Sciencemadness Discussion Board

Unconventional Shaped Charges

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gnitseretni - 14-5-2010 at 11:46

NUKE, aren't you curious what material the target was made off? Maybe have someone else take a look at it, someone with a degree in metallurgy. Or maybe an experienced welder may know, surely there has to be a welder in your area, have him take a look at it. Or maybe the guys here can help you if you give a little more information?
I mean hell, you have to be a little curious, right??

Plasmapyrobattics - 14-5-2010 at 12:24

At ease. The esteemed cranially flatulent Sergeant may go play with his tank now... granny’s water tank in the back yard... quick!! ...before neurotic Sergeant Fart goes on another one of those tell-tale erratic, aggressive PTSD trips laced with foaming mouth tourettes ... And don’t go reading too many books on PMS now... Granny won’t approve... Oh and remember to take some Lithium...

:D

PS: Be openhearted. Try reading this post with a great sense of humor.

:P

NUKE - 14-5-2010 at 12:30

@gnitseretni

Yes I am curious about it! It's just the lathe guy hadn't come by to take a look at it. I'm pretty sure I would get my answer if he had seen it before... Real life inspection is better than the internet one isn't it?

hinz - 14-5-2010 at 13:47

Awesome work, Nuke!

The shrapnel damage of the trees is especially impressive, this is the reason why steel casings are usually avoided =).

The target rod looks also looks like cast iron or hardened to me, as it scatted upon impact and broke without bending.

To determine for sure whether it's cast iron or steel, the easiest method would probably be if you to take a small sample of your target, embed it in epoxy and polish it.

If no microscope is available, it would be also possible to determine the hardness of the target, as cast iron is usually softer than steel.

The micro structure of cast iron looks different (under an optical microscope) than the micro structure of normal steel, as cast iron with high carbon content forms graphite flakes:


In low-carbon steel, the grain boundaries are usually visible if polished, so if your sample looks like this under the microscope, its probably normal steel:



Also normal steel:


To see several examples of polished metal microsctructures, I found a nice page:
http://www.georgesbasement.com/Microstructures/Introduction....



12AX7 - 14-5-2010 at 13:51

Spark test.

hissingnoise - 14-5-2010 at 14:10

Tim, I think it's already been subjected to the 'Mother of All' spark tests. . .
The close scrutiny of such testing though, is a bit, er, problematic!


gregxy - 14-5-2010 at 15:12

Spark test for metals:

http://en.wikipedia.org/wiki/Spark_testing_metals

It must be either cast iron or mild steel. I can't imagine
anyone throwing out a piece like that of any good quality
alloy.

quicksilver - 25-5-2010 at 11:42

Here is an unconventional shaped charge!

http://new.ba-bamail.co.il/View.aspx?emailid=1295&member...

Very nice design

pjig - 30-5-2010 at 08:18

NICE! Thats a lot of stand off for a charge, but its very effective looking.

hissingnoise - 30-5-2010 at 08:28

A smaller standoff would be more likely to penetrate doors than knock them in. . .


mabuse_ - 3-6-2010 at 13:02

Hi,

i've got one question about these improvised SCs based on cones like Whinebottle bottoms or martini glasses:

Does the glass act as a liner? Or does it just hold the explosive in the right position, giving it the right shape?

franklyn - 3-6-2010 at 18:08

Glass is a very effective liner having reasonable density,
but inferior to metals which are denser.

.

Justin - 4-6-2010 at 02:46

However as Axt stated, a good glass cone will be much better than a crappy copper one, and its almost impossible to get/make a good metal cone unless you get one from a dummy military shaped charge, I'll stick with glass as its much cheaper and much much easier to come by than a metal one

Microtek - 4-6-2010 at 11:02

Density is not the only factor that determines the effectiveness of a given liner material. In fact, bulk modulus or Young modulus may be a better indicator of suitability.

Quoting myself from the "Martini glass SC" thread:


Quote:

In "Liners for Shaped Charges", Held uses a ranking of liner materials based on maximum jet speed times the square root of the liner density. He further states that, as a rough approximation, max jet speed can be estimated as 2.34 times "bulk sound velocity" of the liner material.
Now, I'm not entirely certain of what he means by bulk sound velocity, but from the numbers in the table (table 1) it seems to be the speed of longitudinal waves.

The speed of longitudinal waves can be calculated if shear and bulk moduli or Young modulus and Poisson ratio are known, but the interesting point is that the formula features the square root of the density in the denominator.
In the ranking formula, this cancels out with the square root (density) factor.

This means that as a means of ranking liner materials, you can simply use the square root of (K+ 4G/3), where K is the bulk modulus and G is the shear modulus. Or you could look up longitudinal sound velocity and multiply that with the square root of the density.

As an even simpler (and less accurate) method you could just use the square root of Youngs modulus.

There are probably many aberrations that would deviate from this ranking system (for instance, it rates steel higher than copper), but it accurately predicts several well known phenomena such as the fact that lead is very poor, that aluminum is decent and so is glass.



Glass and many other ceramics are quite stiff, giving them high bulk sound velocity which is probably what makes them good candidates for SCs.

mabuse_ - 5-6-2010 at 12:09

Thanks.
I think I'll try winebottle, since i found no other common household object.

Another question:

My ANNMAL is working fine.
Is it worth the effort to try something else?

And if you say yes, than what is the best kind of energetic material to use, considering the fact that i don't have access to nitric acid better than 65% and i've got no distillation equipment.

Microtek - 5-6-2010 at 12:43

Well, if you can get sulfuric acid you could make any of the nitric esters (without distillation). So if you can get pentaerythritol, erythritol, mannitol and so on, you are ready to go. Also, Your ANNMAl would probably be more effective if you got rid of the Al.
Personally I think that the amount of explosive required for a wine bottle SC (bearing in mind that nitric esters are relatively sensitive) is a bit much, so I would suggest looking for a smaller cone (a glass funnel maybe if you want to use glass).
The smallest succesful SC I have tested was based on a brass cone 5 mm OD at the base, 0.3 mm wall thickness, 60 degree angle and less than 0.2 g PETN. It penetrated between 6 and 7 mm steel even though the cone was slightly misaligned. So you see, it is quite possible to experiment with SCs at a much smaller and therefore safer scale.

domstp - 6-6-2010 at 03:34

im going to be testing out a candle lightbulb shaped charge soon (30mm tulip shaped glass cone), i will use 30g etn as the filler. the main problem now is finding 2 inches of steel to test it on. the only thick enough steel i can find is the side of an old large hammer, but then the problem of aiming the charge correctly arises.

About nukes target material, im suprised no one picked up on this. he measured the rod as: 0.422m with 0.06 radius.

39
-------------------------- = 8200(ish) kgm^-3 =about the density of a mainly ferrous material.
Pi x 0.06^2 x 0.422

as many people have stated, the density of the material is the main factor that affects penetration depth, not hardness. i would be curious to see this tested, but i currently do not have enough time or resources to produce enough identical charges for an accurate test.

pjig - 6-6-2010 at 09:57

I have shot charges a-while back that consisted of ANNM blended with a binder of DBSP ,and Aluminium (@2% or so, to sensitize the mix). This made a mold-able simi-plastic, It seemed to have a great power output compared to most AN mix's, and work for SC's. It fails terribly in comparison to nitric esters as a SC filler( for power), but will suffice.

My question Is how much is lost "VOD" when using this small amount of Aluminium?V.S.What is gained in cap sensitivity for the mix? Is it worth the Aluminium in the mix, or just remove it all together and initiate it with a hotter charge..?

mabuse_ - 6-6-2010 at 12:03

Hi,


Quote:

a glass funnel maybe if you want to use glass

yeah, i've allready serched for glass funnels, but they are quite expensive...

Quote:

Personally I think that the amount of explosive required for a wine bottle SC (bearing in mind that nitric esters are relatively sensitive) is a bit much

Well, It doesn't gets much louder ;) And ANNM ist not that expensive, about 150 or 200g should do...

I'd like to try smaller ones, but as i haven't found proper cones yet...


Quote:

Your ANNMAl would probably be more effective if you got rid of the Al.

I've read that before somewhere...


