Unconventional Shaped Charges

Wow that plate looks exactly like an EFP result I did using a 30 mm diameter liner and 30 grams powder PETN which didn't work as well as yours.
Look at the attached pictures, same splash of copper around one side of the entry and same dimple on the other side.
I think it is from using powder explosive and not pressing to a high density and mine did not hit 100% straight which I think makes that splash effect on one side where the slug impacted first.
Did you press yours and was the target standing up straight so it was a dead-on hit?

[Edited on 14-8-2015 by greenlight]

I think that would be the problem then, same effect as me when I was hand pressing dry PETN.
Plastic is like the Rolls Royce of HE'S. High density and no need to press

I have never heard of plastique ANNMAL only AN based slurries. You can always try it.
The only potential problem I could think of would be the hygroscopiscity of the Ammonium nitrate so it would have to be stored very dry. Maybe the binder would seal it in away from moisture.
Another problem could be the NM evaporating from the plastic mass. It would be a very volatile PE if it worked that's for sure.



[Edited on 14-8-2015 by greenlight]

paper hole 110

Yes you were correct.
Here is revised soft recovery system that I will test soon
Each square is a foam container 1m long.

[Edited on 15-8-2015 by greenlight]

Quote: Originally posted by nux vomica

Just hand pressed to pack the charge evenly , I mount everything on the board so it stays square to the target, I wonder if you can plasticize annmal ?

I doubt that would work since it would just suck up water from the air and ruin it. Stick with the methyl ricinoleate idea- if you can get it right you can end up with a very respectable plastic and even lower the binder content which would give greater VOD but with great handling properties.
But Even with as little as 8-9% as a phlegmatizer you can gt a nicely pressed dense charge.
I am going to have a go at EFP's and see what i can come up with. feeling inspired by the past few pages and Its been a while since I've made anything that worked well, The last being a CSC filled with cast pentolite. EFP's and shaped charges are so much more than simply "setting off a charge" with a real process involved and precision in their manufacture- well as much precision as can be had without a kitted out machine shop anyways.

Quote: Originally posted by NeonPulse

Quote: Originally posted by nux vomica   Just hand pressed to pack the charge evenly , I mount everything on the board so it stays square to the target, I wonder if you can plasticize annmal ? I doubt that would work since it would just suck up water from the air and ruin it. Stick with the methyl ricinoleate idea- if you can get it right you can end up with a very respectable plastic and even lower the binder content which would give greater VOD but with great handling properties. But Even with as little as 8-9% as a phlegmatizer you can gt a nicely pressed dense charge. I am going to have a go at EFP's and see what i can come up with. feeling inspired by the past few pages and Its been a while since I've made anything that worked well, The last being a CSC filled with cast pentolite. EFP's and shaped charges are so much more than simply "setting off a charge" with a real process involved and precision in their manufacture- well as much precision as can be had without a kitted out machine shop anyways.

Yeah I suppose the annmal plastic is a bit of a brainfart idea, tried dissolving pib in nitro methane no go it just softened it slightly, nm will gel cordite though.

Just been finishing off my first methyl Ricinoleate synthesis, only a small batch of 50 ml castor oil but I got over 45 ml of methyl Ricinoleate out of the separation funnel

Looks like everyone is getting the itch to try these efp,s I suppose I am lucky to be able to fabricate tooling but if I didn't I would still give it a go nuxy



[Edited on 16-8-2015 by nux vomica]

60° copper cone etn plastic

I pulled out a nice piece of 1 1/4 steel from my work scrap bin recently so I used one of my 60° copper cones with 5 grams of etn plastic to have a go at penetrating through it.
It didn't make it but it bulged the back of the plate
I used 52mm standoff the cone dia was 15mm etn had 10%pib 3% methyl Ricinoleate cheers nuxy.



[Edited on 21-8-2015 by nux vomica]

Quote: Originally posted by ecos

I just have one question , where do you get the copper cone from ? is it home-made? if yes , please let me know how you made it.

Homemade the first two cones are formed in the tube on the right which has a urethane rubber pad in it, the sixty degree is formed in the white plastic tool you anneal between pressings and the bigger the cone the more stages need to be used to allow the copper to shrink gradually .

