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Chris Shiherlis
April 25th, 2002, 12:30 PM
I finally found some figures about the performance of linear shaped charges which might come in handy for anyone trying to construct and test those charges.
I came across a site about a LSC called DIOPLEX ( <a href="http://www.elp-logistik.com/" target="_blank">www.elp-logistik.com/</a> click on generalkatalog and 03 sprengmittel) which is a basically a plastic container with a copper liner which can be adjusted to the circumstances (lenght, amount of explosive).
And it said that the DIOPLEX/NEPTUNEX 40mm penetrates mild steel to a depth of 38 mm and it will sever steel up to 50mm. And some other site mentioned that this charge penetrates RHA (rolled homogeneous armour) to about 1".
Conclusion is that the cutting capability of LSC's is about 150 to 200 percent of the actual penetration in a specific sort of steel (most of the time the figures give the penetration in mild steel). And the difference in penetration into steel vs. armoured steel is about 65-75 %.
And a site called <a href="http://www.spreng.de/luzern" target="_blank">www.spreng.de/luzern</a> shows other interesting figures of different kind of "schneidladungen" (LSC's).
This will answer the question of Ray Quick (see "improvised linear shaped charge") but it will also be handy for anyone trying to figure out the effectiveness of a improvised charge.

Anyway, there's still one question that I want the answer to, and that is the penetration or cutting capability of a given LSC in safety glass. I can't find any information about it. I found figures about the performance of LSC's on RHA, mild steel, steel plates and even concrete (the DIOPLEX 80mm for example penetrates about 4" of steel and 460mm/18" of concrete with granite).
But I would like to know how deep the penetration of that DIOPLEX (or some other LSC) charge would be in safety glass.
All I need is one figure, one example of the difference in penetration into safety glass and mild steel (or concrete or other steel). If not from a LSC-jet, maybe some comparable thing, like the difference of a bullet shot into safety glass and concrete or steel, to get at least an indication of what to expect. If someone finds it or knows it it will be very much appreciated.

<small>[ April 26, 2002, 06:50 AM: Message edited by: Chris Shiherlis ]</small>

Energy84
April 25th, 2002, 07:45 PM
Well, I don't understand why you'd need to know how deep a charge will cut into safety glass, especially if it's going to be thinner than 2"...
But whatever, each to his own I guess.
Would it be possible to figure out the density of other materials (ie. the 4" mild steel and 18" concrete with granite) and work out some sort of formula from there? I'm too lazy to do the math right now, but I'm sure a rough estimate could be done. You'd find out the relation between density:cutting depth and just plug in the density of your safety glass.
I don't know if that makes sense to everyone or not, but I hope so.

Chris Shiherlis
April 26th, 2002, 07:10 AM
Penetration depth or cutting capability will surely be dependant on the density of the target material but I doubt it is the only factor. So knowing the density is probably not going to help to figure out the penetration of a LSC-jet into safety/security glass. Unless you have some sientific proove that there is a direct, linear relationshipship between density and penetration. So, I appreciate the effort but I need some hard scientific evidence, figures, tests, theory.

<small>[ April 26, 2002, 06:38 AM: Message edited by: Chris Shiherlis ]</small>

nbk2000
April 27th, 2002, 04:18 PM
If it's that important to you to know, test it yourself.

I'm sure that LSC penetration is at least equal to steel in glass. There's no way that glass could be more resistant to penetration than RHA. Glass is more brittle, and cracks propagate throughout the glass much further than they would through steel.

Al Koholic
April 28th, 2002, 01:13 AM
It would depend on the hardness, density, and internal structure (how brittle the material is) of the target. I imagine it would be a fairly intricate interplay of all these forces but this should be all that actually affects the cutting depth. A graph could not be made based on density in my opinion. Any graph would have to be material specific and would also have to consider all the above factors.

Bitter
April 28th, 2002, 06:18 AM
"There's no way that glass could be more resistant to penetration than RHA. Glass is more brittle, and cracks propagate throughout the glass much further than they would through steel."

Yes; glass would proabably have properties similar to or weaker than granite.

