circular charges

[Neil McCauley]

I have a simple question: if you make a circular/frame shaped charge e.g. by putting a piece of det cord in a shape and the beginning and end meet each other, where and how do you attach the detonator?
Because the detonator should always point in the direction of the end of the explosive charge, that is the direction in which you want the shockwave to move.
Can you put it just anywhere and reliably iniate the det cord? And will the shockwave go both ways, or just one. And if so, won't the explosion blow the end of the det cord away before the shockwave reaches it?
So, how do you iniate a circular shaped charge?

[Mr Cool]

Well if you have a ring of det cord, the only place you can initiate it from is a point on the ring.
I'm sure you didn't need a new post to ask this, there are several threads on shaped charges... although your LOW EXPLOSIVE shaped charge is interesting. Not a good choice of section, IMHO.

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"Nothing makes a man fear much, more than to know little." - Francis Bacon.

[Anthony]

If you have a ring of det cord, no matter which way you point the cap, it's going to be pointing along the cord. Yes the detonation wave will proagate in both directions.

[Agent Blak]

I would just have "Q" style tail and attache the Cap to the tail. But what do I know right.

------------------
A wise man once said:
"If You Dance With The Devil,
The Devil Don't Change The devil will Change you"
Agent Blak-------OUT!!

Go <a href="http://briefcase.yahoo.com/bc/agent_blak">here</a> to download my files.

[nbk2000]

Exactly Agent Blak.

Just take a short length of Det-Cord and tie it around your loop using a prussick knot or clove hitch.

Attach the detonator to the tail and off you go.

I also assume your using a proper tamping mass?

Also, this is more appropriatly suited to Improvised Weapons so I'm moving it there.

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"I have begun evil, I shall end evil. That is the end that awaits me."

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 files and videos.

[Neil McCauley]

Ok, I wasn´t sure in which forum to ask this question. Actually it could be asked in any forum, but since it´s about where to put the detonator I choose the Low Explosives section, although I know (really, I do) it involves no low explosives at all.
Anyway, thanks for the answers. I do think the "Q" shape with the detonator in the tail is the best solution. And the shockwave will travel to both sides of the ring (and meeting each other at the middle). But what if I only use a ring of det cord and tie a detonator (pointing of course in only one direction) to it? Will it initiate the cord in both directions like Anthony said? Although I don´t want to question his authority and he most probably is right, I have some difficulty in understanding how the shockwave which is clearly pointing in one direction (or isn´t it?) can initiate the cord in two directions, so also the other way round (in an opposite direction).
With the "Q" tail it´s just a bit different because then the shockwave is pointed towards the ring and iniates the cord in both directions.
I have to know it because when the ring shaped det cord is initiated in only one direction it will be blown out of shape before the shockwave has reached the end (and beginning). Or am I also wrong in this case?

[DBSP]

It shouldn't matter where you put the det as long as it closely atached to the detCord. It's just like a fuse, take a lenght of fuse and lite it on the middel. What happens? the fuse start burning in both directions. the shoch wawe from the blasting cap will move both out the sides and the bottom, it will also be directed against the top but it shouldn't be as powerful in that direction since there might be some obsicals like wires if your using an electrical cap.

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¤monte¤

[nbk2000]

The explosion of a detonator forms a (basically) spherical shockwave.

This interacts with the det-cord, causing an initiation of the PETN (typically) that travels at about 5 miles per second along its length.

So, any fears of "deforming" the ring is foundless since the explosion travels faster than the energy release can break the inertia of the det-cords mass.

Taping the detonator tightly against the ring will work perfectly fine.

Although, I do have to say, that trying to make a shaped charge using just bare det-cord isn't going to do squat against any metal thicker than a car body panel.

The monroe effect only works well when there is two opposing shockwaves colliding against each other to form a third (more powerful) force to be directed against the target.

A simple cylinder shape (tube) is going to disperse the force in an equal manner in all directions, rather than in a directed fashion.

For clarification of what goes where, the synthesis of an explosive (High or low) goes in the appropriate section. Anything that uses an explosive (but is not explosive itself) goes in improvised weapons. TNT is an explosive, and a shaped charge is a weapon that uses it. Get it?

------------------
"I have begun evil, I shall end evil. That is the end that awaits me."

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 files and videos.