Greenlight I did a quick and dirty sg measurement by cutting a plastic 5cc syringe off at the 1 cc mark then packing to 2 cc I get 1.36 gm per cc. nuxy


[Edited on 21-8-2015 by nux vomica]

Quote: Originally posted by nux vomica

Yeah I suppose the annmal plastic is a bit of a brainfart idea, tried dissolving pib in nitro methane no go it just softened it slightly, nm will gel cordite though. Just been finishing off my first methyl Ricinoleate synthesis, only a small batch of 50 ml castor oil but I got over 45 ml of methyl Ricinoleate out of the separation funnel Looks like everyone is getting the itch to try these efp,s I suppose I am lucky to be able to fabricate tooling but if I didn't I would still give it a go nuxy

Nice, are u going to re-test to try and make it all the way through the plate.
Maybe more standoff will result in complete penetration. Sweet spot should be between 4-6× diameter of cone.

Thanks Greenlight I am going to have another go I will mod the setup slightly , 4x standoff it is then.
------------------------------------------------------------------------
Nice work nuxy! Maybe try different thickness cones while keeping else the same to try to improve results.
Thanks Gnitseretni I will try that one soon
------------------------------------------------------------------------
NM do form a gel with nitrocellulose...
So you should be able to plasticize AN-NM-Al with it and some ETN. The plastic will become brittle if let in open air due to the volatility of NM what is close to that of water.
--> storage in closed recipient and remalaxing before use.
PHILOU Zrealone I have some cordite dissolving in nm at the moment I will use some as soon as I have done some more 60 cone degree testing
------------------------------------------------------------------------
Nux, with a harder casing and slid attachment of the cone in the casing you should be easily able to penetrate even two layers of that thickness steel. much easier working with the ricinoleate hey? The way the entry is elongated instead of a single round hole is a problem i have had in the past and its due to either the det being off centre or the cone is not totally centre that will obviously reduce penetration slightly too. Great work though!
Thanks Neon pulse I am trying to stay away from metal casings if possible ( shrapnel ) Ricinoleate works great thanks , all my setups are machined on a lathe so I don't think misalignment is the problem I am changing the plastic etn charge height to further away from the cone top and angling in from the ebw head hopefully this might work better.
Cheers everyone nuxy








[Edited on 22-8-2015 by nux vomica]

A design similar to this nux?



The added explosive height will help as well I think as a conical shaped charge needs more height for shockwave formation/shape before it hits the liner than an EFP does.


[Edited on 22-8-2015 by greenlight]

Quote: Originally posted by greenlight

A design similar to this nux? The added explosive height will help as well I think as a conical shaped charge needs more height for shockwave formation/shape before it hits the liner than an EFP does. [Edited on 22-8-2015 by greenlight]

The patent is for a shaped charge which a radioactive tracer isotope cap can be placed on the tip of the cone which emits gamma radiation in the resulting hole. By measuring the gamma radiation in the hole, apparently a measurement of depth can be found. The cap is shown in part 20 but can be excluded from your design as I don't think it would be needed.
Part 21 is showing centred placement of the blasting cap/detonator.

No gamma needed here I think I will know if there is a hole in my target

Ok I have made another shaped charge up, I get 6 mm of etn plastic hight above the cone conpared tothe last shot.

Quote: Originally posted by greenlight

Nux is the charge weight the same as the last CSC?

Nice, what was the total explosive height?
Post results when u can

Results are in no penertration, got a nice looking straight hole over 2.5mmin dia can get a 1.6 mm rod to 29 mm deep in the hole, will have to do test again now

i think he mean specific gravity but not sure , just guessing

I went through the document optimized conical shaped charges and photographed a couple of tables that may have answers to some of the problems that have been arising with the CSC's. The document studys cone angle/diameter, standoff, explosive height/width, liner material/thickness, and explosive type and tamper.

The first table is different cone angle's and standoff's and their effects.
The second is jet penetration effects from varying explosive height.
The third is a diagram of the final results from all test's incorporated into making a perfect conical shaped charge.

