Explain glass breakers to me...

Glass is really not hard to break but you do have to focus on the corner where tension is. For fun, in training, we show other firefighters how to take out a side window with a car antenta. I have also seen people bounce a sledge hammer off the center of a window. It really is all about how you hit it and where you hit it.

We normally use an axe or a sawzall to take out the winshield before we remove the roof. You can cut around the edge and take it out in one piece.

Adam
 
Windshields are a lot stronger in resisting impacts from the OUTSIDE. The outward bend or curvature of the glass makes it much stronger when striking against that curvature. Cracking or breaking from the inside is considerably easier. A glass breaker would be much more valuable to a person trapped inside a vehicle, and needing to get out.

More than once, I've known people to 'accidentally' crack or break their windshields when lightly striking from the inside, to dislodge snow or ice, or 'scare away' a bug on the windshield. And that's with just their hand/fist.
 
Personally, I'd just get an inexpensive glass breaker (With a spring-loaded tip) & just get the knife you want.

Yes, hitting a window at the corner is better than striking it at the center & hitting a car window with a hammer or other similar object can be hit & miss affair (That includes a baton & an ASP). It may work, it may not, or it may take many shots at it. Not that I'd know from experience or anything. Just what I've heard.
 
I have also heard from a guy at o'briens glass (repair windshields. other glass related damage), who was replacing my windshield, that when the car's windshield is in the car, the front pillars support it and give it strength, but when its not in those pillars, its pretty weak. To show his point he took it out, and put a small amount of pressure on it, and the crack that was in it spread widely. I guess that would have to do with different directions of pressure?
 
JCK said:
I have also heard from a guy at o'briens glass (repair windshields. other glass related damage), who was replacing my windshield, that when the car's windshield is in the car, the front pillars support it and give it strength, but when its not in those pillars, its pretty weak. To show his point he took it out, and put a small amount of pressure on it, and the crack that was in it spread widely. I guess that would have to do with different directions of pressure?
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Has more to do with the crack already in it than the pillars. If he tried that with a windshield that was new but uninstalled it would not have cracked. The glass is made to fracture after a certain point, once it gets a crack it weakens quite a bit, but that first crack can be a duesy. For instance even a #2 phillips screw driver on an OEM windshield will take a good bit of effort for crack it, the pillars do make a big difference, but if there is already a crack it doesn't take much more than the weight of the glass to spread it. But your target shouldn't be the windshield if your trying to get out of a car, the side windows are much easier to get through as there isn't any lamination to tear through as well
 
Actually windshields can crack easily. Windshields are laminated glass, which means it's two, thin (I believe 1/8" thick) pieces of glass with a film between the two pieces. A screw driver will easily crack a windshield, but you still wouldn't be able to escape from it.


Note: My father is a glazier, so I'm pretty familiar with most types of glass.
 
you might be able to crack a windshield or rear window but will you be able to crawl out thru the hole ? no. it would be better to try to remove the entire windscreen. for quick entry in to a car the glassbreaker can be used on a side window. also be very aware of the clouds of fine glass particles that this creates -they are not good for your lungs. should you carry a glass breaker? in Australia there have been incidents of people leaving children in unattended cars in Summer while they go to the shop/casino/pub- on a hot day the temperature inside the car increases quickly to a fatal level .pets as well are left to suffer like this by thoughtless people-a new window costs a bit but so what?
 
meako said:
you might be able to crack a windshield or rear window but will you be able to crawl out thru the hole ? no. it would be better to try to remove the entire windscreen. for quick entry in to a car the glassbreaker can be used on a side window. also be very aware of the clouds of fine glass particles that this creates -they are not good for your lungs. should you carry a glass breaker? in Australia there have been incidents of people leaving children in unattended cars in Summer while they go to the shop/casino/pub- on a hot day the temperature inside the car increases quickly to a fatal level .pets as well are left to suffer like this by thoughtless people-a new window costs a bit but so what?
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I wonder if there is any info on carrying glassbreakers in Australia. I am not 100 % sure, but I think you have to be a police officer/military/ambo or firey to buy them.
EDIT: but I do agree with what your saying, I'm sure most parents would rather have a broken window than a dead kid or dog, and be up for neglect etc.
 
If you guys get really curious about what works and what doesn't, head to a, pull your own, junk yard. Usually the junkers won't mind if you try stuff out, especially if you ask then if theres one they're about to pull from the yard anyway. I'd recomend this to KYA in particular, try sitting in the drivers seat with a seatbelt, and give the windshield your best hit with a screwdriver, might be surprised, from the outside breaking in I agree, not too hard, but even then most OEM glass has a harder layer externally, then a laminate, then a slightly more flexible inner glass, depends on make as well, which makes it hard for a person without strong wrists and upper body to get a good hit. Try it, its fun as hell. :)
 
JCK said:
I wonder if there is any info on carrying glassbreakers in Australia. I am not 100 % sure, but I think you have to be a police officer/military/ambo or firey to buy them.
EDIT: but I do agree with what your saying, I'm sure most parents would rather have a broken window than a dead kid or dog, and be up for neglect etc.
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hey mate. thats what i was driving at.whats worth more? I'm a firey and carry a small 'RESQME' seatbelt/cutter glass breaker in my kit. Most hardware stores will sell a spring loaded centre punch-make sure you wear gloves tho. Holmatro have a good one that doesn't require you to push into the glass.cheers
 
Thanks for the info. As a Firefighter in Aus, how often do you use glass breakers when you attend car crashes? Are you guys normally the first to arrive on scene? or is that another service (hopefully this isn't getting too OT)
 
dillon_b12 said:
I don't get it. I think it is safe to assume that, for most of the public, glass breakers will only be used in an emergency situation.

If you are already carrying a knife, why couldn't you just use the tip of the blade to break the glass? I realize this could damage the knife/blade, but if you are trapped in a burning car you probably won't care too much about the condition of your knife.

Now for LEOs(or firemen, EMTs, etc...), who may be need to break glass on a much more frequent basis, I can see the use. But for the average consumer, it doesn't make much sense to me.

Do actual purpose-built glass breakers perform better than the tip of a blade?
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As useful as any end of any piece of metal. Just a new way to motivate folks to separate themselves from their money.
 
dillon_b12 said:
I don't get it. I think it is safe to assume that, for most of the public, glass breakers will only be used in an emergency situation.
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Emergencies....yeah thats the idea...or at least the selling point.

But not just for glass breaking. Skull-cracking in self-defense is another "use" for the exposed metal ends.

Not saying its always feasible or needed since there's a blade there too, but it is a potential use for it.
 
I was using the glasbreakers I have in non emergency situations but I found it was much easier just to use the key and lock method, not to mention the money I save.
 
I know the spring-loaded punches work better than the glass-breaker on my Umnum does, but it does work. I came across a rollover about 2 months ago and used my Umnum's glass-breaker to take the driver's side windows out.While on-duty, I'm reaching for the spring-assisted breakers, but I'm glad to have the breaker on my EDC.
 
A glass breaker on a knife has always been a "Wow, that'd be handy..." feature but usually brings about problems with the ergos and hand poking. I've thought about picking up knives with glassbreakers before but I usually end up just passing.

This however go me to thinking, I usually carry a LM Charge oh me... I wonder how successful the screwdriver (either micro or regular size) or tip of the pliers head would be in performing in a glass breaker in a pinch. If any of those would work, would be a rather nice feature :)
 
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