Quote:

My question Is how much is lost "VOD" when using this small amount of Aluminium?V.S.What is gained in cap sensitivity for the mix? Is it worth the Aluminium in the mix, or just remove it all together and initiate it with a hotter charge..?

my solution whould be to use aluminium only close-by to the detonator. This way both advantages should be combined or what do you think?

franklyn - 7-6-2010 at 04:36

Quote: Originally posted by Microtek  
Density is not the only factor that determines the effectiveness of a given liner material.
In fact, bulk modulus or Young modulus may be a better indicator of suitability.


In short , what works is known after exhaustively trying everything
that can be made into a liner. Now it remains to make sense of it in
some formula. There are as already noted many candidates , just as
there are candidate formulas for predicting performance of explosives.

Speed of sound of some substances is seen in the attached tables.
In the lower one , a selection from the CRC handbook ,
Longitudinal ( sound ) speeds are given in the left column marked V1

Substance densities are given in the CRC handbook from 4-39 onward

PS
Beryllium has the distinction of propagating sound at ~ 13 Km/sec
far beyond the detonation velocity of any known explosive. This
makes it incapable of spalling as other metals will do if the applied
detonation wave exceeds it's speed of sound. One reason why it is
used as tamp as well as neutron reflector in implosion atomic bombs.

.

SC Penetration.gif - 4kB Speeds of sound in materials .gif - 14kB Speeds of Sound CRC.gif - 29kB

Microtek - 8-6-2010 at 13:33

@Franklyn:
As you say, many thing have been tested and there is no question that the best compromise between cost and effectiveness is copper, while the highest performance is achieved with things like tungsten or molybdenum.

However, sometimes it is useful for the amateur to have a predictive tool to give some indication of the usefulness of the materials he has at his disposal. For instance, copper is not so easily machined with cutting tools while brass is (and additionally, where I am at least, copper rod is not easy to find in shops), so it is very useful to be able to look at easily found numbers to determine whether it is likely to be a good liner material.

Jetcord

The WiZard is In - 8-6-2010 at 16:18

My ca. 1973 Jetcord® catalogue (the triangular shaped charge
used for controlled demolitions &c.) notes that they make
it using either - Lead, aluminium, copper or silver.
There is no price listing for silver. The 4 000 gr/ft
RDX, copper was $100 a foot for 50-99 feet and
$29 ft for 1000 feet.

Jetcord is a product of Explosive Technologies, Fairfield
California.

They were developing 7 000 gr/ft Jetcord (over a pound of
explosive per foot.)

The 4 000 had a minimum penetration of 1.3" and a minimum severance of 2+ inches. (Rolled steel.)

grndpndr - 9-6-2010 at 18:05

Theres alot to be relearned from the first 10pgs or therabouts of the beginning of the OP.AN/NM/SA makes a first rate simple shaped charge explosive.
Good detail on linear charges even comparisons of how much further a csc will penetrate mild steel as compared armored steel thanks to military charts unlike claims by others who said I was the one unfamamiliar with the charcteristics of metal as relates to SCs.I would think an effort would be made to not squander the info thats proven itself and instead apply yourselves to improving on whats gone before.Instead Reinventing the wheel over and over and not doing a good job at that.

By the way an earlier comment regarding the size of the test plate we so recently debated got me thinking.At the advertised dimensions and my limited math skills the wieght of the target "steel" is something like 240Lbs!? How is it Nuke you managed to wrestle that through what appears an overgrown dense forest or does the name really fit?.Being something Im familiar with 12 in of steel rail wieghs 80lbs how is it the entire target wieghs approx 40kilos?And has the shape(irregular form) and color of a white softwood tree branch.Very similar cracks
with same white softwood interior.Are we in fact looking at a northeastern softwood my gullible friends insist is a metal or is the accent not as put on as it sounds and its a eurasians species.
Also as no one has the time to view the previous genuine amazing SC results made of a sadly done piece of fiberglass no one seems to dare view.This is now a good haven for members from totse etc. as compared to the first pages of a decent Original posts stickie by very professwional folks now gone bad.To call anything but the premade cone a well made fabrication is an insult to reality.
Carefully done epoxy securing the CSC? nicely banded standoff leggs LOL. Ther isnt enough standoff in the steel tubing to accomodate the charge and standoff? Piss poor planning is no substitute for careful assembly.Looks like shit frankly and I suspect the performance matched otherwise we would see a carefully laid out sequence of the events and a schematic of construction as are in the beginning of this at one time excellent resource.:(
Finally for the moment Wizard take a look @ AXT's home improvised linear charges and the commercial ones your touting are far from impressive.And yes I am out to insult most
of you who have posted recently, what little verifiable work thats being done is less than substandard compared to just a few yrs previously.I dont see anyone trying to turn thir own CSC's,Fabricate single efps let alone multiple efps.Proundly dissapointing for the experts you all are!:mad:
[Edited on 10-6-2010 by grndpndr]

[Edited on 10-6-2010 by grndpndr]

[Edited on 10-6-2010 by grndpndr]

[Edited on 10-6-2010 by grndpndr]

nitro-genes - 13-6-2010 at 05:11

Interesting post Franklyn!

Surprised to see such a high speed of sound for tungsten carbide, at 6655 m/s! It is incredibly dense and abbrassion resistant as well. I wonder if anyone has been crazy enough to produce a liner out of this material, hehe...

mfilip62 - 14-6-2010 at 12:29

Liner from that thing would probably barely deform! :D

Anyone tried an Osmium liner!?

Rain - 17-6-2010 at 04:33

I am no expert in these matters and I have a quick question about these shaped charges.

Wouldn't it be better to use a 50 gram shaped charge facing an insensitive explosive like AN, than using the 50 gram booster in a cylindrical shape?

I mean, the penetrating "slug" of the SC travels at say 7 Km/s , essentially shocking the main charge as it penetrates it.
Whereas a cylindrical booster forms a 360 degree dispersing shock wave.

Just a thought.

"One day we will all turn into energetics, as by the laws of the universe."

hissingnoise - 17-6-2010 at 05:43

Detonators usually have concave ends and act as mini SCs. . .


Rain - 18-6-2010 at 07:37

Quote: Originally posted by hissingnoise  
Detonators usually have concave ends and act as mini SCs. . .



Yes......, but thats insignificant compared to a 50g booster.
An detonator is only 1 g of initiation energy.

A booster would have a much more significant effect when in the form of a shaped charge, especially when it comes to initiating large amounts of insensitive secondaries.
Think about it.

I thank you.

mfilip62 - 19-6-2010 at 05:29

ALWAYS mould my booster into shape charge with light bulb,and it always does the job,
yes,this is a great idea and even some conventional boosters have "hole" in the bottom.
Great for ANFO!

grndpndr - 23-6-2010 at 02:05


FWIW very early attempts to weaponize CSC's utilized a minature CSC as a nose fuse the jet obviously penetrating and initaiting the main CSC HE.
Quickly abandoned with the advent of piezoelectric initiators.

More in line with the OP, 7kps for a csc would be a very low jet velocity exceeded by many modern HEs.Seems to be alot of idiosyncracys with jet formation.Itc seems at detonation the jet tip @apex doesnt have the time to reach full velocity while a booster at say close to or exceedinjg 8000 mps is near instantaneous affecting a very large portion of the main charge
versus a limited area for the SC.
On the other hand purpose built SC are used to det enemy IEDs
particyularly those made with old artiller projectiles/bombs with sometimes quite thick steel casings.I do believe the anti IED CSC devices often contain an unusual amount of a pyrophoric material in hopes of the IED explosive takes to fire rather than exploding. Hoissingnoise is absolutely correct in that commercial caps have a small hemispherical SC,at least the ones I was familiar with back in the stone age:(

[Edited on 23-6-2010 by grndpndr]

VladimirLem - 2-7-2010 at 06:50

Hi

Can anybody say me, which explosive might be strogner

ANNMSA (by axt)
NM 70%, HNO3 (65%) 30%

-does 65% work, or is it wasteing of HNO3 and could "replaced" with ANNM-AL (30% NM)




-=HeX=- - 7-7-2010 at 09:14

I would go for the liquid mix...

grndpndr - 8-8-2010 at 13:00

Seems the ANNMSA would certainly be safer and judgujng by axts results seems to posess adequate brisance thw liquid likely give better performance/brisance /VOD, more intimate contact with the cone/ rest of the device.In interests of safety though Id use solid ANNMSA.