[Edited on 23-8-2015 by greenlight]



[Edited on 23-8-2015 by greenlight]



It seems I was wrong and Ecos was right and the optimum cone angle is 45 degrees with 60 degrees still being effective but any more angle and the penetration starts to drop off.

So the optimum CSC configuration seems to be:

Cone apex angle 45 Degrees
Liner thickness 0.01 CD (1% cone diameter)
Explosive height 1.5 -2 CD
Explosive width 1-1.4 D
Optimum standoff 2-6 CD

[Edited on 23-8-2015 by greenlight]

[Edited on 23-8-2015 by greenlight]

I drew the improvements you posted greenlight into a new shaped charge design thoughts?

Nux, that looks very good

Cone angle = 45 good
Liner thickness = 1%CD good
Explosive height = 2×CD good

The shape of the charge casing and the extra head height should nake for nice detonation wave formation.

[Edited on 23-8-2015 by greenlight]

Hi All,

I think making concave metal hemisphere shaped charge is much easier than a cone. check figure below.

The cone should be symmetric , apex should be in the center, .....etc , this makes cone design a real challenge

Most of the videos I saw and papers I read prefer cone ! , What I know that a cone would have deeper penetration distance and the hemisphere would have wider hole in the target.

is there any other preferences for using cone rather than hemisphere ?

Here you go, this might help answer the question more accurately:
Just took some photo's from the pdf document "Introduction to shaped charges" and found pictures of both types of liners.

The first is microsecond pictures of the hemispherical shaped charge being detonated. Note that it still forms a jet but much thicker and not as elongated.







[Edited on 26-8-2015 by greenlight]




Above is two photo's mid-detonation of a conical shaped charge undergoing detonation. Note how the jet is much smaller in diameter and stretches out much more.

So, yes, I believe the hemispherical liner would make a larger hole but you would not be getting as high jet tip velocity as a conical shaped charge.
Hope the photos help..


[Edited on 26-8-2015 by greenlight]

Hemisphere shaped charge

Thanks a lot green light.

I also investigated this point. I found this nice article article



This would make the hemisphere less desired to penetrate targets! I have a real headache for making a symmetric cone ! , it always deform while working on it! pffff

Nice picures greenlight, was the lower one from a tulip shaped liner by chance? The mushroom shape at the tip of the jet is very pronounced with this type of liner IIRC. The angle for tulip shape would go from relatively wide at the apex, to very steep towards the bottom, creating a jet that may have an inverse velocity gradient, effectively collapsing on itself, forming IIRC the "crown". This is opposed to trumpet shaped liners.

Any luck yet with capturing the EFP? Maybe this would be a good option?

--> http://home.boopli.co.uk/product/wilko-pet-bedding-wood-shav...

I would aim for the rabbit


Hemispherical liners supopsedly can reach similar jet tip velocities as conical liners, when the inhibiting pole region of the liner is not allowed to collapse. There should be a patent posted somewhere in this thread about this. Hemispherical liners at these charge diamater may also need some extra subcallibration.

[Edited on 29-8-2015 by nitro-genes]

Thanks, nitro-genes, I am unsure because all it says in the description for the pictures is the collapse of a shaped charge with a conical liner.

I tried to catch the EFP again with a line of boxes using wood shavings and dust I collected from a woodwork shop via the vacuum duct dust removal system that leads it all into a bin outside. It is probably very similar to the stuff in the link that you posted.
I laid about 6 boxes in a line with two styrofoam ones at the front. It managed to escape out the side again though so it was not worth uploading photos. The projectile seems to tumble and ricochet a lot when it loses some of its velocity which makes it hard to collect. The shot was dead-centre as well so it isn't the aiming that is the problem.
An interesting observation is that the styrofoam is burnt quite a bit where the projectile passed through leaving a channel 2-3x the size of the actual slug. It must be pretty hot. I have heard 400-500 degrees C.

I will definitely be trying again as I really want to collect one undamaged.
I will use a triangle shape of boxes starting with one and then two boxes behind it and then three behind that all filled with wood shavings so if it deviates from its intended path I should still be able to retrieve it.

