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twelti
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Centrifuge for pressing primary
This is probably a whacky idea, but I wonder if it would be possible to use a centrifuge to press a primary? No ram, so no friction between ram and
the tube. Spinning up the centrifuge would gradually press the primary down. The coolest part however would be if you used a very small radius, the
force would be largest at the outer end (larger radius), thus the resulting density. The density at the inner end would be lower, and the transition
gradual. No sharp boundary between lower and higher density sections. If you could use a 2" diameter, and ran it at 30,000 RPM, I think that would
be 50,000 g's at the outer end and 25,000 g's at the inner end. For a 1 inch column weighing 1 g, that is 50 kg and 25 kg respectively. Physics is
not my strong point so correct me if it is wrong.
It seems most commercial centrifuges are at least 4" in diameter and running up to maybe 20,000 RPM, so maybe not feasible for the home experimenter,
but interesting to think about. Bonus would be a spectacular explosion if it went sideways!
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XeonTheMGPony
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few 0's missing from that pressing force! so not too much use.
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twelti
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I wonder if it could be scaled up though. I mean, typical I've seen goes up to maybe 20,000, but that is for a 4" size. Any reason a smaller one
could not be spun up faster? Force goes up as RPM^2. Looking at some of LL's diagrams I see forces of 20-70 kg, which would be easy doable. just as
an example...
Maybe we can get some centrifuges from Iran!
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MineMan
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Twelti. Very clever! Great idea,
The thought juices are flowing well. I do want to take a step back and ask, why not just use an insensitive primary or a NEPD? What kind of charges
do you want to kick off?
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Laboratory of Liptakov
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Good idea with an centrifuge for safety pressing. But is it too complicate device for this purpose. Something may go wrong. And the detonators will
become highly penetrating projectiles. Flying in all directions. Conclusion. Use relative insensitive primary and press in classic method in the vice
or similarly. With metal plate around the vise cover.
However pressing is not the most critical operation. Critical is pulling the pressing rod from an cavity. Therefore is iportant using bigger grain,
for example 2x2 mm. With big grains is pulling very easy. Big grain cannot fill the critical point between rod and cavity. However very fine powder it
do it always. For example Lead azide or SA - DS. And it is the most worse critical time, when happend. Twelti, you need more practical exercises with
the vise and with big grains..... ...LL
Development of primarily - secondary substances CHP (2015) Lithex (2022) Brightelite (2023) Nitrocelite (2024)
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fusso
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What about pressing with a hydraulic press?
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XeonTheMGPony
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seems my brain broke and I didn't hit send.
So here I go again:
Can it work yes, but centrifuge can fail too (As Lopkov pointed out) his is best case, worst case is they detonate on mechanical failure of the worst
kind and you have a frag device!
A care fully made die of proper size will not explode on accidental detonation, just scare the crap out of you and bent your pressing mandrel.
there is a reason industry doesn't bother with such things and just presses using additives to reduce sticking and friction, and for my self I have
never had one go off during pressing! mind you I am still below over 1k pressed as of yet (Ya been playing with this stuff too long according to
most!)
take your time, prep every thing care fully, clean every thing well regularly, wipe down mandrel after every press, and just use good protocols and
you will virtually never have a problem, and take the time to learn how to make the tools when one does, it will be an annoyens vs ambulance trip
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Laboratory of Liptakov
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pressing detonators
All the fear from pressing comes only from absence of praxis and experiences. Anyone who has experiences with over 1000 detonators + 10 entire
fingers, can give advice. You take advices from experienced, because you save a lot times and nervs. My conto is over 1500 detonators without
accident. Similarly as Xeon. And my advice is bigger grains with lower sensitivity and use precise tools.
Thats all.........LL
Development of primarily - secondary substances CHP (2015) Lithex (2022) Brightelite (2023) Nitrocelite (2024)
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twelti
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Quote: Originally posted by MineMan  | Twelti. Very clever! Great idea,
The thought juices are flowing well. I do want to take a step back and ask, why not just use an insensitive primary or a NEPD? What kind of charges
do you want to kick off? |
I'm just generally trying to figure out best safest det cap construction (like many others are). My priorities are towards safety. I don't care
about efficiency or cost. There's just so many options, it is hard to decide what direction to go in. Metal tubes scare me, but perhaps that is
irrational.
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twelti
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Mainly just a thought experiment. I am very familiar with acoustics, and for sound propagation, whenever you have a sudden change in impedance, you
get a reflection. Most efficient transmission is having a gradual change in impedance. That is what a horn does. Are shock waves similar? I'm
sure I don't know, but wondered if this gradual change in density would be beneficial in some way. Probably not worth the trouble.
