shatterin' windows

[Robert86]

Hey,

If I wanted to shatter windows with my lights, what would get me there the quickest? Or the flip side, how do I avoid shattering windows with my lights. Under what kind of conditions would it most likely happen. Would putting a couple 2k fresnels outside at night, two or three feet away from a window shatter the glass? What about indoors? The biggest light I have is a 2k fresnel. Is there a rule of thumb? thank you, thank you.

 

[khmuse]

For a piece of glass to be shattered by exposure to a light source, it would have to undergo considerable localized heating. Given enough heat (and quick enough) it is possible to have a different enough rate of expansion on one surface of the glass to cause it to deform and fail. The reality is that glass has a relatively good thermal transfer characteristic, so the heat imparted to one side is going to propagate to the other side and cancel out the differential expansion.

The only type of glass which might be more prone to failure induced by exposure to a large heat source would be glass which has an IR rejection layer bonded to it.

No rule of thumb, but I would venture to say that even very close, a 2k tungsten source (even a Fresnel fully spotted) wouldn't impart enough energy fast enough to cause a failure of any typical glass used in windows.

 

[Robert86]

For a piece of glass to be shattered by exposure to a light source, it would have to undergo considerable localized heating. Given enough heat (and quick enough) it is possible to have a different enough rate of expansion on one surface of the glass to cause it to deform and fail. The reality is that glass has a relatively good thermal transfer characteristic, so the heat imparted to one side is going to propagate to the other side and cancel out the differential expansion.

The only type of glass which might be more prone to failure induced by exposure to a large heat source would be glass which has an IR rejection layer bonded to it.

No rule of thumb, but I would venture to say that even very close, a 2k tungsten source (even a Fresnel fully spotted) wouldn't impart enough energy fast enough to cause a failure of any typical glass used in windows.

Thanks Kevin.

 

[Anhar_Miah]

The quickest way would be to heat the glass, then rapidly cool it. Or Have it frozen and then rapidly heat it, either way a rapid change in heat can cause enough stress to cause it to fracture.

Or you could also impart a large kinetic force within a localized surface area

Translation:

"Hit it bloody hard, with something like a hammer"

 

[Capt Quirk]

I totally agree with Anhar- use a hammer, not a light. The windows will break much easier.

 

[kyle.presley]

Hey,

If I wanted to shatter windows with my lights, what would get me there the quickest?

Throw them through the glass.

 

[Robert86]

Throw them through the glass.

Ok. Well, I was going about it two different ways. So, I was wondering how fast heat wise.

And yeah, I thought that lighting up really really cold windows would cause it to shatter faster. And now I know, thanks guys.

 

[Prairieboy]

I learned the hard way that it does not take too much heat from a light source to crack the windows with the embeded wire in the middle. My college at the time was not too pleased with the lesson either.

 

[Robert86]

I learned the hard way that it does not take too much heat from a light source to crack the windows with the embeded wire in the middle. My college at the time was not too pleased with the lesson either.

What source was the light coming from, a 650, 1k or more? My main concern is at night, because it seems to me that heating up really really cold windows is a bad idea.

 

[Robert86]

lol

on a side note, over here at work there are these chairs with a kind of glass seat, it just spontaneously exploded(shattered). All I heard was breaking of glass, then I go over to see the office the chair was in(a few people looking too) and there was glass on the ground. Jeezus, I guess it really doesn't take too much heat. lol

 

[Prairieboy]

It was a 1K redhead, a couple feet away.
Bet those folks in the chair were alert for thier meetings.

 

[Robert86]

It was a 1K redhead, a couple feet away.
Bet those folks in the chair were alert for thier meetings.

lol
Apparently there was someone sitting in it about five or ten minutes before it shattered. That woulda' sucked if he was still sitting in it when it busted. lol

 

[Luis Caffesse]

I had a ding in my windshield from a rock...had been there for a LONG time.
I kept telling myself, I need to get that fixed...I need to get that fixed...

Then it froze here a few weeks ago.
I get in my car, and without thinking, turn on the defroster to get the ice off my windshield (yeah I know).

About a minute later I heard a fast scraping sound - and look down to see that my quarter inch ding was now a 2 foot crack across the bottom of my windshield.

Now I'm driving around thinking...I've got to get that replaced...I"ve got to get that replaced.


So yeah - quick cold to heat changes will definitely shatter glass - if it's already got something to start from.

 

[Robert86]

I had a ding in my windshield from a rock...had been there for a LONG time.
I kept telling myself, I need to get that fixed...I need to get that fixed...

Then it froze here a few weeks ago.
I get in my car, and without thinking, turn on the defroster to get the ice off my windshield (yeah I know).

About a minute later I heard a fast scraping sound - and look down to see that my quarter inch ding was now a 2 foot crack across the bottom of my windshield.

Now I'm driving around thinking...I've got to get that replaced...I"ve got to get that replaced.


So yeah - quick cold to heat changes will definitely shatter glass - if it's already got something to start from.

Man, you know what else is scary. I was lighting some bottles to shoot in my kitchen a while back. Well, it was at night and I was shining a 2k to the front of the bottle and behind the bottles was a big window. This big window begins from the floor up. Oh yeah, I live on the second floor, so it's a nice view looking down when I look out this window. Anyway, if I would have kept those lights on for long I think that huge window would have broke, meaning it would have been that much easier for someone to fall out, yikes!!!!!! I'm already scared enough just having that window there.