Will post results




[Edited on 29-8-2015 by greenlight]


[Edited on 29-8-2015 by greenlight]

30mm Conical Shaped Charge

Recently I Tested another one of my electroformed liners with pleasing results. total penetration of 80mm, my best effort yet. the angle of this cone was around 50 deg and just over 1.2mm thick. set into a steel pipe with a thread and steel cap. Head height was 2 CD and standoff was 1.75CD The filling was 25g PETN and 16ml NG as a slurry mixture.
For safety reasons the target plates were set in a hole the loaded charge placed and a sheath of 50mmID PVC tubing placed around the charge and this was surrounded by dirt. a plastic cap placed on the tubing with the firing line through it and the remainder of the hole filled and a mound of dirt on top. I Am very aware of flying steel hazards so I was also behind a huge tree about 50m away.
The charge fired underground with a dull thud and a shower of dirt leaving a large crater and a cloud of smoke
The Target plates were dug up with anticipation and the results was worth all the effort.
6 and a half of the 12mm structural steel plates i had bolted together were punched clean through. Not bad considering the small amount of compounds used for the result.

I see of this shot too there is the little false jet near the main entry hole, i spent ages ensuring the lot was dead center but even then it happened.
the pics are of the buried charge the plates unstacked ant the last plate showing the tip, which is kind of the reason i used a stack instead of a block- its so much easier to see the jet path



[Edited on 1-9-2015 by NeonPulse]

Well done Neonpulse, I think the 2x explosive height and metal confinement would have enhanced the detonation wave shape and propagation a lot
Nice penetration!

Nice neon, not a bad idea burying everything to keep the noise down and absorb any shrapnel from the charge.

[Edited on 2-9-2015 by nux vomica]

Quote: Originally posted by NeonPulse

I didn't see that, it was meant to say 60 deg not 50 I have an identical liner and I'll measure the exact angle later.

So it's just less than 60 degrees more like 55.

10 grms through 72 mm steel

I have finally beaten the 32 mm steel plate and then some , I was going for the four 10mm plates tacked together on top of the 32 mm plate but instead of the 32 mm plate being part penetrated it went straight through it

the copper cone was 20mm in diameter and 15 mm high and 0.6 thick I used 10 grams of plastic etn ( 1.6 head height) and 50 mm standoff (2.5 x dia ) fired by my ebw fire set through 7 meters rg6 coax.

The jet had narrowed to 2mm by the time it had penetrated 20mm and it basically stayed that dia through the plates.

cheers nux







[Edited on 11-9-2015 by nux vomica]

Nicely done Nux, seems like that extra 10 grams plastic (you used 5 grams last time if I am correct) and resulting extra head height did wonders for the jet formation and velocity

Thanks greenlight, yeah the extra five grams seem to make a lot of difference to the result I suppose bigger is better.

Nice one nux! I'll bet you could do better still with a PETN or RDX as your main charge. Or perhaps even a mixture of liquid and solid explosives. But the 72 mm from this amount of explosive= awesome!

Thanks neon, the penertration was better than I expected i thought it might go halfway into the 32 mm steel not through it.

[Edited on 12-9-2015 by nux vomica]

Quote: Originally posted by dangerous amateur

Quote: through 7 meters rg6 coax. How do you do these tests, did you bury the setup? 7m is extremely short, must be pretty load. How about shrapnel protection?

No burying theres a sacrificial end on the rg6 which gets destroyed, I am behind a dirt pile and the caseings all plastic plus im already going deaf
Nux

Quote: Originally posted by Hennig Brand

That is a very nice result, 3.6D in penetration!

I found a graph in pdf on shaped charge calculation models that may be able to help answer your question. It graphs non-precision charge vs a precision made charge and then ideal jet performance at the top which would be very hard to explain.
For a non-precision charge it peaks at about 4.5 CD at about 2.5 CD so it seems your standoff was perfect.
Only question is what constitutes a precision made charge because most of the charges on SM are quite precision designed already so where is the line?
I don't know if you could make 7 CD penetration as that is quite high on the table but I couldn't answer until I found out what has to be done to go from a non-precision charge to a precision one according to the graph
So I've kind of given a question for a question

[Edited on 13-9-2015 by greenlight]



[Edited on 13-9-2015 by greenlight]

Yes, I think they are talking about military manufactured charges when they say precision.
If enough time is put into putting the charge together and crafting the liner using special equipment, you could come up with something meeting the "precision" requirements at home surely.
Nux, your liners are perfectly symmetrical and spun on a lathe (proper equipment) if I am correct, they should be above the scale of a non-precision liner. Maybe more penetration is possible
I wonder if they are made in somewhat the same way in a factory that are designing liners for military use?

