| Pages:
1
..
11
12
13
14
15
..
31 |
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
Could Picric Acid and an oxidizer be used in some way in a cap, to increase sensitivety, such as KNO3 or dare I say KClO3. It would' t have the full
power of the pure TNP, but in an improvised fashion it could be made to work possibly with lesser primaries. I have seen figures in an old book, can'
t remember exactly where but I have covered over the material a couple times in the last little while so I could probably find it. They mostly focused
on gas volume and the heat of explosion of the different TNP and oxidizer mixes and compared the results and the products of the results to the pure
TNP figures. I remember for the KNO3 and TNP the gas volume and heat where substantially lower than pure TNP, but with KClO3 the heat was much greater
to the extent that the product of the gas volume and heat was about the same as it would be for pure TNP(pretty cool if reliable). I know , I know it
says everywhere that TNP and oxidizers are incompatible, and while they probably make a valid point a lot of stuff we play with by way of mixtures are
deemed "death mixes" by some. The book did say that it was abandoned because the sensitivity was too high. Well that sounds kind of relative to me, so
I mixed a little up(finely powdered each beforehand). I made a small amount and did not store. I have to say it still took a pretty good clout to
effect detonation, kind of like a drop of nitro on a moderately warm day, and made about as much noise to with about a match heads amount in tin foil.
I know this came from a book that was published either just before the 1900' s or just after, and a lot of stuff in those times was alittle less about
safety. A lot of stuff still hadn' t been figured out about the dangers, but in small quantities, in some fashion(even if possibly not storage
stable), could it be used as an initiator? Could the risks be managable? Is it any more dangerous than a lot of the more excepted things(or commonly
used things) people put in blasting caps? I know its not the purists way but it could easily be set off by even AP I bet, and less primary would help
contribute to less danger. For the military it was unexceptable at the time but a lot of useful stuff is. If it couldn 't be fired more than 8 miles
from a rifled cannon and make it to the target before exploding, or fulfill some initiating need better than something already in use it was
discarded. Probably other reasons to, specific to the military. Even if ignoring the possible dangers, do these oxidizer/ TNP mixes have initiating
ability that would make them useful in some way? If you type up TNP and Chlorate, a lot of hazard warnings come up, but none of the stuff I saw gave
me much more explanation than "incompatible" . Of course these sites say the same thing about kerosene and NH4NO3(I am not trying to trivialize the
possible danger though). If someone has some info on these mixes it would be interesting, if only for curiosity purposes. This may border on the
rediculous to an experienced chemist, it is just a curiosity mostly.
note:I used 70/30, TNP/chlorate, I think it was more like 50/50 in the book example.
[Edited on 26-6-2009 by Hennig Brand]
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
In a word, yes. See the actual "formula" for the material "Melaniite"; it's not simply TNP!
In the commercial development of all the energetics industrial materials back about 80-100yrs there were "standards". For temperature, the methodology
was to add powdered metals, for OB, the technique was to add an oxidizer, etc. An enormous amount of material is reviewed in the study of that period.
See - "EXPLOSIVES - 100yr More or Less" - Hopler. In it, various advertisements are explored as well as information regarding material development in
the dawn of the Industrial Age.
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
The most promising idea that is not something which I did followup experimentation to investigate, involved the use of the easily fusible and probably
much more easily initiated melt cast base charge of the binary composition
of DDNP and TNP, with an initiating cover charge of DDNP,
perhaps having an intermediate compressed charge and/or involving basic lead picrate or the basic lead picrate / lead nitrate / lead chlorate tertiary
clathrate as a component. This seemed to be a logical experiment
towards producing a practical detonator having decent
performance and storage stability, based upon picric acid
derivatives, yet requiring no azide component.