Using granules and additives seems to make sense. If the issue is little bits of primary in the tube, rubbing against the ram when you withdraw it,
it would seem to make sense to use a thinnish disk at the end instead of a solid cylinder (maybe that IS the way it is done?). I could envision
having a small opening at the center of the business end of the ram so you could blow some air out and clear any little bits of primary before
withdrawing the ram (?)
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MineMan
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LLs advice is the best! Use big grains of CHP and you will have little worry.
Yes. Metal tubes scare me too. But LL just did a test where the device worked in .5mm brass. That shrapnel can still hurt!, but that is about what
the thickness of industrial dents are.
It’s funny though friend. Pressing and thick metal tubes makes me very nervous too, if I have been out of the game too long.
The other alternative is to press 300mg of NiAGPechlorate in a small Al Tube. (3mm OD, 2ID) then, even if it goes off there will be very little
shrapnel. In addition the DEG will be so small (15mm) it will be very easy to shield. And ALWAYS hold the diet by the fuse. You see. If it somehow
mysteriously goes off you still have your fingers. Also but SS UHMWPE gloves. There was a study I posted a year ago where one pair of cutproof SS
spectra gloves can help significantly. Truth be told I did by own test and the cap above with 75mg punched through a double layer of the glove. But
you will still be much better off! In that study they showed how double layering can protect from up to 1g of LA
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twelti
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Maybe off topic but related to gloves, just bough these (and some sleeves):
https://www.mscdirect.com/product/details/07050636
I hope they are a good choice.
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Rocinante
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There is no reason to press any primary explosive, I fail to see how this strange, exotic obsession became reality. Light force is enough, you don't
need the efficiency the industry is aiming for - lead azide, mercury fulminate, SA.DS, peroxides.... none require any forceful pressing to work
(beyond very slight force). Obviously, having a completely loose powder inside the cap is a no-no.
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XeonTheMGPony
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| Quote: Originally posted by Rocinante | | There is no reason to press any primary explosive, I fail to see how this strange, exotic obsession became reality. Light force is enough, you don't
need the efficiency the industry is aiming for - lead azide, mercury fulminate, SA.DS, peroxides.... none require any forceful pressing to work
(beyond very slight force). Obviously, having a completely loose powder inside the cap is a no-no. |
because it makes a massive difference in performance and amounts used. Try reading more info on Detonators and efficiencies, it is well listed across
the board of the charts.
Same reason you need to press the secondary.
Amateur / beginner level is lose pack
moderate experience light packed compressed
Experienced Hard pressed = peak performance
Pressed primary pellet and paper carrier
Finished assembly
150mg pellet and paper carrier alone, pressed to apx 100lbs
[Edited on 5-5-2019 by XeonTheMGPony]
[Edited on 5-5-2019 by XeonTheMGPony]
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MineMan
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The cut and penetration level is what you want. But.. it says they are made from cotton. You really want stainless steel fibers and Kevlar type
material.
Yah. I only hand primary’s. But, well. I don’t hardly use primary’s.
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twelti
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| Quote: Originally posted by MineMan |
The cut and penetration level is what you want. But.. it says they are made from cotton. You really want stainless steel fibers and Kevlar type
material.
Yah. I only hand primary’s. But, well. I don’t hardly use primary’s.
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Crud, I only looked at the cut resistance level, which is 5 so how can it just be cotton? Strange... I'm gonna order some of those UHMWPE gloves and
compare.
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markx
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| Quote: Originally posted by Rocinante | | There is no reason to press any primary explosive, I fail to see how this strange, exotic obsession became reality. Light force is enough, you don't
need the efficiency the industry is aiming for - lead azide, mercury fulminate, SA.DS, peroxides.... none require any forceful pressing to work
(beyond very slight force). Obviously, having a completely loose powder inside the cap is a no-no. |
I second that! It has long been amazing me.....the constant compulsive fixation on having to press everything "guudentoit" until the seams burst. And
yes.....I do understand full well what it is supposed to accomplish and what purpose it should serve. But trust me, it is totally unneccessary for
practical approach and it does tend to create more problems than it solves. Not even talking about the safety related issues here.
A light touch is sufficient in 99% of cases that fall under the realm of situations the members here might confront in their research. And for the 1%
remaining there are alternatives that do not require the execution of brute force. At least not on the most sensitive primary part.
