Shaped charges

[freaky_frank]

Well there was a thread about this, so now here it is again.
In the time while E&W was "gone".
I've been experimenting A LOT with shaped charges.
And finally I had a bunch of pictures and movies, I put them all together in a pdf and uploaded it on the internet everyone can download it here.
You can read it all in the pdf about how to make an shaped charges, I've made pictures of assembling a SC and the results of sc with and without standoff and different ratio's of explosives used in the sc.

Shaped Charges.pdf (http://members.home.nl/icexool/Shaped%20Charges.pdf)

Hope you enjoy, ow and BTW if you have any comments please let me know so I can improve the pdf...

[Sarevok]

I like it.

What kind of material is that red stuff where you placed the charges? Steel? How thick it is?

[nbk2000]

Looks good. Nice to see progress. :)

[Crane]

When I worked with aluminum anodizing, we used "aluminum solder" to get a strong, inexpensive aluminum bond. Do you think a stronger aluminum bond might help to improve jet directivity even more ?

[Boomer]

Stronger aluminium bond :confused:

freaky_frank: Your cones look like mine, except that I always wrap exactly two layers. If you wrap it up until the outside diameter matches the pipe, you will have inconsistent thickness, i.e. partly one and partly two layers.

And I use slightly thicker sheets, and copper instead of steel (or is it alu - did he mean to weld the sheets?), because copper is denser AND easier to compress into a jet.

I guess the target was RHS, approx. 2-3 mm thick - right? With a similar SC, also using APAN and a PE pipe, the jet went through 16 mm steel! It would have gone deeper, but I did not expect this and used too little target material.

This proves that though everybody says APAN is too slow for SCs, you get at least some penetration. I doubt that with 4000 m/s max. you get a perfectly liquified jet, it is probably a stream of copper particles. But still penetration is greatly improved compared to a munroe charge of the same explosive without liner.

I moved on to a really fast stuff: 50% RDX, 35% MHN, 15% NG plastique! Energy content is higher than C-4 (more oxygen, no inert binder), and calculated VoD is 8350 m/s (average if ingredient's VoD x percentage) at density 1.73. I just happen to be out of molybdenum liners and HNIW ;) still this plastique is going to make some serious holes ... :D

[Crane]

Sorry, I guess I wasn't descripitve enough in my last post. The "aluminum solder" we purchased was a special paste in a plastic syringe that was used to solder pieces of aluminum together with a soldering torch or iron. Not as effective as a weld, but much less costly and easier to do, and much stronger than super glue would be.

The reason I mentioned it is that I would imagine the aluminim would immediately deform around the join, rather than the tip of the cone as intended. Increasing the strength of the join would (I'm guessing) focus more of the energy in a downward direction through the cone than through the weak join. While the effects of this is probably pretty small, but it might interesting to look into.

[freaky_frank]

Well I used first really good fast glue, but now I just use very little double side adhesive tape, and it works fine, and well I used alluminium...
The red thing is a frame of something and I don't know what it is steel and 4,5mm thick.
When I used EGDN+PETN not all of the plastique detonated.
So I'll stick to APAN or PETN as a powder, not mixed with EGDN or NG.
But well my next project is a bigger tube.

http://members.home.nl/icexool/big_sc.JPG
180gr APAN will fit in there, does anybody know if it will penetrate a high speed camera, used by the government which stands next to a road and if you drive to fast besides it it fill flash and get your license plate...
This is double armed steel....
If it won't what amount would I need to penentrate it, or what amount of PETN with a copper liner?
This is just theoretically....

[Guerilla]

Exactly how pure is this fertilizer grade AN you are using? You sure could improve the VoD a fair bit by purifying it first. Nice presentation nonetheless..

If you want to see what properly made SCs with brisant explosives such as PETN are capable to do, take a look at Axt's page. A .308 shell SC of PETN penetrating an inch thick steel plate is pretty convincing. :)

[freaky_frank]

Well I'll try PETN soon I've still got 10gr lying here, but well it is pretty shit to make shaped explosives with little containers so I'll take a lot of PETN and then make one as where 15gr APAN fitted in, but far more PETN will fit in there since PETN is a lot heavier but then when I made that one I'll put it on a lid of the sewer you can see on the streets that should be quite impressive if it will penetrate that thick steel....
FYI Fertilizer is 85% AN.

[Boomer]

If you hand-compress the PETN into a pipe with the cone glued in, you can use relatively little force compared to pressing detonators. While you can reach 2500 PSI (175 bar) with your body weight on a ¼” dowel, you only get 150 PSI (10 bar) using a 1” pipe. Pressing harder, i.e. in a vice, will crush your cone.

The high performance of e.g. PETN diminishes greatly at lower densities. This is because only brisance counts for shaped charges, and brisance is proportional to VoD squared and to density linearly: For a given volume above the cone, the kinetic energy that compresses the cone to a jet is E = ½ mV2 where m is proportional to the density. Because VoD is also somewhat proportional to density (IIRC for TNT it as approx. (4000 + 3000(d-1)) m/s), this makes brisance dependant on the cube of the density (above some minimum)!

To get from 4000-5000 m/s (150 PSI) to 8000+ m/s, you will either have to back up the cone with a metal cone that fits inside, then use a big vice or hydraulic press. Or you plasticise the PETN with NG (inert binders make it hard to detonate in small amounts).

You will marvel at the effect of density: In a lost post from June, I had a picture of a 1" water pipe. Suspended in its centre were detonated some 0.4g samples of MHN, first hand compressed, then vice compressed at 30000 PSI. The first made small bulges in the pipe wall, the second tore it open! I’ll look for the pic and re-post it.

BTW my distillation column broke :( , I am out of RDX. So the next test (tomorrow?) will be done with my old HDN plastique (see my post in the plastic explosives thread). It did also cut a 6mm steel plate :D , but not as cleanly as the RDX version did (see pics in that post).

[freaky_frank]

Okay well I was fighting a little bit (quite a lot actually) with a lock...
I put 5gr PETN in a shaped charge on top of it, and nothing happened, it was a tiny lock, but strong very strong!
So I went back in the evening with a bigger shaped charge (in the afternoon I used 16mm ID tube 5cm high) I went back with 25mm ID and 65mm high tube.
And I put 4gr PETN in there, and APAN on top of it (6gr AP+8gr AN, so a very high ratio of APAN).
And well this is the result
http://members.home.nl/icexool/shaped.jpg MIND THE HANDLE. It completely got blown up to by the force going sideways!
@ boomer, if you press PETN too hard it will be dead pressed right?
So if you were to put it between a vice it will press the PETN to > 1,73g/cc if so it will not have a higher VoD anymore compared to density...
I do know there is difference in low density and higher density but I think that 30000 PSI is a little bit overdone...
And PETN+NG sucks, it didn't even detonate fully when I made it, and it is not a nice plastic explosive it is very sticky even when you use very little NG and a lot of PETN. More like gelatine it is.
Anyway I do have PIB and soon I'll have bis-2(ethylhexyl)sebecate so that'll give some very nice plastic explosives to use inside my shaped charges.
Shaped charges just rock :D

[SweNMFan]

Was googeling and found this site
http://www.air-and-space.com/20020624%20China%20Lake%20Explosive%20Ordnance%20D isposal.htm

EOD team playing around.. Imp Winebottle SC among other things..


And I found this stuff..
http://www.rbwmfg.com/extrusio1.htm

Check the CHARGE CASES..

[Bugger]

About explosive charges: I have just heard that the Russian crash investigators investigating the near-simultaneous crash of two Russian civilian aircraft while in flight late at night with the loss of 89 lives two days ago have found evidence that it was a terrorist action by two Chechen Muslim female suicide bombers using a "plastic" explosive with the trade-name "hexogen" or similar, probably in bomb belts worn by the suicide bombers, probably allegedly acting on orders from Dog-Spelled-Backwards with promises of rewards in Paradise for committing such terrible crimes against "soft" targets. Does anyone know much about hexogen?

Apparently the "hexogen" was not detected by the usual explosives monitors at the Moscow airport from which the planes took off, which are capable of detecting minute traces in the air of organic nitro-compounds and nitrate salts and esters. So either the stuff was not volatile enough to give off even minute traces, or it is not a nitro- or nitrate explosive (perhaps it is a chlorate, perchlorate, chromate, permanganate, or ferrate ester or ammonium salt, or an organic peroxide).

