Tiny SC Liner Cones

[nbk2000]

Having been to the doctors lately, I took the opportunity to loot their drawers for anything interesting. One of the things I took where a couple dozen of these things:

<img src="http://atc.utmb.edu/aom/images/specula.jpg" alt=" - " />

These are otoscope speculums. Fancy speak for eye/earscope cones.

These are made of polystyrene (at least mine are) and are shaped perfectly like trumpet SC liners. They're also very cheap, costing about $3 for several dozen. :)

Well, the idea came to me of using them as such, for very small SC charges. Since they're made of plastic, they wouldn't contribute anything more than simple monroe effect to the charge, but they could be used for making metal liners through investment casting.

This would entail coating the cones with a ceramic refactory and burning out the plastic using a furnace. Once the plastic is gone, a vacuum pump is used to suck up a molten metal (silver/copper) to form an exact copy of the original plastic cone.

Such materials are readily available as jewelry making supplies with no suspicion. Or easily improvised by skillful amatuers. <img border="0" title="" alt="[Wink]" src="wink.gif" />

Such liners are described in an early patent for making SC's using gelled NC/NG. Simple lead foil cones with less than a 1/4 ounce of HE were capable of penetrating 3/8" steel plate.

Using a specially made liner of the more efficient trumpet geometry, along with more effective metal liner material like silver, should easily increase that.

Uses of very small, but penetrating, charges are many. I could see them being used to disable vehicles, blowing locks, and other uses, without the major hazard of larger charges, and subsequent noise.

<small>[ February 09, 2003, 12:26 AM: Message edited by: nbk2000 ]</small>

[Aaron-V2.0]

And here is a source for steel hemispheres for 1.5" and up SCs.

<a href="http://www.kingmetals.com/Pages/Page10A.html" target="_blank">http://www.kingmetals.com/Pages/Page10A.html</a>

The 1.5" are 11 gauge and cost .65 a piece with a 5% discount at 10 or more. They mainly to ornamental iron but they have the hemispheres and on the same page above you'll see some cheap large caliber iron balls for aircannons. :)

If I'm correct an SC can be made from any HE but the higher Vod the better, but if I wanted to use an AN based explosive the SC would require a thickwall container right? I'd imagine for ease of manufacture, high Vod and ease of ignition Picric Acid seems like the best choice IMO.

Nice find NBK, I rather hate doctors offices but I know a medical supply warehouse nearby that's on my list of places to visit.

[Agent Blak]

I would imagine that you could build a Damping unit around the Small Shape Charge. This Could be done with a Styerfoam Cup and FiberGlass Insultion.

I could see it bee quite useful for Blowing Locks.

Quick Question on Deadbolts: "if you blow the lock how does this change the Plungers position." Can you then just use a screw drives and turn it?

Sorry I always Wondered

[1337bomber]

Wow! I just happened to have tried the cones in the picture a few days ago, just as a small BC with AP and a fuse. I epoxied a plug on the bottom and they worked pretty well. Pretty strange coincidence that I tried this just days before!

[xyz]

I know somebody in the medical profession who could probably get me some of these. :)

[nbk2000]

For a decent SC, you need at least 7,000 M/s, otherwise it's not going to happen. Certainly not with an AN based explosive. Even ANNM is on the low end of useful.

To "blow" a lock is to either destroy the bolt holding the door closed, or to disrupt the lock itself so that the cylinder can be turned.

You aim the SC at the shear line of the cylinder and the jet cuts the pins holding the cylinder immobile, allowing you to turn it with a polish key or screwdriver.

BTW, these cones look very similar to this one:

<img src="http://www.army.mod.uk/img/aht/Contents/equipment/WEAPONS/CANNON/cannon1.jpg" alt=" - " />

At the tip of the cone is a pellet of primary initiator, likely lead azide, that's ignited by the flame from an impact fuse in the nose. This "spitback" fuse throws a hot flame up into the cone, which ignites the initiator pellet, exploding the charge.

I can see a primary, like AP, being compressed into the tip of the cone, and being set off on impact by the flame from a shotgun primer.

Did you know these cones fit perfectly into a CO2 powerlets? You could maybe even make little grenades that'd fly through the air, exploding on impact, to either pierce with an SC, or spray the target with shrapnel. <img border="0" title="" alt="[Wink]" src="wink.gif" />

[supra.supra]

I'm rather confused about SC or least these smaller ones where does all the force shoot out from top or bottom? Do SC have to be made of metal? I remember somewhere using glass bottles.

[Anthony]

Supra, spend a few minutes on google reading about the basics of shaped charges.

[supra.supra]

I already knew some basics of SC and done some more searching.
<a href="http://www.ribbands.co.uk/prdpages/5-5inch.htm" target="_blank">http://www.ribbands.co.uk/prdpages/5-5inch.htm</a>
What I still wonder about what's on the other end of the jet...
<a href="http://www.angelfire.com/id/husar/list/explosivecontainers.html#shapedcharges" target="_blank">http://www.angelfire.com/id/husar/list/explosivecontainers.html#shapedcharges</a>

<small>[ February 10, 2003, 01:27 AM: Message edited by: supra.supra ]</small>

[Microtek]

Supra: You should know that, at the moment judging from those links, you don't know even the basics of shaped charges. I'm not trying to insult you by saying so, merely informing you that more extensive research is in order. I suggest you do a search on the forum for "shaped charges", "SC" or "monroe effect" and start by reading the oldest posts you can find.
About two years ago we weren't very knowledgeable ourselves, so I think you'll find that the posts develop in an appropriate manner to your current level of understanding.