[Agent Blak]

I while back i suggested a Hoola-Hoop Style Charge(PeTN/Mg) with a TNT or ANNM non-Shape Charge in the middle(works as boot would on a door).
The theory behind it is that The PeTN/Mg Would detonate before the ANNM. This would work as follows;

1.The Ring Detonates slicing part way though or scoring a ring into the target.

2.The ANNM or TNT then punches it through so you can enter.
That is the theory anyways never tried it though.

------------------
A wise man once said:
"If You Dance With The Devil,
The Devil Don't Change The devil will Change you"
Agent Blak-------OUT!!

Go <a href="http://briefcase.yahoo.com/bc/agent_blak">here</a> to download my files.

[Neil McCauley]

Ok, thanks very much for the answers, it´s clear to me now. The shockwave is indeed spherical and moving in every direction, I mistakenly thought of it as a horizontal zone in a detonator and moving towards the end. I´m also clear about what topic to put where (I think) http://theforum.virtualave.net/ubb/smilies/wink.gif.
By the way, I´m not gonna use det cord for this frame shaped charge. I know the effect of such a charge is minimal (mostly because the VoD is not so high and the amount of explosive is low), it was just an example to keep it simple.
I want to use an improvised linear shaped charge (although I like the "hoola hoop" idea (easy to improvise! and perfect disguise: if stopped by the police and asked what you´re doing over there, just do the hoola hoop), it´s effect will be much better than with det cord, mainly because of the higher amount of explosive and (thus) increased VoD).
And I will take NBK´s word for it that when I put a detonator a the beginning of the charge and the beginning and end touch each other (but there´s no connection) the frame will not be blown out of shape (not even from the shockwave moving outward from the detonator/starting point?) but will detonate nicely like I want it to and puncture the target (if any doubts please say so, it´s a lot of responsibility http://theforum.virtualave.net/ubb/smilies/wink.gif ).
This leaves me with one more question: is the effect of the metal jet (let´s say from a brass liner)produced by the linear shaped charge on (laminated/safety) glass the as same as on metal? Or do I have to adjust the stand off distance or use an other liner for better effects?






[This message has been edited by Neil McCauley (edited December 19, 2001).]

[Mr Cool]

The jet will cut through anything, as long as it's not too thick. Just treat the safety glass as if it was metal, use the same liner and everything. Although you probably won't get a nice neat hole on glass...
The shape of the charge will not be distorted by the shock wave, as NBK rightly says - as soon as the shock wave hits it, it detonates and therefore has no time to move around. Even if it does move, the whole detonation will be over in a few microseconds so it won't be able to get very far.

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"Nothing makes a man fear much, more than to know little." - Francis Bacon.

[Anthony]

Wire reinforced glass would be much easier to breach than steel and you wouldn't need to adjust the stand-off distance or liner material.

I don't think a shaped charge is ideal for glass, as that concentration (quantity of explosive Vs hole size) is excessive. I think it would be more efficient to use the hoola hoop idea to create a larger hole with the same amount of explosive - or the same size hole with less explosive (more economical, less noise).

[Neil McCauley]

The whole idea behind using a linear shaped charge is that it is THE most effective way for cutting materials. That is, you use the least possible amount of explosive with the maximum result. A LSC is many times more efficient than a ribbon charge (I think 2-3 times as effective at least).
And a tube charge is even less effective because a ribbon charge touches the metal (which is necessary for the shockwave to do it´s work) and a tube only partial. And another thing is that a ribbon charge must be at least 12mm thick (and 36mm wide). Although maybe slightly less might be possible.

And that a LSC will cut through anything I could have guessed myself but I want a more precise answer (please http://theforum.virtualave.net/ubb/smilies/wink.gif ): will the penetration be as deep as with a metal target, or more/less. And will the glass be sort of like melted and pushed out of the way by the jet as can be seen with metal, or are there other effects to be expected?
And where can I find information about more details of LSC´s: for example information about the relationship between the thickness of the liner and amount of explosive and subquent the penetration and stand off distance. So I will be able to calculate those figures when starting with a certain liner (so sort of metal, thickness width and angle are known). If someone has the answer already for a brass liner with a 90 degree angle and 1 mm thick it´s much appreciated.



[This message has been edited by Neil McCauley (edited December 27, 2001).]