John W.

[SweNMFan]

Hexogen = RDX so I think that the Moscow airport needs to buy new explosives monitors..

[kingspaz]

hexogen = RDX

IMO slack russian security was probably partially to blame.

[Boomer]

Yes, Hexogen is the German word for RDX. But is it detectable?

I remember reading both on a supplier site (selling C-4 by the ton :D ) and on some government page that today RDX based plastic explosives must contain a chemical marking agent, also called detection agent. They add this because RDX is chemically so stable it gives off no NOx, and it has such a low vapour pressure it is hard to smell for dogs.

P.S. My next SC is ready, 55g HDN/MHN/NG/GPN/NS plastique (just using up old stuff), 75mm long, 28mm dia copper cone 48 degrees. I was just too lazy to go into the woods on the weekend. So today is it ... :cool:

[K9]

Doesn't C4 contain 2,3-dimethyl-2,3-dinitrobutane (DMDNB) to serve as a marking agent? Now would that help at anytime beforehand, or is it just for afterwards.

[Boomer]

Had to wait another day due to rain. Using my EBW B-box for the first 'real' charge, at 1500 Volts and 1500 Amps, only having badly insulated 2x4mm speaker cable, I did not appreciate wet surroundings. Would be funny to be found electrocuted next to an unexploded charge ... :p

The SC described above (28mm dia, 75mm long, 55 g) had about 10% NG, 40% MHN, 35% HDN, 10% NS and 5% GPN (glucose penta nitrate). I kneaded together three different chunks to get rid of old stuff, it was from March/April and started to smell. Leaving it out of the fridge for three days was a mistake as you will later see.

The EBW det was a 10 mm brass pipe with 2.5 g MHN and a 2A TR5 fuse as a bridge wire. I had only 7 feet of cable and ignited manually by touching a wire end to the capacitor terminal (other wire pre-fixed). I know I was very close, from the EOD formula: distance for eardrum rupture = 18 feet x (charge weight/pounds)^1/3 I calculated 9 feet minimum distance! But I had: A. my ears plugged tightly, B. was sitting behind a concrete wall, and C. I like the shock wave going through my stomach.

The jet did not form properly, it created a big but shallow hole, in the middle of which the real jet hole started. This went only through 18 mm of steel. In contrast an APAN SC went through 16 mm, and this plastique was much faster. :(

The reason was probably that the stuff had started to gas, so much it expanded out of the open end of the pipe. I guess there were cavities inside the charge that distorted the jet formation. And the cone could not be wrapped three layers at 48 degree, I had to add a separate copper sheet to complete the third layer. 60 degree is better as you get exactly two layers from a circle.

But the shock wave was great! It felt like being hit by a (small) sack of sand from every side simultaneously. I guess I’ll use a slightly longer cable next time … :D

[akinrog]

Dear Friends,
After seeing what a javeline antiarmor missile did to a tank in the mpg video from FTP, I did a little search over the net and came upon this flash animation (http://www.usatoday.com/news/world/iraq/_common/_images/javelin/flash.htm).

The concept is very interesting: there are double warheads in the missle. The larger one (at the rear) is fired first on impact and then the second one (at the front) is fired then. And this baby blows apart a tank to the rubbles. :eek:

Anybody has any info as to what is the timing between two shaped charges and if the second (and smaller) one is fired with a det or by the jet of the first shaped charge? In addition what I notice from the animation the second (and smaller) shaped charge at the front is a little bit offset. I believe this type of missile (with IR seeker) is hard to improvise. However the concept of double shaped charge might be useful for hard skinned targets we discussed here too much.

"Off-axis is the precursor charge, "

This means the front charge goes off first? The flash animation shows that the rear charge goes off first and the front charge goes second? :confused: Or have I misunderstood?

[nbk2000]

Off-axis is the precursor charge, to det. ERA, so the main charge can penetrate. Reason for off-center mounting is so the debris cloud from the precursor charge doesn't disrupt the jet of the main charge.

[SweNMFan]

The concept is very interesting: there are double warheads in the missle. The larger one (at the rear) is fired first on impact and then the second one (at the front) is fired then. And this baby blows apart a tank to the rubbles. :eek:

The T72 have had to be loaded with HE .. there is no way 8.4Kg warhead demolish a tank like in the JavelinVsT72 movie

Then it bothers me that the sound of the explosion starts the same time as you see it..

[nuclearattack]

Anyway the javelyn works only on simple armour or on first generation of reactive armour like ERA. The russian T-90 uses a ERA2 reactive armour with double plates, the HE plates are connected with the STORA 2 radar system that is able to lock the missile and to detonate only one "double plate" just when the missile is arriving in proximity of the double plate. The detonation should destroy or unable the missile.
The javelyn is a very powerfull anti tank missile but the T-72 example is only a particular condition. I say this because if you use a javelyn against a modern tank, like the T-90 or T-80 or a Merkava or a M1 Abrams, it's not guaranteed that you stop it! A T-72 is obsolete, especially the iraqi version that is the first tipe of T-72.

[nbk2000]

The missile could destroy the tank completely because of the secondary initiation of the stored ammuntion. This is the major cause of the total destruction of soviet-type armor.

The abrahms and merkva are designed to vent the explosion of stored ammo out panels in the top of the tank, and not retain it inside the crew compartment.

[SweNMFan]

Thought that I should report that the Nitromethane plastique from KIE2 seems to work very well in shape charges.. Will try to post images in a few days..

[knowledgehungry]

I've began work on making some shaped charges out of Fiberglass, currently I'm still in the process of finding the best way to mold and shape it. If anyone thinks that the fiberglass would work worse than the previously mentioned methods in this thread please let me know so I don't waste anymore time on it.

[SweNMFan]

Do you mean as a container or for the liner?

I doubt you get better performance with a fiberglas liner than with soda can alu.. but the charge will work as the impression in the explosive shape the shockwave, guess there is a reason why 98% of all military shapecharges use copper as liner..

As for container I think it's abit overkill as a regular PVC pipe seems to work just fine.. even a paper tube/soda can works if you use 6000+ ms explosives

[nbk2000]

Maybe if you used a metal powder in the epoxy used in forming the fiberglass matting, it might improve things. Precipitated copper?

One thing I've noticed is a lack of a control test using no liner, just to make sure that the results of using the liner are better than simple munroe effect.

If, in the case of freaky franks test, a paper cone gave an equal or better penetration than use of the soda can liner, than we'd know that it had no effect.

I know he used an equal charge as a comparison, but that was a simple block charge, with no munroe effect from a cavity.

[Boomer]

Finally I got a real shaped charge jet with good penetration: A stack of 5 steel plates, each 10 mm thick, using a 1“ SC. Again I did not expect this and carried not enough plates into the woods: It went through another 70mm concrete.

This is even more remarkable (compared to my old tests, not to military SCs) as the plastique used (65g) was bulked up with nearly 50% of a NA/HDN mix! Composition was NG/MHN/RDX 10g/15g/20g (original mix), to this was added AN+HDN 15g each. Density was 1.64, charge diameter 27.5mm, length 60mm, liner 48 degree, wrapped/glued of 4 layers 0.2mm copper sheet.

The much better performance, even with a crappy mix compared to older tests with the same non-diluted plastique, has two reasons IMO:

Firstly did I use a steel water pipe with end cap opposite the liner. This ensured high order detonation, which is NOT easy to reach with voild-less plastique in plastic tubes. With pressed PETN etc this much confinement is probably not necessary.

Secondly did I make the liner twice as thick as in all other tests.

The picture speaks for itself. I estimate that without slowing the EP down with AN/HDN, and using more plates, 100mm are possible this way. This is nearly 4 x cone diameter and close to mil spec devices (5-6 x).

[chemistr1]

I am currently trying the same thing with 25% fibreglass epoxy 75% Al cast liners as I have not yet ordered in Cu powder.

In the modelling industry they call the process cold casting.

The best thing with this method is that the cone can be designed to any shape or size very easily.

I use wax covered plaster of paris moulds for the designs.

