Best way for getting high density ?

Hi Guys

Im a hugh fan of shaped charges and optimizing them.

But after some different tests, im not sure which way ist the best to get a high density und especially high velocity compound.

Possible:


Gelantine - maybe with Cellulose Hexanitrate and NG
Pro: All stuff of the compound is reactive (and much powerful too :-) ) but the density is not really high which gives not the "maximum" of velocity...

Wax - Dunno if normal wax would work...the "montan wax" seems not to get easily AND is an unreactive stuff - pro: only around 5-7% are needed

PIB - Have it already but would need 3-8% and some oil or NM to make it kneadable - Pro: able to get high density without many problems, but the velocity is fucked

another question...is it possible to get a velocity of around 8000m/s when usind PETN(~87)/RDX(~5%) and then the plastic/wax/gelantin stuff?

Quote: Originally posted by nitro-genes

1. After neutralization, don't crash the PETN/RDX in cold water, as you will get a very fine crystal fraction that needs more binder 2. Recrystallize slowly from warm solvent, I normally used a styrofoam box as insulation and stored it at -20 overnight to recrystallize. 3. Precipitate the last fraction instantly with cold water, which will give the fine crystal fraction

great idea

how about substutuation of oil (when using PIB) with some liquid/kneadable energetic coumpounds like sorbitol hexanitrate ?
(not compleately SHN, just a few percent instead of the oil)

for example:

Main Explosives 90%
PIB 5%
Oil 3%
SHN 2%?

cause SHN also have an positive oxygen balance - if i dont calculated it wrong - which sould increase the coumpound...

Quote: Originally posted by Phantom

Have you ever tried NG/PETN ? Density >1.6 g/cm*3 and it's VoD=~8000m/s

Quote: Originally posted by Phantom

And what about ANNMSA ? It's pretty effective.

Quote: Originally posted by hissingnoise

Quote: It is basically a mixture of ammonium sulphate, nitromethane and conc. HNO3 VoD is around 8100m/s While an oxygen-balanced binary mixture of NM/HNO<sub>3</sub> will have a VoD which can exceed 8000m/sec, it will also be very shock-sensitive! In ANNMSA, the presence of H<sub>2</sub>SO<sub>4</sub> will greatly reduce brisance!

Quote: Originally posted by Phantom

By the way C-4 works great which is plastic RDX. I`m pretty sure you all had seen this video-> http://www.youtube.com/watch?v=LudNqf56AFo

C4 is a strong explosive, thats for sure, but the VoD suffers exremely from the 9% plastic stuff.

AND:

RDX needs around doubble as much high concentrated HNO3 than PETN needs - when not having Acetic anhydride...so thats for the most users nearly impossible to build huge (CD 6cm< chaped sharges with pure RDX...

Quote: Originally posted by Phantom

Still has around It is easy to make WFNA out from H2SO4 and KNO3.

Quote: Originally posted by hissingnoise

Quote: sure...but are the results much better then with normal "pure" HNO3 (~97%) ? What do you think WFNA is . . .?

WFNA...W stands for White - means adding urea to the normal "pure" - yellow colored HNO3...

I made RDX without using urea, and just "normal" HNO3

or did i get something wrong?

Quote: Originally posted by VladimirLem

*bump* ^^ what about "phlegmatizing" some (lets say PETN) H.E. with FTN ? fine powdered PETN into a ethanol-FTN -solution (7% FTN of PETN weight) stirring the solution and then wait up to the ethanol is "away"...(1-2 days dunno) then a thin layer of FTN is around the PETN crystals...if that would work, there are very high VoDs possible... good idea? bad idea?

Quote: Originally posted by VladimirLem

C4 is a strong explosive, thats for sure, but the VoD suffers exremely from the 9% plastic stuff.

Quote: Originally posted by Goorlap

Quote: Originally posted by VladimirLem   C4 is a strong explosive, thats for sure, but the VoD suffers exremely from the 9% plastic stuff. Don't think so, otherwise it wouldn't be used by the military

Propellant approach???

The patent QS referenced certainly provides some ideas. It suggests you can use the basic approach used to make ammonium perchlorate composite propellants. Just add your energetic solid (AP, PETN, etc.) to your binder system. Certainly 88% solids loading is quite doable; I've done it with AP and HTPB as a binder no problem. I briefly perused the patent, but I didn't notice them giving any actual results though.

You could get wilder and "soup up" your binder system with an energetic (ETN, NG) plasticizer; though that would be certainly increasing the risk level.

The one thing I'm unsure about is if the catalyst would react with the energetic solid in some unpleasant way. These systems are usually hardened by some sort of isocyanate (isophorone diisocyante for example) or an epoxy depending on the exact binder (HTPB, CTPB).