I agree with NP, I think you could enhance the penetration depth by using a more powerful explosive.
I attached a picture from a page comparing HMX and the new explosive CL-20 in shaped charges and co-crystallization of the two.






CL-20 is on the left and HMX on the right.
It does not state how thick the steel plates are but that is quite a lot of penetration especially considering that the page says that both charges only had 30 grams of explosive in them!

This also shows that more powerful explosive does help with penetration in CSC's (9100m/s for HMX and 9660m/s for CL-20). The extra 550 m/s gives a increase of 40% penetration power assuming that the charges had the same confining geometry/liner dimensions.
Differences in heat of explosion, brisance, etc between the two explosives could also increase/decrease penetration I am guessing.


[Edited on 13-9-2015 by greenlight]



[Edited on 13-9-2015 by greenlight]

Quote: Originally posted by nux vomica

Precision vs. non precision bit of a hard one

Quote: Originally posted by greenlight

I agree with NP, I think you could enhance the penetration depth by using a more powerful explosive.

@Greenlight,
The plates must be 3cm because 30g shaped charge CL-20 is able to pierce through 21 cm iron steel armor (7*3 cm = 21 cm)

[Edited on 13-9-2015 by PHILOU Zrealone]

Quote: Originally posted by gnitseretni

Nice work Nux! But you sure are making me miss the days when I made shaped charges. Lol! Based on the graph Greenlight posted... since your cones are very symmetrical, I think you could increase penetration if you increased your standoff. By increasing standoff you'll stretch the jet and reduce its diameter which should result in deeper penetration.

Thanks gnitseretn, its a pity you cant still dabble in them
I am thinking of making the top cone radius larger as I can just get a 1.5 mm rod through the bottom of the hole and think that might enlarge the hole dia.
With a larger diameter jet and more standoff hopefully I can get some more penertration out of my setup.
Nuxy



[Edited on 13-9-2015 by nux vomica]

Quote: Originally posted by greenlight

I went through the document optimized conical shaped charges and photographed a couple of tables that may have answers to some of the problems that have been arising with the CSC's. The document studys cone angle/diameter, standoff, explosive height/width, liner material/thickness, and explosive type and tamper. The first table is different cone angle's and standoff's and their effects. The second is jet penetration effects from varying explosive height. The third is a diagram of the final results from all test's incorporated into making a perfect conical shaped charge. [Edited on 23-8-2015 by greenlight] [Edited on 23-8-2015 by greenlight] It seems I was wrong and Ecos was right and the optimum cone angle is 45 degrees with 60 degrees still being effective but any more angle and the penetration starts to drop off. So the optimum CSC configuration seems to be: Cone apex angle 45 Degrees Liner thickness 0.01 CD (1% cone diameter) Explosive height 1.5 -2 CD Explosive width 1-1.4 D Optimum standoff 2-6 CD [Edited on 23-8-2015 by greenlight] [Edited on 23-8-2015 by greenlight]

Quote: Originally posted by greenlight

The graph says that the optimum standoff for a non precision charge peaks at about 2-3 CD. For a precision charge, optimum standoff appears to be between 4 and 6 CD like ecos said, maybe even up to 8 CD The only question is because Nux uses proper equipment to form his liners, where does his charge fit on the graph? Precision or non- prescision? Its probably down to guess work but we will know what category his are in by the penetration of his next CSC test.