I am getting good results just using AN/HMTD charges as nitrations are out at the moment as since the baby was born 7 months ago I have avoided them in the house.

I havent thought about trying blank liner cones just to see if it was the Munroe effect or the cones themselves doing the damage.

Quite a good idea NBK and that why the forum helps because sometimes you just can't see whats right in front of your nose. :o

[SweNMFan]

Found this in some text about the TOW-2a

JET CHARATERIZATION
The TOW-2a CSC is 231 mm long with a 146-mm charge diameter (CD) and a biconic copper liner.
The liner is specified by two angles, an interior 30° angle where the liner thickness varies between 1.70
mm at the apex and 2.41 mm at the angle change and an exterior 42° angle where the liner has a constant
thickness of 2.41 mm. The main charge is LX-14, with a PETN type pellet booster and lead waveshaper
positioned at the aft of the charge.


The image is ripped from a pdf so this one is as good as I can get it..
The whole pdf is here:
http://www.autodyn.com/autodyn/papers/paper151.pdf

[nbk2000]

SweNMFan:

Looks like the picture could have been better done with a .GIF, unless the .JPG was the only format it was available in. Try a .GIF instead.

[SweNMFan]

Did dream that a 50mm SC with .4mm 30° Cu liner detonated against a boulder. Filler was 180g KIPE NM#1 .. A stone should make a better SC target than a tree right?

[nbk2000]

Should, though it may crumble or shatter, whereas steel targets retain the shape of the SC hole in the exact condition it was formed, thus making it easy to section and examine.

[SweNMFan]

Well the boulder only had a small impession in it, and it was Cu colored. So the SC failed. And it had somehow managed to cut down a 5cm tree 2m up and 6m to the side.

The KIPE NM plastic worked nicely again, and I'm still imressed with the power of the stuff. I've seen it VOD rated at 7000-7500 m/s and I think that that is the case.

Will try to find some steel plates, but they arn't easy to come by, atlest not something that I can carry with me..

[nbk2000]

Find a place that sells scrap metal by the pound and have them cut you off a length of steel round stock. It'll cost you about $15/foot for 2" 1018 steel round stock.

Then, blast a hole into it, and pay them a couple of dollars to cut it for you where the bottom of the hole would be. :)

OR

You can have them slice it up into inch thick sections and use that for your testing. Make a pile of them inside of a heavy cardboard tube (to keep them aligned) and, once you've off your charge, you can easily see just how deep the hole went.

Just like how the pro's do it. :)

[Myrol]

Well, I know its a sudden rupture in topic but trough the similarity of this Idea I think I'll post that here. I have heard sometimes something about Diamond Charges. Umm, Diamond Charges??? What is this :confused: , it was explained in the BTM but I didnt understand the picutres.

Its embarassing, normally I should know that but this time.....Ohhh, I think its a Liner cast into an Explosive wich looks like a four sided pyramide, am I right? A Tetraeder like liner should also be worth a try. You have then a very special sort of Shaped Charge. The Pyramide itself rolls up like an ordinary cone but the small roofs inside the Cone create also a munroe effect so that four of these Jets get tied together to a maximum power Jet.

If someone disagree, don't be shy to correct something. It was jsut my own explanation how a Diamond Charge could be constructed.

[SweNMFan]

Diamond charges are primarily used to cut round steel things, like shafts.. It isn't really a SC as it use the colliding shockwaves to cut.

Construction is described in the CIA Improvised Sabotage Devices.pdf

[nuclearattack]

So it uses only the Munroe effect? What if you add a pyramid liner?
A pyramid liner is also easier to make.
I'm thinking about another material for liners...what about lead? It has a low fusion temperature and it is dense, it should work well in theory.

[knowledgehungry]

Be sure that lead doesn't react with whatever explosive you are using. I think that is one reason why lead is not commonly used for SC's.

[Boomer]

There is nowhere to put the liner - the charge is only 1/2" thick!

It is either made of sheet explosive, or of plastique rolled out like cookie dough. It resembles no diamond (only in a cut section) but a 'salmiak pill':

It's a sheet as wide as the shaft circumference and twice as long (from edge to edge, it is NOT a rectangle). It is wrapped around the shaft so that two edges meet, and initiated at the other two edges. The shock waves meet at the centre and deflect down into the material (and up of course), all around the circumference.

The navy cut a 15" propeller shaft with one! (IIRC; or was it 12" or 15" ...) :eek:

Maybe I test some DCs once I get bored with conical SCs. The IMH says only few LSCs were tested to be more effective than ribbon charges, and diamond charges are said to be far superior to ribbons! Plus they are much easier to improvise! :D

P.S: I wonder that nobody called me a liar for claiming 50mm steel + 70mm concrete penetration with a 1" SC. I was under the impression that AXT's 25mm were the record here, but maybe people just don't talk about it, and several inches are common.
That would explain why I seem credible - it was nothing special ! :o

Anyway, I would like to know what performance others here got with improvised SCs - guys, how many inches is your dick ... errr sorry, your deepest jet hole :D

[SweNMFan]

You can't line a diamond charge as it is supposed to be wrapped around the target. It detonates from the two "shorter" ends at the same time, so the shockwaves meet in the middle..

[nbk2000]

A decent SC will penetrate at least 5x it's diameter, and that's through steel, with concrete being 8x or more, so 2" of steel plus 3" of concrete from a 1" SC is entirely within the possible. :)

'Course, pictures DO help with validity.

And Axt's 1" is paltry, but good for what it was made from...FMJ bullets.

[Myrol]

Ok, the thing with the DC is clear for now. :) If someone try a square perhaps 4 Inch each side and 1 Inch thick and prime it accurate on all four corners the effect of collapsing shockwaves should be nicely improved ;) You have nearly the same effect with an ordinary SC. Just in a flat form where space is a critical factor. Plus the Charge should create TWO Jets one for each side, but thats just an Idea, normally not worth to mention it.

Soon, in Winter time I can try some more SC, but the Liner cause serious problems to me. My choice is ANNMAl, I dont know if its better then ANNM, I just know it's not so HUMID as ANNM. My older SC with APANAl worked totally unsatisfactory. The cones aren't to bad.....they looked like in the .pdf from the nice guy who have created it (tests with APAN). Are there some way's to BUY such good cones? Martini glasses are a pain to kill them. Oh man, I think I must use the hemispheres from empty Gascans. Someone tried it before?

[nuclearattack]

Use liquid dynamite! It's faster than ANNMAL and it has a perfect uniformity because liquid.
Making good cones it's hard also for me so i'm trying with wine bottles.
Some wine bottles (the one used for good DOC wine) have a cone bottom very deep, simply cut the bottle and use the bottom has a charge contenitor with the linear already placed. To cut the bottom i'm going to use a kind of arc saw made to cut glass. It can be bought on harware/hobby stores.
I have never tested the wine bottle liner but it can be a good idea.
On december i'm going to make some tests with wine bottle liner and piramid liners.
If piramid works it can be a good idea because a piramid is very easy to do.

[The_Rsert]

I love shaped charges.
But which diameter is reportet the best?
2.00cm, 2.50cm, 3.00cm, 3.50cm, 4.00cm, 4.50cm or 5.00cm?

Tommorow I will make a test with a 5cm PVC pipe an strong AN/NM/NC/AP/TNT/MHN mixture. But I have no target for the detonation at the time :(.

[freaky_frank]

1,8times the diameter in lenght.
So 1cm diameter and 1,8cm length is the best ratio according to a militairy pdf.

[SweNMFan]

Hmm the larger diameter the better, penetration is about 5X diameter on a good homemade SC.. 8X+ on a MilSpec.

[akinrog]

Dear Friends,

Recently I was reading david harber's Improvised Landmines. In various sections, the author mentions about a shaped charge improvement called wave shaper. The wave shaper is a simple disk with a tail at its bottom. According to the author, the wave shaper increases penetration depth four folds. :eek:

This might be a great improvement for our improvised shaped charges. :D

It is a simple device but what I could not understand is where the detonation starts i.e. at the back or in front of this disk. Anybody has an idea? Regards.

[SweNMFan]

If you take a look at the TOW warhead drawing I posted here before there is a Lead disc after the initiator charge..