[Axt]

Is the SC shaped that way due to the way its initiated, in an effort to keep the detonator out of the way? So for rear initiated SC's I expect it would be better to have a normal conical cone, is that right?

One thing ive found out that there is no such thing as a half arsed shaped charge, I personally have never had good results. There's a science to it, you cant do it by eye and expect it to work. Heres one I bothered to take photos of -


The Charge -
<img src="http://ww1.ft100.com/~45653/guns.ft100.com/images/shaped.jpg" alt=" - " />

10-15gm of PETN "plastified" with polyamine resin in an effort to keep it a consistant density. 1.2mm Cu liner. Standoff approx. 25mm.

The Damage -
<img src="http://ww1.ft100.com/~45653/guns.ft100.com/images/shaped2.jpg" alt=" - " />

Target was 6mm RHS - Result was smeared Cu impregnated in the pitted and dented steel, the dark area is where some penetrated one 6mm side.

And the crappy <a href="http://miss.fnpsites.com/shaped.avi" target="_blank">movie.</a> :p

<small>[ February 11, 2003, 06:17 AM: Message edited by: Axt ]</small>

[xyz]

Axt, where did you get the pentaerythritol for PETN from? What part of Australia are you in?

<small>[ February 16, 2003, 03:26 AM: Message edited by: xyz ]</small>

[Maniak]

Hemisphere liners for SC can be easily made from copper plate by small hammer.
But you can penetrate steel with SC wihout the liner. It is poor, but easy.
First test: I put 20g shaped plastic explosive (45%PETN + 30%RDX + 25%plasticizer) to 1cm thick steel. Liner wasnť used.
After explosion, penetration is complete and width is 1,2cm....
Second test: 30g plastic (60%PETN + 15%RDX + 25%plasticizer) as a linear SC for cut off of steel U profile (wall thickness 5-8mm). It was totaly cut!
You mustn´t to use standoff distance, when the liner isn´t used, of course.

I have got some photos of it, but I don´t know, how can take it here.

Now I have a few nice copper liners from my friend (he has hydraulic press...) and I want to try it with a few hundred grams of cast explosive.

[Maniak]

unstead SC, EFP is good for penetrate steel. You can use a long distance (5times diameter) and 20g plastic make penetration about 2,5cm (in my tests).

<small>[ February 16, 2003, 04:39 PM: Message edited by: Maniak ]</small>

[kingspaz]

Maniak, do you have any pictures or videos of your tests?

[Mr Cool]

Maniak, to post pictures, get an account at <a href="http://www.boomspeed.com" target="_blank">www.boomspeed.com,</a> upload your pictures there, and post a link to them here.

<small>[ February 17, 2003, 01:29 PM: Message edited by: Mr Cool ]</small>

[IPN]

Mr Cool there is a slight problem with your link <img border="0" title="" alt="[Wink]" src="wink.gif" />

Anyway this sounds like something very interesting to try. Just that I don’t have any major HE´s. Or could I use something like ANNM?

[kingspaz]

Maniak sent me an email and here's the pics:
<img src="http://www.boomspeed.com/kingspaz/cutoffprofile.jpg" alt=" - " />
<img src="http://www.boomspeed.com/kingspaz/penetrated1cmsteel.jpg" alt=" - " />
<img src="http://www.boomspeed.com/kingspaz/penetrated1cmsteel2.jpg" alt=" - " />

[Nihilist]

just as a note for those of you who can't get these from a doctor, you can also buy a very similar cone(though not quite as good) as the cover for one of those things that takes your temperature from your ear you can buy them here: <a href="http://www.mypharmacy-secure.co.uk/acatalog/Shop_Braun_213.html" target="_blank">http://www.mypharmacy-secure.co.uk/acatalog/Shop_Braun_213.html</a> they are the "lens-filters" although they probably wouldn't be that good for SC's in and of themselves they would still be good for making casts.

[Terry Collins]

Axt is right in saying there's a science to it. In theory it seems quite easy to construct a (L)SC. But in practice it's quite difficult. There are all kinds of problems and factors to be taken into account.
The first one is what explosive to use, then what liner, what angle what thickness, what Stand off distance and so on.
And even if one succeeds in getting a SC with a clear cutting effect it still might not be very effective in relation with amount of explosive used versus penetration depth.

I experienced like Maniak also mentioned that the effect of the explosive without the liner but with the V shape is sometimes bigger than with the liner. So the Monroe effect creates a deeper cut than the partcilar SC with liner.
It all has to do with the material of the liner and the thickness.
Of course if the right liner is used a (L)SC is the most effective explosive, gets the deepest and smoothest cut with the least amuont of explosive. But that will take a pro and a lot of testing.

[Mr Cool]

Here's a <a href="http://www.boomspeed.com/mrcool/MiniSC.jpg" target="_blank">picture</a> of a tiny little SC I tested yesterday. Obviously, I deliberatley designed it to fail, to illustrate the point that you can't just throw one together and hope that it works <img border="0" title="" alt="[Wink]" src="wink.gif" /> :p .
It's 1cm wide, 1cm high, about 1.4cm long and the stand-off is a little under 2cm. Angle is close to 60^o. HE was 75% PETN, 25% EGDN to give a more uniform high density, although it did settle slightly. Liner is 0.15mm Cu. Detonator is PETN/AgN₃ in a narrow drinking straw.
The shiny stuff on the bit of paper is not leaking EGDN, it is epoxy glue that I used to seal everything. Target is 1.5mm Al plate, backed by a load of flour/water dough.