Dont put any pressure on me will you greenlight. Hahaha



[Edited on 14-9-2015 by nux vomica]

Quote: Originally posted by nux vomica

Quote: Originally posted by gnitseretni   Nice work Nux! But you sure are making me miss the days when I made shaped charges. Lol! Based on the graph Greenlight posted... since your cones are very symmetrical, I think you could increase penetration if you increased your standoff. By increasing standoff you'll stretch the jet and reduce its diameter which should result in deeper penetration. Thanks gnitseretn, its a pity you cant still dabble in them I am thinking of making the top cone radius larger as I can just get a 1.5 mm rod through the bottom of the hole and think that might enlarge the hole dia. With a larger diameter jet and more standoff hopefully I can get some more penertration out of my setup. Nuxy [Edited on 13-9-2015 by nux vomica]

No pressure Nux

Like knitseretni said, keep charge specs the same and see how much penetration can be obtained from it.

Had a break from trying to catch the EFP slug and decided to try a small scale EFP for a change.

This time diameter of charge was only 18 mm and explosive height was 1.5x liner diameter.
Liner was 1.79g in weight, 0.9mm thick and had a depth of curvature of 3mm.
Charge weight was 9 grams 79/5/16 PETN/RDX/plasticizer/binder.
Target was 6mm steel and standoff was 35 cm.

Result is a nice through and through with a hole diameter of 11mm. I think that it could go through 10 mm which I will eventually attempt as well.



[Edited on 16-9-2015 by greenlight]








[Edited on 16-9-2015 by greenlight]

More pictures with scale.

[Edited on 16-9-2015 by greenlight]

This began as an experiment on improvised reinforced blasting cap design.

Capsule is made of a 6mm bullet jacket on primary end, pressed inside of a 7mm jacket on output end. Epoxy is applied to exterior of 6mm tube, and a miniature tubeing cutter is used to swage a locking groove on overlapped area after assembly-

Primary is 350mg of 80:20 Mercury fulminate:Potassium chlorate. A commercial electric match embedded in epoxy putty is used to fire the device.

Base charge is 500mg well pressed & plasticized PETN under 500mg of hand pressed pure PETN.

After a couple of contact tests on steel plates, a couple more shots were tried with 3 and 5 X OD stand offs. The holes in 10mm steel target are at least 5mm deep- There is still some of the "carrot" down in the hole I could not remove, will section plate and measure full depth later. The output end seems to behave more as an EFP than a SC- Wide angle of the cavity liner was a fortuitous accident, not my original design intent! Output end profile of 7mm Copper capsule is spun into it with a 120 degree center punch chucked into a drill press, inspired by Copper smithing disclosed here by Laboratory of Liptakov-





[Edited on 16-9-2015 by Bert]

Right, copper is attacked by O2 and CO2 and atmospheric moisture.

2 Cu (s) + O2+ H2O (g) + CO2 = Cu(OH)2 + CuCO3 (s)

This is not a one step process. The copper first oxidizes forming cupric oxide (copper I oxide) . The water and carbon dioxide form carbonic acid (H2CO3), then the copper I oxide and carbonic acid react forming copper hydroxide and copper carbonate.

The jet from a shaped charge moves at different speeds and that’s why it will stretch. As it stretches it will break up into particles. Also, at the apex of the cone, which forms the very front of the jet, does not have time to be fully accelerated before it forms its part of the jet. This results in its small part of jet being projected at a lower velocity than jet formed later behind it. As a result, the initial parts of the jet coalesce to form a pronounced wider tip portion. As the jet forces through a target, the high pressure and fluid-like behavior of the jet along with the stretching and break-up of the jet causes the copper to “coat” the inside of target and expose the clean copper that I too really wish was gold.




[Edited on 17-9-2015 by Joeychemist]

Quote: Originally posted by nux vomica

Bert are you drawing the jackets or are they commercial

20 mm shaped charge second try.

Well I had a success and a fail with the second 20mm csc I have a cool looking carrot sticking out of plate no 2, and my tack welds failed so the plate stack broke apart before I got full penetration.

The charge was exactly the same as charge no 1 but I used 3x standoff and had 100mm of tacked plates on top of the 32mm plate, i still got 79mm penetration but as I said it looks like the stresses were to much for my tacks so the jet broke the stack apart and it stop penetrating after the 79mm mark.

Looks like I will need to weld the plates better for the next test nuxy.

[Edited on 18-9-2015 by nux vomica]