Exact science is a figment of imagination.......
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MineMan
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| Quote: Originally posted by markx | | Quote: Originally posted by Rocinante | | There is no reason to press any primary explosive, I fail to see how this strange, exotic obsession became reality. Light force is enough, you don't
need the efficiency the industry is aiming for - lead azide, mercury fulminate, SA.DS, peroxides.... none require any forceful pressing to work
(beyond very slight force). Obviously, having a completely loose powder inside the cap is a no-no. |
I second that! It has long been amazing me.....the constant compulsive fixation on having to press everything "guudentoit" until the seams burst. And
yes.....I do understand full well what it is supposed to accomplish and what purpose it should serve. But trust me, it is totally unneccessary for
practical approach and it does tend to create more problems than it solves. Not even talking about the safety related issues here.
A light touch is sufficient in 99% of cases that fall under the realm of situations the members here might confront in their research. And for the 1%
remaining there are alternatives that do not require the execution of brute force. At least not on the most sensitive primary part.
|
I believe the above is correct. The exception is NPED. Anyways, duds are the most dangerous as they can catch the material on fire. I don’t see a
need for over 100mg of primary. Light pressing is all that is needed.
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twelti
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Would it be correct to assume that if using an (energetic?) binder to safely get higher density without pressing, the loss from using the binder would
offset the gain due to increased density? Or, can we have our cake and eat it too?
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markx
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| Quote: Originally posted by twelti | | Would it be correct to assume that if using an (energetic?) binder to safely get higher density without pressing, the loss from using the binder would
offset the gain due to increased density? Or, can we have our cake and eat it too? |
Depends on binder, energetic and a load of other factors, but as a rule of thumb one can assume a drop in sensitivity (thus a stronger tendency
towards failure) and an increase in critical diameter (thus it might render a small device inert for practical purposes).
What is this mystical "gain" that we actually talk about here? Something that punches through 2mm steel plate vs. something that punches through the
same, but with "extreme prejudice"? Depends of course what the objective of your research is, so I'm not suggesting that one should not work towards
the sharpest bang in the smallest volume. But consider wether that is really a requirement for your purposes before entering the realm of brute force
and high density.
Keeping it simple, thoroughly planned and avoiding strong forces are your best allies. Shield yourself, but within reason.....packing on a kevlar
armor suit, two sets of gloves, a massive mask and trying to accomplish intricate tasks by working around a shield that blocks your access shall
likely make one very clumsy and provoke dangerous situations as a result. Usually things do not go off on their own, they do go off if strong forces
are redirected by mechanical failure and translated into shock loads. And working on the type of compounds that do react without provocation should
be avoided like the plague. There are alternatives.
Exact science is a figment of imagination.......
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XeonTheMGPony
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| Quote: Originally posted by MineMan | | Quote: Originally posted by markx | | Quote: Originally posted by Rocinante | | There is no reason to press any primary explosive, I fail to see how this strange, exotic obsession became reality. Light force is enough, you don't
need the efficiency the industry is aiming for - lead azide, mercury fulminate, SA.DS, peroxides.... none require any forceful pressing to work
(beyond very slight force). Obviously, having a completely loose powder inside the cap is a no-no. |
I second that! It has long been amazing me.....the constant compulsive fixation on having to press everything "guudentoit" until the seams burst. And
yes.....I do understand full well what it is supposed to accomplish and what purpose it should serve. But trust me, it is totally unneccessary for
practical approach and it does tend to create more problems than it solves. Not even talking about the safety related issues here.
A light touch is sufficient in 99% of cases that fall under the realm of situations the members here might confront in their research. And for the 1%
remaining there are alternatives that do not require the execution of brute force. At least not on the most sensitive primary part.
|
I believe the above is correct. The exception is NPED. Anyways, duds are the most dangerous as they can catch the material on fire. I don’t see a
need for over 100mg of primary. Light pressing is all that is needed.
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To two of you: There is a reason Industry does what they do, if it wasn't needed I can assure they wouldn't be doing it!
The goal of any one is to ever seek to improve their craft and aim for best efficiency. When you can't press you need to use more of the active
material, the more caps you wish to make the more primary and base charge you need to achieve what I and lipkove and others can do with a fraction of
the material.
This in practicality means one needs to make and handle more materials, this increases risks across the board far more so then having a good assembly
method that involves a press system, why I call this an advanced level, you really can't go further with out inventing some new and novel system.
making the tooling is a one time investment and will last your life, do if you intend to play with this for any length of time you should be investing
in the tools to do it safely.