The target was penetrated, but was clearly ripped and not cut, and the hole was not the shape that you would have expected. It was also severely fragged, indicating that the Cu was ripped up and not made into a nice jet.

I think small SC's are harder to get to work than larger ones. Small creases or bends in the liner will have a more significant effect, and also due to the thin liner you are more likely to deform it.
My liner was bent by hand with the aid of a straight-bladed knife, not pressed using a mould, which would probably have been a good idea..

[DBSP]

Nice, would you mind taking a pic of the hole int the Al plate?

I tested something similar a week ago, I used the reflector from the flash I ripped out of an old disposable camera as the cone. I must admit it was also just something i just whipped together. I only used thick paper as casing and about 2,5g of AP. The LSC made a hole just as large as the linear and in the same shape, no jet in other words. But the hole itself was quite nice after I flattened the bottom of the tincan I used as target. Most of the bottom had been pushed into the can by the gases you see.

I've got pics of it all. And I've just found an FTP to put my stuff so I'll put the pics up as soon as I can.

[Mr Cool]

Sure, here's two views. They're pretty much the same, but I couldn't decide which was better so I've used both.
<a href="http://www.boomspeed.com/mrcool/uSC.jpg" target="_blank">1</a>,<a href="http://www.boomspeed.com/mrcool/uSC2.jpg" target="_blank">2</a>
As you can see, it has been pierced (one main hole and one smaller hole), but I'm sure it wasn't by a jet, just a combination of frags and blast. The target was also sprayed with frags, leaving little copper-plated craters all over the surface, but the pictures don't show this very well except in a few areas.

(Sorry about the low quality, I'm trying to save space on my Boomspeed account to fit in as many pics as possible)

<small>[ March 02, 2003, 03:23 PM: Message edited by: Mr Cool ]</small>

[NightStalker]

I had the idea of using a mercury amalgamation to cast a liner cone.

Mercury has a very high density, higher than lead or copper, which is very important for penetration. It's available in the form of electronic switches without hassle.

Take an ear cone, embed it in plaster with a small wax sprue attached to it, then bake it in an oven (or furnance) to melt out the plastic cone. Then suck up a mix of mercury and (zinc, tin, whatever) into the mold, using vacuum, to remove all air bubbles which would ruin material continuity. It'll harden into a solid cone in a bit, which can then be used.

Cut liners don't have continuity, thus the stamped or spun liners of manufactured SC liners, which DO have continuity.

Also, SC's need a standoff of 3 to 6 times the charge diameter to allow for full jet formation. Mr. Cool, you're standoff was only 2x, so you didn't have enough room for a penetrating jet to form, just slug.

[DBSP]

OK got the pics up.

<a href="http://dbsp.sensorystatic.com/pictures/micro_cone.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/micro_cone.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/mic_LSC_hit2.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/mic_LSC_hit2.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/mic_LSC_hit3.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/mic_LSC_hit3.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/mic_LSC_hit4.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/mic_LSC_hit4.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/mic_LSC_hit.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/mic_LSC_hit.JPG</a>
<a href="http://dbsp.sensorystatic.com/mipictures/cro_LSC.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/micro_LSC.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/micro_LSC_arrangement.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/micro_LSC_arrangement.JPG</a> (LSC marked)

The cola can was placed inside the tincan as a further check of the hole.

It is hard to make LSCs and SCs that actually work as they are supposed to. I've only succeded one time, it was a LSC I made out of a piece of pipe and a V-folded plate about 1,5-2.0mm thick, I cut a segment out of the pipe so that the linear fitted and secured it with chemical metal. I propelled it with 40g of ANNM primed at one end by 2g of AP. It sliced a 6mm thick plate very nicely.

<a href="http://dbsp.sensorystatic.com/pictures/6mm_plate_cut_with_LSC1.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/6mm_plate_cut_with_LSC1.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/6mm_plate_cut_with_LSC2.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/6mm_plate_cut_with_LSC2.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/LSC_cut.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/LSC_cut.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/LSC.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/LSC.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/blast_site_40g_LSC.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/blast_site_40g_LSC.JPG</a>

Another SC I tried on new years eve that worked great but not the way it is supposed to: I made a cone out of tincan bottom with a 60* linear, which I soldered together. I put it into a small plastic medicine bottle and hotglued it into place. I think I got about 25g of APAN into it. I had a standoff of about 4cm. In the SC_1 pic you see the plates I tested it on. The left one was put on top of the right one and they where held about 1,5cm from each other.

<a href="http://dbsp.sensorystatic.com/pictures/SC_cone2.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/SC_cone2.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/SC_cone1.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/SC_cone1.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/SC_1.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/SC_1.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/SC_1_1.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/SC_1_1.JPG</a>
<a href="http://dbsp.sensorystatic.com/pictures/SC_2_1/.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/SC_2_1/.JPG</a>

(NOTE that the pics might still not be up, if they arent, just wait I'm upploading lots of pics right now and they'll get up as there turn comes)

<small>[ March 03, 2003, 01:29 PM: Message edited by: DBSP ]</small>

[Mr Cool]

NightStalker: <a href="http://www.risi-usa.com/0products/3sc/page34.html" target="_blank">1.5x stand-off</a>, 1.5" penetration into mild steel using 3.5g of RDX.