Anyone hear of HESH AT warhead circa ww2?Used/developed by the brits mainly for the new low velocity recoiless rifle by a man named Mr Burney.Intended for use against concrete bunkers it was equally successul against armored vehicles.Acronym for High Explosive Squash Head Shells the explosive in early warheads was contained in ss mesh bags.On Impact the thin shell would peel away
leaving the explosive pancake pressed tightly against the target.Highly tamped if you will,combined with the large are of contact on detonation the material to be defeated would build up a
shockwave that overstressed the material steel, or concrete causing the interior of the material to scab/spall away @ HV causing severe damage within a tank or bunker, steel or fist size chunks of material tossed about the interior at hundreds of MPH causing secondary explosions in tanks and bunkers as well as severe injurys from the spalled steel and concrete.Obsolete as an antitank warhead its still used by the brits in thier engineer vehicles in large demolition guns 165mm against fortifications.That should be included as an odd shaped charge!?:D

[Edited on 8-8-2010 by grndpndr]

[Edited on 8-8-2010 by grndpndr]

NUKE - 18-8-2010 at 14:09

Well sorry guys for not managing to get 2nd opinion on target material... I've been pretty busy lately.

Quote: Originally posted by grndpndr  

By the way an earlier comment regarding the size of the test plate we so recently debated got me thinking.At the advertised dimensions and my limited math skills the wieght of the target "steel" is something like 240Lbs!? How is it Nuke you managed to wrestle that through what appears an overgrown dense forest or does the name really fit?.Being something Im familiar with 12 in of steel rail wieghs 80lbs how is it the entire target wieghs approx 40kilos?And has the shape(irregular form) and color of a white softwood tree branch.Very similar cracks
with same white softwood interior.Are we in fact looking at a northeastern softwood my gullible friends insist is a metal or is the accent not as put on as it sounds and its a eurasians species.
Also as no one has the time to view the previous genuine amazing SC results made of a sadly done piece of fiberglass no one seems to dare view.This is now a good haven for members from totse etc. as compared to the first pages of a decent Original posts stickie by very professwional folks now gone bad.To call anything but the premade cone a well made fabrication is an insult to reality.
Carefully done epoxy securing the CSC? nicely banded standoff leggs LOL. Ther isnt enough standoff in the steel tubing to accomodate the charge and standoff? Piss poor planning is no substitute for careful assembly.Looks like shit frankly and I suspect the performance matched otherwise we would see a carefully laid out sequence of the events and a schematic of construction as are in the beginning of this at one time excellent resource.:(
Finally for the moment Wizard take a look @ AXT's home improvised linear charges and the commercial ones your touting are far from impressive.And yes I am out to insult most
of you who have posted recently, what little verifiable work thats being done is less than substandard compared to just a few yrs previously.I dont see anyone trying to turn thir own CSC's,Fabricate single efps let alone multiple efps.Proundly dissapointing for the experts you all are!:mad:
[Edited on 10-6-2010 by grndpndr]

[Edited on 10-6-2010 by grndpndr]

[Edited on 10-6-2010 by grndpndr]

[Edited on 10-6-2010 by grndpndr]


I have managed to move it with help of my loyal spectators ;) It's not very hard to do it if there's a path nearby... And also ~40kg doesn't present huge logistical challanges (like hiring a crane to lift it for you etc.) so it's perfectly managable...


I see you are still insisting on your amusing claims... I have to say I'm feeling flattered by your continuous disbelief. Well I guess you guys will never know what really happened since you weren't there so I suppose it's perfectly valid to leave it to grndpndr and people alike to speculate until a time machine (or something) is invented.

Don't forget EVERYTHING is a conspiracy THEY exist...

grndpndr - 19-8-2010 at 20:10

I must have really hurt your feelings to dredge up such an old post.
All due respect but Im afraid it really does appear to ME as suspect, if others feel its genuine thats fine ive no beef with them or even you for
that matter.
Even though I feel the posting is fraudulent It wouldnt be the first time ive been wrong. So My advice is get over it, I have my opinion and unless there are photos that dont appear doctored to me my opinion stands.Why that should even phase you is beyond me unless thers truth in what I say.If Im wrong,have misinterpreted the pictures which i really dont believe. my most hunble apologys are owed to you.And would be forthcoming with proof.Speaking of proof ther are metal supply shops that sell 1to 4in diameter solid round stock up to 24 to 48in long and they will cut the stock into 1
in long pieces for a few dollar an inch,Buy a dozen 1in round slabs place your device with the correct standoff before after pics.seperate the 1in slabs and pictures of them would be undeniable proof.If shipping wasnt so high Id send you 6 to 12 3x3 squares of 7/8 mild steel to prove your device.I live next to a RR yard with plenty of mild steel for the taking both short pieces of track to demostrate the effects of line charges capability of splitting the track and sections iof steel plte for penetration test as us done professionally.If the pics are genuine why worrie about what i thinkanyway:(

Miszany-Shardin

The WiZard is In - 25-8-2010 at 11:54

I am not 'bout to read 30-pages of posts, I will note
I did not find this searching soooo I will note in passing
the Misznay-Shardin Effect albeit it is not all that
unconventional.

http://www.experiencefestival.com/misznay-schardin_effect

being a good place to start.

grndpndr - 31-8-2010 at 02:23

Theres nothing unconventional about 99% of any of the sc effects in any of the 30 plus pages I can see Wizard!

Miznay Chardin is also an accepted spelling,maybe that makes it unconventional.

hissingnoise - 31-8-2010 at 03:18

The correct spelling, of course, is Misznay-Schardin effect. . .


grndpndr - 31-8-2010 at 10:50

Maybe an 'adult' pissing contest where instead of lenghth we compare how many pages spell it one way how many another.LOL
Im sure your correct in the spelling however and Im sure youve seen it spelled both ways w/o comment by people who know better but have better things to occupy themselves with.:D

A winner for the Mizsnay Schardin effect 10 to 1:o I for one am certainly glad thats cleared up!:D

[Edited on 31-8-2010 by grndpndr]

[Edited on 31-8-2010 by grndpndr]

hissingnoise - 31-8-2010 at 11:33

You're a gas, grndpndr. . .


grndpndr - 31-8-2010 at 12:09

Quote: Originally posted by hissingnoise  
You're a gas, grndpndr. . .


Literally i must assume as this is the internet!?:D

grndpndr - 3-9-2010 at 00:22

Quote: Originally posted by grndpndr  
Quote: Originally posted by hissingnoise  
You're a gas, grndpndr. . .


Literally i must assume as this is the internet!?:D


And why not Hissingnoise? Lifes so short take no shit enjoy every minute.If people get pissed along the way they will either get over it or not.Either way Im not in the least concerned.All i worry about especially at this time of nite is living life as best I could hurting no one if I can help it and helping everyone I can.Cheers everyone ive pissed off now, in the past ,and in the future,may you get over it.:D

grndpndr - 3-9-2010 at 04:21

Quote: Originally posted by grndpndr  
Maybe an 'adult' pissing contest where instead of lenghth we compare how many pages spell it one way how many another.LOL
Im sure your correct in the spelling however and Im sure youve seen it spelled both ways w/o comment by people who know better but have better things to occupy themselves with.:D

A winner for the Mizsnay Schardin effect 10 to 1:o I for one am certainly glad thats cleared up!:D

Besides as the great leader says it was a "teaching moment" for those who may not have been familiar with all the effects the misnay/ schardin/neuwman effect have,From use in the famous or infamous claymore mine depending on whose side you favored to platter charge antitank mines used by all major forces to the mainly obsolete OT demolitions british AT shell, the sqaush head platter charge IS old now and conventional but at one time it was quite unique,sadly some have no appreciation for some of the finer more unique things.If not new its a conventional Idea! How boring an attitude and very likely a personality!?