Pressing isn't just for performance either, it all so covers handling safety, it vastly reduces risk of accidental detonations. I do not think you
guys have don any serious research into this stuff to be making the statements you're making!
If you just want to linger in the kwel realm of things as you do it rarely then fine, I understand this, but if serious about it there is no escaping
pressing, there is a reason why armies and industry do it, it isn't a "fad" of the hobbyist nor a simple obsession, it is grounded on hard data and
safety reasons to say other wise is to parade ones ignorance of the field.
To Mineman: You are quite right, there is no need for more then 100mg when one has perfected their art with a good primary and basic good pressing
system, even less with a strong mechanical press! As I said in another thread how ever for the start it is better to use more then ideal to ensure
initiation as you have stated, best to overdrive then have a fizzle.
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XeonTheMGPony
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| Quote: Originally posted by markx | | Quote: Originally posted by twelti | | Would it be correct to assume that if using an (energetic?) binder to safely get higher density without pressing, the loss from using the binder would
offset the gain due to increased density? Or, can we have our cake and eat it too? |
Depends on binder, energetic and a load of other factors, but as a rule of thumb one can assume a drop in sensitivity (thus a stronger tendency
towards failure) and an increase in critical diameter (thus it might render a small device inert for practical purposes).
What is this mystical "gain" that we actually talk about here? Something that punches through 2mm steel plate vs. something that punches through the
same, but with "extreme prejudice"? Depends of course what the objective of your research is, so I'm not suggesting that one should not work towards
the sharpest bang in the smallest volume. But consider wether that is really a requirement for your purposes before entering the realm of brute force
and high density. -Parsed- |
A detonators job is to detonate, this is achieved by a powerful impulse transmitted to the secondary.
Rather simple in theory, takes some effort in reality. the #8 cap of old, this was achieved with 3 grams of pressed mercury fulminate and chlorate at
80/20% mixture, this evolved through several iterations befor being replaced by better materials and compound caps.
The goal is a sharp, well focused shock wave, the plate tells us how well we achieved this, I use 3mm plate atm but would like to see the same result
through 5mm as this means peak performance, and it will set off any thing out there!
If his goal is to make a initiator then the goal is to have as described above, the only next question is how many.
if just a handful then the kwel method may suite their needs, but given the nature of his question sounds like they want to get to a more professional
style cap.
I have found that the 6mm/5.5 OD/ID Cap loaded with 500mg of ETN, Primary being Lead Azide/ Lead Styphnate 80/20% pressed, is sufficient for most
energetics the only difference between it and an industry standard cap is a "P" missing.
For added safety you can press the primary into a small carrier sabot by its self, then press that into the shell loaded with the base charge. (This
is my method, I use a paper sabot holding the pressed primary, and a small seal of the Base charge on the bottom to fill any remaining space, this
acts as a small booster as well)
Attachment: Efficiency of detonators.pdf (759kB)
This file has been downloaded 413 times
Attachment: Initiation and propigation in primaries.pdf (2.6MB)
This file has been downloaded 390 times
[Edited on 6-5-2019 by XeonTheMGPony]
Attachment: Critical diameter of fulminated mercury and Pb Azide Naval report.pdf (3.7MB)
This file has been downloaded 383 times
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Laboratory of Liptakov
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I Agree. 500 mg ETN is enough for in basically any using. Quality detonator with exact charging inside (density, amount) is base key for any next
attempts. And not, that every attempt had different detonator. Because on amateur field is often tested sensitivity, or brisance, or the power for
secondary, thus own secondary EM, or booster. Is tested is almost always different material. But detonator must be always same. And reliable.
Development of primarily - secondary substances CHP (2015) Lithex (2022) Brightelite (2023) Nitrocelite (2024)
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markx
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No of course I have not don any serious research into the "stuff".....what on earth made you think along these lines?
I'm just trolling here and trying to give bad advice to keep you all from striving towards excellence.
With your kind permission I shall therefore remove my further presence from these topics.....
Exact science is a figment of imagination.......
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twelti
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@XeonThe MGPony, you mentioned this "sabot" method before. It makes sense to me to press primary and secondary (if you ARE going to press it)
separately, then simply/safely slide them together in a tube. I don't understand why the need for your special pellet press, or how it works. can we
not just press the primary into a "sabot" as you call it, using a small ram, add squib or fuse, then slide that into a larger tube which already has
the secondary in it? Does your gizmo press it up from underneath? Not gettin' it.
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