[andreas]

I,ve made a sc today using a 1mm lead liner. It was 25mm in diameter and was of a 60 degrees angle. The charge consited of 10 gram MHN. i HAD 1,5X cone diameter standoff. I expected more penetration but the effect is definitly a sc effect. I think it could have penatrated about 6 to 8 mm of mild steel. I think I make up some ng to mix with the MHN to get a more uniform density and use a metall cilinder. Instead of the cardbourd one I used this time. furthermore I'll make a thin coper liner
A few pictures.
<a href="http://www.boomspeed.com/andreas/MVC-214F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-214F.JPG</a>
<a href="http://www.boomspeed.com/andreas/MVC-215F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-215F.JPG</a>
<a href="http://www.boomspeed.com/andreas/MVC-216F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-216F.JPG</a>
<a href="http://www.boomspeed.com/andreas/MVC-223F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-223F.JPG</a>
<a href="http://www.boomspeed.com/andreas/MVC-225F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-225F.JPG</a>
<a href="http://www.boomspeed.com/andreas/MVC-225F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-225F.JPG</a>
<a href="http://www.boomspeed.com/andreas/MVC-226F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-226F.JPG</a>
<a href="http://www.boomspeed.com/andreas/MVC-227F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-227F.JPG</a>
<a href="http://www.boomspeed.com/andreas/MVC-228F.JPG" target="_blank">http://www.boomspeed.com/andreas/MVC-228F.JPG</a>
I have put one in of my gun just for fun. Tell me what you think of my little experiment. The pictures with the tin can are foto's of what the detonator does alone.

<small>[ March 03, 2003, 03:29 PM: Message edited by: andreas ]</small>

[NightStalker]

In US Patent 6393991, issued to General Dynamics Ordnance and Tactical Systems for the Javelin ATGM warhead, they state:

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">...The standoff distance _{(of standard SC)} is typically defined as a multiple of the charge diameter, D, and is typically on the order of 3-6 times the charge diameter.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">Maybe the ratio changes with smaller values of D, or maybe not, I dont' know. I'm just going with the most reliable source of info I have at the moment.

[Mr Cool]

Yes, I'm sure you're right it does vary with the construction of the charge.
Good pics andreas. Could you take a pic of the target, with a ruler for scale?

[DBSP]

Andreas, how did you "seal" the cone? did you just solder it?
And did you use a 1mm thick lead sheet for the SC?

[Maniak]

I ussually use one diameter distance (for hemispheric liner), about 2,5 diameters (for 40-60° liner) and 5-7 diameters for EFP charge.
when you use very brizant explosive, distance must be longer......when I tried small amount of plastic 75%RDX + 25%NIBT blast.gel. with 30° liner and 1,5 standoff, effect failed.

[andreas]

My baterys of the digicam are low therefore I have to discribe the target. It's a 23mm round target47mm long. the hole you see has about 10x6mm area. The liner was soldered together from 1mm thick lead sheeting. You need any clarification just tell me and I'll post it.

[DBSP]

This doesn't really belong here but it is the only active SC thread so what the fuck.

Today I made an SC out of an aerosol can which had a very large cone, relatively speaking of course, it has a diameter of 50mm and a cone 13mm "high". I filled it with 126g of ANNM and added a small 2g AP det, (center primed) and a fuse into that.

I cut the top and bottom of a half liter fanta bottle and put the SC in it so that the standoff would be 8cm, I waterproofed everything as I where going to detonate it under water, I taped it securely to a 6,5mm thick piece of steel meassuring: 80x300x6,5mm. Tied a rope to it so that I would be able to retrieve it after the detonation.

I lit the fuse and threw it into the water and waited, filming at the same time off course :)

The results where as follows: (a note here, all pics are bigger than 640*480 scince I had forgotten about what size I had set the camera on, sorry bout that, they aren't to bog though.)(A nother note, as I'm upploading right now the FTP is giving me a hard time and the speed is slower than a snail, so I might wait untill I finish upploading the pics and the vid, some of them are up, but all might not be up untill sunday, sorry about that too.)

I am a bit supprised about how the damages where placed, I had expected more at the center insteat allmost everything is located at the outer edges, at two places it has been penetrated. One thing I'm shure of is that it has been one hell of a bang between the fragments from the SC and the steel plate, the craters aren't excactly small, the largest are about 7mm in with and about 5-6 deep. Take a good look at the high res. pic and magnify it a couple of times and You'll get a prety good look at it.

<a href="http://dbsp.sensorystatic.com/pictures/SC/126g_ANNM_SC.avi" target="_blank">http://dbsp.sensorystatic.com/pictures/SC/126g_ANNM_SC.avi</a>

A picture of the penetration:(high res. 2048x1536)

<a href="http://dbsp.sensorystatic.com/pictures/SC/DSCF0001.JPG" target="_blank">http://dbsp.sensorystatic.com/pictures/SC/DSCF0001.JPG</a>

The rest of the photos are found here:

<a href="http://dbsp.sensorystatic.com/pictures/SC" target="_blank">http://dbsp.sensorystatic.com/pictures/SC</a>

I know I have a typo here somwhere but I can't find it now.

<small>[ March 23, 2003, 01:11 PM: Message edited by: DBSP ]</small>

[THErAPIST]

Nice. Lemme get this right, you didnt want two holes? I'd say you got alright penetration out of it though. Much better than I could do. Also I'd like to say that either something is wrong with your video or there is something wrong with my comp. I tried to play it and I get a message that says that your vid isn't in the right AVI format... I'll assume its just my comp though.