Brits sure knew how to give a weapon pinache simply by the name.Dambusters!Now that gets your attention even though the designs rather mundane.A motorized spinning trashcan filled with torpex.Get this!TALLBOY, sounds fearsome doesnt it?
And it was,
trveling supersonic from 20,000ft altitude they did not disappoint!
Almost 21ft long, wieghing 12,000lbs with a payload of torpex of
some 5,200lbs created a crater 80ft deep and 100 ft across and capable of penetrating 16ft of concrete.they were in fact TALLBOYS!
Better yet although not due to any explosive phenomena the so called "GRAND SLAM" or earthquake bomb as it was aptly named.But still not dependent on any special physics or unusual effects OT size.Also capable of traveling the speed of sound its wieght was 22,000lbs with a 9,135lb torpex warhead.In combat it penetrated 4.5meters of reinforced concrete w/o any type of SC effect?!Miraculous!:cool:

Well I hope that "teaching moment" has helped clear the air about whats an unusual SC and whats a big ass bomb! Everybody savy?



[Edited on 3-9-2010 by grndpndr]

[Edited on 3-9-2010 by grndpndr]

NUKE - 1-10-2010 at 12:34

Quote: Originally posted by NUKE  
http://www.youtube.com/watch?v=Ku4uUP_z-Gw
.....


Video was down I can't guarantee this one will stay forever either...

http://www.youtube.com/watch?v=w0Xk-TgGcDE

Late date apology/retraction;NUKE.

grndpndr - 12-10-2010 at 20:09


Id like to offer my apologys to Nuke for over the top nitpicking of your posts.Particularly the effort hes said to have invested in the 90mm CSC.I wont try to justify my criticisms but in my defence the pics seemd w/o order.The effects somewhat suspect at least to 60s/70s RHA armor steel.
Recent reading as regards target effects other than armor steel have clarified how kinetic and chemical weapons react on mild steel and worse brittle cast iron.
The only questions I have are noncritical/non accusatory, just curious as to the sources of the 84/90mm Conical copper SC that appeared so perfect it appeared to be made by a nation state contractor.Failing that a very costly$250 US piece of 4inx4in solid cylindrical copper chucked in a lathe and machined out by a tool and die maker.Unliikely so either it was a very well turned piece of which Im envious.Or It may have been liberated from a demonstration set of how the Carl Gustav recoiless rifle warhead worked,or even the 90mm us RR demo set.Byda the spec ops still use the carl gustav with modernized warhead extended range rocket propelled 84 mm swede RR.
Ive had some success with EFPs but nothing to = what you did with the SC.I love the simplicity of the efps and off route damage that can be inflicted using proper platters.Next one I*m hoping to buy 33$ worth of 4inx1in thick OD copper round
so I can have a local machinist make 1maybe 2 120degree angle copper platters with mild 4in steel confinement and end cap/plate welded to concentrate every bit of energy into forming and propelling the efp at close to 2kps using a 7500mps + HE.Using a kinepack type HE 75/25 and a salvage steel concave platter 4 ozz penetrated 1in of hot rolled steel plate.Nothing compared to your accomplishment but I was pleased as the imp platter performed from 3in dia reformed ityself to less than 1in penetrating with a 1in1/4 hole looking more like a HV cannon strike than Imp device.
As I said IM WORKING ON SOME COPPER,as well as trying to fab a imp woodworking type lathe in order to attempt copper cone forming,and I wopuld like to buy a 1in piece of 4in solid cylidrical co0pper stock and have it machined wuith a 120degree angle on each side,modernized platter charge .Steel is the last thing to worry about here its a waystation crew relief rrtrack repair depot with mounds of 1-2in cold rolled steel and pieces of worn out RR track, the mil claims 1 lb of TNT will split80lb yd rr track w/o tamping! I will find out with a 3ft piece of worn track that walked into my yard witha TNT equiv, as this is 80lb/3ft RRtrack, very thick.
I have lost count of the 1in rolled steel by8x6/12x14!HEAVY steel tough to cvarry for a witness plate,my cars to small!Fr4iends PU truck w/tommy lift. In any event I hope my apologys accepted.If not I cannot blame you or worry over it. Humbly yours, PNDR :(

Lastly I have a qu3stion regardoing if anyone has a clue as to proper alloys of copper to use in a SC?Online metyal suppliers have quite a few copper alloys to choose from.Some with higher tensile strenghth particularly after work hardened and of course it can also be annealed to be as soft as possible.IIRC I ran into a chromium alloyed copper,obviously a high tensile strenghth copper alloy.
Tellurium copper alloy? the purpose??Some meant for electrical use another a general purpose copper alloy and Im sure there are dozens more and we havent even discussed
what types of mild steel or mallebale Iron are or can be used used in modern EFPs in material shortage emergencys.
I had read a malleable but very hard heat treated Iron was used with good effect in EFP's. The exotic materials/designs havent even been discussed where$isnt an issue;nation states,or backers.

nitro-genes - 14-10-2010 at 10:31

Just one question, not accusing you of anything....:D

Based on what facts exactly do you not only seem to know it is RHA, but from the 60's/70's as well?

Please enlighten us!


grndpndr - 14-10-2010 at 16:02


Havent the slightests what your talking about.I never implied it was in any way RHA from yesteryear.Only that i wouldnt expect it to behave as such and obviously it didnt.

Reread the posts and youll discover the "target plate" was discussed as a mystery metal my reference to RHA was as a baseline not claiming the material was RHA AS ITS BEHAVIOR AMPLY DEMONSTRATED.THAT my friend you dont find lying about for the taking.So If you have suspicions take them elsewhere AS I COULD GIVE A SHIT.:P

In any event modern steel armor is no longer called RHA,it was back in my day ergo my reference to armor plate as RHA
which this material was quite obviously not if youd ever had any experience with armor

[Edited on 15-10-2010 by grndpndr]

VladimirLem - 16-10-2010 at 02:52

Hi guys

does anybody got some detailed infos about the L/D-ratio to the Linerthickness at a normal EFP ?

example:

EFP-Charge, Steelpipe with 70mm D, Head Height 1.2 CD or 1.0, Explosives will be manitolehexanitrate, picrid acid, and only a few percents PETN...

Thickness of Liner if steel: ?
Thickness of Liner if copper: ?

grndpndr - 10-12-2010 at 07:35

I was fortunate to finally see Nukes video under different name.Intentional or no it was his vid.What was lacking in the posted SM video was 2 shots of the target material a light tan straight stump with the bark removed.The second shot showed the top of the cylindrical 'metallic" target with a light outer core of newer growth and inner core of heartwood.Yall been had.:P 'You tube' under "Explosivly formed penetrators",it was mislabeled but identical OT the shots of the wooden target.Vindication.:P
He goes un der the Nombre incognitus 001 the expanded video is mistitled 'Explosive compilation 2'.I was simply browsing and came upon (nukes or) this video. Theres your reference and proof HS.[Edited on 10-12-2010 by grndpndr]

[Edited on 11-12-2010 by grndpndr]

hissingnoise - 10-12-2010 at 07:54

Right, you saw a video confirming your suspicions . .
Where's the link, grndpndr?




grndpndr - 10-12-2010 at 09:04

Youtube Explosively formed penetrators hes under the name incognito oo1 look in the post above yours for specifics.

I got nothin against the guy Hissingnoise except BS pees me off

PS look at the video carefully once he gets to the device atop the target 'cylinder'(the target dwarfs the device?wieght guestimates) its light tan looks very much like debarked sec tion of a log and a final shot of the top of the target reveals growth rings lighter outer wood and inner dark sapwood!Not a characteristic of metal fellas:D

[Edited on 11-12-2010 by grndpndr]

NUKE - 14-12-2010 at 11:51

I think he might have been referring to one those two videos (both are practically identical at least as far as "shaped charge material" is considered)

http://www.youtube.com/watch?v=Ua0F68etB0M
http://www.youtube.com/watch?v=w0Xk-TgGcDE

http://www.2shared.com/file/J-4Fsmxe/compilation_material.ht...