Personally I have favored the technical predictability involved with using compositions which are chemical
compounds or fused "alloyed" mixtures, as distinguished from ordinary physical mixtures, even while knowing that physical mixture compositions indeed
do have their usefulness. Ordinary mixtures can certainly produce
good results, I just haven't focused much of my interest
on such mixtures, for being preoccupied and more intrigued by the chemistry of compounds. Therefore I can't really speak well to the specifics of
mixtures and
a pyrotechnics related source would be better consulted on that. There is an inherent variability about mixtures for
reason of the physical nature of the reactants, particulate size, homogeneity and uniformity, which makes mixtures
less predictable and probably more dangerous to handle,
even though such disadvantages may not necessarily rule out their use.
We momentarily interrupt this regularly scheduled Rosco broadcast to bring you the following chain reaction 
Get 'em while they last
http://www.youtube.com/watch?v=H9YKPx2tFKQ&fmt=18
http://www.youtube.com/watch?v=BvM1JIRi65k&fmt=18
http://www.youtube.com/watch?v=D3CJOyBHPwI&fmt=18
http://www.youtube.com/watch?v=tyiEO6CO1x4&fmt=18
http://www.youtube.com/watch?v=o2d2llB4oIQ&fmt=18
http://www.youtube.com/watch?v=Lmsxr4pj0aQ&fmt=18
http://www.youtube.com/watch?v=1pDBtULvB7A&fmt=18
http://www.youtube.com/watch?v=gKtdlZQIRYc&fmt=18
Attachment: US1428011 DDNP and Picric Acid eutectic.pdf (242kB)
This file has been downloaded 822 times
[Edited on 27-6-2009 by Rosco Bodine]
|
|
|
grndpndr
National Hazard
Posts: 508
Registered: 9-7-2006
Member Is Offline
Mood: No Mood
|
|
IIRC a turn of the century paper "metallic picrates" compares the use of fulminate of mercury and pottassium chlorate as well as lead
picrate/pottassium chlorate physical mixes i would imagine to increase OB balance and thus power in use simultaneously and with some competition.
As far as a melt/ cast TNP, Trimonite is another of the family again dating around the turn of the century and which ive mentioned before used
mononitronapthalene to lower casting temp. although it also decreased det velocity to slightly better than 7000MPS.Strangely enough I still see it
listed in what I assumed to be relatively current lead block/vod listings .
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
compounding of mixtures is an old art unto itself even older than chemistry which is a derivative art
http://www.youtube.com/watch?v=2B6WtP66gQo&fmt=18
http://www.youtube.com/watch?v=wacyMhxIOd0&feature=relat...
[Edited on 27-6-2009 by Rosco Bodine]
|
|
|
grndpndr
National Hazard
Posts: 508
Registered: 9-7-2006
Member Is Offline
Mood: No Mood
|
|
Interesting patent.I could see where a far more sensitive
castable TNP/DNP could be useful in an initiator but never hearing of difficulty with using TNP as a booster in a composite cap I wonder about its
utility/safety when mercury fulminate,HMTD,or many others will easily det. pressed TNP
without the risk of melting TNP/DNP.
DNP looks to be quite useful in AN.
Correct me if Im wrong but wasnt a reason for using mononitronapthalene/TNP the lower melt temp of the mononotronapthalene and increased safety?
As far as being useful in an arty shell... or really any military munition where a sensitive secondary is very undesirable,TNP/DNP seems unfit from
that standpoint.
Might make a good rifle target Regards
[Edited on 27-6-2009 by grndpndr]
[Edited on 27-6-2009 by grndpndr]
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
Interesting, I have never seen anything before on melt, cast charge made of DDNP and TNP. Just got back from a short work trip out of province and I
found a chemical company which deals mainly in industial cleaning supplies, but they did have huge quantities of NaOH(so I got 5Kg, even though 40Kg
would have been much cheaper per Kg). They also had lots of 28% NH4OH solution so I got a few gallons. The slippery characters that they were though,
one of the gallons was all swelled and weakoned on the bottom(maybe was frozen or something before). To make a long story short on the way home it
started leaking(nasty stuff!). I was right beside a gas station so I pulled in, removed the offending gallon then bought some windsheild washing
fluid, put fluid in car and used poly ethylene jug to hold the ammonia solution from the busted jug. It took a couple hours with the windows down to
fully air out the car, even after soking up the bit spilled. The amount spilled was probably less than an ounce, but man was it stinky, and
irritating. I guess they saw a way to get rid of a bad container, I think I will be able to get a free gallon of ammonia out of this though,
probably .