I made my first sc about 2 months ago. I made it with a 1.5 inch wide paper tube with a wall thickness of about 2mm. I used the top of a small plastic easter egg for the liner. I packed 30g of HMTDAN into the tube and center primed it. I cut the top off of a 3 liter pepsi bottle and stuck the charge in the mouth of the bottle to give me a 3 inch stand off since my explosive has a VoD of under 6000 m/s. The liner was 1.5 inches tall. I placed my charge on top of a metal shelf that was on some sort of discarded cart in the woods. The metal shelf has a thicknss of about 2mm. on detonation the blast was focused but not as much as it could have been. The hole that was made was the same width as the charge, dont know why. I think my liner was too thin to focus the blast enough. The liner also wasn't exactly sharply pointed to form a good jet of pressure. I think I'll use PA for my next sc as it would no doubt offer much better penetration.

pics
<a href="http://i-was-bored.8m.com/sc" target="_blank">http://i-was-bored.8m.com/sc</a>

A little off topic here... Does anyone know where NBK ran off to?

(NBK taps The Rapist on the shoulder)


I'm right behind you...


<small>[ March 23, 2003, 06:14 PM: Message edited by: nbk2000 ]</small>

[Mr Cool]

I couldn't view the video either.

With a shallow/rounded liner like that, you will have made one of these:
<img src="http://www.dres.dnd.ca/ResearchTech/Products/MilEng_Products/RD95017/3-135-34_EFP.jpg" alt=" - " />
Which is an EFP (after firing...). It is a shaped charge in the sense that the charge is shaped to produce a desired effect, but does not form a jet. Instead, the explosive squishes the metal into a fast-moving blob. These can be quite advanced, with computer simulations and clever firing circuits and charge geometries used to produce the fins that you see on the image above, which help keep the projectile stable.
Unlike SC's, these can have ranges of hundreds of yards, but are generally less penetrating.

<img src="http://www.globalsecurity.org/military/systems/munitions/images/cbu97_34.jpg" alt=" - " />

I love these things!!

Edit: EFP's generally use much larger stand-offs than SC's. A good rule of thumb would be ten diameters, to allow the metal to form properly.

<small>[ March 23, 2003, 08:01 AM: Message edited by: Mr Cool ]</small>

[DBSP]

My connection is really giving me a hard time now, I can hardly enter this site. So uppload is not an option at the moment, sorry bout that. This is the reasong you can't see the movie, I haven't upped it yet. I made a post erlier today but that one only got half way to the thread before my connection got fucked up so I got realy pissed and left things.

I've seen that pic before, I never actuallt knew what an EFP was untill now, but I had the feeling the linear would look something like that after looking at the warheads used in the picture.

I think I'll try a similar one but with a much greater standoff next time, soon I hope.

I'll do my best to get those pics and the vid up as soon as my connection is fixed.

[Mr Cool]

Just a few random pages dealing with EFP's that might be of interest to people:

<a href="http://www.arasvo.com/efp.htm" target="_blank">Simulation</a>. This page briefly mentions an interesting problem: If the velocity gradient over the penetrator is too large, it'll stretch out and break in the middle. Clearly there's more to designing one of these than you might think... Although I don't think the explosive needs to be as brisant as with SC's.

<a href="http://www.fas.org/man/dod-101/sys/land/hornet1.jpg" target="_blank">Hornet Mine</a>. The sequence is right to left. Not a lot of useful information for us, but this thing is just too cool to leave out. When it detects a tank, it fires an EFP up into the air over the tank, and this uses an IR sensor to tell it when to detonate. <a href="http://www.fas.org/man/dod-101/sys/land/m93.htm" target="_blank">Main Page</a> here.

<a href="http://homepage3.nifty.com/weapons/images/efp2.gif" target="_blank">Just a little picture</a>

<a href="http://www.globalsecurity.org/military/systems/munitions/images/sofdk_demo.gif" target="_blank">A little .gif</a>. Watch it blow a hole through the wall...

<a href="http://www.tokamaki.hpg.ig.com.br/moldada.htm" target="_blank">Some nice pictures</a>, but not in English.

<a href="http://www.sandia.gov/isrc/Capabilities/Integration_Technologies/Fire_Ant/fire_ant.html" target="_blank">Fire Ant</a>.

Damn it, there is a really useful site that I remember seeing but can't find now. I'll post a link when/if it pops up.

[DBSP]

Good news, my connection is fixed, the video is up and so is the high res. pic and some of the others.

Nice sites, I've seen some of them before but the fireant is new to me, I like the hornet too.

[Mr Cool]

Nice pics you've got there! It's strange how the damage is around the outside, isn't it? I can't think why that might be the case ATM...
Downloading the video now... :)

[DBSP]

My first thought when I saw the damage was: how the fuck?

I then had a look at the the pictures of the aerosol can and found something that might explain this thing.

The edges around the bottom of the can that holds the bottom cone in place are folden twice. If we say that the explosive detonates at the to and then propagrates down towards the cone expanding the casing and it finally gets large enaugh to completely cover the edges of the bottom(if you look at things from above). The ANNM then pushes the cone out of the casing and at the same time the ANNM throws the edges towards the target plate, partially penetrating it and making large craters in the plate.