There you go, higher resolution of pictures I presume you were referring to. Cannot give you any more than that

My explaination: inequal distribution of water on dirty rusty target

[Edited on 14-12-2010 by NUKE]

Microtek - 14-12-2010 at 14:15

If that's a "debarked log", it's the most perfectly straight one I've ever seen. And those "growth rings" look quite a lot like machining marks to me.

grndpndr, I think you should stop pursuing this and just acknowledge that you were wrong (in fact I thought you did). You'll end up making a fool of yourself by persisting.

grndpndr - 16-12-2010 at 06:40

Then with all due respect you havent seen many trees Microteck ,and my world doesnt revolve around my reputation here,I been round the block more than a few times.FWIW I think nukes work is outstanding . A founding member judging by his join date/post count I communicate with has/had a high opinion of Nukes/ incognitus001 work as well but he has indicated to me the photos bother him as well so Im not as alone as you would think.His CSC appears to have one of the finest cones ive seen from a garage.The tubing appears to be seamless quality well casing from what little I can see of the booster that may be a machining of his as well.Though effective using hose clamps instead of welding is about the only change I could think of .OT improving the photography of the suspect target
I think the listv of photos starts on page .These 3 are by far the most troublesome.Thers No photoghraphic faux paux that causes whats happened in those 3 photos perioud.No lighting ,dirty rain,overexposed film cause a solid steel cylinder to split like a logWith a CSC of that quality.Ive had several people look at the offending photos and w/o exception fraud was the conclusion.I dont really care if your trying to pound smoke up somewhere but if theres smoke thers fire.If thers a reason i dont care either but I know what Im seeing.

[Edited on 16-12-2010 by grndpndr]

magneet - 16-12-2010 at 12:25


Quote:

Thers No photoghraphic faux paux that causes whats happened in those 3 photos perioud.No lighting ,dirty rain,overexposed film cause a solid steel cylinder to split like a logWith a CSC of that quality
Maybey not the jet, but the shockwave arriving later causing brittle meltcasted iron to fall apart.

nitro-genes - 16-12-2010 at 14:49

lack of experience, my guess would be he was either a radio officer or the camp-cook during service, lol...

Microtek - 19-12-2010 at 03:43

Have you looked at the higher resolution pictures that NUKE provided? I suppose you could possibly make a piece of wood or plastic look like that with massive amounts of work and a flair for movie effects - but it would be much easier to make a quality shaped charge and penetrate it as NUKE has described.

I may not have extensive experience with all of the species of log on the planet, but I have fired my fair share of shaped charges into both steel and wood. I can tell you that wood doesn't behave like what we see in the pictures when hit by a SC, at least when the jet hits perpendicular to the fibres.

The pictures show what you would expect to see when an SC jet penetrates a relatively brittle target such as some types of cast iron. As I have explained to you previously, much of the material that used to be where the hole is after the penetration is not expelled out the back of the target, but instead pushed radially away from the channel. This produces tremendous stress in the target and would very probably fracture the target as shown.

franklyn - 22-12-2010 at 15:25

Computer Simulation of Explosively Formed Projectiles
http://www.mater.upm.es/isb2007/Proceedings/PDF/Volume_1/Vol.I(20)WM14.pdf

Manual for Shaped-Charge Design
Cited by octogen - www.sciencemadness.org/talk/viewthread.php?tid=10575&pag...
http://handle.dtic.mil/100.2/ADB954297
Redirects to :
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADB954297&Locati...

.

grndpndr - 25-12-2010 at 20:49


Well, where to start.My apologys first and foremost to NUKE. Ive reviewed the new Pics and they certainly seem genuine to me.If these same pics of the pieces of the target had been posted with the same clarity to begin with this misunderstanding would have been avoided altogether. I
I would never have questioned their authenticity and saved myself the embarressment(Pg. 27,9 photos- retrieved pieces).:(

Still. the tgt metal had to be quite brittle judging by the entrance/exit and general shattering of the target..Even before I had seen the enhanced pictures I did give credit where I thought it was due.The cone in particular seemed well made(obviously the entire device well designed/made) and Im still curious as to its origin, but brittle cast iron/ or not 5x CD penetration from an imp device is impressive.In fact the Carl Gustav 84mm RR HEAT RD is reputed to be capable of penetrating in excess of 400 mm
RHA!
Whatever metal( iron/mild steel) the target was thats good company and excellent work Nuke. Again ,My apologys.

[Edited on 26-12-2010 by grndpndr]

Assorted refs

The WiZard is In - 26-12-2010 at 08:35

I am not about to peruse 31 pages of posts so forgive me if
these are not new upon the collective.

As previously suggested dtic.mil is treasure trove of information.

A quick look turned up these.

William P Walters

Explosive Loading of Metals and Related Topics
ADB102693

The Shape Charge Concept
Part 1, Introduction ADA226401
Part 2, The History of Shaped Charges ADA226772
Part 3, Applications of Shaped Charges ADA228492

Introduction to Shaped Charges

And a SL more than I have time time on earth too read!


Uses for shaped charges your mother never told you about

The WiZard is In - 29-12-2010 at 14:08

Just finished reading Willaim F. Walters three-part The Shaped
Charge Concept. 1990.

Part III.

A shaped charge meteor simulator was developed for NASA (Need
Another Seven Astronauts) A rocket was used to carry the charge
above the atmosphere , “turn and allow the detonation of the
shaped charge to accelerate at hypervelocity through the earths
atmosphere. The intent was to simulate a body (meteor)
re-entering the earth’s atmosphere.” A nickel – iron liner was used.

Using a Aerobee rocket launched from Alamogordo, NM October
16, 1957 “the first particles from a shaped charge jet were
successfully launched into orbit about the sun.”

A really stupid-stupid-stupid experiment “was contemplated that
would allow the jet to impact a heavenly body, such as the moon.
A spectroscopic analysis of the impact; flashes would reveal the
elementary chemical composition of the moon’s surface. The later
experiment although feasible, was never carried out.”

“… two unlined cavity conical shaped charges improvised from
coffee cans (used as the casing) and 10 pounds of C4 explosive
felled trees of up to 34 inches in diameter when detonated in
diametric opposition to each other. Larger diameter trees were
felled by multiples of 3- 5 charges detonated symmetrically at
points one-third to one-fifth of the circumference of the trees.”

I am of the drill a hole in the tree and insert dynamite school of
though. Or if there is no rush … drill two holes and pour in white
arsenic dissolved in sodium hydroxide.

Takes several months – a dead tree is guaranteed.

Bet you didn’t know there was a US patent on dissolving (white)
arsenic oxide in sodium hydroxide!

djh
----
Today's chemical trivia question —

At room temp after mercury this
is the second heaviest liquid ?



The WiZard is In - 29-12-2010 at 14:33

Quote: Originally posted by The WiZard is In  
Just finished reading Willaim F. Walters three-part The Shaped
Charge Concept. 1990.

Part III.

A shaped charge meteor simulator was developed for NASA (Need
Another Seven Astronauts) A rocket was used to carry the charge
above the atmosphere , “turn and allow the detonation of the
shaped charge to accelerate at hypervelocity through the earths
atmosphere. The intent was to simulate a body (meteor)
re-entering the earth’s atmosphere.” A nickel – iron liner was used.



From NASA — more than most really want to be knowing
me thinks.

http://tinyurl.com/29myhvt

franklyn - 31-12-2010 at 10:28

Good Find Wiz,
direct links for cited NASA papers

Development and testing of advanced shaped charge meteoritic simulators.
Part I - Shaped charge design and development

http://hdl.handle.net/2060/19670008288
Redirects to:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1967000...

Development and testing of advanced shaped charge meteoritic simulators.
Part II - Calibration of flight guns

http://hdl.handle.net/2060/19670008289
Redirects to:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1967000...

Design, development and testing of bi-explosive shaped charge meteoritic simulators
http://hdl.handle.net/2060/19680021751
Redirects to:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1968002...

Explosive oxidations initiated by simulated meteoroid penetration into spacecraft atmospheres
http://hdl.handle.net/2060/19710010761
Redirects to:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1971001...

- cited in the bibliography of the paper above -
Oxidative Detonations Initiated by High Velocity Impacts , AFFDL-TR-65-41
http://handle.dtic.mil/100.2/AD466558
Redirects to:
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD466558&Locatio...


The last two above treat the incendiary effects of liner material. Imagine for example
Cesium explosively driven into an oxidizer tank, or even just water. Metal hydrides
explosively decompose on their own when liquified, something I had mentioned in passing
at the end of the following post.
http://www.sciencemadness.org/talk/viewthread.php?tid=10575&...

