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franklyn
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This video shows the rope braided in slow motion
fast forward to a third of the way into the video
and view the middle third of it.
http://www.youtube.com/watch?v=UyDHBNix6hA
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quicksilver
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The astounding level of intricacy in both the machinery and the production itself is appropriate since in many instances the rope displayed will be
relied upon to save / protect human life.
But in a sense couldn't that also be said about fuse or explosives? I would love to see a video of that quality on the production of det-cord,
blasting fuse (the real thing) or related industry-standard production techniques. ISEE's web site once had that from the Institute of the Makers of
Explosives. But it's been replaced for some time now.
If you search ARCHIVE.ORG you can still find a film I saw as a grammar-school kid with a title called "Blasting Cap Danger!" We used to have to watch
several films of that classic genre'. It's a serious safety issue but it may make some people laugh themselves silly.
http://www.archive.org/search.php?query=explosives%20AND%20m...
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gnitseretni
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Here's a video of such a toy.
http://www.youtube.com/watch?v=6Ya0UdAm7Io&feature=relat...
Forward to where you can see the sleeve being formed. You could lower a funnel filled with your HE right in the middle of the sleeve.
Now the only problem I see here is that the HE is not compacted at all. But if you ran this sleeve through the fuse machine I posted a link to
earlier, that would compact it somewhat. Or maybe tie the sleeve to a post at one end and then pull on the other end.. the stretching will compact it
a little, keep the sleeve under tension (hang it over something and tie a weight to the sleeve or something like that) and wrap the sleeve with tape
as tight as you can. Or compress the sleeve between your fingers and guesstimate the diameter.. get a piece of tubing with a smaller inner diameter
than what you measured and see if you can pull the sleeve through the tubing.
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quicksilver
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The toy is a good one and the fact that it drops from the bottom, even better. Realistically though, after examining the real thing, I don't know if
there is a way to pack powdered material within woven structures alone after certain diameters have been reached. The real thing uses a "core tube"
& BP blasting fuse as well as time fuse uses a "core tube". The advantage there is not only one of production but of variation in energetic
material weight per meter. You would have much finer control over alterations of weight / volume with the "core tube" concept. The woven hull is very
valuable to prevent kinks, protect the tube (which would be thin walled) from abrasion, & aid identification. In times past, the use of tar or
similar adhesive would further reduce kinks. But I am convinced that the right selection of tubing material and level of compression will help a great
deal. It seems to be a two tiered system.
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franklyn
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Det Cord in action
Slow motion view as two lines detonate from the lower left into the shack.
http://www.youtube.com/watch?v=zNP2xCfOdjI
Slow motion view as the line detonates from the lower left on to the bus.
http://www.youtube.com/watch?v=kYjzIMLQYVs
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Microtek
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I think those two clips actually show shock tube instead of det cord. But then, I would much rather have a good way of making shock tube than det
cord....
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franklyn
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@ Microtek
Yes I'm sure you"re right , my fault for not distinguishing the two and using
the term indistinctly. Detcord and Shock tube refer to different materials.
http://www.shocktubesystems.com/drontey.htm
The clue in the video is there is no evident blast effect such as dust in the
immediate vicinity of the traveling wave as you would expect from detcord
which is quite violent. Shock tube can be initiated with a handset as seen here _
http://www.youtube.com/watch?v=1AuTxeV0lxU
http://www.youtube.com/watch?v=C0nEaYL1kps
Shock Tube
http://www.iie-online.com/download/fs/doc/safety_pdfs/shock-...
Detonation Cord
http://www.dynonobel.com/NR/rdonlyres/209B7E9F-6C15-40EF-B67...
Det cord demo from a safe distance.
http://www.youtube.com/watch?v=kdycQR0BnmM
P.S.
In case some missed it in my earlier post in this thread
there is a third method being developed
Light speed detonation velocity
Optic Fiber Laser Detonator
http://www.osti.gov/bridge/servlets/purl/219536-Awf457/webvi...
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-=HeX=-
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Here is something (Microteks idea originally... That man gives me all my best ideas to be honest!)
You know you can buy, from various magic suppliers, a product called 'Flash String'. Well one US suppler sells 'Flash Cord' that is like a thicker
flash string made from several 'Strings' braided together. The one I got, 30 feet, was about 6mm diametre.