This place can order a lot of other stuff as well, but they wanted cash up front,andI wasn' t feeling all that flush. I priced sodium sulfide, which
was $150 for 500g, and phenol(crystaline/pure, technical) for $140 for 500g. This seemed kind of pricey, and the guy I talked to admitted that he had
to order stuff from a lab supply place a high price(probably with hazard charges to boot).
I wanted to say that KClO3 is a very powerful oxidizer, but it is also a very powerful sensitizer. Mixtures that use this compound generally have much
lower reaction initiation energy requirments. Oxygen balance effects may be interrelated, but with KClO3 I think it is much more to do with the
chemical nature of this compound(it actually gives of heat when it decomposes for one) and tends to greatly sensitize most pyrotechnique mixtures(TNP
and KClO3 for example). I am not sure of the proper way to mix the TNP and the oxidizer, since it didn' t say in the book I saw I believe. I think
they said mixture though.
How much easier would it be for a charge of primary explosive to initiate TNP, if the primary was completely imbeded in a charge of the TNP(normal
charge with blasting cap), versus the same primary charge pressed on top of the TNP in a compound cap configuration? I guess I am just curious how
easy it would be comparably to set off a small charge of TNP(maybe 20-30g for instance) with a cap placed in the material. Anyone try setting off a
few decagrams as a test or anything?
I think tomorrow I will make a couple pounds of hexamine(it is so nice to not have to make ammonia when one wants hexamine)
http://www.filestube.com/6d8906f8c8eb7d0a03e9/go.html
This is an active link for free download of the book Propellants and explosives. Thermochemistry and combustion
It is a zipped file. I downloaded it and it seems like one of the better books that I have seen on the subject, in the sense that it wasn' t too
advanced and/or convoluted and it has lots of good info and charts on most common explosives. It also spends a lot of time explaining the science of
explosives with some math, but in a way that is easily understood by someone who is not an expert. Probably a good reference for anyone, even the
advanced.
[Edited on 2-7-2009 by Hennig Brand]
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
Propellants and Explosives By Naminosuke Kubota, this book has a chart for some critical diameters for some common explosives, and Picric Acid is
included.
TNT=8-10mm
Picric Acid=6mm
RDX=1-1.5mm
PETN=1-1.5mm
AN=100mm
Now it would seem that a lot of folks(including me), have been using tubes that are not much larger in diameter than the critical diameter. Very
strong tubes will make up for a small diameter to some extent but still. Even if it does detonate the detonation velocity and hence power will be
greatly reduced probably. A 5/16" tube is only about 30% larger than the critical diameter for TNP( of probably a perfect pure sample). This is all
assuming that their numbers are correct of course.
How It Works By Marshall Cavendish Corporation, in this book it talks about the sensitivity values of some commonly used explosives. Picric Acid was
used as the standard with a sensitivity value of 100, and was not descibed as an intermediate charge at all, but as a definate secondary. It described
intermediates(for compound caps, etc) to normally practically have sensitivety values of 60 or less. Primaries had sensitiveties around 20, on
average(rough figure).
Sensitiveties of some common explosives from book-
Picric Acid=100
Gun Cotton(dry)=as low as 23 sometimes
Gun Cotton wet=120
TNT=110
PETN=40
RDX=55
Tetryl=70
I know that this book is not a chemistry text book, and is probably more of a book for the laymen to get a feel for explosives technology a bit, but
it seemed like a good book taken for what it is. The sensitivity figure is a little confusing to since different types of initiation stimuli and
conditions under which it is performed can make results differ greatly between different explosives. It does give a useful, albeit general picture I
would say. Picric Acid and TNT are both much more insensitive and with greater critical diameters than what would be considered suitable as an
intermediary charge say in a compound cap(if info is correct). I guess anything is possible if one is obstinate enough and has very good primaries,
and has good skill in detonator fabrication, and has a need to use TNP because of the inavailability of something easier to use, or more suitable.