.

grndpndr - 5-1-2011 at 23:40



On the topic of unconventional shaped charges. A couple of shaped charges Ive mentioned before here are the Saddle charge and Diamond charge.

From an old FM,5-25 Explosives and Demolitions circa '67' are illustrated and formulas
given for explosive wieghts/shapes for cutting billets of various steel alloys.
The first is called a saddle charge for use in cutting solid steel billet material up to 6-8 in in diameter.
Above 6-8in diameter/high carbon alloy steels a Diamond charge is reccomended .


Appearing to be a elongated triangle the SADDLE charge is placed on the long axis of the target, the apex of the saddle is the point of detonation.Made up of C4 ,thickness of the charge as well as size of the base and length are determined by the circumference of the TARGET.
The base of the charge is 1/2 the target circumference.The long axis of the charge is equal to the circumference of target.Finally the thickness of the charge is 2/3in for targets up to 6in diameter,from 6-8in diameter thickness/up to 25in circumference is 1in of C4.(mild steel)

For targets in excess of 6in-8in diam. or made of high carbon/alloy steels the DIAMOND charge is reccomended.Shaped like a diamond it to is made up of C4.Here again the long axis is = to circumference and the short axis is also 1/2 circumference.Thickness is
to be 2/3 in for a 15in circumference high carbon/ alloy steel detonated at the short axis points simultaneously.I suppose one would have to extrapolate thickness to 1in for a target 6in diameter-larger
Rather than placed on the long axis as the saddle charge. T
The diamond charge is wrapped around the billet then detonated simultaneously at the short axis points.

This FM is a wealth of demolition info I think these likely less well known shaped charges are equally fascinating although I know even less about how they function than an EFP or CSC .

PS; Im taking a leap that if the design of the shaped charge is less well known that qualifies them as an unconventional shaped charge.If Im wrong in that assumption or if its felt that what Im derscribing doesnt qualify as a shaped charge I disagree.Regards:)Please excuse the many revisions I was attempting to make the post decipherable.

[Edited on 6-1-2011 by grndpndr]

[Edited on 6-1-2011 by grndpndr]

[Edited on 6-1-2011 by grndpndr]

[Edited on 6-1-2011 by grndpndr]

grndpndr - 6-1-2011 at 09:25

Little more 'unconventional'.

'Project Orion'," shaped charge fusion boosted fission explosive" designed for the lift off stage Of the 'Starship':o

God help those of us left on earth.An estimated 800 nuclear devices would be required to reach low earth orbit IIRC the articles specifics.Fallout anyone?

[Edited on 6-1-2011 by grndpndr]

[Edited on 6-1-2011 by grndpndr]

gnitseretni - 15-2-2011 at 14:29

Finally got to try one of my liners. CD: 2 inch. Charge: 350g PETN plasticized with 10% by weight Propylene Glycol. (Wanted to use PGDN but ran out of time)

3 blocks of steel welded together, each 1-1/4" thick, so a total of 3-3/4". (looks more in the pic, but it's not)
All 3 blocks were penetrated but the carrot plugged the hole in the last one.

Here are some pics...

Blocks stacked together:

Direct link: http://img831.imageshack.us/img831/8258/sl731117.jpg

Entry holes:

Direct link: http://img20.imageshack.us/img20/2046/sl731118.jpg

Exit holes:

Direct link: http://img714.imageshack.us/img714/1193/sl731120.jpg

EDIT: forgot the short video http://www.youtube.com/watch?v=_oDSM_q_3BE
Video does NOT do it justice but thought I'd add it anyway.

[Edited on 15-2-2011 by gnitseretni]

[Edited on 16-2-2011 by gnitseretni]

grndpndr - 16-2-2011 at 22:31

Most Impressive post ive seen in some time.3.75 in mild steel penetration by a 2x CD
Conical Shaped Charge and judging by the exit holes they had some more penetrating to do.And the cones manufactured by plating! Great stuff,repeatable-consistent
cones from, #1 -#50!

That in itself is an accomplishment worth note all in itself.From spinning inconsistent nonrepeatable cones( no disrespect intended) to nearly cookie cutter cone manufacture.
What was the foremost block to repeatable CSC's?!Consistent cones!

3.75-4in+ mild steel penetration.And from the looks of the exit holes they were far from done penetrating.The exit holes after penetrating the near 4in were nearly the size of
the initial entrance holes the sure didnt look like the last hurrah for that charge.
If we assume at least 4in mild steel penetration from the 2CD SC a rough comparison
between the penetration ratios are 2/3 for armor steel versus mild steel thats roughly 2.5 in+ rolled homogenous armored steel /4in mild steel.VERY respectable performance from improvised munitions as complex as shaped charges.


Many yrs and long time since AXTs 2in glass csc/2in mild steel penetration. I began to wonder if anyone would top with a copper SC. Its been several yrs w/o competition it seemed and now performance has been doubled.

Just a few specifics if I can ask about details?Material the body of the SC was constructed from.Approximate thickness(ML) of the 2in diam CSC?Anything different in terms of accepted construction specs such accepted stds as head hieght,stand off.Strong confinement? Again what i think to be an excellent effort,I hope others will take up the challenge!Hats off to you gnitsernetni!!

gnitseretni - 18-2-2011 at 10:54

Thanks grndpndr. I wish I had more of those blocks, because I too think it could have penetrated a bit more.

Container was PVC pipe. Standoff was about 3 inches. That's about it for specs. I know I didn't document it well, but that's because I wasn't planning on sharing. Due to circumstances I have to put this hobby on the back burner again. So I quickly put together one more charge to get rid of my PETN and be done with it. But at the last second I decided to take my camera with me after all. I promise I won't be this sloppy again :P

grndpndr - 18-2-2011 at 17:39

Dont worry the target plates speak volumes.

Do wish you had or could measure the liner thickness?

gnitseretni - 19-2-2011 at 09:42

I have another liner, I'll be sure to measure its thickness when I can make another charge.

Btw, I was a little surprised that a carrot had formed. I didn't think a carrot would form considering the way the liner was manufactured.(electroformed) I thought it would be brittle, just like a liner made from compressed powder because basically electroforming is just particles that build up on a form.

grndpndr - 20-2-2011 at 02:59

Another topic beyond my payrade but ill ask a friend who spent years in an electroplate shop, clues as to why the electroplate would behave as a plate/casting might.I was under the impression in electroplating it was bonded on a molecular level rather than sintering which is heat and pressure a mechanical bond.

Why the enormous pressure of the CSC doesnt make the sintered copper liner act as a plastic I dont have a clue.
If CSC's depended on a mallebale cones so much for glass CSC
liners.

[Edited on 20-2-2011 by grndpndr]

quicksilver - 20-2-2011 at 08:42

Just out of curiosity was the form for the cone, a fence post top? And have you made a (simple) record of the time in which a production cycle ran?

gnitseretni - 20-2-2011 at 15:29

Quote: Originally posted by quicksilver  
Just out of curiosity was the form for the cone, a fence post top? And have you made a (simple) record of the time in which a production cycle ran?


Yeah, fence post top from Ace Hardware, they call them Bullet Caps. That liner (and yours) took 3 days of plating. Mine was almost twice as thick as yours because less of the post top was submerged in the plating solution, which decreased voltage, but because current density stayed the same it plated at a faster rate.

grndpndr - 10-3-2011 at 20:30

This is a fascinating leap for CSC and EFP's.Similar to a hobbyist what interchangeable parts were to manufacturers.

Theres an awful lot of variation possible on the theme, something unavailable not long ago.Along with precision repeatability one less factor to consider in a design if you can assume your CSC liner was identical to the last.Whats that worth to experimetation?

Repeatable, easily made cones fired into target plates professionally arranged as is possible to identify and repeat results.I cant find any real fault with the concept, seems equally as useful in making single finned long rod hard tgt EFP's to multiple efps.

Unfortunately it would seem gang type forms could be crafted
easily so that availability of platters/CSC's could be to common to discuss any more on natl news
Seems exceedingly simple process easily available materials
and if a custom shaped EFP-CSC design were contemplated
the aluminum Dies could be easily made on a simple lathe.

