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Marsh
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| Quote: | Originally posted by chemoleo
I think partly the reason that people do not comment is because not many have access to ammonium perchlorate. If you did the same thing with NH4NO3,
it might be of more direct use to people. However I think this's been discussed a lot elsewhere.
But don't fret, we all read it with interest!
BTW, for 200 g, do you really think this is impressive? It is quite a large amount.... and SC's have been made with smaller amounts. Did you try the
same wiht proper HEs?
PS I also don't think you'll get much appreciation for mixing x with AP - I think it has been established that this is a risky thing to do.
I do like the MEKP idea though!
PS2 I can't imagine that a 5 % difference in AP supposedly makes such a big difference! ARe you sure there weren't other factors involved? This would
be most surprising.
[Edited on 13-8-2006 by chemoleo] |
I thought ammonium perc was fairly easy to come by, I guess not (it is for me).
At 200g it is a huge charge for a crater that small indeed, but this wasn't effectively the harnessed amount used for the actual cut...the surrounding
amount around the cone was less.
The only reason I tried this shaped charge is simply because I was curious if a small jet would form, from the much improper setup (plastic liner).
I have seen people use larger charges, and get not even as much as a dent on the target from a half-proper liner. So I was surprised to see
penetration from plastic and a mixture such as this.
As far as mixing TCAP being frowned upon, well as you said, the mix always involves MEKP which is seemingly much safer. There isn't a scary dry
mixture on hand.
After I posted that the TCAP really isn't needed, I really wanted to take that back. After firing a few more charges, and like Rosco is talking about,
I really feel brisance is much greater with a TCAP/MEKP mixture (it's simple to figure out as density rises a bit).
By the way, that 5% change made an extreme difference. I cannot over emphasize this. The 80:20 seemingly made a longer lasting fireball in the video.
The 85:15 (actually only 4% difference because it was closer to 84:16) made a much sharper crack (by this I mean noise, which echoed more), and
obviously did a lot more damage to the steel. I have that video, but it is at night so all that can be seen is the flash. But, the mixes using the
TCAP do seem to leave a cleaner residue after detonation I noticed, I do not know why this is exactly...must simply be a more complete det.
I haven't ventured below the 85:15 ratio, but possibly more brisance can be gained, I do not know for sure.
I really think the test for this stuff would be with shaped charges and various TCAP/MEKP ratios, as well as various ammonium perc/MEKP ratios.
I simply do not have thin steel to try any other tests on now, unless I find some plate.
I do not have NM, but I really would like to see an ANNMSA comparison.
About the TCAP det's, I know it's kewlish and weak to use, but it is the best I can do until my pent arrives anyday. Also on this note, I will try to
test an equivalent PETN plastic charge (with plastic liner) on this steel for result comparison.
And also about the various minimum SC diameters which aren't yet determined, I do realize this as well.
There is really a lot of testing I would like to do with this mixture. I just simply do not have the materials I need at the moment. If I can figure
out how to cut these lightbulbs properly I can use them as liners for a test.
Mainly what's keeping me going on this mixture, is the fact that it seems relatively powerful so far for its simplicity. Although it uses the
peroxides, in this scenario it isn't exactly a bad thing. I know it will never cut steel like a true high-Vod explosive, but if it can manage to be
perfected to deliver good results, you really cannot limit something like this out completely. I know it isn't as "exotic" etc, but of coarse a lot of
us do seek something as simple as this.
So whatever I can find out through experimenting, I will and post. In the end it may not be a "wonder explosive" like I may seemingly make it out to
be at the moment, but it has just come off as an appealing mix to me so far, and definitely not expensive.
[Edited on 14-8-2006 by Marsh]
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Boomer
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Two points:
1. That big a difference is *impossible* to be reached by just 4% ratio change. Compare 80/20, 60/40 and 50/50 amatol, quite a linear change. 4% would
make less difference than random things like packing density/cap placement/container shape etc.
What I strongly suspect is that the drier mix went high order, the 80/20 mix went below max potential. Read the kinepack patent to see why they add
xylene to the NM, it is done to keep OB while preventing the stuff from getting saturated with liquid, which would happen if they tried to get zero OB
with just NM.
2. The dent is clearly *no* jet hole, but the result of munroe forces alone. They are under-estimated by most. Try an identical charge with just a
paper cone (or remove the cone before placement) and you'll see.