Without careful fabrication, and/or very good "hot" primaries how suitable is Picric Acid in this application as an intermediate, used in caps in
small quantities, and in small diameter sizes?
[Edited on 1-7-2009 by Hennig Brand]
[Edited on 1-7-2009 by Hennig Brand]
[Edited on 1-7-2009 by Hennig Brand]
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
For a base charge of TNP a 5/16" bore is okay but
a 3/8" bore is better. And yeah it takes a geometrically increased initiator charge to initiate it appropriately.
Those small diameter and small initiator weights which
are given in the literature for "test data" simply do not translate to real world practical application performance in my experience. If you want to
use a 1/4" column diameter base charge, and fairly small initiating charges then use compressed particulate PETN as the base charge. If you want to
use TNP at that diameter, or any diameter really, be prepared to substantially overdrive it with a hefty initiating charge or it will quench and not
demonstrate the kind of output needed.
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
I' d say you have been there once or twice Rosco The more I play with this
compound the more your posts make sense. I know you have said it all at least a couple times with this topic, but I appreciate it. Sometimes I need to
hear something at the right time or in the right context, makes me less than an ideal student, but probably not that far removed from average forum
folks in that way.
I think a lot of folks are simply trying to make their TNP do things it is just not going to do, or at least not well. This stuff is technically
challenging, in comparison to a lot of the other explosives I have dealt with. The synthesis has little pit falls, and the use of the explosive also
has little pit falls. I am sure there are other things much more difficult, but I have to say that this compound forced me to learn more than most
other things I have done. The lessons learned are also applicable in many ways to other similar chemicals I think.
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
Yeah TNP is energetic materials 101. TNP has much to teach you if you want to learn. One thing you will notice as the column diameter is increased
comfortably beyond the critical diameter, then the difficulty of initiation based
upon the unequivocality of the initiating material is reduced, meaning the base charge requirement for the more efficient initiators is greatly
lessened, and more
mundane initiator materials may be usable similarly as
is the case for when a reenforcing cap is used. Those
two factors can be combined in order to facilitate the use
of less technically advanced initiator schemes to successfully detonate a TNP base charge, and a configuration may be found which has excellent
reliability and performance, even for it of course being a device
which is substantially larger in dimension than a compound detonator having something like a PETN base charge. The press loading requirement is also
greatly reduced for the column diameters comfortably larger than the critical diameter. Even though the economy of materials required on a "per unit"
basis suffers for having to use larger quantities of energetic materials in the device as compared to a device optimized for economic manufacture, the
technical demands for the
improvised device are greatly lessened. It is good to know what you need to do in the way of materials and design parameters in order to make
efficient use of what resources are available, dependant upon the capabilities
of your tooling and workshop. The applicable principles are the same whether you are in the most advanced research setting having all the exotic
tooling and materials, or are limited to primitive and minimal resources. Knowing what you are doing you can then make the best use of what you have.
Bluegrass
http://www.youtube.com/watch?v=2P7J1_hZ7iM&feature=relat...
http://www.youtube.com/watch?v=EvKtxTsVoMo
[Edited on 2-7-2009 by Rosco Bodine]
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
Well said, and it rings true Rosco. I appreciate it.
I have read a couple places that stainless steel is fine for Picric Acid casings as well as aluminum(which has been stated lots).
Back in the early part of the last century, I think(even though both available), aluminum and stainless were more uncommon and expensive. I don' t
remember hearing about either in the old books,(I have read from) where Picric Acid was discussed.
I live close to a scrap yard and if one is patient and drops in from time to time, a lot of stainless tubing could be collected for $1-2 a pound. In
my little book of shop materials it shows tensile strengths for different metals and their alloys(can' t find the book right now though). From what I
remember steel can have huge variations in strengths, with the softer and weaker ones being not much stronger than the stronger alloys of aluminum.