Actually looks like a nightmare for both homeland security and our troops in afghanistan Iran.no longer are machine shops with lathes-punch presses required but tupperware,copper tubing etc, electrical power supply and a suitable aluminum form.

Its one heck of a good idea it seems to me if your lacking
several thousand dollar lathes and several hundred thousand dollars worth of hydraulic punch presses.

[Edited on 11-3-2011 by grndpndr]

Hennig Brand - 10-9-2011 at 08:12

I have been using the electroforming method to make some copper cones lately. I was having trouble finding suitable aluminum forms, so I got a few short lengths of aluminum round stock from a machine shop in various diameters, then me and a friend turned the cones on a lathe. I will get to the results of this later, but just for fun I wanted to show the results of using a brass candle holder as a liner.

Using nitro-genes's methods for making putty explosives from the thread PETN vs RDX as a general guide, I made putty, but with ETN instead of PETN. I have been making this for a while actually. I used about 44g of this 85% ETN and 15% inerts plastic explosive.

The candle holder liner looked fairly symmetrical and uniform in thickness. The thickness of the liner was slightly more than the thickness of a dime, or a little more than 1mm. The candle holder was definitely not a cone shape, maybe closer to a trumpet shape.(?) The liner was approximately 1 inch in diameter.

The steel pipe that was used was from the frame of a swing or something I found at a scrap yard. It was convenient because the smaller diameter pipe was just slightly smaller than the liner, and the larger pipe was just slighly larger. The liner could be locked between two pieces of the smaller pipe with a short length of larger pipe over the join. I tacked the thing together with a brazing rod and an oxy-acetylene torch. I used bamboo skewers as standoff sticks, trimmed to length. About 1.5 cone diameter standoff was used.

I got about 1 inch of penetration. Each steel piece in the picture is 3/4 inches thick. I piled up four pieces of the steel, (I was ambitious). I got reasonable penetration I think even though I didn' t have the liner perfectly straight, (I didn't want to take it all apart again to straighten it). From the picture with the tooth-pick in it, it is obvious that the jet went through at an angle. The jet also spit, you can see where parts of the jet penetrated about 1/4" or so in several places, and the main hole is very large at first and after an inch of penetration is quite narrow. The top two steel pieces, post blast, are shown in the bottom row of pictures. The second piece was only penetrated about a 1/4".

Candle Holder.JPG - 377kB Load Putty.JPG - 794kB Loaded Charge and Cap.JPG - 422kB Cap in.JPG - 393kB 3 quarter inch blocks.JPG - 321kB Results.JPG - 384kB First Steel Block 01.JPG - 278kB First Steel Block 02.JPG - 236kB Second Steel Block.JPG - 289kB


[Edited on 11-9-2011 by Hennig Brand]

Hennig Brand - 11-9-2011 at 08:36

I have moved the post regarding electroforming copper cones to the thread "Electroforming Copper Cones". The post gives a description with pictures of aluminum electroplating forms which were turned on a lathe. If and when I test some of the copper cones I will post the results of that here.

gnitseretni - 11-9-2011 at 10:06

Nice to see someone's still doing some experimenting with shaped charges ;)
Can't wait to see the performance of your electroformed cones. Should do better than mine as mine weren't plated onto a machined form. The next one will be though, as I got me a lathe now too :P

Hennig Brand - 12-9-2011 at 13:17

It was a friend's lathe actually. I have been keeping an eye open for one of my own for a while though. It takes a bit of time, but it is very easy to make an aluminum cone on a lathe. Working with aluminum is not nearly as hazardous as working with steel, which is another nice benefit. For example you can easily pick up a big handful of the aluminum turnings with your bare hands and not worry about getting cut, something you wouldn' t want to risk with most steel turnings. Aluminum also cuts very easily relative to steel. I think you will have a lot of fun with your lathe.

[Edited on 12-9-2011 by Hennig Brand]

Hennig Brand - 18-9-2011 at 06:28

I haven't tested an electroformed copper liner yet because I am in the city right now. Hopefully I will get the chance soon.

The following is a copy/past from "A Brief Histroy of Shaped Charges", by William Walters. A pdf of the full report is also included. The copy/paste is supposedly some of the results of Japanese study on shaped charges around the time of the second world war.

"The Japanese also
concluded that a hole in the apex of a conical or hemispherical liner was desirable.
Also, the size of this hole was critical, an optimal value for the apex hole diameter
being 1/10 of the warhead charge diameter. (The wall thickness was taken as 1/25
of the charge diameter and the liner diameter was taken to be 4/5 of the charge
diameter for both conical and hemispherical liners.) The optimal cone apex angle
was determined to be between 35° and 50°. The optimal open apex diameter was
concluded to be 3/16 of the charge diameter for this warhead."

I am particularly interested in finding an optimal liner thickness for copper. Does what they report seem reasonable?

Attachment: A Brief History of Shaped Charges.pdf (97kB)
This file has been downloaded 1433 times

[Edited on 18-9-2011 by Hennig Brand]

VladimirLem - 18-9-2011 at 07:57

Quote: Originally posted by Hennig Brand  


I am particularly interested in finding an optimal liner thickness for copper. Does what they report seem reasonable?

[Edited on 18-9-2011 by Hennig Brand]


Yes...the infos seems okay...


@liner-thickness:

i would go for this:

6-7cm CD Shaped charge using TNT - 1.25mm (Cu)
7-8cm CD Shaped charge using TNT - 1.50mm (Cu)
8-10cm CD Shaped charge using TNT - 2.00mm (Cu)
10-14cm CD Shaped charge using TNT - 2.50mm (Cu)

Using PETN/RDX, all Liners +0.25mm

Hennig Brand - 18-9-2011 at 10:09

Thanks for the reply, but unless I missed something the numbers for liner thicknesses seem about half what they should be. It seems like you stated CD (charge diameter), and then proceeded to take approximately 1/25 of the charge radius, or 1/25 of half the diameter.

[Edited on 18-9-2011 by Hennig Brand]

gnitseretni - 18-9-2011 at 10:59

I found a small txt file a long time ago that says thickness of cone is 0.032 x CD (in mm).

So for a 1" (25.4 mm) cone, thickness would be: 0.032 x 25.4 = 0.81 mm.

Whether that formula gives the optimal liner thickness, I don't know.

VladimirLem - 18-9-2011 at 11:03

Quote: Originally posted by Hennig Brand  
Thanks for the reply, but unless I missed something the numbers for liner thicknesses seem about half what they should be. It seems like you stated CD (charge diameter), and then proceeded to take approximately 1/25 of the charge radius, or 1/25 of half the diameter.

[Edited on 18-9-2011 by Hennig Brand]


the liner-thickness is just at a rough guess...

yes, ists hard to find good sources for liner-thickness

maybe i find a good pdf at my harddrive, the i upload it...


Hennig Brand - 19-9-2011 at 12:00

Well 1/25 CD is 0.04 CD, so your 0.032 CD is not too far off the Japanese numbers I guess. I don't have this down to an exact science yet anyway so as long as I am in the ball park I am happy. The ratio for optimal liner thickness most likely varies with other parameters as well, like charge size and liner material perhaps. In VladimirLem's post, a couple of posts ago, the liner thickness values had an amount added if the more brisant explosives were used. I think I will aim for between 0.03 and 0.04 CD, thanks.

[Edited on 19-9-2011 by Hennig Brand]

VladimirLem - 20-9-2011 at 08:08

Hi Guys


The value of 0.03 CD seems a bit many - especially at the smaller CD-Charges !

1.8mm at 60mm is a lot ! I would only go for that with really powerfull stuff AND by the way - better you take a bit too thin liner that a bit to big ! If too thin, you get a (super) high velocity jet BUT if too big, the performace and velocity will go extreamly down !

i would use 0.025 CD for PETN<




nitro-genes - 27-9-2011 at 14:17

Wall thickness is probably optimized for:

1. Detonation pressure of explosive (higher = thicker liner)
2. Density of liner material (higher = thinner liner)
3. Speed of sound in liner material (higher is thinner liner)

My guess would be that a shaped charge is mostly a tradeoff between these 3 factors, chosen in such a way that the liner is not accelerated beyond the speed of sound for the material under the pressures during the detonation (~1.2x compared to ambient pressures) and that the resulting jettip has the highest velocity possible. Cone angle and charge design also have an effect on jettip and liner collapse velocity, EFP for example use somewhat thicker liners, though I'm not sure whether a general rule exist for this. :-)

When in doubt of your liner or charge precision, 3% will probably do better than 2% of CD for materials in the density range of copper

gnitseretni - 15-10-2011 at 13:47

Did another shaped charge.