On a side note: Why not use some (inert) solid fuel, with less peroxide in exchange? Would be safer, cheaper and not too much weaker. You'll never get
a good SC explosive from an ammonium salt plus fuel anyway, unless the fuel is TNT or HMX, or the mix is cast and highly dense. What you *can* get
from this is something similar in performance to kinepack (ANNM) and straight dynamites.
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nitro-genes
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Well, the munroe forces alone decrease rapidly with standoff, and he did use almost 1 CD space between cone and target. I was surprised to see the
crater at all and I don't think kinepack would have had the same effect with such a standoff. Then again, maybe the plastic did contribute in
tranferring some more energy to the target than with no liner. Looking at the crater it looks like there has been a good focus of the liner, but the
low mass (density) of the plastic would make any possible jet rather low in energy, thus not penetrating very deep.
Since it is obvious though that plastic does not make for a good liner, try one of your charges without any standoff. 10 mm charges pressed with 2
grams of PETN made this way (no liner, zero standoff) bang through 6 mm steel plate easily. For larger charges, high brisance explosives can do almost
1 CD of penetration. I don't think it will perform like that though since the VoD of your mixture will be alot lower, it would however be a good
indication of brisance. I think that addition of the 5% of MEKP may not boost the brisance by higher density or energy content, but more by reducing
critical diameter for a high VoD a bit.
Some more people were asking how to cut the lightbulbs properly since the flame engulfes almost the whole lighbulb. The solution however is very
simple, turn the lightbulb upside down so that the flames only touch the downside, which you will dispose anyway. 
[Edited on 14-8-2006 by nitro-genes]
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Marsh
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I'll have to disagree as well, I feel this in no way was caused by munroe forces at 30mm standoff.
The crater seems clearly the result of a jet formation.
And again I know some are thinking, "why mess with shaped charges?". Well it simply seems that more can be learned about the explosive through use of
a shaped charge, that's all (even though performance may not be up to par).
I don't think the munroe forces can really be tested with this composition, other than with thin plate/larger charge diameters. Certainly no tests
which could be directly compaired to PETN (well at least not at 10mm CD).
Right this moment I will go and attempt to crack the lightbulbs I have to try another shaped charge. These 40w lightbulbs just seem much too thin to
transfer much energy, I guess I will find out.
As far as the 80:20 vs 85:15, this is sort of unexplained to me also, although it is probably correct that the 85:15 simply went high-order. The main
difference was that much more black residue was left after the burn of the 80:20.
It was my assumption that by default this mixture should outperform kinepak explosives when mixed correctly. The fuel/oxidizer potential just seems to
be greater than an AN mixture...obviously with the much higher oxygen content in the NH4ClO4.
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Marsh
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So I did a quick web search to come up with some Vod's on AP compostions, there seems to be some info about this in the Rogue forum. Well gee what do
you know, I have a user name there, and have not attempted even 1 post, I get there and am greeted with a message: BANNED. Reason:
Wow this is a great forum, you get banned for posting or not posting...does anyone know how that large of an object got up NBK's ass?
Oh well, cookies cleared and I'm in...got some info saying that pure NH4ClO4 detonates at around 3677m/s, although actual without voids should be near
4000m/s.
While at the same time a 65:25:10 AP/Al/Acetic acid will give 6900m/s.
Lactic acid replacing acetic will det at over 7000m/s.
These results look promising for AP compositions. I do have quite a few pounds of Al powder, maybe I could try something a bit different, possibly
using this (AP/MEKP) mixture as a booster.
[Edited on 15-8-2006 by Marsh]
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Boomer
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Those AP comps are highly dense, with the acetic filling the voids? I was surprised myself of the brisance a *melt/cast* AN mix showed compared to the
usual ANxx. See the pic of a 5mm steel plate on which was placed a 22mm cylinder of AN/HDN/UN/NaN. It is not so much that it *did* penetrate, but the
cleanly punched hole with no bending of the edges.
Unfortunately you cannot melt AP, at least there is no eutectic I know of melting as low as AN/GN/NQ or the above mentioned mix which is castable even
from a water bath.
And sorry, my munroe-assumption was probably wrong, overlooking the 30mm stand-off. The dent was then likely caused by the plastic eroding the metal.
Still, it is very different from a typical jet hole, which is not that rounded but rather looks like drilled, with a clean edge.
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Rosco Bodine
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@Boomer
What exactly was the proportions on the melt cast
AN/HDN/UN/NaN ( NaNO3 ) ?