The reason there is litte damage in the center might be that this in fact was an EFP thus not having enaugh time to form properly, the cone might perhaps just have gotten flat when it smashes into the target plate..

I'm not shure wether this might be the case but it is a cenario that might prove to be true. I'm certainly going to test this agin, this time with a 10x diameter standoff.

[nbk2000]

DBSP, did you take down the pictures? I can't connect to the provided link to download them.

[DBSP]

The FTP the pics are hosted on is temporarely down because of problems with a new motherboard. The guy who has this FTP(Photonic) is working on the problem and it will hopefully be solved soon.

Anyway, nice to seee you back here, where the hell have you been?

Ah on the beach, picking up girls, nice :D

[nbk2000]

Working on the DVD.The day-to-day upkeep is being handled by the other staffers while I concentrate on my PDF.

Don't mind me, I just monitor the daily postings, otherwise I'd be hopelessly lost if I was to come back after being gone months.

[Terry Collins]

DBSP nice pictures, especially the 6 mm steel strip cut by your LSC was interesting. It's a really nice cut by a jet and no signs of the Munroe effect or fragments, so it proves LSC's can be made with ANNM. There has been some discussion about that because normally high density, high VOD explosives with a very uniform density are used. And ANNM lacks a uniform high density, becuase it's more or less powder like.

And the strange effects with the aerosol can seems to me caused by a scattered jet and slug and the Munroe effect. Because of the (very imperfect) shape of the cone and large stand off the liner is formed into that 'liquid' jet which collides and scatteres on the way down just like the shockwave (causig the Munroe effect) producing the strange effects.

<small>[ April 06, 2003, 07:55 AM: Message edited by: Terry Collins ]</small>

[Jager]

General information:
the blasters training manual lists the standoff distance as 1.5 to 2 times the diameter of the charge

Question:
Instead of using a solid metal cone, why cant you use liquid metal ie a 1" by 2" disk of mercury in a thin container shaped like a hockey puck with the high explosive on top of it in a cylinder shape? I see no reason why it wouldn't work, and you dont have to make a cone.

Jager

[Mr Cool]

Because if you just have a disc of mercury and a cylinder of explosive, then you don't have a SC and all you will do is contaminate your testing area.
I have seen references to other liner materials though, for use in UXO disposal - an interesting one being a "liner" of water. But you'd still need to find two very thin cone shapes to keep the water in place, and it would not be as effective at penetrating as a metal liner due to water's lower density.

Edit:

<img src="http://www.army.mod.uk/img/aht/Contents/equipment/WEAPONS/CANNON/cannon1.jpg" alt=" - " />

Is anyone else thinking "filter funnel"??

<small>[ April 07, 2003, 10:12 AM: Message edited by: Mr Cool ]</small>

[DBSP]

The funnel idea has crossed my mind on several occations, I've been looking for sutible ones in the stores but I haven't found any one that might be good enaugh.

I've allso been thinking about what you should doo with the "pipe", should one leave it open or should it be closed/folded together or what? This is the hardest part I belive.

DO you have to use a seemles funnel or might it work anyway?

If it would work it would be extremely simple to make nice SCs.

[Mr Cool]

A normal glass filter funnel from a lab supplier should work fine, I would've done it ages ago but it'd be a bit too big for me to do safely :(.
The "pipe" bit obviously can't affect performance much, otherwise that round would use a different arrangement. So either leave it on or melt it closed.
"Do you have to use a seemles funnel or might it work anyway?" All funnels I've seen are seemless in the sense that they don't have any gaps and are constant thicknesses all the way around. They should work. They're probably formed by some sort of injection moulding, so they should be totally uniform.

Anyone with some space going to try it? Go on, you know you want to :) .

[DBSP]

Glass would offcourse work but it will only be a munroe, not a liquid jet which is what I would like to get.

I have a metal funnel which I probably could have used but it's far to big for me to feel comfortable detonating it.

I'll have a look for some smaller metal ones.

[Al Koholic]

I have an idea regarding explosively accelerated projectiles. I think it should be possible to place a steel ball bearing inside the cone of a shaped charge. The ball, being situated right at the bottom of the cone would be subject to the maximum explosive force and assuming the charge has a decent uniformity and the cone is very well shaped, it should be fired straight out from the charge upon detonation at amazing velocities. Is the reason this is not done because the ball will not survive the explosion since it will basically be riding right on the monroe jet? I would imagine that the ball would survive with deformities of course but should still be moving extremely fast.

If this would not work, does anyone consider it possible to have a system like I described only with an injection load. An already moving metal slug is fired down a barrel or track and when it hits the end of the track, it connects a circuit which detonates a high explosive charge that is shaped like a shaped charge only with the narrow end of the cone cut off to allow the projectile to enter the space between the explosive. This way it spends less time in the explosions path and does not get subjected to as extreme a monroe jet but still experiences GREAT acceleration. I''d like to try out both experiements when I have time. I can see the potential to get extremely high velocity projectiles of any size with this type of a system. Could be done on very small scale with BB's maybe.

[Mr Cool]

I've had the same idea, never got round to trying it though.
I'm not really sure what the detonation of a hollow cone of HE would "look" like without a liner (I've seen simulations / flash photos of SC effects, but not plane Munroe effects), but I've got a feeling that the stronger shockwave along the axis would knock the ball out of the way, rather than carry it along. Testing is needed.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">Glass would offcourse work but it will only be a munroe, not a liquid jet which is what I would like to get</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">I'm not an expert on SC's, but does glass not form a jet? The improvised SC's book on the FTP has some photos of good SC effects using eg martini glasses...