There's about 225ml PGDN in that container in the picture, but used about 200ml of it.

The cone was the last one I had. Diameter was 1.89". Unsure of exact angle, but I guesstimate it to be about 75-80 degrees. It was plated onto a non-machined form (fence post cap). The cone was off-round and it's thickness was non-uniform. I only measured at the base as I only have calipers (no micrometer) and it was 1.46mm on one side and 1.64mm on the other side. The stainless steel tube was off-round as well. The only thing that was machined was the top to center the detonator. I only did that because I can use the practice :P

Total penetration was 6-1/4". I'm satisfied :)
EDIT: Forgot to mention standoff, which was 3".

Video really sucks, but here it is anyway..
http://www.youtube.com/watch?v=XqhA0FeVfEo

SC.jpg - 60kB Charge.jpg - 53kB entry.jpg - 82kB exit.jpg - 106kB result.jpg - 57kB

[Edited on 10-16-2011 by gnitseretni]

Bot0nist - 15-10-2011 at 15:33

Wow, That's impressive!

That big jug of PGDN makes me nervous, lol.

Formatik - 15-10-2011 at 23:00

That's a pretty interesting result gnitseretni. What are those metal blocks made out of?

gnitseretni - 16-10-2011 at 04:47

Just regular mild steel I think.

EDIT: I think more standoff would've improved penetration. I mean, look at that big entry hole. Making an inch wide hole takes more effort than a half inch hole, so that big entry hole must have slowed down the jet some (substantially?). By increasing standoff I would have given the cone more distance to stretch, making the jet narrower, which would have resulted in a smaller entry hole. And this decrease in resistance would have improved penetration. Or that's my theory anyway, and I'm sticking to it :P

[Edited on 10-16-2011 by gnitseretni]

hissingnoise - 17-10-2011 at 04:17

Quote:
That big jug of PGDN makes me nervous, lol.

And the yellow colour doesn't inspire too much confidence in its keeping qualities!



VladimirLem - 17-10-2011 at 07:34

Quote: Originally posted by gnitseretni  
Just regular mild steel I think.

EDIT: I think more standoff would've improved penetration. I mean, look at that big entry hole. Making an inch wide hole takes more effort than a half inch hole, so that big entry hole must have slowed down the jet some (substantially?). By increasing standoff I would have given the cone more distance to stretch, making the jet narrower, which would have resulted in a smaller entry hole. And this decrease in resistance would have improved penetration. Or that's my theory anyway, and I'm sticking to it :P

[Edited on 10-16-2011 by gnitseretni]


You're right...just look some technical pictures at Google-images about the russian RPG-Series warheads...
The Standoff value is most times far about 2,5 CD.

With a coppercone (all pure metal-cones), no problem...just for improvised liners (glass etc) i would go for smaler Standoffs like around 1.5CD

and yes...the thinner the penetration-hole, less energy is lost and will increase the penetration dept much !

hissingnoise - 17-10-2011 at 08:46

The cone height-to-radius needs to be factored in too, BTW!



gnitseretni - 17-10-2011 at 16:43

The color is because of the sulfuric acid I used (drain cleaner).

Hey Hiss, your turn for a SC is way overdue amigo :P Come on, help keep this thread alive!

watson.fawkes - 17-10-2011 at 18:14

Quote: Originally posted by gnitseretni  
Did another shaped charge.
What strikes me about these pictures is how clearly visible is the heat-affected zone of the metal. It extends all the way to the edges of the top sample. It seems clear to me that it's compression heating of the metal. Surface oxides from the heat are just like what you get from tempering heats.

The edges of that top block are really obviously no longer straight. You're well into the elastic deformation range of forces outward from the penetration path.

You're right at the edge of getting useful quantitative results from these tests. All that's needed is to standardize the test target. The reason for standardization should be obvious. Picking an alloy number would be useful too. 1018 is the most common cold-rolled steel. It's very possible that's what you've got there already.

I'd recommend enlarging the targets to minimize the bulk deformation. This would reflect better what actual penetration into plate would look like. I'd say squares of 6" or so on edge. You want squares to that you measure total permanent deformation. I'm sure that even with 6" you'd be able to pick up the bulging with a dial indicator.

VladimirLem - 18-10-2011 at 01:00

Hi guys

Im a bit confused of non reading a single "peripherally initiated" chaped charge at this thread.

So i present you my "researches" with them.

It started with looking at a technical drawing of a "Panzerfaust 3" Tandemshaped charge warhead - i wondered why there is a secon cavity inside the maincharge. I knew that couldnt be a drawing-mistake or someting else and came to the point that the detonation wave goes throug the thin explosive at the cavity and then ignited the charge - look at my drawings.





This makes that many detonation pressure goes direct to the liner.


And not like a "normal" shaped charge, where amny detonationpressure goes to the outside and not direktly to the cone (drawing 3)...


Now imagine the shaped charge that one dude made with the PETN/NG and the huge coppercone which penetrated over 40cm steel - HOW many power it would get with this method - i say up to 60cm are no problem !

I tested it some times...the first failed a bit cause of a assymetric building...the second - 1,0kg ANNM-AL with not really good quallity and a glassline penetrated a 5cm Steelplate...






Download US Patent 5565644 and take a look at "Fig. 1"

It works, and it increases the penetration ALOT :cool:



Username - 18-10-2011 at 04:13

The principle you're talking about is the use of waveshapers.

nitro-genes mentioned the use of them on page 19 of this thread. He used epoxy resin to form the inert-filled cavity in the explosive.

hissingnoise - 18-10-2011 at 06:11

Quote:
Hey Hiss, your turn for a SC is way overdue amigo :P Come on, help keep this thread alive!

Uh, plans in the pipeline - you know how it is . . . ?


gnitseretni - 23-10-2011 at 11:15

You're right. That top block is pretty deformed. I think that if I had used a larger block (like you suggest I do next time) that penetration would have been less. Would you agree? Ah, I guess there's only one way to find out for sure :P

Quote: Originally posted by watson.fawkes  
Quote: Originally posted by gnitseretni  
Did another shaped charge.
What strikes me about these pictures is how clearly visible is the heat-affected zone of the metal. It extends all the way to the edges of the top sample. It seems clear to me that it's compression heating of the metal. Surface oxides from the heat are just like what you get from tempering heats.

The edges of that top block are really obviously no longer straight. You're well into the elastic deformation range of forces outward from the penetration path.

You're right at the edge of getting useful quantitative results from these tests. All that's needed is to standardize the test target. The reason for standardization should be obvious. Picking an alloy number would be useful too. 1018 is the most common cold-rolled steel. It's very possible that's what you've got there already.

I'd recommend enlarging the targets to minimize the bulk deformation. This would reflect better what actual penetration into plate would look like. I'd say squares of 6" or so on edge. You want squares to that you measure total permanent deformation. I'm sure that even with 6" you'd be able to pick up the bulging with a dial indicator.

watson.fawkes - 23-10-2011 at 13:22

Quote: Originally posted by gnitseretni  
You're right. That top block is pretty deformed. I think that if I had used a larger block (like you suggest I do next time) that penetration would have been less. Would you agree? Ah, I guess there's only one way to find out for sure
I don't know. I came up with arguments going both ways. One one hand, your test blocks might exhibit less penetration than into an "infinite plate". You're expending energy with inelastic deformation of the steel. Jet confinement isn't as good in the first block, loosening the pulse confinement and broadening it. On the other hand, it might be more, because a small block might act like a thinner block, more flexible and getting out of the way. As you say, testing is required.

Another deviation from ideal behavior is the way you've stacked up plates. It looks like the gap between the first and second plate bulged out like a disc-shaped balloon, allowing a gap between them and surface spalling. Using a solid test block, though, is only viable if you don't care about dissection and don't have a metal-cutting bandsaw. What you've done with tack-welds seems like a decent compromise.

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