Testing a glass breaker?

WolfSpring

WolfSpring

Joined
Feb 25, 2015
Messages
126
I tried doing a search on here and even on google found a lot of actual windshield tests, but I'm not about to go breaking windshields. I want to test some glass breakers for review purposes and was wondering if using old salsa jars or something like that would be an efficient or even relevant test in any way shape or form. I mean obviously I'd wear protective gear, glasses long sleeves and gloves and probably do it over towel on a table. Would this test be in anyway relevant? I want to test fixed points vs spring activated and the like. Has anyone done any testing, any tips on what works what doesn't or what to watch out for. Obviously whatever tests need like items to be broken to make it relevant, at any time I have 10-15 salsa jars around used for kids projects, holding screws and what not. Am I wasting my time even considering this?
 
Any jar available is simply plain old glass that will break when hit with just about anything.

If the designed target medium is side window safety glass in a vehicle, the only way to test the tool is to use it in conjunction with laminated auto glass. Any other glass is wasted effort.

The only tools that work with the typical laminated windshields are saws and axes.

The tool needed to break a side window is "just about anything that will concentrate a lot of force at a small point". The first auto extrication class that I took back in 1989 emphasized that. The instructor had a variety of tools and tool-like objects for us to use on several junk cars. The first thing he showed us was the "real" auto glass breaking tools, i.e., the tools every firefighter has on his/her person daily, as well as those stored on a fire truck. Spring punch, crowbar tip, fire axe point, etc. They all worked.

He also showed us what DIDN'T work or didn't work well. Baseball bat, crowbar swung like a bat, 2x4, etc. Many of these just bounced off several times until the user happened to hit "just right" and the window would break.

He then showed us improvisation "tools" that could be used in the event no "real" tools were available. Knife point, knife hilt and of all things, a radio whip antenna. So many vehicle antennas back then just screwed on and most didn't even have a set screw holding them on. You unscrew the antenna and then "whip" the little ball on the tip at the window and "poof", the window cracks up into those neat little safety glass squares.

The safe way to use a knife tip is to place the tip of the knife on the window glass and drive the tip into the glass with a blow to the pommel. May end up breaking the tip, but the window breaks every time.

ETA: Fillet knives and regular kitchen knives don't work. The blade needs to have rigidity.

A pommel hit works best if there is a sharp point, e.g., the sharply angled pommel of full sized BK2/3/4/5/7/9. A flat pommel, such as those found on Kabar 1217/variants will work, if the knife pommel SIDE strikes the glass. Power concentrated in a small contact area. The flat pommel strike like using a hammer will frequently bounce off without breaking the window.

The only way to breach a windshield with a knife is to use the knife to cut the gasket holding the window in place and then removing the windshield with one person on each side.
 
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I actually think bottles and jars are fine as long as you use the exact same type of jar or bottle in each case if trying to compare. Not all glass that needs to be broken in an emergency will be tempered and have a tough time with. And having had numerous knives with "glass breakers" I have found the least effective to be microtech steel glass breakers. The only glassbreaker I have ever had that impressed me is the little ones used on lionsteels. Those little do hickeys work surprisingly well with little effort. The best is when i used a microtech glassbreaker It deformed considerably. The lionsteel looks like new.
 
Wow... Thank you for that information, I consider myself educated. I know a lot of what you said but the antenna thing is new. I was just looking for a way to review all the parts of a knife. I hate seeing all these reviews where they go into all the flashiness of the detail and never use the dang thing in any way shape or form "table top" reviews. Thank you.
 
PURPLEDC said:
I actually think bottles and jars are fine as long as you use the exact same type of jar or bottle in each case if trying to compare. Not all glass that needs to be broken in an emergency will be tempered and have a tough time with. And having had numerous knives with "glass breakers" I have found the least effective to be microtech steel glass breakers. The only glassbreaker I have ever had that impressed me is the little ones used on lionsteels. Those little do hickeys work surprisingly well with little effort. The best is when i used a microtech glassbreaker It deformed considerably. The lionsteel looks like new.
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I want to try the benchmade one, I think it's an ERT with the spring loaded one vs some of the cheap standard ones.
 
WolfSpring said:
I want to try the benchmade one, I think it's an ERT with the spring loaded one vs some of the cheap standard ones.
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As long as its carbide I have hope. Decorative steel glass breakers might not fair so well. I dont think there will be much control in the experiment to determine which glassbreakers may be better than another but it would show if a glassbreaker seems more decorative than functional which is always useful info.
 
I'd say, make some contact with a junk yard or maybe even a body shop. There must be some cars with broken windshields on one side and you can test the other. Not the perfect test since the stress on the glass will be different, but still perhaps a reasonable substitute.
 
I carry but haven't used a large automatic center punch. Always hit the lower corners of the glass as is more rigid and doesn't flex to absorb the tool
s force.The windshield is a different story .I'ts figured as a structural member !!
 
The glass breakers I have on folders seem to work fine on automotive glass, particularly the ones specified as 'carbide' and likely hardened. The best one I have is the one on a HEST 2.0.

Where the mistake can be made is striking the center areas of windows or windshields---where the strength in the glass is en masse.

Try striking the lower corners of a window or windshield--where the strength of the sheet structure is weakest and has the least mass. One or two good strikes and the whole thing should shatter. The corners, not the centers.
 
I have broken quite a few windows. I can tell you that most bottles are no where near as strong as auto window class. Having said that, location of hit is everything. If it were me doing testing, I would do the test on old Dalwhinie 15 year scotch bottles. You get some good scotch out of it and the bottles are much thicker than a wine or beer bottle.:D
 
Just go to pick and pull. BTW wear gloves or wrap a rag or sleeve around your hand. Have fun haha.
 
zzyzzogeton said:
Any jar available is simply plain old glass that will break when hit with just about anything.