[Anthony]

I'd be very surprised if a ball bearing at the tip of a circular SC would travel any faster than the same ball bearing placed in contact with a block of explosive. In fact I'd assume it would go slower, due to the less intimate contact with the explosive.

Firing a projectile into a forming SC jet would be *very* hard, microsecond accuracy required, and be repeatable consistantly!

Plus, if your explosive has a VoD of 20 000fps, and you fire your projectile into the jet at 1000fps, assuming complete efficiency, you'll gain a megre 5% in projectile speed for all your efforts...

[Al Koholic]

Well what it should look like would be 2 nice pressure fronts coming in at an angle to each other. Then where they meet, vector addition and a linear and straight line of force. I think the ball could ride this quite well assuming you had a very smooth detonation and a very uniform ball. I have a hard time seeing how this wouldn't work unless the detonation just blows past the ball because of the balls inertia, although I doubt this would happen. If it was an issue then like I said, you could use an injection mechanism to make sure the ball is already moving as the charge detonates just behind it.

I was thinking of how this could be done Anthony. I believe it would be feasible to build a pneumatic cannon type device with a nice long and fairly precise barrel. At the end of the barrel, the ball must pass through a segment of barrel during which it will provide the connection for a circuit which will cause the discharge of a pretty good size capacitor bank into a detonator like DDNP and then the SC semi cone will be an RDX cone or some other high VoD charge. The acutal construction of the cone would be the hard part because since you are cutting off the apex of the cone to allow the ball to enter the "acceleration region" you'll have no way of initiating the charge right in the center like you could if you just bored a cone into a block of explosive. You'll have to have a multi-point detonation to ensure congruent detonation of the cone just while the ball has entered the cone region. The detonation will be so fast that the ball will have barely moved by the time the explosive is detonating and the it'll be getting propelled like crazy I believe.

[Mr Cool]

Well if you look at two straight water ripples colliding at an angle to each other, you will notice that the point of intersection is not a sharp angle like you would expect, there's a little sticky-out blob in the middle. I'm not sure if a similar thing will happen with shockwaves from a HE or not.
I think it should work though, to some extent at least. It'd be a bit like squeezing a wet bar of soap. I think it would be more effective than just having the ball sitting on a block of HE, asuming the HE cone was shaped such that the rear half of the ball was surrounded by HE. This way you have the same area of contact as with a flat charge, plus HE all around the rear half of the ball, all of which will provide a component of force in the forwards direction when it detonates.
Ah, but wait: having the ball "surf" on the shockwave created would be pointless; the shockwave doesn't accelerate (if using a simple cone...), thus it can't accelerate the ball. The same effect would be achieved by having the ball half sunk into a block of HE, with no cone extending outwards. See what I mean?
In order for the ball to undergo any extra acceleration, shaping of the cone would be required, so that it was shaped like a sort of inverse trumpet shape. A diagram would probably help right now, but I'm too tired to draw one. Maybe tomorrow...

[Al Koholic]

Yes diagrams would be very helpful...unfortunately I don't have time to go into detail making one for the next couple of weeks!! Anyway, I don't understand what you mean by the shockwave doesn't accelerate and therefore won't accelerate the ball. The way I see it, even if the ball is not "surfing" on the shockwave (which won't happen anyway b/c of the balls inertia) the pressure behind the ball of the expanding gases will push it out at great velocity. With the cone it is like the proverbial bar of soap. In fact, the way I imagine this in my head is like the cone forming a "barrel" down which the ball travels just like a gun...The detonating gases form the sides of the barrel and the difference in the pressure due to the angle is the propelling force.

BTW, that GIF image above you linked to is SOOOOOOOOO fucking cool!!!!
I want better videos of those EFPs!!!!!!!!!!!!!!!!!!!!!

[A-BOMB]

I just got some great SC liners they are made of 1mm brass, and they fit up perfectly with a one of those black film cans. I'll have to see this guy I know that does Ham radio because I got them in a box of old ham stuff at a garage sale, I think they are covers for some type of electron tube or some type of antenna.

[nbk2000]

I was going through a local arts and crafts store that I never noticed before, when I ran across ready made SC cones, in the form of cake decorating nozzles.

:)

The majority of them would be useless because of the big holes in the cones apex, but they had one that was perfect. It had only a microscopic hole that would be easily sealed by a mustard seed sized blob of solder.

Seamlessly stamped from stainless steel, and only $1.50 each. It was about 3/8" dia. by 1" long. It was a nice and deep cone that, I'd dare say, would fit perfectly into a CO2 powerlet. :D

If only they made copper nozzles. :(

[GibboNet]

I've been doing a lot of research into these recently. (All SC's - Conical, Linear and Cylindrical(if that counts))

Has anyone got a copy of the improvised SC PDF mentioned above ? I can't find it in my FTP folder !!

I plan on writing a fair bit of info up into a webpage (maybe PDF I suppose) and I would like to know what you all think should be included too, so any ideas..... please tell.

I'm using the Australian Demoloitions manual as a base, but I need some more info....

Also, Any ideas for getting accurate drawings ? I'm looking to create a scale drawing of a charge, including all dimensions to scale, including correct angles etc. Any ideas ?