One feature of this approach is that the needed chems are easily available and relatively inexpensive. Now if we only knew if they worked

Sorry for the long post. I was on a roll!

Plastic explosives made from PIB seem to work fairly well even if they are not the perfect thing.

I think Quicksilver quoted Gerald L. Hurst, well I remember reading archived material from the old Alt.Eng Explosives forum and he said (in my own words) that the type of inert material used in a plastic explosive was of very little importance as far as the performance of the explosive goes.

From Yarchive, in section on plastic explosives:

"There is no particular magic in the specific plasticizer mix other
than that it has good stability and low-temperature plasticity. It
may be viewed as an inert diluent as far as explosive properties go."

Jerry (Ico)


At the bottom is a picture of some ETN plastic explosive made a couple of weeks ago. It weighs 54.3g and has a volume of ~ 30.7cc. That’s right, the density is about 1.77g/cc, and I couldn't believe it myself.

The volume was estimated by rolling it into a nearly perfect ball and then taking the average of three diameter measurements. The diameters were measured on the three perpendicular axes, the x,y & z axes if you will.

Volume of Sphere = 4/3 *pi * r^3

I measured the volume twice, the first time gave a density of 1.78 g/cc the next time 1.76 g/cc. I took the average of these, which as I said before gave a density of 1.77 g/cc. This seems awfully high to me.

The explosive was made from PIB, methyl ricinoleate and SAE 30 non-detergent motor oil/compressor oil (I think that is what the auto parts store guy said people buy the non-detergent stuff for mostly, compressors).

The methyl ricinoleate was made from castor oil laxative. It was made basically the same way one would make biodiesel. I guess biodiesel made from methanol & castor oil is ~90% methyl ricinoleate.

The 15% inerts (PIB, oil, methyl ricinoleate) are all dissolved in white gas, and then the ETN is added and mixed well. I have to find my notes but I think I last used about 5% of each, or close to it. After it is mixed well the gas is allowed to evaporate, not in the light, especially not sunlight.

I have a little table with a smooth plastic surface on it. I found a really good way to knead the dough .....er I mean plastic explosive. Once the gas is gone or almost all gone, put the mass on a nice clean smooth surface, and use a glass rolling pin to knead it. Knead it really well, just like making pizza dough. I found that an old beer bottle with the labels cleaned off makes a great rolling pin.

A little more methyl ricinoleate usually needs to be added during kneading to get the right consistency (few drops at a time while kneading).


Last year I did a little explosive test with 30g or so of this type of plastic explosive. I stuffed the 30g or so into a plastic pill bottle and used a paper blasting cap to initiate it. I normally use about 1.5 g of ETN, MHN or PETN with a little primary on top, all well pressed in a paper tube to initiate this stuff. The inerts make the explosive surprisingly insensitive to initiation.

The charge was duct taped to the side of a large barrel (that old barrel is nothing but holes now). It was fired with safety fuse. When it detonated it formed shrapnel, 6 or 8 pieces about the diameter of a pencil eraser went through the other side of the barrel like tissue and embedded themselves in a woodpile 15 ft behind the barrel. None of the dynamites I ever made created shrapnel like that.

It is unbelievable the difference in brisance of this stuff relative to most dynamites and the common blasting agents.





I would like to thank nitro-genes for outlining his process to produce a plastic explosive using PIB in the thread PETN vs RDX. I used his work as a guide, which helped me when I was first attempting this a great deal.



[Edited on 25-4-2012 by Hennig Brand]

I just noticed something really interesting when I was looking at the Semtex composition numbers on the Semtex Wikipedia page. I had a hunch and I plotted the data just to show that my hunch was correct.

Here is the data table taken from the Wikipedia page on Semtex.





Here is a plot of percentage Inerts vs. percentage PETN, for the three different Semtex types, done in excel. Now I don't know about you, but I don't think I have ever gotten an R^2 value of 1, for any straight line graph, unless of course the data was deliberately set up that way.


Attachment: Percent Inerts vs Percent PETN (23kB)
This file has been downloaded 1013 times


Makes sense really, that Semtex would need more inerts than C4 in order to meet the sensitivity requirements. Simply adjusting the amount of inerts in proportion to the amount of PETN is quick and easy and obviously gets the desired results (more or less).



[Edited on 28-4-2012 by Hennig Brand]

Ok, I am now convinced that C4 produced in North America and Great Britain uses silicone oil. After reading some patents and a journal on characterization of C4 explosives, I am convinced.

This does not mean that other oils are entirely unsuitable!