If the designed target medium is side window safety glass in a vehicle, the only way to test the tool is to use it in conjunction with laminated auto glass. Any other glass is wasted effort.

The only tools that work with the typical laminated windshields are saws and axes.

The tool needed to break a side window is "just about anything that will concentrate a lot of force at a small point". The first auto extrication class that I took back in 1989 emphasized that. The instructor had a variety of tools and tool-like objects for us to use on several junk cars. The first thing he showed us was the "real" auto glass breaking tools, i.e., the tools every firefighter has on his/her person daily, as well as those stored on a fire truck. Spring punch, crowbar tip, fire axe point, etc. They all worked.

He also showed us what DIDN'T work or didn't work well. Baseball bat, crowbar swung like a bat, 2x4, etc. Many of these just bounced off several times until the user happened to hit "just right" and the window would break.

He then showed us improvisation "tools" that could be used in the event no "real" tools were available. Knife point, knife hilt and of all things, a radio whip antenna. So many vehicle antennas back then just screwed on and most didn't even have a set screw holding them on. You unscrew the antenna and then "whip" the little ball on the tip at the window and "poof", the window cracks up into those neat little safety glass squares.

The safe way to use a knife tip is to place the tip of the knife on the window glass and drive the tip into the glass with a blow to the pommel. May end up breaking the tip, but the window breaks every time.

ETA: Fillet knives and regular kitchen knives don't work. The blade needs to have rigidity.

A pommel hit works best if there is a sharp point, e.g., the sharply angled pommel of full sized BK2/3/4/5/7/9. A flat pommel, such as those found on Kabar 1217/variants will work, if the knife pommel SIDE strikes the glass. Power concentrated in a small contact area. The flat pommel strike like using a hammer will frequently bounce off without breaking the window.

The only way to breach a windshield with a knife is to use the knife to cut the gasket holding the window in place and then removing the windshield with one person on each side.
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That was a very informative post, Thank you :thumbup:
 
Going to an auto salvage yard is the right thing to do. Wear gloves and any other protective clothing you have. Having a second person come along with a first aid kit might not be a bad idea.

As a retired medic, I can tell you that the glass breakers you want to test are not designed for windshields. Side and rear auto glass only. You will find that a spring loaded center punch works better that anything else. I once watched two firemen hit a rolled up car window over six times before the glass gave way. When it broke, one of the the fireman followed through with his swing about 18 inches into the car and scattered glass everywhere.

Take your test a little farther. Depending upon how you break the glass, you may have micro chunks of glass everywhere. Think about the victims that would be in the car or truck that you are using. Also, try one or two windows while you are sitting in the car and try to get out without getting cut up.

We were taught to tape the window with duct tape, if the situation allowed, (except the corner were we used the punch), so that glass was not scattered all over place. It was to make patent treatment cleaner and faster. The neat thing about it was that you could peel the glass out as a sheet and slide it under the car so it was out of the way. In fifteen years I never taped a window.

Training where you got to break something was always fun.

You should have a enjoyable afternoon testing different glass breakers. Also, Victorinox makes a rescue knife with a glass saw. Maybe you could test that also.

I hope you are doing a write up here on BFC.
 
If you do decide to go through a windshield, might want to pack a lunch and a whole lot of bandaids. Laminated glass will take a while to get through all the way. As mentioned side windows of vehicles as well as the back windows. W tch some youtube videos on the topic. It will give you a visual perspective. If you visit a junk yard, make you you pay for the windows you bust, most junk yards try and sell whatever the can salvage, windows included.
 
Tempered glass is easier to break than glass jars, but needs the right hit. As a buddy of mine told me after fire-fighter training, everything had seven uses. Use 7 was a window breaker. Tempered glass can be found in glass fridge shelves, old shower doors, and coffee table tops. Worth looking at your local dump for glass to break.
 
Not sure if this is relevant, but it's certainly interesting. For more on youtube, search for "spark plug glass."

[video=youtube;QhlmKHbPFhU]https://www.youtube.com/watch?v=QhlmKHbPFhU[/video]
 
Scott Free said:
Not sure if this is relevant, but it's certainly interesting. For more on youtube, search for "spark plug glass."
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I had the unfortunate experience of having had somebody use spark plugs on my rear window quite a few years back.

Some vandals decided that punching holes through a Toyota Tercel that had child seats would be a good idea while we were off at the local steam locomotive attraction. Ended up with glass fragments all over the kid's seats. Luckily some locals nearby were nice enough to shopvac the glass and help me duct-tape some sheet plastic so that we could get on the highway to drive home afterwards.
 
I know the ways of breaking. I'm just looking at a way to make knife reviews more relevant, showing what each of the features do. I try to find a review on a knife anymore and it' ssome 15 year old talking about how awesome a china mart knife is with all it's bells and whistles and never once does anything with it. But from seeing the comments I've gotten the answer I needed, doing practicality tests on a glass breaker on a knife would require using them on what they are designed for and unless I've got some money set aside for windows or the like it's almost impractical. I'd even thought of using dollar store picture frames, but what I'd need is safety glass. As stated, yes it would show a difference in how they operate on whatever they are breaking, but not how well they work on automotive glass.

Thank you all for your input and thoughts it's given me some stuff to think about for my own reviews.
 
maybe take a trip to your local pick-n-pull yard. Maybe ask them if they don't mind your testing before the hulks go into the crusher for recycling since the glass will be breaking anyway. Offer to push the broom a little after it's all done.
 
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