[Mr Cool]

GibboNet, by cylindrical, do you mean the method in which HE is detonated around a hollow metal cylinder (initiated at one end), so it first pushes the walls inwards (into a cone-like shape), and then produces the jet? I saw a document on that and thought it was interesting, I've been searching google for twenty minutes now to try and find it but no luck so far. Please post any info you might have on this technique.
Meanwhile, I will keep looking for that document...

[DBSP]

NBK: I did a search today and found a pic of a cake decorating nozzle:

http://www.clasohlson.se/images/products/S/hi/B/341500_Sw2.jpg

The one to the right in the pic might work.

Are those cones actually called "cake decorating nozzles" or have they got any other name?

I don't know if I can find them locally but I'll have a look the next time I get a chance to.

[nbk2000]

As far as I know.

I'm sure there's some fancy technical name for them that bakers use, but cake decorating nozzles is what they are. :) Any bakery supplier would have them, as well as most grocery stores (that I've seen), and arts/crafts stores.

[nbk2000]

DBSP:

The reason why your test charge made a circular gouge was because of the shape of the "cone" you were using. The bottom the can, while concave, had a small flat spot at the center. This shape is almost like that being experimented with to make cookie-cutter EFPs.

The platter for a cookie-cutter (ring shaped) EFP is like a higly squashed "m", where the center is dimpled, or in this case flattened.

I'll get into more details tommorow, but I've got a picture that shows the test results that look almost exactly like your test, if not quite as successful.

They've got designs that will cut a 6" plug out of 2" thick RHA. Hmmm...hole big enough to reach through...2" of steel plate...wonder what a person could do with that? ;)

[nbk2000]

Apparently the important thing is the initation of the charge from the topmost edge of the explosive loading, rather than the center as is usual for shaped charges. With central detonation, the platter gets turned inside out, with the center of the platter becoming the leading edge of the EFP. However, because of the continued expansion of the explosive gases trapped within the annular ring, the front edge of the ring continues to open till it becomes like a funnel and begins to tumble, negating penetration.

By using edge intiation, the outer edges fold forward first, with the center apparently being ruptured and folded inwards against the interior of the ring. Although the platter may already have the center removed, with the platter looking like a washer, trather than a solid plate. It may also be asymetric, with the plate having an elliptical, rather than spherical, arc. Oh, did I mention variable web thickness too?

In the experiment I saw referenced, they used an explosive charge made of machined PBX bar stock. A plastic explosive (PE4) was used as a relay charge within a steel housing with a diameter of 45 mm. A steel cup was inserted into the annulus to effect good contact between the PE4 and the main charge and to enforce axial symmetry.

It was hoped that a relay thickness in the region of 1 mm would suffice. However, it was found that this thickness had to be increased to nearly 3 mm to ensure reliable corner turning in the PE4 on the axis. This increased thickness had an effect on the ultimate EFP shape.

The relay web thickness of the charge with the best results was at the minimum 3 mm, achieved by forcing the cup in to a greater depth, while in the other the web thickness was 5 mm. With a thinner relay the manufactured item (and the observed EFP shape) is much closer to the required annular shape, since the inner rim of the liner will be relatively slower than the outer rim.

The more sharply defined the initiation point, the better the results.

The hole profiles at stand-offs between 2 and 20 calibers were generally symmetrical, with maximum depths ranging between 11 and 14 mm. The length of the ring was satisfactory, and there are indications from the serrated front edge of the ring and from FX photographs taken soon after initiation that the outer rim of the liner had spalled off early on. Such spalling could be reduced significantly by using heavier confinement.

With standoffs of up to 90 calibers, the ring only impacted edge on about half the time, retaining good penetration. Annular rings are not good for penetrating multiple plates because the rings disintegrate during penetration.

[Herr Doktor]

I was working at my shit job in construction, and we were doing an upscale condo job. I was in the parkade, and I was just looking through the boxes, ect, and I found what I think may be the solution to the problem of a decent hemisphere for shaped charges... AND they're dirt cheap.

Hemisphere (http://www.thomasregister.com/olc/SmartCat.aspx?&az=73226961&type=list_order&show=part_number+part_name+dia+thickness+unit_pric e&number=7&showdiscounts=no&template=http://www.sharpeproducts.com/temp.htm&ptno=9100+9101+9102+9103+9104+9105+9106+9107+9108+ 9109+9110+9111+9112+9113+9114&iwidth=200&stripecolor=ccccff&bgcolor=no&tablewidth=425)

Other Hemisphere Site (http://www.mcnichols.com/requestquote/quoteforms/handrailcomponents/endcaps/so_f_typec.htm)

PDF Catalog (http://www.jgbraun.com/pdf/wagnerc/wagnerendcaps.pdf)

[Haggis]

Fence caps such as these are sold at home stores for around 75 cents a piece. However, there are caps called 'bullet caps' and, being cone shaped, would work better. They are usually 2 3/8 on the bottom to accept the 2" pipe. There is a 'ridge' of sorts, that can be used to hold the charge tube. I found that 2" coupler pieces fit on this ridge nicely, and could be JB Welded to the endcap. Then, a segment of 2" PVC pipe can be glued on, the fuse coming out of an endcap that could be glued on as well. The remaining fence cap sticking out could be ground off or incorporated into the standoff.

[Herr Doktor]

The thing I noticed about the pipe caps in the links is that they are quite heavy. I think that you would almost be able to get away with not having to reinforce the cap on the back with anything, since the one I saw was probably 3/8" thick. Also, if you were to weld some 1/4" thick bar on the side in a few places, you could even screw it or bolt it to the object you are "affecting"