It seems like the HDN should decompose in that mix
when melted , but could additionally form a bit of methylamine nitrate in the melt .
There is also potential for a urea-formaldehyde
polymer / sensitizer to form in the melt . Did you notice any foaming in the melt or did it become opaque from microbubbles ? Any color shift in the
melt observed ?
I have speculated about melts of this sort being
possible to be close equivalent to TNT in velocity ,
and it looks like you have something there which
gives confirmation on this . There have been a few
clues in the patent literature but very few specific
melt cast multiple eutectic compositions mentioned .
Also what sort of sensitivity to initiation did it have ?
[Edited on 16-8-2006 by Rosco Bodine]
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quicksilver
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| Quote: | Originally posted by Marsh
. Well gee what do you know, I have a user name there, and have not attempted even 1 post, I get there and am greeted with a message: BANNED. Reason:
Wow this is a great forum, you get banned for posting or not posting...does anyone know how that large of an object got up NBK's ass?
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There is really nothing anyone can say about that whole issue: it happens so damn much that it's just expected. - I really don't know what that object
is however.
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nitro-genes
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| Quote: | Originally posted by Boomer
See the pic of a 5mm steel plate on which was placed a 22mm cylinder of AN/HDN/UN/NaN. It is not so much that it *did* penetrate, but the cleanly
punched hole with no bending of the edges. |
Impressive performance, escpecially considering the small diameter of the explosive cylinder! Did you use a booster of some kind, or add few %
microballoons to sensitise?
Using a waterbath to meltcast this eutectic is very conveniant, it also means that the melting temperature is less less than 100 deg. C. This makes it
ideal for making meltcasts with other explosives like PETN or RDX, analogous to pentolite or cyclotol...
Hoepfully you wouldn't mind sharing some more information about the exact composition of this mixture?
[Edited on 16-8-2006 by nitro-genes]
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Marsh
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| Quote: | Originally posted by Boomer
Those AP comps are highly dense, with the acetic filling the voids? I was surprised myself of the brisance a *melt/cast* AN mix showed compared to the
usual ANxx. See the pic of a 5mm steel plate on which was placed a 22mm cylinder of AN/HDN/UN/NaN. It is not so much that it *did* penetrate, but the
cleanly punched hole with no bending of the edges.
Unfortunately you cannot melt AP, at least there is no eutectic I know of melting as low as AN/GN/NQ or the above mentioned mix which is castable even
from a water bath.
And sorry, my munroe-assumption was probably wrong, overlooking the 30mm stand-off. The dent was then likely caused by the plastic eroding the metal.
Still, it is very different from a typical jet hole, which is not that rounded but rather looks like drilled, with a clean edge.
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I too am very impressed by that photo. Cleanly punched right through.
It would be highly desired to have an AP melt, but as said, it melts at temps a bit too high to be workable.
On a second note, a PBX explosive using AP should result in good performance as well, any thoughts on possible mixes?
I was thinking AP/Al/PETN, or AP/PETN.
My pent arrived yesterday.
Edit: I tried detonating 42g AP/Al/SP 60:20:20 mixed with acetone and pressed into a film cannister today with a 2g TCAP det. I did not get any bit of
detonation.
I know I know, I need a better det design, but this shows this mix is not easily initiated.
[Edited on 16-8-2006 by Marsh]
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quicksilver
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ETN / AP melt exceedingly well. Initiation is not too difficult with less than perfect detonation devices. On the other hand AP / NM leaves Kinepac
behind albiet the cost difference is such that it was never favoured by industry. I saw a test of the above and it is impressive in small
weights/diamiters.
A very interesting item is the re-crystalization of ETN -=with=- PETN 50/50 and that used as a melt cast base for AP or what have you. ETN lowers the
temp needed for same.
Why not use ETN exclusivly? When compaired in an impact test one finds ETN to be MUCH too sensitive (extra care is really needed with a well made
product) - - on the level of NG. The PETN appears to alter the level of sensitivity to a more comfortable one.
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Boomer
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Sorry I did not come back with ratios on the melt/cast comp, will do so soon.
Where is the sense in mixing ETN with AP, it is already OB positive. All you can do is lower power and brisance. You might boost power by adding Al to
use up the oxygen from the AP, but these would have to be hot pressed instead of cast due to low ETN content. It would be binder and sensitizer in
one. Compare 80/20 amatol.