MHN and NG form a collidon of sorts, as does NG and NC.
I first tried a ten foot length.
Acetone dissolves them all. MHN is mixed with NG (I did not make any measurements, it was more of a timewasting experiment in boredom) and acetone is
added. The cord is soaked in this and the acetone allowed to evaporate by heating at 50* celcuis, leaving the cord impregnated uniformly in explosive,
and moreso a collidon than a cord. Its physical characteristics were somewhat altered, and it also propagated detonation.
Next, another ten foot length of cord was cut, and a thread tied to one end. The thread was pulled through ten feet of shrink tubing which had an ID
of 8mm. It was 'low temp shrinking' stuff.
The cord was treated, and the acetone mostly evaporated normally prior to drawing it into the shrink tube sleeve where it was heated again for several
hours at about 50*. use of a hairdryer shrank the tube, sealing it up. Some composition now came out the end, as an 'extruded' plastic. Interesting, I
thought.
The cords ends were simply taped shut. Taping a cap to the side, I found again that it propagated detonation.
I know that NC NG MHN mixes sometimes fail so perhaps addition of a nitramine (RDX) would help a bit, I think it would.
What do you think about this idea? Hardly optimum but I think it makes a nice consistent product.
BTW, Microtek, I recall your idea involving tubing, butane and oxygen in stiochemetric ratios as a shock tube. Anything ever happen with that idea?
If you give a man a match he will be warm for a moment. Set him alight and he will be warm for the rest of his life.
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The WiZard is In
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Quote: Originally posted by -=HeX=-  |
BTW, Microtek, I recall your idea involving tubing, butane and oxygen in stiochemetric ratios as a shock tube. Anything ever happen with that idea?
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Acetylene perhaps?!
A Plumber! A PLUMBER!! My kingdom for a Plumber!!!
"In a time estimated to be about 6 sec, an accidental fire-initiated decomposition
flame in acetylene at ca 200 kPa in an extensive piping system traveled
successively through 1830 m of 76-203-m pipe, 8850 m of 203-mm pipe, and
760-m of 152-mm pipe." [37,180 feet of pipe.]
K&O 3rd
djh
---
There are two things a real man
likes — danger and play; and he
likes woman because she is the most
dangerous of playthings.
Frederic Nietzche
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Microtek
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Well the idea with a gas filled tube was something I saw in a patent. I tried it out with hydrogen and acetylene as well as the propane/butane mix
which is commonly used in camping stoves and lighters. I experimented with fuel/air mixtures within the explosive limits, but found that in small
diameter tubing (2-3 mm IIRC) you are likely to get a very sedate propagation, at least when simple ignition is employed.
So, I would think that to come up with a system that actually works as a shock tube substitute you should:
- Use pure oxygen rather than air
- Use larger diameter tubing
- Initiate with a small cap rather than simple flame
Personally, I would prefer not having to increase the size of the tube.
Edit: Of the three systems, hydrogen worked best by far under the given conditions.
[Edited on 7-9-2010 by Microtek]
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franklyn
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Hydrogen and Chlorine is photoactive and explosively reacts upon exposure to light in a 1 to 1 molar ratio
to form HCl. Opaque tubing filled with this mixture would achieve wave propagation at some fraction of the
speed of light since the light emitted by the reaction triggers the unreacted portion ahead in the tubing.
The admitted gas mixture follows 3 or 4 ball bearings introduced inside the tubing snugly fitted at one end
but not tightly , so they move through by just jerking the tube , and are pulled along by applied vacuum at
the other end. This assures complete purging , so the charged gas mixture remains unadulterated.
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Microtek
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Nice idea, Franklyn. The question is whether the emitted light is of sufficiently short wavelength to propagate the decomposition at a higher than
usual rate.
I remember seeing a demonstration where a photo flash was used. It involved three vials of H2/Cl2 behind three screens of glass. One screen was clear,
one was blue and one was red. When the flash was fired through the clear or blue screens, the gas mix would pop, while the red one would block the
short wave lengths so no ignition took place.
Or course, it might be possible to use the gas mix as a sort of primer mixture in an ampule preceeding the blasting cap, with a fiberoptic cable in
place of the actual shock tube.
