breaking glass

[Ctrl_C]

I just remembered some experiments I tried recently in breaking glass during my little sabatical that I thought I would share with you all.

1. Break some ceramic off a spark plug. Take a piece even smaller than a dime and throw it at a windshield or window...you don't even have to throw hard. The glass will shatter.

2. This is a little more high tech. I found <a href="http://www.thinkgeek.com/stuff/computing/5a15.shtml" target="_blank">these</a> nifty little things a while ago. They can generate up to 75dB. If you were to run one of those car audio test tones that go from 20kHz to 20Hz, the tone would eventually match the resonant frequency of the glass and shatter it effortlessly. Depending on the type of glass too, you could put duct tape on the glass where you want the break to stop and it could possibly allow you to break out only a section of glass (the rest would probably still crack but it could easily be broken out of the taped off area only.

Also, strong adhesived contact paper could make the job very silent as the glass will stick to it, but I'm not sure how this would interfere with the resonance. The ceramic would still work though.

Happy glass breaking

[PYRO500]

The thing about the first one is that I have herd that a ceramic chip off a sparkplug will shatter a window, but I am not sure about thowing it into a winshield, that is kind of alot of thick shatterproof glass. as for the second one I don;t think you'll be able to match the resonant frequency of the glass with any speaker you could buy, the idea is to reach a multiple of it but I don;t think you could easily match the frequency and keep it long enough and stable enough at the right amplitude (power) to shatter it, also the vibrations are going to be dissipated, maybee a sonar transducer or something buy they are huge and will make a loud noise, smash and grab freaks around here throw pebbles at side windows till they shatter and grab the loot, as for tape you can put tape over where you wan toshatter the glass and slowly crack it with your flashlight or something, then you can pull out the glas easily and gain entry.

[SATANIC]

I believe there was a thread on this a long while back. If anyone knows, what is the reason behind the ceramic being able to break the glass easily? i originally read a text that claimed it would break the glass silently! (kewl claim no doubt)

The 'contact' (sticky paper idea is good, though not practical for most uses. I think the best variation on that idea would be to use duct tape in strips across the window. If they were overlapped somewhat, the noise would be a lot less, and you could lift most of the broken glass away in one piece.

I think the best idea would be to coat witha few strips of contct / duct tape, the score the edges of the window with a glass cutter, then smash in. the sound will be minimal, because the glass should break cleanly with the cuts, then fall out with the duct tape, in only a few large pieces.

Another idea that was raised was the use of silicone sealant, in the tubes. if you had time to let it dry, it would do very well to block any noise.

Personally i think it too much trouble, and a last resort. If you are breaking in somewhere simple, (house etc.) then you can usually find an open / weak window to be forced. In slightly better places (schools etc.) there is often another weak point, though they are more likely to have aluminium framed windows. (schools will always have a broken window somewhere, just look around) The bigger places will probably have good security system, so the window is the least of your worries, and you're often better to try smashing and completeing the job quicky, without worrying about the noise.

Any way, who lives near an abandoned building and wants to do some testing???

[Zero]

I do, but most of the windows on the ground level are gone. I was planning on doing some testing with a pickaxe on the wall. I hear this is a viable means of entry if you have two or three people and the place uses cinderblock walls.

~Zero the Inestimable

[Tyler_Durden]

Wow... so that ceramic-from-spark-plug thing works? I have never heard of that, but I will most definately try it!!! Why on earth would it do such a thing?

I am trying to get a mental picture of myself throwing a little white thing the size of a penny at a window and it shattering. I will try it for sure.

How well does a pellet/BB gun break glass? If sound is not a concern, this seems like it would be pretty easy. A few shots from an air-pistol, knock out enough to safely enter, and you're in. That is, of course, if a bb/pellet would break glass.

Do they sell those glass cutters at hardware stores, or would a tool like that necesitate more of a specialty shop?

When I find a good testing ground, I would like to try using the glass cutter in a small spot (maybe a circle 6" in diameter, or a 5" by 5" square), then covering it with duct tape. Next, smack this section in. With a hole, you can hopefully unlock the window by sticking your arm in. This technique is, of course, limited... but it would be pretty quiet if it works like I imagine it would.

[Pu239 Stuchtiger]

BB guns won't cause windows to shatter, but it will form a cone-shaped vacancy in the window, and will weaken the glass. Shoot the window several times at close range with a BB gun, and it should be easier to break the window. I have been able to form cone-shaped vacancies in windows just using three broccoli rubber bands tied together, and launching a BB with it (sounds kewlish, but it works well, considering how easy it is to hide; anyways, I thought it was interesting that something believed to be so innocent could damage glass in such a manner).

[Polverone]

I hope these tests were run on glass that you own or was abandoned. Vandalism and theft really piss me off. When I lived at home, in high school, I had a shed in the back yard that I used as a lab. Sometimes I gave pyro demos to other people living in the neighborhood. A couple weeks after I gave a demo to the local juvenile delinquents, I discovered that my lab had been broken into. My good pyrex was stolen, as was the batch of flash powder I had on hand and my visco. They dumped copper oxide all over the place - very messy. I'm not sure I've ever been more pissed off then I was then. I hoped that the morons would try to light the whole batch of flash at once and blow their fucking arms off. And then, a moment later, I hoped they didn't, because I would probably end up in trouble with the law. Yes, I was stupid to let people I didn't trust see what I had on hand, but I didn't think at the time that they'd go right into my back yard.