On a side note, not only is it possible to replace AN with AP in kinekack. Jerry (the inventor of kinepack and also astrolite) wrote on a.e.e. about
it. An excerpt:
"...Beware of Astrolite in cylindrical tubes of high shock impedance. It
loves a good LVD (low velocity detonation) under such conditions and
most anything is liable to set it off. (this just for info - B.)
BTW, Astrolites A and G were pussycats compared to some of the other
letters that nobody ever wrote about in public.
(...) Both of these mixtures are known as Astrolites, a trade name. Astrolite is
a binary explosive, consisting of hydrazin perchlorate and nitrate,
when mixed. Some astrolites are made of only the perchlorate (the most
powerful ones)...."
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quicksilver
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Yes, from the standpoint of OB there would be no doubt that it is not appropriate but from a strictly utilitiarian standpoint there may be some unique
things it could do. ETN melts fast and is very viscous. The interesting issue would be what ratio is used. 50/50 would not be apprioriate but there
may be other ratios that yield a very fluid cast, filling spaces well and solid. The example of alumitised Amatol is a sound one on certain levels.
[It was economicly justified, I believe] From reading patent literature I found that many well made SC models funtioned only if the energetic material
behind them had little or no air pockets. Pressed material seems frought with difficulties but cast material seemed to make even poor designs funtion
well. OB being secondary to a good cast. Would any perchlorate have as much brisance as a well made nitric ester? I doubt it - but it would stretch
the available castable ester material. My only real point in that matter being that ETN is such a good candidate for same.
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Marsh
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I was able to test the AP/TCAP/MEKP in another shaped charge today, 85:7:8 ratio.
What may be useful here is to note the munroe forces demonstrated from this mixture.
The cylindrical lined charges previously tested by Axt (in the Unconventional shaped charge thread) had me interested. It appeared to me by the photos
in that thread that the exits were roughly the result of a combination of transferred munroe force/minimal (or very low mass) jet formation.
It just really didn't look like an efficient jet was formed by the cylindrical-lined charges. This was also mentioned, stating it may have been a
hole-punch effect.
My experiment compared to the previous one by Axt in the respect that I used 16mm diameter copper liner tubing (vs aluminum), and that my liner tube
length was just slightly shorter; 57mm vs 65mm. The base of the charge was 60mm diameter, tapering back from over 70mm.
I felt that the minimal tube length I gave up (8mm compared to Axt's) was acceptable as it helped achieve more head-height above the tube for a
flatter shock wave in my charge, and my cup container was less than optimal for mass conservation.
I felt that the L/D ratio of the tube should have still permitted a decent jet to form (if one was going to do so), so I too used zero-standoff. I
also did this to give an idea of close munroe forces generated from the AP/TCAP/MEKP mixture.
Like always, I used a plastic drink cup you see at the grocery store in bulk packs. The copper tube was glued to the base, and the cup was packed 3/4
of the way.
This time around, I really wanted decent head height above the liner, and a whole 465g total was used to fill the cup mostly to allow this. I could
have used much less had I used PVC pipe as the container. This is a large amount of explosive, but of coarse the amount which contributed to the jet
should have roughly been in the 270-300g range. It was again initiated by one of my weak TCAP dets.
The charge was detonated and the results achieved were not particulary impressive of the design to me, although it did confirm my assumption that
cylindrical-lined charges are not effective at sufficient penetration through thick targets.
Munroe forces bent the total 2.25" of steel all the way through, but unfortunately cylindrical liners do appear to give limited jet formation, and
allowed a maximum of about 17mm jet penetration.
However by munroe force comparison, it is seemingly apparent that the mixture rivals ANNMSA.
On the back of the first plate, I could actually see a pinpoint (actually about 2mm) of copper which penetrated completely, only to be stopped by the
second plate. Thus it is shown jet formation was minimal and/or low-mass.
I have pictured todays crater viewable against the other crater made by using a plastic cone. What I see is interesting, the jet formation (or cavity
shape) seems to play a big role in penetrated material displaced, almost of equal value to that of the liner material chosen (but then again this may
seem like a given). The plastic cone charge actually removed almost the same mass of steel it would appear, but with not as deep a penetration.
I have no doubt that if only one plate was used, damage would have occured duplicating the 1" plate test with 16mm tube which Axt performed using the
ANNMSA.
I will place this info here, and place more of the same pertinent info in the unconventional shaped charge thread, since it seems the info covering
both topics should be in both threads.