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franklyn
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@ Microtek
There's nothing to say that the H2 / Cl2 mixture cannot also additionally be
seeded with something having a different emission spectra , argon perhaps.
Regarding your application of acetylene :
Enthalpy of elemental Oxygen is zero. Substituting a more energetic oxidizer
such as ( N2O ) Nitrous Oxide should markedly improve wave propagation.
On page 185 of International Critical Tables regarding Explosive mixtures is
described a mixture of 1 to 2 molar ratio Acetylene to Nitrous Oxide , noted
as having ~ 2580 m/s velocity of detonation.
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The WiZard is In
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| Quote: Originally posted by -=HeX=- |
BTW, Microtek, I recall your idea involving tubing, butane and oxygen in stiochemetric ratios as a shock tube. Anything ever happen with that idea?
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No doubt the collective will —
A. Be astounded to know that there is a book on gaseous detonations
B. Be amazed to know that I own a copy.
That said la book is tres theoretical.
MA Nettleton
Gaseous Detonations Their Nature, Effects and Control
Chapman and Hall
1987
'bout the only useful easily found info dobe —
(2H2 + O2) + 5He Calc. 3613 m/sec Exp. 3160
4H2 + O2 Observed 3344 Theoretical 3425
Vapours
100% HN3 2.60 km s
100% ClN3 2.3
100% C2H2 1.92
90% H2O2 + 10% O2 1.92
NB - Velocity does not guarantee ignition.
djh
----
One of the
few remaining
analogue people
in a digital world.
[Edited on 8-9-2010 by The WiZard is In]
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DNA
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Maybe a bit of a bump in this topic but I had this idea for a while.
Get a silicone tube and fill it with plx.
Critical diameter can get low as 4.7mm with 2.5 wt% of ethylenediamine.
What are your ideas about this?
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Bert
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One of the nice things about commercial det cord is you just cut what you need and go- liquid or gas filled tubes can propagate a detonation, but I
don't see them as practical for field work. Solid is the way.
The original "cordeau" was made by filling a short heavy walled Lead tube with cast TNT (or a tin tube filled with picric acid) and then drawing it
through a series of dies in the same way wire is drawn- Producing a long thin moderately flexible tube filled with crushed HE. Perhaps another look at
this technique?
[Edited on 4-2-2011 by Bert]
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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quicksilver
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@ Bert:
The "draw" concept could work no doubt. but with TNT. I have seen wire drawing machinery before and the Pressure is substantial. TNT appears safe from
friction/impact enough to attempt a small section. but the COST (of the device) is substantial. There is a tubing reduction machine that can be hand
cranked (if one could be located) it's used in some jewelry applications and there may even be a way to work with this on a manual basis. But where to
get lead tubing?
ANY tubing has criteria that is challenging. It must be thick and tough enough to bend without tearing of permanently kinking, yet thin & flexible
enough to receive initiation from adjacent shock (cap blast).
[Edited on 4-2-2011 by quicksilver]
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DNA
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But besides the field practical side of it. If you just consider you want a certain length of detcord then you can make it.
The liquid plx has a constant and uniform density therefore no problems with loading and very quick to manufacture.
I tested a 9mm ID tube, but it didn't detonate (blasting cap inserted in the liquid)
While from the same batch of plx a vial of 25ml did detonate (1 minute later) with an exact same blasting cap... how could you explain that?
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DougTheMapper
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Jeez, what about a liquid energetic soaked into a thick string which is pulled through the tube?
I make MEKP caps with straws and cotton wool...
Put a thread through a tube with compressed air, soak a thick cotton yarn in EGDN, methyl nitrate, or maybe NG, then use the thread to pull the yarn
into the tube while the end is submersed in the explosive as so not to introduce air. Seal the ends when done...
Heck, dissolve some more powerful explosive into a liquid explosive to make a syrup. Even better! Is ETN soluble in EGDN?
Victor Grignard is a methylated spirit.
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vulture
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This could be an ignorant idea, but for people in the US (or other countries with lax gun regulation), couldn't one use double based powder as
absorbent for the ETN or explosive of choice?