[The_Duke]

Linear Shaped Charges
I have done a few searches around here and found almost no mention of LSC or PLSC, (Linear Shaped charges or Precision Linear Shaped Charges) so I figured I might be able to strike up a conversation about them.

Linear shaped charges and PLSC work under the same basic principles as any other SC.
The main difference between a CSC (conical shaped charge) and LSC or PLSC is that a CSC is designed to punch or cut holes through metal while LSC and PLSC are designed to make a straight edged cut though the target metal.

The difference between a regular LSC and a PLSC is that the PLSC design concept involves the independent fabrication and assembly of the liner and tamper/confinement which allows you to be able to use different materials for the liner and tamper. PLSC have tested to perform better than LSC and cut deeper.

I have had GREAT results using 2mm AL bent exactly and precisely to a 90% angle for my liners and using 4mm steel for the tamper. I have used a few different explosives and I have made long and I have made some sort, most off the time they work flawlessly. I have successfully cut 3/4” steel with one of these PLSC using aluminum and I know I can cut deeper (3/4” steel is all is could find). My main and only problem is that I WANT a copper liner for one of these, but it’s hard to find thick copper bent to a 90% angle.

I hope that there are other members the have tried this and would like to talk about their experiences with LSC. :)

This following PDF will be most interesting to some members…
http://www.oes.org.uk/Explosives.pdf#search='Linear%20shaped%20charges' (http://)

[The_Duke]

It would seem that the link from my previous post does not work and the edit button is no longer appearing. I appologize for any inconveince I may have caused, the file can be found here. :)
http://www.oes.org.uk/Explosives.pdf#search='Linear%20shaped%20charges'

[V2A]

hi

today i tested 2 small shaped charges, but the steel pentration effect wasn't as good as expected and i really dunno why... so please help me!

the construction of my charges was very similar to the one in freaky frank's .pdf file.
only difference was that i used a carton tube with 25mm ID and 1,5mm thickness and filled the pure AP directly into a hole in the APAN and not in a drinkstraw.
everything else: dimensions of standoff, liner and tube were exactly the same.

for the first charge i filled the space around the liner + 20mm with pure PETN, about 10g. the rest was filled with extra-dry 1:4 APAN + 1g AP to set it off.

the second charge was completely filled with APAN.


the half-petn filled charge was placed on a 7mm thick steel v-profile.
-> nice loud explosion :) but the steel wasnt even bent. there were only a few small holes going about 1-3mm into the steel.

the pure-apan charge was placed on a 5mm thick steel tube (about 40mm diameter).
-> the pentration was better than the one from the other charge but also bad compared to freaky frank's pictures. it was bent to the inside and nearly a hole.


how can that be?
normaly both charges should have been stronger and especially: the one filled half with petn should have been MUCH better than pure APAN.

a friend said that maybe the carton tube i used was to unstable compared to frank's PP tube but i dont really belive that.

[The_Duke]

a friend said that maybe the carton tube i used was to unstable compared to frank's PP tube but i dont really belive that.
Nope, it doesn’t really matter if it's paper or PVC as long as the charge is made correctly. When you're using a HE confinement is not a problem.

You might want to use some PVC for better confinement when using APAN but paper tubes will work. What did you use for a liner? The reason your SC did not work is because you didn’t make it right. Pretty simple eh? Your charge probably did not form a “jet”, if it does not form a jet then it does not work. Check out my post above, there is a link that might help you to understand. Also copper is the best choice for a liner. ;)

[V2A]

What did you use for a liner? The reason your SC did not work is because you didn’t make it right. Pretty simple eh? Your charge probably did not form a “jet”, if it does not form a jet then it does not work.

i made the liner from a coke can, exactly the same way freaky frank describes in his .pdf file.

an i think a jet has formed, cause there are there are sparks on the first explosion frame of the video (http://home.arcor.de/kkv2a/shapedcharge.avi).
on the picture in the pdf u posted there are also sparks where the jet hits the target...

[nuclearattack]

To V2A:
a better confinement will give a higher vod, use PVC or steel, i always use PVC and it works perfectly.
Use a real cap...how can you dead press your AP if you simply pour it in a hole in the APAN? Especially with small charges use a compound detonator because 1gr AP is poor, a 5gr AP detonator is too big for small charges so it's important to use a compound detonator.
A coka can liner? You used the bottom of the coca can as a liner?! :rolleyes:
Can it really work? It isn't so hemispheric, but at least is cheap and easy to do!

[V2A]

@nuclearattack
i will try a PVC tube and ammonal next time... should then work better.
steel is to dangerous i think because of the splinters with comperative high density flying around at the blasting site.

when using APAN i always pour the pure AP into a hole in the APAN. thats the same amount of AP that would be in a drinkstraw, and its pressed (a bit) too, only the weak plastic confinement of the straw is missing...

the liner was made as in freaky frank's .pdf, thus not out of the bottom of the can.
but maybe one could deep-draw (is this the correct word?) the bottom to make it conic - would be a bit thicker and more constant.

[nuclearattack]

To V2a:
about the cap the problem is not the confinement but the fact that pressing AP in APAN is too dangerous, if AP detonates during pressing in drinking straw you loose a finger, if it detonates in APAN...you know. :(
Pressing AP is very important to rich max vod and power.
Try to use ANNM or ammonia dynamite instead of APAN, i also recommend my liquid straight dynamite, see it's thread in high explosives section.
Enjoy your experiments! :D

[V2A]

@nuclearattack
i have build a press (http://home.arcor.de/kkv2a/IP/INI%20Presse%201.jpg) for making blasting caps without loosing a finger if the primary detonates (that never happened as yet). for the test with Ammonal i will make a hard pressed 1g AP cap with it.
ANNM or your NM based dynamit is a problem cause i have only 50ml NM left from previous experiments and no glycerine or ethylene glycol which i could nitrate (yes, i really sould buy some :D). first see how good Ammonal works, if not as expected i'll try PETN/SHN plastique.

[knowledgehungry]

For any of the low velocity explosives a cardboard tube will not be sufficient to give good results. As general rule the slower the explosive the more important it is too make the charge well, and with good containment.

[V2A]

damn, the ammonal charge was a misfire. although i used a well pressed 1,5g AP cap the Ammonal wasn't set off.

maybe the AN got to wet while mixing with coal and Al, or i wasn't fine enough (electric coffee mill).

[Jacks Complete]

I would suggest that whatever explosive you are using, you will get better results with a better confinement system.

A cardboard tube is not going to help get a good detonation, and it certainly isn't going to help concentrate the energy down into the Munroe shape. A fairly thick copper liner is your cutting mass, which is accelerated up to high speed by the interaction of the wavefront. If the liner is tougher than the tube, you are going to get very poor results. If your explosive is at all slow off the mark, or has any voids, you are likely to get a partial.

I would suggest making a wooden cone form, which can be put under the soft liner cone. This will let you pack the explosive without collapsing or deforming the cone.

An alternative to copper might be to try lead flashing. This is easily available and quite thick, and heavy. It has a much lower melting point than copper as well, which might cause issues, or might actually enhance performance for less effective charges, since it will all be liquid and moving fast, rather than a partial jet of copper. Any thoughts?

There is another thread about casting copper platters/liners, but the general consensus is that forming one over a form on a lathe would be easier and more uniform, without access to professional spinning moulds. Lead forming doesn't require a lathe, as a hard wood form could very easily be driven into a disc of lead flashing to form a good cone shape.

[Boomer]

To back up nuclearatack, knowledgehungry and Jack's, I sum up some of my results:

1" Thin-waled PE pipe, 0.4mm copper liner, MHN/NG/HDN plastique: <5mm

2" Thin-walled PE, 0.4mm copper liner, MHN/NG/HDN plastique: <5mm

2" Thick-walled PE, 0.4mm copper liner, APAN/ANFO mix: 16-18mm

1" Steel water pipe + endcap on top, 0.6mm copper liner, MHN/NG/HDN plastique: 50mm+

The millimetres are penetration into steel plates, for the last one I used only 5 plates a 10mm, it went trough some more inches of concrete below.

Conclusion: Confinement *IS* important, not only for low-end HEs, but also for plastiques without air bubbles, they otherwise tend to det low-order and form no real jet! And a slightly thicker liner won't hurt, can metal is quite thin, lightweight and less ductile than copper.