Anyway, my point is that vandalism and theft directed toward me or friends piss me off to no end. If I found my windshield shot up by some punk with a BB gun I would gladly lie in ambush if there were any chance of a repeat. I'm not typically an angry or violent person but this pushes me into rage faster than you can say "jump."

[green beret]

I can see your point polverone, but if you new they where delinquents then why did you show them what you had and where you kept it? :rolleyes:

Also, do you hate theft in general? I see nothing wrong with doing it to a government owned installation like water treatment plants etc, lots of chemicals in those......

I wasnt flaming, just making an observation.

Ctrl_C I am glad you mentioned that ceramic from a sparkplug technique, I always thought it was pretty kewlish, I guess its not!

<small>[ May 07, 2002, 05:34 AM: Message edited by: green beret ]</small>

[Anthony]

These are my observations on breaking car glazing (don't worry, teh car was abandoned by the owner):

The front screen won't shatter because it's laminated, you're going to have a hard time making a hole in the without something like a hammer.

Side and rear windows are all hardened safety glass, they're quite tough, but once you get a crack, the entire pane turns into a mass of small pieces and you can push the thing in with one finger.

The glass resists brute force quite well, it took me a few kicks to put one in, although I am quite short (had to jump up and kick). I tried stabbing one window with a flat bladed screwdriver, I nearly broke my wrist doing that:) I then flung the screwdriver at the window, it hit handle first and shattered the (cheap) screwdriver handle and left the glass intact. However, flinging the metal rod from the screwdriver never failed to break the glass.

I belive that the key to breaing this stuff is pressure rather than force. You need something very hard, moving at reasonable speed. I think that's why the ceramic piece works so well, because it's very hard. Likewise, BBs, or in my case a spinning (high tip speed) metal rod generates a similar pressure at impact point.

I also got those cone shapped pieces from shooting a CRT tube with a BB gun. I thought they were very cool, being perfectly smooth :)

[Hvoroba]

Why break glass if you can cut it? Anyway, perhaps a layer of quick drying cement could work to avoid noise and expanding cracks which are not wanted.

[Arkangel]

Pressure is part of the key, but impulse is the other - i.e. force/time.

That's why a very hard object like the ceramic is successful, since it does not deform in any way, and whatever angle hits, the pressure is concentrated over a small area = higher pressure.

The faster you throw it, the more energy (E=1/2MVsquared) is imparted, and the harder/more pointed the object, the quicker that energy is transferred to the target.

By the way, the side windows of a car are very tough, but can be broken by a surprisingly light blow in the centre. Try the same thing on around the edges and you will have a much harder job.

Kiddie thugs in the UK used to really like those automatic centre punches, but cops realised they were "going equipped", and could prosecute for that. Nowadays, they just use a reasonable sized coin, thrown on it's edge at the window

[Pu239 Stuchtiger]

Yes, the tests were carried out on glass that seemed to have been abandoned. This was quite a while ago, when I was at a relative's home (he lives out in the country). There's an abandoned shed a long ways out in the woods, that, over all the years I've visited there, I've never seen a sign of that it has been used.

I would be similarily pissed off if someone violated me, as those punks violated Polverone's property. Several months ago, there was a political sign in my front yard. Some ass habitually pulled it up in the night, bent the metal frame beyond repair, and hurled it into the neighbor's yard. I soon grew sick of this childish behavior. I took a "pull firework", and a 0.5g acetone peroxide device; attached the pull firework to the metal frame and a rod that I securely implanted in the ground... the next time he yanked the sign from the ground, there was a rather startling bang. I didn't have problems after that. :D

<small>[ May 07, 2002, 12:49 PM: Message edited by: Pu239 Stuchtiger ]</small>

[Polverone]

I showed the pyro demos to the punks because I was young and foolish. I am not saying that I get pissed at every thief - not that I'll trust or respect you either - just that people become quite attached to their property and you may be inviting serious retribution if you steal or destroy it.

I also have a problem with vandalism for vandalism's sake - no matter whose property it is. I don't agree with the Earth Liberation Front, but their acts of vandalism/sabotage have a directed purpose and so I can respect them more than people who (for example) shoot up highway signs or break car windows, even if the sign shooters/window breakers do less damage than the ELF. The people who break stuff just to break it have no justification other than "I was bored." Their expensive acts of entertainment are eventually subsidized by everyone, through increased highway maintenance or insurance costs or some other channel.

Sometimes the "other channel" is "loss of irreplacable items." This includes the idiots who spraypaint/smash natural rock formations or dynamite river rapids. I'd like to spraypaint the insides of those punks' lungs. Something that took millions of years to form is no longer around for our appreciation. The actual impact of such vandalism on the economy or ecosystems or anything is minimal, but the loss is not insignificant.