Here are the photos:
16mm Cylindrical charge vs. Plastic cone charge crater
2.25" Bent steel
Penetration w/ carrot
Back of first 3/4" plate
[Edited on 22-8-2006 by Marsh]
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ethan_c
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| Quote: | Originally posted by Marsh
I was able to test the AP/TCAP/MEKP in another shaped charge today, 85:7:8 ratio. |
I assume AP stands for ammonium perchlorate?
| Quote: | | My experiment compared to the previous in the respect that I used 16mm diameter copper tubing (vs aluminum), and that my tube length was just slightly
shorter; 57mm vs 65mm. The base of the charge was 60mm diameter, tapering back from over 70mm. |
I don't quite understand this…you say the tubing is 16mm diam, but the base of the charge is 60mm? Could you draw a quick diagram on paint or
something?
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kiknet
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I believe he means that the diameter of the Cylindrical copper liner tube is 16mm and that sat inside a 60mm cup
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quicksilver
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By what determinate have you concluded that the cap is "weak"? Knowing if a material is overdriven is often evolved by comparison or in a lab but if
the material does indeed detonate leaving behind none of the original compound could it not be said that the detonation was complete?
As an aside, if the stacked plates shown are not bolted together tightly there will be a "spring" factor upon detonation (albiet minor) that MIGHT
have a negitive effect on penitration.
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Marsh
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| Quote: | Originally posted by quicksilver
By what determinate have you concluded that the cap is "weak"? Knowing if a material is overdriven is often evolved by comparison or in a lab but if
the material does indeed detonate leaving behind none of the original compound could it not be said that the detonation was complete?
As an aside, if the stacked plates shown are not bolted together tightly there will be a "spring" factor upon detonation (albiet minor) that MIGHT
have a negitive effect on penitration. |
I re-worded slightly for the person who hasn't been following this thread, I hope this helps you understand better. And yes, it is simply a centered
tube glued standing in a plastic cup (of coarse!)...
Quicksilver, detonation is indeed complete, and obviously powerful. I used the word "weak" because I feel if I considered my TCAP det's anything more
in this forum, it would be apparent I was lacking knowledge of det compositions.
Like Rosco said, if I was to do some sort of true brisance test for this composition, I should really use a PETN det to ensure the shockwave begins at
a high rate of speed. I simply feel this stuff is sensitive, and TCAP sure as heck does the job. I never have quite understood this, because to me it
would seem (upon initiation) the wave would accelerate instantly reaching the compositions max Vod, but apparently the det may be small factor of
achieved Vod.
And at the spring factor, I really don't know if I would ever worry about this. The jet should be through the plates before inertia of the plates even
begins to move them a mm.
[Edited on 22-8-2006 by Marsh]
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quicksilver
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| Quote: | Originally posted by Marsh
And at the spring factor, I really don't know if I would ever worry about this. The jet should be through the plates before inertia of the plates even
begins to move them a mm.
[Edited on 22-8-2006 by Marsh] |
I really mis-spoke when I used the term spring. I tried to dig up the material before I posted but couldn't find it in time....but there is a military
test of armor for a light vehicle wherein the structure is in series (sort of like the plates shown above) and they were quite a bit more effective
than thicker singular plates. True enough when a jet is measured the time frame is such that one would wonder how any type of "spring" could be
repellant to a jet from a SC but apperently there is some factor being experimented with that reduces the effecency of that jet. It's not a spring
effect, per se' but an element of physics wherein the jet is reduced in effecency by pocket defusment. Seems incredable in the light of the speed of
the jet but I believe that some validity exists to that concept.
On another note you spoke of the head-height of composition above the cone and it started to make me think of the depth of the det in relation to this
level. If one were to experiment with the depth of the det so as to allow the det to encompass a greater degree of base energetic material perhaps
more efficiency could be achieved....The most useful thing about making one's own det is that construction could be altered to fit one's needs. If the
det were wider and flater than the typical tube det a greater area of base composition might receive efficient initiation wave....just a thought.
It seems that since you've come this far and achieved success the individual experiments and their notes have much greater importance. And after
reading this thread the one issue that (for me) begs an answer is: What is the lowest VoD explos that can produce a jet and could the Monroe effect in
itself (no cone, etc) be achieved regardless of the speed / brisance?