[nbk2000]

Here's a link to a very through (and technical) PDF file on linear shaped charges (with pictures). Right click on this url (
http://www.prod.sandia.gov/cgi-bin/techlib/access-control.pl/1996/962031.pdf ) and choose "Save target as". It's a 10 meg download so it will take a while, but it will tell you just about everything you
could want about designing LSCs.

PS: This is from my December 16,1999 post in the High Explosives section of the Forum Archive PDF.

------------------
"I have begun evil, I shall end evil. That is the end that awaits me."

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 files and videos.

[Neil McCauley]

Very much appreciated, thanks. That´s the kind of information I´m looking for.
Although I have some problems getting it on paper. Yesterday the printer didn´t work and today I can´t seem to download it from the site. And I have difficulties finding the topic where it came from. But that´s all my fault.

[This message has been edited by Neil McCauley (edited December 27, 2001).]

[Noct]

The idea behind shaped charges seems simple to me, you want the force from the most explosives to collide at the same time, so if you have more surface area equal distance away it will "come together" and the forces of the two will sort of merge, and the strength of the final force is dependent upon how much surface area is facing the target (and obvious factors, like amount of explosives and what explosive is used).

So, if you had an ice cream cone made of TNT, and set it circular side down on a surface, the detonation would cause an indention opposite the inside of the cone... like this:

/\ <-- explosive
== <-- surface

====\/===== <-- surface after detonation

Does that make sense? Am I correct?

... this is just my perception of what I have read, and I am mostly just trying to see if it is correct by saying what I think is true... and if my explanation helps others understand the principle, then that is great too.

But the question remains, is this an accurate description?

[Anthony]

Colliding/focused shockwaves do play a part but IMO the liner does most of the work. The liner is turned inside out upon detonation and froms a long comet like shape. The liner is apparently not molten, but since it posses more energy than is needed to totally deform it, it behaves like a liquid. The head of the comet contains not very much material but is moving very fast, the rest of the comet - the "slug" contains most the liner material and moves more slowly. When the head of the comet strikes a target it exerts a pressure so great that steel will flow like a liquid. This moves the target material out of the way and then the slug generally follows though the hole probably giving follow-through.

[PYRO500]

Remember you need to initiate the charge so that the detonation waves will travel the direction you need them to go. in the "ice cream cone" of cast TNT example you would need to initiate the device fron the tail of the cone, the liner on the shaped charge behaves like anthony jsut described but it is important to note that the liner is right up aginst the explosive and I think that it might transfer more energy than the gasses of a shaped charge alone. the liner under extreme pressure is likely to acctualy be molten due to the extreme pressure against it, same thing goes for gasses, ever compress air into a tire and have it get hot? that might have some effect but I have herd that pressure on a substance lowers the melting point, an example is squeezing an ice cube with pliers slowly, you get water while there is little friction. an example that has been stated before is ice skates but that is an incorrect example I have been told.

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Society creates the crime, the criminal completes it.

[kingspaz]

i was just wondering. if you made a detonator from a small cone with a concave underside (instead of flat base), to make use of the munroe effect, would it be more efficient than a regular detonator?...less explosive needed, maybe no need for a base charge or insertion into the explosive to be detonated?
just a thought...

[Anthony]

Dunno Kingspaz, might be worth investigating.

I read of a test concerning whether shaped charge liners become molten, they cut a liner into multiple pieces, glued it back together and reinserted it into the charge. The charge was fired into water and the liner was recovered in as many pieces as it was previously cut into. The reasoning was that if it had become molten then it should have fused back together. Dunno whether this is correct, there seems to be a bit of a mystery surrounding some aspects of shaped charge technology.

[Yikes]

I read about that test too, I actually have an article about it:
Experimental Verification of the Theory of Jet Formation by Charges with Lined Conical Cavities
the Journal of Applied Physics, vol 23 nr 5, may 1952

That journal has other very interesting articles about shaped charges, too! (Maybe you could search the library of the nearest university, sometime?)

Any material can withstand a specific pressure. When the liner of the shaped charge collapses, a dart-like 'projectile' is formed, consisting of a very fast moving , long and thin tip (the jet), and a slower moving thicker end (the slug). The thin jet impacts at the target material with a very high speed (some 30000 ft/sec, depending on explosive, liner material etc.). The pressure created by that is many times higher than the pressure any material could withstand, under favorable conditions may well exceed 250,000 atmospheres! The target material simply has no significant resistance to such high pressures. From then on, the material of the impact zone REACTS as if it were a liquid.
But it still is a solid which, as Anthony wrote, was proved by a test cutting a liner in pieces, then firing the charge, and retrieving the slug that was formed in pieces too. Not molten together, no.