[BoB-]

You'd be surprised what a little vandalism can do politically, gangs in the city where I grew up would completly trash bussinesss' that would fuck with them (calling the pigs, harrassing). It doesnt matter how much damage is done (although it can reach the millions) if the owner knows about it he will be very mad (look at Polverone, still pissed after all this time) and if the owner doesnt have the money to restore it...

And vandalism is an easy way to check for a perimiter/burglar alarm, in fact a bank robber up in Canada (eh) threw a rock through the pane glass door of a bank to see if the alarm would go off when he drilled out the locks. "just some kids out starting trouble" I beleive the pigs said.

"Back in my day" :D we'd just use centerpunchs and awls on car windows, place the tip against the glass and hit the butt with a rock. The best spot is about in the center around 2" up from the bottom, I actually got this spot from a "20-20" special about what to do if your car is sinking in water.

Pulling off a strip of duct tape is really loud, and duct tape picks up EVERYTHING it touches, your DNA, the carpet fibers from your car, threads from your clothes.

Its actually not really that difficult to remove entire panes of glass from there frames, it takes a while, and its not easy, but its almost completly silent.

Last resort; silenced glock.

[vulture]

If you want to go through windows in a sophisticated manner, use hydrogen fluoride. Dissolves the glass without a sound (obviously).
Shame it's so bloody toxic.

[A-BOMB]

My mother about 14 years ago was really into stained glass work, And the thing she used to cut the big peices was a glass cutter and a spray can of compressed nitrogen to freeze the glass before cutting and then she would heat it with a pen torch and the temp change would break the glass exactly where she had scored it. So I got her old stuff out and tried to cut the glass out of a old window and WOW was the cool I scored aroung the outside of the pane and did the freeze heat thing and it cracked the glass almost exactly where I had scored it. Now I just need to find a place where I can get more of that compressed nitrogen.

[Ctrl_C]

I've never actually cut glass before...I always had my dad do it. I know what a glass cutter is and looks like and all but do you just run that little wheel wherever you want the glass to cut?

Maybe you could rig up a little jig to hold a glass cutter, a compressed nitrogen bottle nozzle and a couple inches away, a propane torch. This has the potential to be very quick and silent. Hook it up to a big vacuum powered suction cup and attach a swivel to the suction cup with an adjustable rod, and it would be like in the movies only this might actually work.

I don't think you would necessarily have to use nitrogen. Most compressed gas cylinders, when turned upside down, will discharge gas in the liquid form. There are also siphon tubes in some bottles that allow this to happen without the cylinder being upside down. I have a CO₂ cylinder with a sipon tube...I may try that. Also, electronics duster might work.

EDIT: I just learned something important upon trying this. Electronics duster is inflammable.

<small>[ May 09, 2002, 10:26 AM: Message edited by: Ctrl_C ]</small>

[Anthony]

"Inflammable means flammable?! What a country!"

:D

[PYRO500]

Ok, to start with this stuff is not compressed nitrogen, it is a LPG that is boiling away as it expands, many gasses do this some at lower pressyres than otheres, for example propane, butane and pc duster, freon, and many others. there are a few types of glass cutters you can buy there is the wheel type and they type that looks like a tooth brush witha dimond tipped metal triangle, you can use either all you need to do is score the glass and tap it hard and it should crack on the scoring. Have you tried not freezing the glass and heating it with apen torch?

[vulture]

How about "drawing" a circle on the glass with flammable gel, for example the alcohol gel used in little stove burners, igniting it and then shock cooling it?

[Zach]

i dont think that idea would work to get a circular cutout in glass. (correct me if im wrong) the fire would just heat up the surrounding glass equally (right?) so it might break but not in a circle. another reason i just thought of: alchohol gels and such do not heat the surface they are placed on much as long as there is fuel to burn above it. (fire burns up) the same reason you can dunk your hand in denatured ethyl alcohol and light it on fire... it doesnt burn until most of the fluid is gone (then you dunk it in water)

[Ctrl_C]

yes, the alcohol gel doesn't actually burn, its the vaporized alcohol above it that burns...just like a candle: the wax doesn't burn, the wax vapor burns.

Also, a bit off topic but still relevent to our conversation: the difference between flammable and inflammable. The root word in "flammable" is "flame." Therefore the word "flammable" means "able to be flamed." The root word in "inflammeable" is "inflame." This is why this case is particularly odd. The "in" in "inflame" is not the traditional prefix "in-" meaning not, but rather just part of the word. Therefore the word "inflammable" means "able to be inflamed."

EX.
Gasoline is both flammable (you are able to set flame to it) and inflammable (it inflames, catches fire).
A brick is flammable (you are able to set a flame to it) but it is inflammable (it will not inflame...and don't even tell me about plasma type temps)

In conclusion, everything is flammable, but only things that catch fire are inflammable.

<small>[ May 10, 2002, 05:33 PM: Message edited by: Ctrl_C ]</small>

[Pu239 Stuchtiger]

I remember there being an entire thread on that...