The reasons I see (so far) for using silicone oil are as follows.

1. Much more stable viscosity over a wider temperature range than other oils. This is the same reason why some vehicle shock manufactures switched to silicone oil.

2. Chemically very stable and unreactive with most other chemicals. This helps ensure longer shelf life even in severe storage conditions.

3. Essentially Non-Toxic. This is important from a handling prospective.

4. Non-Flammable. Having a flammable hydrocarbon mixed with a high explosive seems like added liability.

If people could add, or make changes, to my list I would appreciate it.


Anyway, I have included a couple of figures from the journal I was reading. The journal article is from "Analytical Chemistry", 2010, and is called.

"Characterization of Composition C4 Explosives using Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy"

By

Christine M. Mahoney, Albert J. Fahey, Kristen L. Steffens, and Bruce A. Benner, Jr.
All from the "National Institute of Standards and Technology"

And Richard T. Lareau, from "Transport Security Laboratory"





Notice the amount of Si and Oxygen, in the X-Ray Photoelectron Spectroscopy (XPS) results, for English C4. Apparently all three samples, American, American commercial and English, showed the same general make up, but with variations in proportions.

note:
X-Ray Photoelectron Spectroscopy (XPS), is a quantitative test. There is a good Wikipedia page on it if interested.


Also notice, from the C:N ratios chart, the large variance in the proportion of inerts and RDX between the American, American commercial and English C4 samples. The English sample had the highest C:N ratio, therefore the highest amount of inerts. The American commercial sample had the lowest C:N ratio, therefore it has the lowest amount of inerts.

It is obvious from this journal that there are several different types of C4, each with its own composition. It was also clear that all three types of C4, studied in the journal, are made from the same or very similar components.



[Edited on 29-4-2012 by Hennig Brand]

I have a question regarding picric acid. Is crystallization from solution the best method for acquiring high density?

A picture of crystals of TNP:

I found another interesting journal article. I have included a couple of lines from the abstract below. I am trying to get ahold of the whole article, but so far no luck. The article is titled,

"Characterization of Semtex by supercritical fluid extraction and off-line GC-ECD and GC-MS"
by
Gregory C. Slack, Harold M. McNair, Lou Wasserzug
Journal of High Resolution Chromatography
Volume 15, Issue 2, pages 102–104, February 1992


"Researchers using electron capture for the detection of explosive vapors currently claim the ability to detect the presence of RDX in Semtex – a plastic explosive comprising hexahydro-1,3,5-trinitro-1,3,5-triazane (RDX) in a matrix of styrene-butadiene copolymer and hydrocarbon oil."

This would seem to be in agreement with Maniak's assertions about the plasticizers used in Semtex.



Ok, I just found another good article.

"Characterization of Three Types of Semtex (H, 1A, and 10)"
by Stephanie Moore, Michele Schantz, William MacCrehan

Received: November 13, 2009; revised version: December 14, 2009

From Propellants, Explosives, Pyrotechnics

I have included a couple of the results tables from the report.





It seems like they do rely heavily on hydrocarbon oils, but some other plasticizers are used as well. It also seems like many different things that could end up in the mixer.

You know, I don't see any octyl phthalate or dibutyl citrate in either of those lists.



[Edited on 3-5-2012 by Hennig Brand]

Sorry, but when I see these analytical articles... I think that it would be better if autors will throw away their costly instrumments (or give it to us) and then they will just ask manufacturer which materials are used and of which purity. For forensic analysis, manufacturer will probably give them correct numbers so that they can write some review article

This is the abstract, from the article referenced in my last post, which should have been included.

"Abstract
Solid phase microextraction and solvent extraction were used
with GC/MS to determine the vapor and compositional profile
of three samples of Semtex (1A, H, and 10). Semtex is reported
to contain PETN and/or RDX, along with plasticizers, binding
materials, and fuel oil components. In an effort to differentiate
and compare these three variations of Semtex, this report summarizes
the headspace and solvent extraction results for each
material. Components that can be used to differentiate varieties
of Semtex were identified and all three Semtex profiles were distinguished."


I thought I should add the following quote from the same journal as well. It explains why Styrene Butadiene did not show up in the results tables.

"The styrene/
butadiene copolymer took the longest to dissolve in
dichloromethane and once injected, did not provide any
components that eluted from the column. A higher
column temperature (300 C) was applied, but still no
peaks were observed. In a similar fashion, Sudan IV did
not result in any detected peaks."

and also:

"As
previously mentioned, 4-phenylcyclohexene was seen in
the SPME profile of the styrene/butadiene analytical
standard. Since 4-phenylcyclohexene (4-PCH) has no recognized commercial use, it is safe to assume that detection
of 4-PCH at 16.3 min suggests the presence of the
reported styrene/butadiene copolymer in Semtex 1A."