BTW Jack, you ARE no longer his complete lack ... why the change?

[V2A]

@boomer
how did you make the 0.4/0.6mm cooper liners?

[nuclearattack]

To V2A:
if you are looking for easy to make liners i think that wine bottles should work quite well. I say should because i never tested it but i'm going to do this since in this moment i'm busy with others tests.
If you look at some wine bottles you'll see that sometimes it have a conical shaped bottom, this is very common in very good wines since this kind of bottom is used in some restaurant, anyway i don't want to explain it's use but how we can use it! ;)
If you look to this pictures you can see the shaped bottom it should be very good, the bottle is from a very good italian wine :) but i'm shure you can find it easily.
You have only to cut the bottle at a distance twice at least the height of the cone, fill it with the explosive (choose a fast one and enough easy to initiate, like liquid dynamite) cap the charge and reinforce the whole structure with something strong, like: steel/pvc tube that fits perfectly the bottle, a concrete bath, a lot of strong tape...
Let me know if you have success with it! ;)

[Boomer]

I think copper liners are far superior to glass - glass does not form a jet, rather the effect relies on munroe plus some glass powder.

V2A, look at this: http://roguesci.org/theforum/showthread.php?t=2562&highlight=copper+liner+roll

In the "forming shaped charge liners - archieve file" thread I described the method complete with pics. The sheets are 0.2mm, so 0.4 mm are two wraps, 0.6mm are three (for three you have to use a second sheet where the first stops. For 48 degree cones, you get two wraps from one circle.)

[SweNMFan]

In the book Firewall (By ex sas Andy McNab) the operative makes a improvised linear cutting shape charge by cuttin out square holes in styrofoam sheats , but leavin a "toblerone" shape in the bottom of the hole.. I think that it will work IRL also .. He also writes that if "reinforcing" the toblerone shape with copper would increase the effect.. :)

Again have a look at
http://www.air-and-space.com/20020624%20China%20Lake%20Explosive%20Ordnance%20D isposal.htm

There is pics of a improvised winebottle charge and the hole it did in a steel plate, glass may not be ideal but it will work..

[nuclearattack]

For toblerone (the famous chocolate :) ) you mean that i should leave a piramid in the styrofoam?
Damn! Myrol was right when he said that piramid liners could work in LSC!
That should be a nice liner because it is simple to do a piramid with a copper sheet.

To Boomer:
glass is not the best liner but why it shouldn't form a jet? Glass should melt quite well.

[The_Duke]

Nuclear attack;

I hate to rain on you’re parade but glass is probably the worst improvised liner you could use in a shaped charge.

Copper or other soft metals are far better liners because they are not brittle and they heat up as they “fold” over themselves in the explosion forming the “jet” and the slower “slug”, where as glass can’t “fold” over itself or form a “jet” and “slug” without breaking or unless it is melted.

Glass does melt, you’re right about that, but the glass is still too brittle and does not melt like you might think, remember that even though the liner is positioned starting at the epic center of the explosive and explosion, the shock wave leaves first, and is then followed by the hot gases. So the tremendous pressure and shock causes the glass to shatter before it is melted and has a chance to form a “jet” in the traditional form, but until someone tests this, it is still just speculation. ;)

So for now I agree 100% with Boomer when he said glass liners rely only on the Munroe effect and the power of the explosive used, not the formation of a jet.

I have a PDF called improvised shaped charges where three different glass liners were used, the pictures are pretty much shit, but the writing is legible. If anyone wants a copy you can PM me. Also here is a file titled disturbance of shaped charge jets caused by bulging amour.

[Microtek]

The liners in shaped charges do not melt when the charge is detonated. This has been proven quite conlcusively, but remains one of the most persistent myths in this field.
The temperature of the copper has been measured as the jet was formed, by some sort of high-speed method that I don't remember the details of. It was shown to be less than 400 C.
In another investigation, a liner cone was sawn into several pieces and then carefully glued back together. The charge was fired into a basin full of water to collect the jetted liner. The drawn out liner which had been formed into the well known thin jet was still divided into the same pieces as before the detonation.

[trinitride3]

Has anyone experimented with brass linings in their shaped charges? When I was cleaning my garage the other day I found a role of .016 thick brass flashing. It seems a little thick compared to the aluminum soda cans I usually use to make my liners, could it be used successfully?

[The_Duke]

Microtek,
Not that I don't believe you, but do you have any references or files you could share to back your claim. I find the above statement to be very interesting indeed. :D

[Boomer]

Here are two references, IIRC they are also on the FTP. Both clearly emphasise the importance of ductile liner material. One gives interesting numbers, like 10 Mbar, max. 450C, 25 million g jet acceleration etc.

[SweNMFan]

For toblerone (the famous chocolate ) you mean that i should leave a piramid in the styrofoam?
Damn! Myrol was right when he said that piramid liners could work in LSC!
That should be a nice liner because it is simple to do a piramid with a copper sheet.



Not really a pyramid, more like a extruded triangle.. just like a Toblerone box.. The nice thing about styrofoam is that you can make it with a hot blade and as you can build in the standoff.. Attached a pic of how I think the "hole" should look like..

[The_Duke]

It would seem that the glass liners perform relatively well after all. :D
http://www.sciencemadness.org/talk/viewthread.php?tid=2219
I found this on the Sciencemadness forum.

[nuclearattack]

This "toblerone" shaped charge should be a very good cutting charge an alternative to ribbon charges.
How would you prime this kind of charge?
In the center but with the detonator parallel respect the charge (like in FM 5-250 pag 3-13) or perpendicular like in a block of explosive?
What about priming the charge by a side from the left to right?
I think that the best priming is the same for a ribbon charge.
What about using a standoff like for standard LSC? A different kind of jet should form anyway...a lengthened jet perhaps.

[The_Duke]

I noticed that when Boomer attached the files “Some metallurgical aspects of shaped charge liners” and “Liners for shaped charges By Manfred Held” that they were only stubs, and not the whole files. Well I do not have to tell you guys how irritating it is to read the first page of a file and then notice the rest of the file is nowhere to be found. So I broke down and bought “Liners for shaped charges By Manfred Held”. It’s a pretty good file and worth reading, I have upped it to the ftp.

Now does anyone want to buy “Some metallurgical aspects of shaped charge liners” and up it to the ftp? :)

[Edit] for those who do not have access to our ftp, you can PM me and I will gladly send the file to the mailbox of your choosing :)

[The_Duke]

I noticed that when Boomer attached the files “Some metallurgical aspects of shaped charge liners” and “Liners for shaped charges By Manfred Held” that they were only stubs, and not the whole files. Well I do not have to tell you guys how irritating it is to read the first page of a file and then notice the rest of the file is nowhere to be found. So I broke down and bought “Liners for shaped charges By Manfred Held”. It’s a pretty good file and worth reading, I have upped it to the ftp.

Now does anyone want to buy “Some metallurgical aspects of shaped charge liners” and up it to the ftp? :)

[Edit] for those who do not have access to our ftp, you can PM me and I will gladly send the file to the mailbox of your choosing :)

[The_Duke]

I noticed that when Boomer attached the files “Some metallurgical aspects of shaped charge liners” and “Liners for shaped charges By Manfred Held” that they were only stubs, and not the whole files. Well I do not have to tell you guys how irritating it is to read the first page of a file and then notice the rest of the file is nowhere to be found. So I broke down and bought “Liners for shaped charges By Manfred Held”. It’s a pretty good file and worth reading, I have upped it to the ftp.

Now does anyone want to buy “Some metallurgical aspects of shaped charge liners” and up it to the ftp? :)

[Edit] for those who do not have access to our ftp, you can PM me and I will gladly send the file to the mailbox of your choosing :)

[chemofun]

I tried to see the pdf but I cant get to it. If its in the FTP...well, I can't get there either. If its not too much trouble could somebody please upload it directly to the forum or e-mail it to me at gastonios6@yahoo.com. I've been curious in shaped carges for a while now and I wanted to make some with TNP. I want to put liners on them though, otherwise I would just use glass bottles for the munroe effect. I know copper is supposed to be among the best liners but how does aluminum compare?