Funny thing: lead plate offers more resistance to the jet impact, since it's molecules are heavier! More energy must be used to move them.
Why aren't armor plates made of lead then? Well, after impact from the jet, the slug will also hit the target. And the slug,although it moves much slower, is considerably heavier, and so will penetrate soft lead plate easily...
(Nope, too bad, lead plating is not a cheap & easy way to reinforce your house to counter Maverick attacks!)


[This message has been edited by Yikes (edited December 29, 2001).]

[Microtek]

Concerning the munroe-effect detonator: Gerald Hurst mentioned detonators of this kind on alt.engr.explosives. They are used for deep-well blasting and have the hollow cavity configuration in order to be able to withstand the pressure at those depths. The munroe-effect apparantly doesn't have any effect on initiating ability.
Before I read this, and before I learned very much about ammonium nitrate, I tried to initiate pressed AN with a 12mm hollow charge. It didn't work ( it wouldn't have anyway; the charge was much too small ).

[Neil McCauley]

Since you guys seem to know a lot about the subject, you probably can tell me also about the difference between (laminated/safety) glass and steel in regard to the behaviour when subjected to the jet produced by a linear shaped charge.
As stated earlier the jet produces a pressure on the target so high, it will be pushed aside like a liquid. And the penetration depents on the strength of the material.
And there's another factor to be taken in account: the overall cutting capacity of a specific LSC is not only defined by the penetration of the jet but also of the "fracturing" of the material behind the penetration zone. That also depents on the type/strength of material. This fracturing can be as much as 50% of the overall cutting capacity.
Now, it's clear that even different metals will react differently to specific LSC, let alone a complete different material like glass.
So can someone please inform me how (safety) glass will behave compaired to steel. Is the material strength stronger/weaker than steel. And will the penetration be deeper or not. And what about the fracturing zone?
Thanks.


[This message has been edited by Neil McCauley (edited December 29, 2001).]

[mrloud]

There are too many variables to be considered just to give a straight answer. I assume you are interested in cutting out a circular hole from a plate of either steel or laminated glass. Take a plate of 20mm thick steel and a plate of 20mm thick laminated glass. Hit each with a large sledge hammer. The glass will fracture all over but it wont fall to pieces. The steel will emit a loud 'bong' and sit there with a smug look.
Glass is amorphous, ie, a liquid. It flows, albeit very slowly. If you force it to flow faster than it naturally wants to, it will just snap. Just like toffee. Any sort of shaped charge should be quite effective at cutting through laminated glass. (well, more effective than steel of the same thickness).
"Steel" is a generic term given to any iron based alloy. Different steels can have pretty much any sort properties. These properties will even change depending on the temperature. It is impossible to say "This is how such-and-such shaped charge will affect steel". Remember, metals are maleable. They will bend and deform before breaking. This acts as a kind of shock absorber and will absorb some of the energy from the explosion. Steel is also dense and its crystaline structure is strong.

What it comes down to is: if I had to blast through either a steel panel or a glass panel; I'd go for the glass.

[Anthony]

Depending on how thick the wire in the reinforced/armoured glass is, a sledgehammer blow may well just snap it all.

As Mrloud said, glass is much easier to breach than steel (with the exception of glass hard tool steel :) ) because all you need to do is start a crack and it'll spread through the material and glass has very little "give". The spreading crack affect can be seen if you've ever broken safety (not laminated) glass used in cars (front screen is usually laminated with the rest being safety). If you break a small hole in the pane, you can watch and listen as the cracks slowly spread out across the entire pane, until you can collapse in areas with the tip of your finger.

The thing about glass being a liquid - I really don't think it's true. The evidence for it being a liquid is usually that old window panes are thicker at the bottom, as though the glass has slowly flowed down over the decades. It was found that glass manufacturing at the time was inconsistant and panes were not of uniform thickness. As a result glaziers, logically, would fit panes with the thickest end at the bottom.