I probably should have included tables 1 & 2 which have the results of testing the standards. Tables 1 & 2 show the results gotten from testing pure samples of known/suspected Semtex components, obtained from chemical supply houses. Here are tables 1 & 2, from the journal referenced in my last post.



[Edited on 6-5-2012 by Hennig Brand]

Quote: Originally posted by Hennig Brand

Picric acid can be melt-cast for highest density. Pure picric acid melts at ~122.5C. Unlike water most substances, including TNP, increase in density when they solidify from the liquid state. When picric acid crystals are simply compressed there are many tiny air spaces, which lower the overall density relative to a solid cast of the explosive. The tiny air pockets make the explosive much easier to initiate though.

I don't have any personal experience with casting Picric Acid. I do know that it was done a lot, especially in WW1. For safety an oil bath should be used and no open flame (use a hot plate). I would make sure the Picric Acid is as pure as possible; some contaminants can increase sensitivity and add to the danger(metallic impurities especially). Keep in mind even pure picric acid is much more sensitive in the hot, molten state. Picric Acid is often mixed with other lower melting point explosives, making a mixture with a lower melting point than pure picric acid.

The vaporizing chunks could maybe be vaporizing or subliming dinitrophenol. Taken from Wikipedia:
"2,4-Dinitrophenol is a yellow, crystalline solid that has a sweet, musty odor. It sublimes when carefully heated and is volatile with steam, boiling point 113 C....Picric Acid boiling point > 300 C, explodes."
Maybe all one has to do to remove the DNP from their TNP sample is to distill it off.

I think I am starting to see why I always seemed to loose a little weight during the times I was experimenting with Picric Acid. There are times during a TNP synthesis when a person could be exposed to more DNP than you might think. When recrystallizing TNP I noticed anywhere the vapor would condense that there would be a bit of yellow stain. DNP being so much more volatile than TNP, if present, would have been the major component of the dye in this "yellow steam" (I think).

I hope I have helped some. I have made TNP quite a few times, but truthfully I have never cast it.

[Edited on 7-5-2012 by Hennig Brand]

My ETN plastique has a measured density of only 1.43 g/cc, however it still packs a mean punch. I have used large marble sized pieces to puch holes in steel plate up to 1/4 inch thick. A friend and I placed 12g on a 1/4 inch plate and it punched a nice neat hole (well it ripped a scab off the back actually). I don't have a picture because the piece of plate was given to my friend and I didn't have a camera at the time. He was very impressed and asked to keep the piece of plate, so I let him have it.

Here are a few pictures from the other day, which show the result of initating 10g of the same plastique on a piece of rectangular structural steel. The steel is 1/8 inch thick. Notice how it cut out a disc and then drove it through the other side and deep into the ground. I still didn't bother to dig up the piece, but can tell it went down at least a few inches.



[Edited on 8-5-2012 by Hennig Brand]

I think quicksilver is right. I have looked at several journals and texts now and it appears that detonation pressure can mean two different things depending on the source. In some references it is the CJ pressure, and in others it is the pressure the detonation can generate on its surroundings. It seems like the CJ detonation pressure is close to double the "blasters" detonation pressure for the couple of examples I checked.

The following is mostly stuff I wrote last night. I was a bit confused.

I am not an expert and I may have spoken too authoritatively. I read a little about detonation pressure lately, found it interesting and was surprised how high they could go. I posted the calculation just for interest, because energetic materials producing millions of psi truly is amazing.

Now, you could be right. In the case of military explosives it may make little difference (maybe). I don't know about the hydrodynamic model but, in most explosives especially with small charge size (like ours usually), confinement has a lot to do with the detonation velocity of the charge. All the equations I have seen show detonation pressure as a function of the detonation velocity squared. This means a small drop in VOD can dramatically affect detonation pressure.

I suppose military explosives (ideal explosives), probably do not suffer diminished detonation velocity caused by poor confinement or small charge size the way commercial explosives do. For many commercial explosives the published VOD is best case scenario, often not obtained. The formula and information I referenced in my last post came from an explosives engineering paper on rock blasting. Many of these explosives are not ideal explosives and will behave differently than a military explosive.

Yeah, I suppose I wasn't thinking and the ETN plastique's VOD would be affected much less by confinement and charge size than the explosives used for rock blasting (like in the paper I referenced).