[The_Duke]

I had totally forgotten about that file!

The other file was found for free and can be found on tmp’s ftp! :D

Also, 2,4,6-TNP is not a choice explosive for shaped charges, I suggest you look at other alternatives. The attached file demonstrates the difference between Cu and Al as liner materials, there is really no contest between the two as Cu will effectively penetrate almost double what Al can penetrate!

I will email the files to you now, chemofun.

[Hobbit Porn]

chemofun : I've sent Liners for Shaped Charges by Manfred Held to your streamload account.

[Viper III]

did anyone know if annm +h2so4 (40:40:20) is good for shaped charges ?

[xyz]

Viper, have a look here hxxp://www.sciencemadness.org/talk/viewthread.php?tid=2219 (http://www.sciencemadness.org/talk/viewthread.php?tid=2219).

I assume (and definitely hope!) that English is not your first language...

[Viper III]

Thx, this link had helped me a lot.

Sorry for my bad english, I am from austria....


a few days ago i testet a LSP with annmal....the results are ashaming....but it was just a part of a pc...so the metal plate was too thin..


I have to say I like this forum,.....everything is proffesional...

[Viper III]

here is the vid of the LSC....

it was quite funny.

http://rapidshare.de/files/11736125/LSC.mpg.html

[Flake2m]

That video is quite impressive.
Do you know what SWIM used as the explosives compound and linear?

A brick or reinforced concrete slab is also good to test on. SWIM might also want to remember that shaped charges also have a standoff range.

[Viper III]

The ends of this V-form (there where no HE was) + 8mm was the standoff....today i got a 2" steel plate ....i am gonna test a cylindrical SC in a few days:

65mm long and 16mm wide al liner, + around 300g ANNMSA (Axt had a success with this at a 1" plate....)

[mike16]

Yay, I'm so happy, my first shaped charge success after about 8 or 9 previous failures.

Specs: 1inch Conical shaped charge

Liner: copper 0.6mm thick, 60 degree apex, 28mm wide

Casing: Steel, 2mm thick walls, 60mm long

Charge: 30g Dynamite ~ 80%NG/20%Flour

When I got to the test site, The standoff legs had fallen off, and I could not stick them back on, so I decided what the heck, I'll use ZERO standoff! :p

So I place the charge directly onto the target (18mm steel block), put the cap in the end, and retreat about 50 meters to press my remote control button.:p

Sadly there is no video as I did not have my camera with me, but I have pictures!

The casing:http://i155.photobucket.com/albums/s300/kpppppk/Picture149-1.jpg

The charge: http://i155.photobucket.com/albums/s300/kpppppk/Picture140.jpg

Liner was rolled from 0.3mm copper sheet:http://i155.photobucket.com/albums/s300/kpppppk/Picture154-1.jpg

Due to zero standoff, the entrance hole in not visible as too much copper is in the way.

Entrance wound:http://i155.photobucket.com/albums/s300/kpppppk/Picture190-1.jpg

Exit hole circled in red:http://i155.photobucket.com/albums/s300/kpppppk/Picture182-1.jpg

Also you can see the block ( from an old air rifle) has been bent by the force:cool: .

Conclusion: I think this shaped charge worked because this is the first time I've used steel casing for the charge, and the liner was solidly hammered and superglued into place.

Also the cone apex was tapped flat slightly with a hammer to 1mm wide, to give the shockwave something to push on.

Edit: I've managed to get the copper "slug" off the entrance hole, so you can see it!

Here it is: http://i155.photobucket.com/albums/s300/kpppppk/Picture191.jpg

[MRUD]

After I was able to make PETN, I started in developing shaped charges this year.

First try was not a full success, but it penetrated 10mm of steel.
http://img22.imagevenue.com/img.php?image=39199_DSCF0200_122_161lo.JPG
http://img18.imagevenue.com/view.php?image=39206_DSCF0198_122_271lo.JPG
http://img167.imagevenue.com/img.php?image=39225_DSCF0202_122_199lo.JPG

Cone made from 0.8mm thick copper with soldered ends.

After severel tries, now I am able to penetrate 20mm steel with a configuration as following:

Con diameter: 40mm
High of con: 40mm, so you have around 60 degree apex
Standoff: 40mm too
Charge: 35g of PETN

The ends of the cone are soldered and polished to give a maximum of accuracy.

This are the pics of the last try:
http://img103.imagevenue.com/img.php?image=53646_DSCF0248_122_122lo.JPG
http://img120.imagevenue.com/img.php?image=53650_DSCF0254_122_53lo.JPG
http://img40.imagevenue.com/img.php?image=53656_DSCF0253_122_63lo.JPG

I think, PETN is working best in small charges such these

[Chaosmark]

Very interesting mike! Your small shaped charge has made me realize something that I've heretofore been overlooking: small explosives are easier and cheaper for testing than full blown 'ka-boom'ers.

Thought: could a small shaped charge like this be used as an engine for rockets, or is the jet moving just a tad bit too fast for anything but a hypervelocity rocket like the Gy2?

[nbk2000]

I cropped and resized MRUD's pics to have mercy on the dial-uppers amoungst us.

http://rapidshare.com/files/26050765/MRUD_PIC.rar.html

486K versus 7M orginally.

Good work MRUD.

What changed between the 10 and 20mm attempts? Standoff, cone construction...?

[MRUD]

Thanks, nbk2000

The main improvement between the first and last charges are my technique how to: cut the copper plate, weld it and solder it.

The first cone was a piece of crap, not well welded and made at all.
Diameter and high was 30mm with 30g PETN. Standoff equals to the diameter.

Picture of the first cone:
http://img120.imagevenue.com/view.php?image=19558_DSCF0042_122_109lo.JPG

For a good result, you have to make sure to give maximum precision to the cone.

+++

It's cone, not con. I'm a con, not a cone. ;) :D NBK

[Microtek]

Indeed, precision is of paramount importance when manufacturing shaped charges. I recently started a series of tests to determine if liners of pressed Cu-powder were good candidates for shaped charges. The powders would remove the need for precision machining the liners as you would just need a good mandrel for ramming.
I produced some tools for producing shaped charges that were as close to identical as possible. The charges consist of 1.600 g PETN with copper cones ( ca 60 degrees ) in the 0.2-0.6 g range. The cones are 9.65 mm in dameter with no subcalibration. The explosive filler and liner weight is determined down to milligram accuracy and then rammed into the casing which is machined to a tolerance of a few micrometers. Using the tools I prepared, I can make sure that both the liner and detonator are perfectly centered. This precision work was to ensure reproducibility as well as high performance.

Unfortunately they performed very poorly, consistently giving only 2.5 mm penetration into mild steel. I eventually made a cone of laminated copper foil in the same weight range and with the exact same charge size and geometry for comparison. It penetrated 4 x 4mm mild steel and went 3 mm into the fifth. A total of 19 mm mild steel ( and it would have been more in a monolithic block ) using 1.6 g of PETN.

[stupid939]

Microtek - It sounds as though you spent quite some time perfecting your copper powder shaped charges, and you have come up with an interesting idea.

Awhile ago, I had an idea of using copper wire for shaped charges to save money and time. I wound it around a 60° PVC mandrel that I turned on the lathe. First, I put high strength double-sided tape on the mandrel and then I wound the copper wire around it (I think it was around 22 gauge). It ended up being quite large (about 1" diameter), and I could not do much testing on it because I was using AN/NG, which isn't really suitable for shaped charges. I also did not give it a high enough stand-off when I used it, but it still worked a little bit. I think that this method has some potential, but in order to test it more extensively, I would need to make some RDX or PETN. I have pictures of my mandrel and how I wound the wire if you would like to see them.

If you don't mind my asking, do you live in the US, and if so, where do you go about finding pentaerythritol? I have been searching for it for a few months now, and I haven't had much luck. I know it is used in certain paints and varnishes, but I have not been able to find a source in the US.

[Microtek]

No, I don't live in the US but I weren't able to find PE OTC either. I ordered it through a lab supply ( which doesn't sell to individuals; I know someone who owns a small company ).
When I get to it, I will test geometrically identical charges using RDX, HMX, TNGU, DNAF and whatever else seems promising, so then we will know if you really need PETN or if RDX is just as good at this scale.