[Edited on 23-8-2006 by quicksilver]
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Marsh
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| Quote: | Originally posted by quicksilver On another note you spoke of the head-height of composition above the cone and it started to make me think
of the depth of the det in relation to this level. If one were to experiment with the depth of the det so as to allow the det to encompass a greater
degree of base energetic material perhaps more efficiency could be achieved....The most useful thing about making one's own det is that construction
could be altered to fit one's needs. If the det were wider and flater than the typical tube det a greater area of base composition might receive
efficient initiation wave....just a thought.
It seems that since you've come this far and achieved success the individual experiments and their notes have much greater importance. And after
reading this thread the one issue that (for me) begs an answer is: What is the lowest VoD explos that can produce a jet and could the Monroe effect in
itself (no cone, etc) be achieved regardless of the speed / brisance? |
At the det height, I have really thought about this in my mind lately, and here is what I come up with...
When using a cylindrical detonator with a composition which has a lower Vod than the charge being initiated (my current scenario using TCAP), I have
come to the conclusion that minimal insertion would work to flatten the wave travel.
If you simply imagine, the det being a column expanding from the top as the detonation wave travels, as soon as the expanding portion reaches the
charge, initiation should begin. If you have a detonator holding 5000m/s Vod material, and around it 7000m/s material, the higher Vod material will
obviously race the wave in the det, traveling faster (in this scenario, we are assuming the det is well placed into the material to better imagine the
event).
Since both waves are continuing downward, as well as expanding in all directions, the faster outer waves work inward on the detonator itself (like a
cylindrical lined charge). This should, although being minor, try to force a small jet from the ends of the detonator itself, also initiating a
sharper wave below the detonator. This would be due to two waves whoms speed becomes matched (TCAP being boosted to the higher Vod of the surrounding
charge), but the outer material possesing more energy, thus creating a small jet with the weaker material. Although when imagined this way, it can get
tricky trying to imagine if a jet would really be allowed to form, or if energy of materials would stop this from happening.
If the detonator is placed in contact with, but not into the detonating material, as you can imagine the wave travels downward until reaching the
high-Vod material, and one wave of the same Vod begins. This would be best suited for sensitive shaped charges.
The best suited det design actually for a shaped charge like this, would be a circular ring detonator in which the ring could be completely initiated
from the outsides at the same time. This would start a wave effect similar to using a lens (a reverse wave) and would impact the liner at higher
impeding angles, thus driving a more powerful jet.
I do know that the dets used for some commercial shaped charges look like flat thin pancakes, I assume they must initiate from the middle with a very
high-Vod material to achieve the flatter wave they are after to strike the base charge. If they could electronically initiate all the way around from
the sides instantaneously this would be desireable.
As for the asking of lowest Vod material to achieve a jet, any detonating material is capable of forming a jet in a shaped charge, the dynamics are
always at play. It is the simple fact that, in combination with liner thickness etc, this jet may simply be too weak to permit penetration of steel
targets etc. It would be interesting to see the penetration of a lower Vod material on wood etc simply for view of this, although it is known upwards
of 6000m/s becomes useable for steel cutting, with jet potential basically becoming unlimited with increasing Vod of the material.
Munroe forces are always there, it is simply a term, it's just that the more powerful materials leave these munroe imprints more clearly visable on
steel etc. The charge being a shaped one has nothing to do with the overall munroe imprint left on the steel, for instance in my photo; without the
liner there would have still been the munroe effect (wide) crater.
[Edited on 24-8-2006 by Marsh]
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Boomer
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Is not the phrase "munroe effect" used for *colliding* shock waves, i.e. for charges with a cavity (usually no liner)? You seem to use it for the
inprint on the target having (at least) the same dimeter as charge.
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nitro-genes
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Nice one Marsh...
The cylindrical charge in particular, it looks like the first centimeter there was mainly the hole punching effect from the colliding shockwaves
(munroe forces), but you are the first that also had clear evidence of at least some jet formation!
Although I suspect that this might be due to the fact that your composition may fire at lower VoD's than you think, using this setup and detonator.
Chris did the same setup with methyl nitrate (8000 m/s), and got no penetration at all. It is discussed on the bottom of page 16 of the "shaped charge
thread" IIRC...
[Edited on 24-8-2006 by nitro-genes]
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Marsh
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| Quote: | Originally posted by nitro-genes
Nice one Marsh...
The cylindrical charge in particular, it looks like the first centimeter there was mainly the hole punching effect from the colliding shockwaves
(munroe forces), but you are the first that also had clear evidence of at least some jet formation!
Although I suspect that this might be due to the fact that your composition may fire at lower VoD's than you think, using this setup and detonator.