Chris Shiherlis
April 28th, 2002, 09:43 AM
Yes, it's important to me, and I will test it. But I like to come prepared. I also assume that the penetration in glass will be deeper, certainly if you see the difference between the penetration of DIOPLEX 40 in mild steel vs. granite concrete. Glass is probably more similar in brittleness and tensile strength to concrete and rock than to steel. But then again, the laminate security windows are very flexible and can absorb a lot of energy. So I can assume a lot, but KNOWING is something different. And I like to know things, that's a strange habit of mine.
And by the way NBK, I remember you had some files about explosive entry/cutting techniques by SWAT-teams, showing a video where they use those frame charges attached to doors and windows. I can't find it anywhere, can you tell me if it still exists? And where to find it? Maybe it will shed some light on the possibilities of using LSC's on security glass, since those frame charges are also made of LSC's. And the windows they use it on might be safety glass (or maybe not, but it was a nice video anyway). Thanks anyway.

Oh, and something else: I just saw I did get a rating. Only one f*cking star?!! <img border="0" title="" alt="[Wink]" src="wink.gif" />

<small>[ April 28, 2002, 08:48 AM: Message edited by: Chris Shiherlis ]</small>

nbk2000
April 29th, 2002, 07:57 PM
I still have the cutting charges video, though it'll be included in the DVD. It was on the yahoo briefcase but the bastards have cut off public access to those now. PUNKS! :mad:

Some other members here should have a copy of it you could see.

Terry Collins
December 23rd, 2002, 08:38 AM
Chris if you want to see the cutting capability of a LSC on safety glass you should go see the postoffice in Brakel (Belgium). Two days ago a gang placed an explosive in the shape of a square frame to the safety glass window and busted their way in. They left with 200,000 euro (but since they came with at least 4 guys they have to split it fourways).

I can't find a picture on the internet to show you but the glass was between 1 or 2 inch thick and it was very sharp cut in the shape of the square. Only some plastic layer remained. Even the edges were very precise.

So it looked to me the gangsters used a LSC. But somehow I find that hard to believe. Most of the time they use just a charge of semtex or pentrite to shatter the safety glass or blow the entire window out of it's frame. And LSC's are very rarely used here in Europe and I don't think they have the knowhow to built it themselves (although it's not that complicated).

So maybe it was just a contactcharge of semtex/pentriet the shape of a square. But can it produce such sharp edges?

(don't know why this topic ends up in 'Chemistry related' but it should be in Improvised weapons or Detonations and Demolition)

<small>[ December 23, 2002, 07:51 AM: Message edited by: Terry Collins ]</small>

Terry Collins
February 27th, 2003, 11:22 AM
Can anyone help me out? Is a frame shaped contact charge of semtex able to cut steel or glass with sharp edges or do you get a very rough cut and torn corners?
And I want to know if these guys used LSC's.

Mr Cool
February 27th, 2003, 12:05 PM
I'd be surprised if even a LSC could cut glass cleanly without smashing the glass surrounding the cut. It might work better on polycarbonate (which is often called "saftey glass", I believe). It depends on what you mean by "precise" I guess, a LSC would make a precise hole compared to a lump of HE or a big hammer, but not compared to a glass cutting saw.
IMO, for a SC to cleanly cut glass, the stand-off distance would have to be quite large so that the glass was cut by the jet but not smashed by the blast. This would require the use of some sort of stand, which would take time to set up, requiring the criminals to be hanging around at the site, which is not something I'd want to do for very long. So, again IMHO, a LSC would be unlikely.
Maybe they scratched the glass deeply in the shape of a square, and then used a smaller HE charge in the middle to blow it out. I haven't heard of the job in question so I can't provide more than speculation though.
But I personally have never done any tests on glass or polycarbonate, maybe someone here has and could better answer your question..?

Microtek
February 27th, 2003, 01:42 PM
I can't offer any insight on explosive effects on glass or other transparent materials, but I can tell you that a HE charge placed in intimate contact with a steel surface will produce a very clean 'footprint' when detonated. Of course, if the charge is sufficiently powerful, secondary blast effects such as the expanding gases will curl the edges of the hole. The FM dealing with explosives has more info on blast effects, and is worth a read.

Terry Collins
March 1st, 2003, 06:40 AM
OK, thanks for the information.
I too find it hard to believe they used LSC's. They probably aren't that sofisticated and even more so because normal explosives are very rarely used over here even for legal purposes (like mining, demolition) and LSC's even less. So acquiring them is not that easy.


But effects on the glass would suggest a LSC. Because there were no signs of secondary blast effects just a very sharp 'footprint'.
I will try to find a photo.