Regarding the powdered liners, I certainly wouldn't call them perfected; they only penetrated 10-15 % of what the laminated cones did. Anyway, I'm working on my metal spinning skills ( I have a lathe too as you may have deduced ) to make some really good liners.

[Charles Owlen Picket]

Extrapolating from another discussion on SC, I was wondering if anyone had tested powdered liners with the use of a plastique HE????

It would seem that the density of the plastic mass of the HE would allow for the optimum formation of the cone w/ powdered copper, etc. The reason I ask is that I had heard of a 'dimple" setting for plastique charges achieving fair results by itself.

[nbk2000]

Powder liners need to have a TMD of at least 80% to become comparable to normal spun liners, and should be sintered, though 'green' pressed will work too.

[Microtek]

I was inspired by patent number US3255659 which uses simple compression of the metal powder into a cone shaped cavity in the explosive charge (using a conical ram). The thing is that copper powder can be made quite easily by reducing CuO with propane (or better, H2) at easily achievable temps. Maybe the produced powder is spongy or otherwise unsuitable for use in liner production, or maybe the charge design needs to be different (or maybe the patent is flawed - that happens).

[Charles Owlen Picket]

I have spun on a wood lathe with fair results (copper) but it had been quite time consuming. I found a simple way to cut with a tin-snips the shape needed for a cone and simply super-glued it together. The results were not too shabby providing all the other issues were squared away.

However I have never seen fair results from powdered liners. Keeping in mind that I had no idea that the 80% figure was the goal -I know that what I have seen tested was close but certainly not 80. And with this subject I've found there is very little "slop" in construction if the intention is to produce a usable jet, etc.

HAS anyone had even limited success with copper powder - that was reproducible?

[Cyclonite]

I don't think powdered copper will work well at all, it needs to have a certain density (that can be achieved) and strength. If you were able to melt down the powder enough to fuse than you might have something to work with.

[Zait]

I don't think powdered copper will work well at all, it needs to have a certain density (that can be achieved) and strength.

There are quite a few oil well perforators that use pressed copper powder as the shaped charge liner and they work very well.

The key is that the copper would have to be pressed to the proper shape and density which is probably beyond what most on this forum could do.

[Kleng]

When you say pressed, do you know then how much force is required?

It's not hard to build a small-scale hydraulic press which has a force of 20ton.

[stupid939]

Ok, well SWIM got around to testing the copper wire shaped charge idea that I came up with, this time with ETN and better cones. Success! The pictures and specifications are below.

Tools for forming the wire.
http://img142.imageshack.us/img142/3025/cwcsc1yg1.th.jpg (http://img142.imageshack.us/my.php?image=cwcsc1yg1.jpg)

The die. It is at a 45° angle and is made of aluminum. The small hole at the top is to loop wire through.
http://img530.imageshack.us/my.php?image=cwcsc2zy0.jpg

After the wire is wound, the end is bend and it is held in place for soldering.
http://img171.imageshack.us/my.php?image=cwcsc3qg5.jpg

The torch, 60/40 solder, and a generous amount of flux.
http://img367.imageshack.us/my.php?image=cwcsc4eb5.jpg

A small spatula is used to pry the formed cone from the die.
http://img300.imageshack.us/my.php?image=cwcsc5cl9.jpg

A small bead of superglue seals the hole on the top of the cone. A file is used to flatten out the bottom of the cone.
http://img171.imageshack.us/my.php?image=cwcsc7ng5.jpg

The finished cone was made to a diameter of 0.825" to fit the inside of the pipe.
http://img72.imageshack.us/my.php?image=cwcsc8dg1.jpg

A piece of 3/4" Schedule 40 PVC pipe is used for the charge. The explosive used was 7.7g of ETN/PGDN in a 85:15 ratio (oxygen balanced).
http://img254.imageshack.us/my.php?image=cwcsc9iu1.jpg

First the cone is glued in place.
http://img253.imageshack.us/my.php?image=cwcsc10ze1.jpg

Then the Explosive is pressed. The electronic blasting cap contained 1.5g of AP.
http://img171.imageshack.us/my.php?image=cwcsc11rv7.jpg

The standoff used raised it 2x the cone height and was constructed from styrofoam.
http://img464.imageshack.us/my.php?image=cwcsc12lm4.jpg

Upside down.
http://img265.imageshack.us/my.php?image=cwcsc13th6.jpg

The target material was 1" (2.54cm) square 6061 aluminum.
http://img511.imageshack.us/my.php?image=cwcsc14mp6.jpg

All wired up.
http://img522.imageshack.us/my.php?image=cwcsc15rv0.jpg

The entrance was ~1/8" all the way through. Nice.
http://img265.imageshack.us/my.php?image=cwcsc16hh9.jpg

Exit (it also went about 1.5" into concrete, so it could have gone through more aluminum).
http://img483.imageshack.us/my.php?image=cwcsc17cr9.jpg

The video. The reason for the weird voice is because SWIM always calls out a warning. He wouldn't want anyone having records of his voice.
http://img532.imageshack.us/my.php?image=fullxh8.flv

The original video at 60fps (much better quality and you can go frame by frame).
http://rapidshare.com/files/48855994/Copper_Wire_CSC.avi

Here are the pictures in a .rar archive. Password is roguesci.org
http://rapidshare.com/files/48860519/Copper_Wire_Conical_Shaped_Charge.rar

[inventorgp]

Hmm.. very creative way of making a shaped charge, I like it! I wish I thought of that because I have one kilogram of 1mm enameled wire.

You could of added your ImageShack page (http://profile.imageshack.us/user/stupid939) to that list if url's. Anyways, nice.

[stupid939]

I thought about putting a link to my ImageShack page, but I like to describe each picture.

Enameled wire will not work for this because solder will not stick to it until it is cleaned off of the wire. this can be done by burning it off and then rubbing it with sand paper.

[nbk2000]

I assume you using the solder to hold the wire in the coil form, but did you know that solder-metal is often referenced to in earlier patents as a SC liner material?

Perhaps the effect you are getting is from the solder metal and not from the wire? You should make a duplicate charge, using epoxy instead of solder, and see if you get the same results.

[inventorgp]

@stupid939: Obviously, you would have to remove the enamel, either by scraping action or by means of a solvent.

@NBK: very interesting. hmm.. if only my country wasn't becoming communistic, I would be able to try it. :o

[stupid939]

It may be awhile until I compare epoxy and solder, but I will post my results when I complete the tests.

NBK - I was using 60/40 solder but I was under the impression that lead and tin are too ductile to be used effectively. After looking over some patents, I have found that my idea is not original. I found a few patents describing the method I used, and the wire is usually brazed, soldered, or bonded with methyl-2-cyanoacrylate (super glue) or plastics.

I searched for the use of solder metal in shaped charge liners, but I could not find anything. Do you by any chance have a link?

[nbk2000]

The ones that mention it are so old (40's-50's) that they're image-only, thus not searchable. I have them on my other computer, but I'm not digging it out.

[Boomer]

Since I did not post for a long time, and before I get deleted here .... just an update, this time on linear SCs:

From the hardware store you can get U-shaped Al and L-shaped Al, 25x25x25mm and 15x15mm respectively, easy to cut into 100mm length. If you fit the L into the open end of the U, BINGO --> liner + casing, more precise than you could fold it from sheet metal.

These cut easily through 10mm steel plates, at approx. 40g HE per 100mm length. Both plasticised PETN or MHN works, and even high velocity gelled dynamite (65% nitro) works, though the cut is less straight (more bending of the edges). See for yourself:

P:S: The one in the left had a hand-bent 1mm/60deg copper liner, the two others were made as described. Even with Al, and at 90deg, they perform better than the copper!

[nbk2000]

What was your stand-off?

[Tinton]

I hate to interject into LSC conversation, but I had a question about "collection" of jets.

I was curious about the feasibility of retrieving a fired shaped charge. Such as firing a shaped charge into 6 or more feet of water. I'm somewhat doubtful about any of the jet or slug surviving, but still I would love to see reminants of a shaped charge. Especially a LSC, I have seen no pictures of a formed LSC jet.