Chris did the same setup with methyl nitrate (8000 m/s), and got no penetration at all. It is discussed on the bottom of page 16 of the "shaped charge
thread" IIRC...
[Edited on 24-8-2006 by nitro-genes] |
Sorry guys, my understanding of munroe forces were assumed and now I see that they are simply the effect of a cavity with no liner, I stand corrected.
For some reason I had assumed that munroe forces were direct high-energy impact zones visably produced simply from very close material-to-energetic
material proximity. Or in other words, the large craters left around the charges with zero standoff.
Nitro, I read about the certain characteristics of cylindrical liners in those thread pages, and have learned things I did not previously know. You
now have me much more excited about my outcome than previously! I didn't realize there was so much in question about the failure of these charges.
It is quite interesting though, as in case you may have noticed in the penetration photo, I too have a copper splatter which strayed off-axis like
some of your charges. Although mine seems very minor at the most, it is still seemingly happening in a few different charges. I guess here it could
simply be attributed to the not-so-perfect density of a charge this large which is packed.
I have purchased quite a few light bulbs, as I would still like to try a glass charge with this material. I simply haven't had the time to assemble
one correctly myself lately, the cylindrical was quick and easy. I really need to get the bases of the bulb cones flat, or else material could get
underneath and/or they would sit off-center. I could possibly pour epoxy into a cup, and submerge the imperfections of the bulb, then simply drill out
the epoxy from the cone center I guess.
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nitro-genes
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| Quote: | Originally posted by Marsh
I too have a copper splatter which strayed off-axis like some of your charges...
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Yes, I was puzzled by this too at first. After some reading it appeared to be completely normal though. (Experiment first, read later  ) Like you said, small abberarions in the explosives density, the allignement and
symmetry of the liner, and even internal stresses in the metal of the liner.
| Quote: | Originally posted by Marsh
I really need to get the bases of the bulb cones flat, or else material could get underneath and/or they would sit off-center. I could possibly pour
epoxy into a cup, and submerge the imperfections of the bulb, then simply drill out the epoxy from the cone center I guess. |
Hehe, I hope you're an expert in anger management!  I cursed quite some times
myself when I tried to make perfect cones out of those lightbulbs. In the end I gave up, and decided to simply glue the lightbulb to PVC tubing
(explosive container), leaving all the imperfections just to stick out a little into the standoff tubing. Not that they matter in the first place.
Glass glues reasonably well to PVC with PVC adhesive...
But, I only used the lightbulbs because I wanted the liner to be smaller than the 5 cm glass funnel Axt used. Since you use diameters in excess of 5
cm already, these funnels would be a much better choice I think...
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Marsh
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| Quote: | Originally posted by nitro-genes
Hehe, I hope you're an expert in anger management! I cursed quite some times
myself when I tried to make perfect cones out of those lightbulbs. In the end I gave up, and decided to simply glue the lightbulb to PVC tubing
(explosive container), leaving all the imperfections just to stick out a little into the standoff tubing. Not that they matter in the first place.
Glass glues reasonably well to PVC with PVC adhesive...
But, I only used the lightbulbs because I wanted the liner to be smaller than the 5 cm glass funnel Axt used. Since you use diameters in excess of 5
cm already, these funnels would be a much better choice I think...
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I know, the second lightbulb I did had me cursing in my backyard, since the first one turned out OK and then it was hell from there.
Gee, this is starting to turn into the shaped charge thread... Seems to have
drifted this way though so it's alright I guess, since I am really observing just what this perchlorate mixture is capable of as parallel discussion.
But if you guys think I should continue the practical aspect of this to the USC thread, then so be it.
By the way, I'm ordering those glass funnels in a minute here too (but still envy Nitro for his perfect copper cones  ).
I didn't really explain my epoxy idea too great...what I meant was to have the base of my charge be a layer of epoxy that the base of the bulb lies in
and cures. I feel I need the extra charge diameter there (instead of a pipe which fits the exact bulb diameter) to use just a bit more of the
lightbulb for the jet formation, since my charges are usually quite moderate in size.
So yesterday I'm outside talking to the neighbor when he takes some copper pipe out to his garage where he collects it from construction work. I
didn't want to ask for free copper, but then on the top of the pile I see one which looks very interesting to me, and was forced to ask for it...
Any ideas what outcome may result from this? (It is 16mm diameter spun-formed to a closed tip):
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