Unless we have equipment for measuring detonation velocity, most of us will use the published values. The note in the last post was meant to acknowledge that this may be over optimistic. In the case of more ideal explosives maybe it isn't.


edit:

Ok, I have been trying to read a little about this. The hydrodynamic model is made to model pure explosives, not mixtures. Apparently the biggest reason non-ideal explosives are not well defined by the model is because of incomplete reactions during detonation. Can a plastique with 16% inerts be treated like a pure/ideal explosive?

I found this Los Alamos paper online:
"Quantification of Non-Ideal Explosion Violence with a Shock"
by
Scott I. Jackson and Larry G. Hill

It would seem to indicate that C4 behaves in a way which is very closely represented by the thermodynamic model. So my homemade plastique most likely would behave similarly.


A snip-it from the report:



[Edited on 11-5-2012 by Hennig Brand]

I apologize if some of what I wrote above is incorrect. I found this in the course notes for an engineering rock excavation course from the university of Arizona. It seems to agree fairly well with what Maniak said. The problem I am having is, one not being all that familiar with the material but also, finding that the terms are not necessarily always used in the same way (I think).

"MGE 415 – Rock Excavation 2004

2.3.2.6 Detonation Pressure
The detonation pressure is the maximum theoretical pressure achieved within
the reaction zone and measured at the C-J plane in a column of explosives.
The actual pressure achieved is somewhat less than this maximum due to
non-ideal loading conditions always present in practice and due to certain
explosive formulation. Most commercial explosives achieve pressures in the
range of 0.29 to 3.48 x 106 psi (2 to 24 GPa). Although detonation pressure
is related to the temperature of the reaction, a number of simplifying
formulas are available for estimating detonation pressure for granular
explosives based on detonation velocity and density, for example

(in English units):
P = 0.00337 ρ V2
where P is detonation pressure in psi,
ρ is density XXX
V is detonation velocity in fps.

2.3.2.7 Borehole Pressure
Borehole pressure is the maximum pressure exerted within the borehole
upon completion of the explosive reaction measured behind the C-J plane.
Such measurements cannot be made directly and are done during
underwater tests performed for energy and strength determinations. With
the use of hydrodynamic computer models, theoretical calculations of
borehole pressures are made. There is little agreement in the literature
regarding specific estimates of actual borehole pressures. In general,
pressures after detonation within the borehole are estimated to be less than
30% of the theoretical detonation pressure."


edit:

I did a little explosive testing today and took a few pictures. Here are 5 of the better pictures. The charge in the picture is 14g of ~1.43 g/cc, 16% inerts plastique (using polybutene binder instead of PIB this time). In the final picture is included the disc from the bottom of the steel tubing (I think), which was retrieved from 4 inches below the surface of the rocky ground. The target is as before, rectangular structural steel tubing. Tubing sides are 1/8" thick.

It seems like the steel next to the explosive got pulverized and the steel disc is what was left of the bottom piece. The side of the disc facing out in the picture was ground off, because I was trying to see if the disc was two discs welded together. I now think it was just the bottom piece, because it has a seam that matches the bottom and no other pieces could be found.




[Edited on 13-5-2012 by Hennig Brand]

Just for fun, and a bit of affirmation, I initiated 13.5g of the same 81-82% ETN plastique, twice, using caps made of all the same materials. The difference between the tests was that for the first test the PETN base charge was hand pressed as hard as could be comfortably done and for the second test the PETN base charge was pressed much harder using a simple lever press.

The caps were 3/16" id aluminum tubing with about 25-27 thousands of an inch wall thickness. The base charges were 0.5g of PETN, initiated by 0.1g lead azide and a bit of basic lead picrate as flash igniter. Black powder, core burning, fuse was used for delay and ignition. The target was structural steel tubing with 1/8" wall thickness.

What a difference! The hole on the left is from the first test. The first test resulted in a larger top hole with a lot of tearing, but the hole on the bottom side was much smaller. The explosion from the first also sounded much more impressive; the second explosion was a much sharper crack rather than a huge boom like the first (at least that is how it was perceived by me and two others). Because of the greater roar, and the tearing, the two others thought that meant that the first explosion was much more powerful than the second. The second explosion obviously had much higher velocity and power. The explosion was a very sharp snap, which cut out nearly a perfect hole, on both sides of the tubing. The holes top and bottom where also of nearly the same size, while in the first test the bottom hole was significantly smaller than the top.

The hole on the left is from the first test (hand pressed base charge). The hole on the right is from the second test (lever pressed base charge). The last picture is of the bottom of the target.





[Edited on 18-8-2014 by Hennig Brand]

Good demonstration, yes the charge pressed by lever is obviously more powerful

What kind of press and how you pressing your blasting caps?