[Neil McCauley]

OK, thanks for the replies. But I was hoping for a more precise answer. I know how glass cracks and doesn't bend like steel (although: have you ever seen how laminated glass acts when subjected to a bomb blast? It looks like a balloon! and it will return to it's original shape and not break. And what about the fact that bullets from an AK47 pierced the metal of an armoured truck but didn't go through the laminated safety glass in the front?). But I do agree laminated glass is probably more vulnerable than steel when subjected to a jet produced by a LSC. But I would like to know how much. And excactly in what way.

I would also like to know if, because of the already mentioned different properties of laminated glass in comparison with steel, a ribbon charge might be a better option (because it is easier to make and if glass is so much more vulnerable than steel, you can probably use far less than the amount considered necessary for steel according to the demolition manuals). But again, I want to know precise amounts, penetration depth, properties of the glass, etc. Don't tell me what I know already.

I know I ask a lot, and probably the only way to find a definite answer, is to just actually try it: find a piece of 1" thick steel and 1" thick safety glass and see what a LSC/ribbon charge does. Unfortunately it's not that easy to do such tests, because it's illegal and penalty's are high! So if someone has the answers or knows where to find it's much appreciated.

[ December 31, 2001: Message edited by: Neil McCauley ]</p>

[Anthony]

The thing is, unless someone on this forum happens to have done comparison tests between glass and steel against verious kinds of charges, you're unlikely to recieve an answer nearly as precise as you want.

There are just far too many variables to work it out theoretically, the only way is to try it. If the punishment is harsh then don't get caught.

[Ctrl_C]

Anthony: I read an article in Popular Science explaining glass being liquid. They stated that while, in fact, older windows are thicker at the bottom, it is not because glass is liquid.

They do say though that glass is a liquid but would take longer than the life of the universe to exhibit any noticible change.

also, on the subject of glass, the safety glass in cars is manufactured in a really ingenious way. the molten plate of liquid glass is blasted on all sides with super cooled air that instantly hardens the outside edges. the inside, however, is still semi-molten. as the inside cools, it "tries" to contract, but can't because it is in a sealed environnment. It sort of creates a vacuum of sorts, only without air, although that is the wrong analogy. In an accident, when the outer shell of glass breaks, the inside instantly contracts and causes minute stress fractures that, with the added force of the collision and their own weight, break into those little pieces that scatter everywhere. sorry about the offtopicness of this. :)

[Anthony]

The amazing thing about safety glass is that although it has a weakness designed into it (to make it crumble as you describe) it is much more resistant to impact than ordinary plate glass.

[nbk2000]

Here's a picture showing pro linear charges.

http://server3001.freeyellow.com/nbk2000/Linear%20Shaped%20Charges_Copper_Cross-Sections.JPG

Note how it's just copper tubing rolled into a certain shape? I'mve been thinking that if a person used a router, they could form two blocks of hardwood into a shape that, when a copper tube was placed between the two blocks, that the blocks, when hammered together, would reshape the pipe into the proper cutting shape.

I've also been visiting other forums while our Forum was down. One of these was a firefighters forum that has a section to discuss forcible entry techniques (AKA Burglary School :) ).

When they need to get through laminated windows, they first punch a hole with a pick-ax (in your case a shaped charge), then use a sawz-all to cut out a flap that they can peel back.

Oh, and side impact bars on the latest high-end cars are made of titanium and are impervious to the saw, ax, jaws of life, and similar. They have to use exothermic lances to cut them. Make of this tid-bit what you will. ;)

[Neil McCauley]

I know I asked a lot, but in thought there might be a chance that someone knows the answer.
And NBK thanks for the suggestion for how to improvise those copper sheathed linear cutting charges. The ones in the picture are very effective. The ones with just as less as 21 gram/m will cut through 6mm of mild steel.

