his hatch. But I do appreciate the offer.

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MJ, I would imagine someone probably busted the glass and the cracking you heard was just the cold stressing the already present cracks further. As others have said, glass doesn't typically fail from cold unless it's in the negative degrees. Even if it's already cracked it will only extend that crack. Water in the gasket channel wouldn't place enough pressure on the glas to cause that. The rubber would give more than enough to keep that from happening. Sorry to say, but I'd be sitting outside with a pellet gun in the bushes waiting for some neighborhood punks.

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Ever close a door at -40 and have the glass shatter?

 

What sucks is then driving back to the rental car agency with no driver's window...

 

The unsympathetic rental agency people conveyed that 'external forces' (i.e. me slamming the door "excessively hard") caused the breakage, and therefore I would have to pay for it.

 

Curiously, when I got the bill, it was for TWO windows. Apparently the other glass broke when they took it to the replacement shop. They got the CC Charge Protested, and I gave them the 'go pound sand' letter after a month or so of arguing.

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Glass is made with sulfide nitrate impurities. The odds of a lite breaking are 8 lites per 1000. If they break it due to this it would have broken within a year or so, not 30. The most likely reason (if nothing hit it) would be a chip in the glass grew due to changes in the temperature. Also if a blunt object hits the glass it doesn't always cause a spider effect.

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Glass is made with sulfide nitrate impurities. The odds of a lite breaking are 8 lites per 1000. If they break it due to this it would have broken within a year or so, not 30. The most likely reason (if nothing hit it) would be a chip in the glass grew due to changes in the temperature. Also if a blunt object hits the glass it doesn't always cause a spider effect.

Certain materials can break glass in funny ways. Ever break the ceramic off a spark plug and throw it at a window? Tried it in a junkyard once when I was younger. Hardly made a sound, but went clean through the window and caused the glass to shatter without falling through. Really neat to see. Anyhow, point being, I'll bet something hit the window. Highly doubt it just broke from age or weather.

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Back in HS, a guy had an old Dodge Omni hatchback (the one where a voice told you "the door is a jar") that the glass in the hatch dropped in on him during winter, but after he turned on his radio... Maybe the same type of thing.

 

Hey MJ, if your friend needs his hatch back, I have loads of hatched and bare glass. Hit me up.

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  • 3 weeks later...
Well I was cleaning out all of the glass getting ready to put on the new hatch (Thanks Dig280!) and I did find a rock... ... ... ...

 

See what happens when it takes half a month to fix your broken hatch glass? People put rocks in the hatch! :P

 

Vandalism just plain SUCKS!

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See what happens when it takes half a month to fix your broken hatch glass? People put rocks in the hatch! :P

 

Vandalism just plain SUCKS!

 

 

HAha, thanks for getting me to laugh about it, that was pretty funny. I still dont see how the glass broke the way it did though, the edges of the hole raised up like a small hill, and shattered to every corner like it was. But hey weirder things have happend

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The laminate in between the layers can do strange things if it has 'shrunk' over time. Like curl back when cut.

 

The glass simply adheres to the laminate substrate.

 

Cut a tightly stretched piece of saran wrap on the top of a glass...the edges curl upwards slightly. Imagine if the tension was uneven and you had little pieces of glass firmly adhered to one side and not the other---it curves where it can relieve the tension.

 

It's not like a bullet through metal where plastic deformation occurs. It gets stretched, then relaxed...somewhat. Follow?

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