Considering the jet is basically plasma, maybe a coolant/water mixture would do well, possibly even a gelatinous mixture. I have absolutly no experiance with stopping 8,000 m/s jets of molten metal intact, so excuse me if i sound like a dumbass. :o

[Alexires]

Tinton - I do not know the answer to your question, but thinking about it brings up this: Newton came up with this nifty law that says (paraphrased by MacGyver): For every reaction, there is an equal and opposite reaction.

If 10g of molten jet moves downwards at 8000ms-1 and what is left of your SC weighs 10g, then the remains are going to be moving in the opposite direction, at the same speed, eg. upwards at 8000ms-1 (assuming that it remains intact....which it probably doesn't).

Besides, I would think that the plasma would actually be hot enough to crack the water into H2 and O2 and thus some more exploding. Of course, the energy input is the same as the output (the energy required to crack the water is the same as the energy put out by the combustion of the hydrogen and oxygen) but the small localized explosions would throw the remains of the jet stream around.

Throw in some differential heating of the metal, and it would shatter like a little child's innocence upon the rocks of reality.

In short, I'd say your chance of finding the remains of the charge is about 1/10th of smeg all.

[nbk2000]

Clarification:

The liner of a SC doesn't turn into 'plasma', a superheated state of ionized matter, but rather cold-flows under the extreme pressures...like putty being squeezed out of your fist.

Also, in FoSC, you'll see that SC liners have been recovered in various stages of collapse by replacing the normal explosive filling with water, and using the force of a small explosive charge to hydraulically deform the liner.

[Alexires]

Thank you NBK, I had no idea they operated like that (my ignorance is probably obvious).

In response to my lack of knowledge, I have started researching shaped charges. I have found an interesting journal article which I have placed in the Journal Articles thread.

I have no idea what FoSC stands for. Perhaps Foil (lined) Shaped Charge?

Does anyone know of some texts that I could read to get a better idea about shaped charges? I'm currently looking for an article titled "The Hows and Whys of Armor Penetration", but the request is in the Journal thread.

[LibertyOrDeath]

Does anyone know of some texts that I could read to get a better idea about shaped charges?
Explosives Engineering by Paul W. Cooper has a section on SCs. It's not very long (maybe 10 pages or so devoted specifically to them), but it has some very handy info. For example, referring to conical SCs (p. 440):


1. Greatest penetration is obtained at cone angles of around 42 degrees.
2. Optimum standoff is between 2 and 6 charge diameters.
3. Penetration is normally around 4 to 6 charge diameters and could go as high as 11 or 12.
4. Optimum liner thickness is about 3% of the cone base diameter for soft copper. This can be scaled for changes in density (change of material) by keeping weight constant. That is, lower-density liners should be thicker.

Do you have that book? Someone here has probably scanned and uploaded it, but if not, then I can do it (though it'll take some time to do the whole thing). Or I can just scan the pages on SCs if you want them fast. Feel free to PM me if you like.

[nbk2000]

FoSC = Fundamentals of Shaped Charges.

On the FTP somewhere, or you can find it in SM's library, where they're hosting it as a backup mirror for me (whether or not I asked them to).

[Thermiteisfun]

As I'm relatively new to this hobby please excuse any ignorance, but what is the eficacy of using a thermite or "exotic thermite" liner in a shaped charge? would the energy of the blast be enough to start the reaction and if so would it increase the energy output?

an earlier post stated that the jet is a cold metal flow propelled by the charge, if a thermite liner is used would that cause an explosive expansion of gasses in the target (assuming it was an airtight vehicle)?

[Gammaray1981]

Thermite, being a powder, would not be a good liner. It would, however, sandblast your target nice and smooth.

[nbk2000]

Thermite can be a good SC liner if you want increased behind-armor incendiary effects, and are willing to sacrifice penetration for it.

But, it has to be pressed and sintered, not just loose powder.

[Roy Paci]

It's sad to post after NBK2000.

Do you think I can?

[ProdigyChild]

Yes, you've already done!
Do you believe, he prefers tears to progress in the forum?
I do not. Keeping 'his' form in motion is more respect towards NBK than shutting up.

[Roy Paci]

Mods could have erased my post If I couldn't.

And after all, I agree. But asked In case of any of the forum member who knew him could get offended by me start typing like nothing has changed.

Any way:

I couldn't read anyone saying he used NG/NC or ammonia dynamite in shaped charges. Is there any reason for it?
Wouldn't ammonium picrate plasticized work?

debase me, if I need it

R

[Zait]

I couldn't read anyone saying he used NG/NC or ammonia dynamite in shaped charges. Is there any reason for it?
Wouldn't ammonium picrate plasticized work?


To a certain extent almost any explosive will work. Remember that the theory was first proofed by Munroe using a block of nitrocellulose inadvertantly detonated on a piece of steel.

[KemiRockarFett]

The casing of a shaped charge.
As I noticed many here uses steel. I think the important thing is to have as much mass as possible around the explosive. (offcourse not in the cone direction). Steel has a density of 7 to 8 kg/litre but unfortunatelly it gives a lot of shrapnel, I think that the strength of the steel could be negligble compared to the force of inertia. a=F/m , acceleration*mass = force
The high acceleration of the casing will result in a big force of inertia.
I suggest to increase the mass of the casing by using two casings with a lot of water between !
The force of inertia will increase the kinetic energy in the desired direction.
The casing to cone mass relation should be considered.

[teshilo]

My choice for SC. This is:cool: :heavie body: steel dual point intiation with dc ;liner copper; explosive- pbx with VOD -6000 m/s, like C- series..

[Setharier]

http://myofficeproxy.com/browse.php/e5e206ce/bbc52Oi8/vaW1nNDE/yLmltYWd/lc2hhY2s/udXMvaW1/nNDEyLzI/yNzMvMjc/yNzg5NjN/0bzAucG5/n/b5/

I wrote something off this at the Countermass Weapon topic at the Improvised weapons section. I speculated using detcord as the initiator for the main charge, but found an issue: will the detcord ruin the conical charge when wired stright through or even from the side?

[Alexires]

That would be my thinking. It probably wouldn't have as good penetration characteristics. I would go for a momentum fired pin from behind, as opposed to being initiated from the front.

[fluoroantimonic]

Axt got surprisingly good results from using glass funnels with the stems broken off as liners. I'm not sure, but I would imagine a small hole in the apex of a liner would not reduce its performance much.

[slarter]

Axt got surprisingly good results from using glass funnels with the stems broken off as liners. I'm not sure, but I would imagine a small hole in the apex of a liner would not reduce its performance much.

There should be very little effect as many military shaped charges are open at the apex. Usually for a PIBD (Point Initiating Base Detonating) fuze using a "Spitback" initiator. This is seen in most current 40mm HEDP rounds. In fact I have one liner that looks just like a funnel.

BTW, I have a collection of military shaped charge liners that I need to take a picture of and upload here. I have from the M42 HEDP Grenade up to a glass liner from the M2 15 lb. shaped charge.

[Alexires]

It wasn't the hole at the top I was talking about, it was more the direction of explosive force. As opposed to having a shockwave propagating towards the target, you suddenly have some detcord messing up your funnel and the direction of shockwave.

I also said it might not be as effective, not that it wouldn't work.

[fluoroantimonic]

As opposed to having a shockwave propagating towards the target, you suddenly have some detcord messing up your funnel and the direction of shockwave.

That's a good point, you're probably right. An alternative might be to use "shock-tube" since it transfers the low velocity detonation without even bursting the plastic lining of the tube. I know this because I found about 20 feet of it used that was still perfectly intact. The tubing was yellow with a wall thickness similar to the inside diameter (~1mm) and looked to be HDPE. Interesting stuff.

[stupid939]

The shock-tube is interesting stuff. I attended an event where they strung it around the room, letting us hold it (one person held it between their teeth) and put the end up against a piece of paper. They used a spring loaded detonator with a primer in it, and the dusted RDX inside popped quite quickly and blew a small hole in the paper.

I have been pondering for some time now what the best way to initiate an airborne shaped charge, and the shock-tube would be the way to go. Run it through the center, and as long as you used the right primaries, it would work great.

[Setharier]

If the SC is being shot, an inertia-detonator will come in question:

http://img373.imageshack.us/img373/801/15722850bi2.png