And about the "forcible entry techniques": I don't see myself sawing out a laminated glass window. It probably goes very quickly with the right kind of saw. I think I saw it once and it was done in a few seconds. But I like it more when it's done in milliseconds ;) .
And those firemen have also another way to gain entry or make holes in roofs/walls: they use a "flexible cutting charge". That's a flexible linear shaped charge put in a polyethylene frame (as could be seen in your file "breaching charges"). And that flexible linear shaped charge is known as BLADE and consist only of a piece of copper with a 90° angle on which a layer of RDX-based explosive is put.
Now this would be rather easy to improvise. The only disadvantage is this type of LSC is not as effective. For example, BLADE 100 containing 100 gram of DEMEX per meter will cut through 6mm of mild steel. That's 5 times less effective as those LSC's in the picture.
I wonder why it's not as effective. One would assume it's because of the lack of confinement since they both use a copper liner and RDX as explosive. But I think it's not that simple (what's a sheet of copper going to add to the effect when you're using such an explosive as RDX anyway?). I read the article of "precision linear shaped charge analysis" and Table 1 clearly shows that when you make a LSC, a variation of any constant will have an effect and there are no rules to follow. It's impossible to say: when you use a thicker liner, the Stand Off Distance will be higher/lower and the penetration will be deeper/shallower. Every LSC has different properties and different effects. It seems impossible to predict the effect if you change the angle or the thickness of the liner or the amount of explosive. So a test is indeed the only way to get answers to all my questions. But I was wondering if there's not someone who could do it for me. That way I won't get caught and get to know what I need to know ;) .

[ January 04, 2002: Message edited by: Neil McCauley ]</p>

[nbk2000]

Even if someone here DID a test, it still wouldn't answer your question because there's as many different types of laminated glass as there is steel (almost).

Without a sheet of the EXACT same glass, any test would be meaningless.

Also, why is it that you're trying to cut glass for? I don't expect an exact description of your "heist" but the purpsoe may be served better by some other means if the objective is suitable.

The flexible charge may be less effective because, in order to be flexible, the copper isn't as dense/hard as the shown LSCs. And confinement is ALWAYS helpful, regardless of the explosives power.

Standoff is an important factor too. The LSCs are usually attached to the target with plastic stand-offs. A flexible charge probably doesn't have that.

It may even be that BLADE is deliberatly underpowered because of its intended application as a rescue tool for fireman, and not military/demolitions.

Also, the RDX is more diluted in a flexibel PBX configuration than straight cast in the more convential LSC types. This will have a significant impact on d/v. And even a few hundred m/s decrease in VOD can cut performance in half.

[Neil McCauley]

I don't agree such a test would be useless, it would at least give an indication of how laminated glass reacts to a LSC. And I don't expect someone to do such a test, although the laws in some countries are less harsh and the possibilities to use and test explosives are much better, and performing such a test wouldn't be such a problem (wish I was living in America ;) ).

And BLADE is not deliberately less powerfull, it's used by the military and demolition industry as well. And the Stand Off is build in: the explosive and liner is surrounded by some low density foam. A nice site with pictures and data about LSC's you can find if you search for "BLADE" and "Schneidladungen".

The lower performance of BLADE compaired to other commercial LSC's is probably, like you say, the slightly different explosive used (with different density and VoD) and a copper liner which is flexible (probably by using (a layer of) thin parts of liner that can move indepently from each other).

[ January 05, 2002: Message edited by: Neil McCauley ]</p>

[nbk2000]

It would have helped if you'd posted a picture of it in the first place.

<center>http://www.spreng.de/luzern/img15.jpg</center>

Anyways, I know the reason for the low performance...it's the liner.

It's not actually solid metallic copper, but rather a flexible polymer composition doped with copper powder.

These powdered metal liners are mentioned in US patents for similar purposes. And the lack of "solidity" means lower density, less even jet formation, etc.

But it does have the neatness of being wrapable. I could imagine wrapping one around a big metal light post and blowing it as you zoom past, leaving the piggies to eat it when it crashes to the street. :)

[ January 05, 2002: Message edited by: nbk2000 ]</p>

[Neil McCauley]

Yes, pictures are better than a thousand words, but I'm just not such a genius with computers. And are you sure about that polymer liner because I thought it would be pieces of copper liner moving indepently like described in US patent 2,543,057 "elongated tubular charge" (again no pictures sorry). But that's a very old patent and probably an old method so probably nowadays they use those polymers but do you have some patents that can prove you're right? ;) .

And still my most important question remains what the effect of a LSC on laminated glass is. I think I read somewhere that a LSC penetrated a piece off acrylic glass about just as much as steel (but I can't remember where and when I read it and if I'm right). But assuming I am: one would expect those charges would cut through plastics like cutting through air but apparently not. And since laminated glass is nothing else than pieces of glass with layers of polymer/plastics in between, there's no reason to believe that a LSC will cut laminated glass easier than steel. Also when you consider the facts I mentioned earlier (laminated glass is very(!) flexible, and can absorb a lot of energy)
So any information on this subject is more than welcome.