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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grndpndr
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Smokeless powder grains are rather large for a small diameter tubing although DBSP/ETN and combinations would be relatively inexpensive.As far as
Lax gun regulation thats a matter of opinion and a political statement not altogether popular
in the USA.
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holmes1880
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How to do it the easy way....
We suspend the very thin nylon tube from 50f-100ft with a weight on the bottom, so this way it is straight. Then, we start filling in all that hotness
from the top by simply using an appropriate diameter metal rod (but that can slide more or less freely through the tube....so pretty thin rods that I
saw at Home Depot) and just have it tied by a thin fishing line/weaving thread. So we just let it slide down all the way to the bottom, bringing with
it all the ETN, then pull back up and repeat until the thing is full.
And you ask me if that's impractical and you don't have 50ft.......no doubt but it is easy, cause I have a staircase that's over 80 feet high or
so...... If that's not enough, I suspend that hotness from somewhere higher. But if you want practical, than I suggest getting some type of pressure
machine, having some kind of light fit plug with a lead line. So you put in the pressure, pushing the plug, which pushes ETN. Once done, pull the plug
back out by a thread.
I should so flaming patent that!  But det cord makes too much noise, so not my
specialty.
P.S. Wizard, WTF? seriously.....replying with essays is ridiculous. Sentences of 100 words or less work too. 
[Edited on 5-2-2011 by holmes1880]
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DNA
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Would plx soacked in cotton also work, like NG?
And when using pure liquid PLX it didn't detonate with a blasting cap.
While it did while it was in a vial where there was more plx right around the blasting cap...
Still can't figure out why that didn't work...
9mm ID tube, 7mm blasting cap OD, glued inside the tube full of plx...
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vulture
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| Quote: |
Smokeless powder grains are rather large for a small diameter tubing although DBSP/ETN and combinations would be relatively inexpensive.As far as Lax
gun regulation thats a matter of opinion and a political statement not altogether popular in the USA. |
I wasn't implying to use the grains as is, rather dissolving them with the explosive of choice, in the hope that this would form a paste. The added
bonus is that the stabilizers in the powder reduce the hazards associated with NC.
As for lax gun regulation, I fail to see how that statement is political. You are trying to make it political. In my book it simply means easy access
to guns without regulatory hassle. I fail to see how that is a political statement, as there is no judgement or ideology associated with it.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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quicksilver
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The tubing is actually the most critical component. I have already thought of how to fill it with no problem in lengths of up to 10 meters (perhaps
more) but the material is not something that can be some ridiculous item like vinyl tubing or such. It must be thin, strong, yet able to transfer
shock energy very easily.
A "fuse-weave" machine could be used obviously but the cost and the final sealant would be a serious mess and lack professionalism. A fuse-type weave
machine is also unpredictable in-so-far as it's total length as the spools are not that predictable until it's been used for some time.
It's actually a problem in mechanics. A simple experiment will prove what I mean. Use a 10meter section of .25" clear vinyl tubing so that you can
watch the interior. To that afix a funnel so that it's quite tight and re-enforce it with a clamp. Use common table salt and go to any area with an
over-hang or roof and start to "twirl" the tubing by holding the funnel so that it makes gentle figure "8"'s. as it continues it's movement gently
pour in salt and the tube will fill with remarkable compactness. HOWEVER vinyl will never transmit effective energetic shock and you are really only
left with 25-30 feet at best. It's a very ghetto method but the filling- per se' is NOT the problem......the tubing and it's characteristics ARE!
You could also do this with forced air and make it actually continuous but the most I have experimented with was several feet and the method worked
well. Again....it's not the method to get it within the tube but the choice of tube itself that is a challenge. If you ever really want to experiment
with the mechanics of this cheap table salt is a fair go as it does have similar consistency albeit a bit tougher, than many energetics. For Heaven
sake NEVER consider peroxides as a kink will be a disaster....
This whole subject had been a "how-to toy idea" for many, many years. I really believe that the best method is to eventually buy a fuse making
machine. If anyone has any experience with leather or braiding they know there is several types of braiding that would work manually but it's simply
to much bother by hand and with anything but proper tightly woven cotton or a blend. A device similar to a KUMI Loom may be workable (Kumihimo
braiding).
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