[nbk2000]

Page 14 (I believe)(img13.jpg) of the powerpoint presentation on the german URL you cited says:

"plastifizierter kupferliner"

Which, referring to the above picture, we know that kupferliner is the copper liner.

And it's not unreasonable to assume that plastifizierter means "plasticized" or "flexible plastic". Thus my statement.

And it's not my job to search out details for people. Go to <a href="http://164.195.100.11/netahtml/search-bool.html" target="_blank">http://164.195.100.11/netahtml/search-bool.html</a> and look for it yourself. It's there 'cause I've seen it.

Also, you're getting dangerously close to beating a dead horse with the glass vs. metal question. See post about ATM cash machines in misc section to see a similarly persistant poster and the results.

We can assume (though perhaps incorrectly) that glass is as vulnerable to an LSC as a similiar thickness of metal. The only way to know for sure is to test it out yourself.

If it's life or death that the glass be penetrated, use a massively overpowered LSC that could cut a tank in half.

RTPB: "Victory through superior firepower!".

:)

And the images are easy to do, that's why we now have a button in the "Instant UBB Code" list (see below your posting window) that you can just paste the pictures URL into. Or click the edit button on any post with pictures in it to see how it's done. Don't be lazy, learn how, it'll come in handy in the future.

[ January 06, 2002: Message edited by: nbk2000 ]</p>

[Neil McCauley]

OK, no reason to get irritated. You´re right about the "plastifizierter Kupferliner". It means plasticized copper liner and I did actually see it but gave a different meaning to it, because I was not familiar with copper metal bonded in a polymer.
And you don´t have to do a search for me, I just thought you might have the patent numbers at hand.
But I can find it myself. And I will. Just like I will find an aswer to the most important question myself, as no one seems to know the answer.
(Ooh, I wished I could just experiment for a couple of days without the danger of getting caught, just go out there and try the different explosives and targets...... Anyone doing it for me will get 10% of the profit, promise.... ;) .

Since I cannot ask the same question again here´s a different one: since a ribbon charge might be a even a better (or just as good) choice for blasting laminated glass, I was wondering about the Genius system: it uses a 20 gram det cord placed in between two tubes filled with water and the whole construction is hold together by some paper container. The advantage of this system is obviously that there´s no shrapnel: water (and paper) is used as a tamper mass. And it´s used for blasting out doors.
Would this kind of explosive be effective for blasting laminated security glass? Let´s say I would use a tube filled with 100-200 grams per meter of explosive instead of the 20 gram det cord, what would the effect be? (any estament for steel, glass is appreciated). I know normally metal/steel doors are not opened with det cord (only used for wooden doors because of it´s low (difuse) power) but with (F)LSC´s but maybe with the tamping and increased amount of explosive it´s possible (as it actually could be considered a tamped ribbon charge).

And what the hell is a UBB code? Let alone an instant UBB code. And what the fuck is URL? ;)

[ January 06, 2002: Message edited by: Neil McCauley ]</p>

[Anthony]

I would be helpful if you could give more details about the target besides it being made of laminated glass. Roughly how thick? What's the application (car windscreen or fire resistance etc), is it intended to ward off attack? (windows in rooms/containers/vehicles containing things of high value, simply to resist vandalism, or just strong enough for the application).

Also, acrylic is not glass. It's still very brittle but is more flexible than glass, softer too.

Why can't you conduct any tests? We all live under oppressive, non understanding governments and societies but find a way.

[nbk2000]

Yes, the country you live in doesn't make squat difference in the legality or severity of the "crime" of explosives since you obviously don't have a license for it. So regardless of where you live, if you don't have the governments approval, it's your ass if you get caught.

You'll also notice we have people here from britan, germany, australia, france, and other countries not well known for there tolerance for guns and bombs.

But we do it anyways.

And if you're too scared to test things in some remote quarry or forest, how will you suddenly get the nuts to do it in an (implied) heist when there's likely to be people around to hear it and call the cops?

Since I cannot ask the same question again here´s a different one: .....Would this kind of explosive be effective for blasting laminated security glass?

:mad:

SAME FUCKING QUESTION, DIFFERENT PHRASING!

Don't be a smart-ass. I delete smart-asses.

Topic closed.