However, the better steels, and better stainless steels can have 4-5 times more strength for the alloys in common usage(than strongest aluminum). I
wonder if stainless steel would be OK for HMTD or if the chromium or possibly nickel, or maybe still the iron would be a problem. Good stainless is
pretty unreactive stuff, and a strong alloy would make a proportionately strong casing I would guess. Although the relation between between tensile
strength and strength under blast conditions is still a bit of a mystery to me, but it should give a good idea. The strength is measured per unit
volume to by the way(by thickness of tube in our case), not by mass.
A composite cap in strong stainless, which could allow for the cap wall thickness to be proportionately thinner( or thinner anyway) and still provide
great confinement for insensitive TNP, and be safe(chemically) for both the TNP and HMTD would be nice. Is this workable?
[Edited on 2-7-2009 by Hennig Brand]
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
I wouldn't use HMTD in contact with any metal period.
HMTD is something I wouldn't use at all except for a very near term usage where convenience or necessity was
governing, as it is least desirable among the possible
alternatives. HMTD is basically a quick and dirty short term solution. And that is all it is.
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
I think it is time for me to try a bit harder, and develop a little more sophistication, and options in the primary explosive department. Thanks.
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
You will be happier with the result in most cases to come up with a storage stable device you can tuck away for that special occasion when it is
needed instead of having to press into service something needed on the spur of the moment when you may have a lot else on your mind.
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
That is probably what I should strive for, for sure. There is an appeal to the more easily improvised compounds, and are good to have in ones skill
set, but they are inferior usually and should be used as you have said as a quick and dirty solution only if something better can not be
made/obtained.
I would like to thank Quicksilver for pointing out Practical Organic Chemistry, looks like a very good book indeed. I downloaded it last night from
www.archive.org(the other links didn' t seem to work well for me). I have only looked through it a little yet but it looks like the perfect thing for
my level of functioning. A lot of practical stuff(preparation, etc) on useful common chemicals is in the book, and basic laboritory techniques.
This is a little embarrassing, and scary, but is kind of neat as well, as well as being a good lesson. Last night I made some HMTD with 5g
Hexamine,22mL 35% H2O2, and 15g citric acid. I know it seems like a lot of acid but it seems to take that much or nothing much happpens, even after
sitting for hours. I let it form overnight, and when I woke up this morning (still half asleep) I decided to filter and rinse my product. I grabbed
the first funnel I had close which was poly ethylene, but it had a brass screen in it(I use it for my homemade vaccum filtering setup, it is an
automotive filter). Anyway still in a sleepy stupor I put a damp filter paper in the filter and poured the HMTD and waste liquid on it, then left it
for couple minutes to gravity filter. In less than a minute I started hearing this hissing sound which was quickly getting louder and louder(like a
big fuse burning down, with the threat of an explosion soon to follow). When I took a look in the filter there were blue spots bubbling through(from
the copper in the brass, I would say?). I quickly got the filter paper off the filter, rinsed the HMTD into a beaker, then drowned it in some water. I
rinsed and filtered a couple more times, and all the blue seemed to rinse away fairly easily right away, and it seems to have completely stopped
decomposing. I quess it still could be sensitized, so this stuff would be best avoided, I quess. It is only a few grams, and I am drying it now, but I
will be very careful with this stuff! Definately not the brightest thing to do! The incompatability issues are worse than I thought. Better to witness
it this way then have it happen in a cap!
|
|
|
quicksilver
International Hazard
Posts: 1820
Registered: 7-9-2005
Location: Inches from the keyboard....
Member Is Offline
Mood: ~-=SWINGS=-~
|
|
When looking at a lab that didn't turn out as expected (speaking just for myself) I look at what I could improve upon in such a synthesis. Did I pay
attention to temperature & weight of precursor materials? Did I look at the lab in terms of what is being accomplished overall? Did I pay
attention to time within the synthesis?
Stephnic Acid had many folks stifled due to the need for more exacting techniques that TNP. Once I got to the point that I understood what was
actually happening within the synthesis, my TNR was just as simple as TNP.
The areas often tripped up by many are timing, temperature, weight, & technique. I try to avoid "recipes" & stick to molar weights at first.
HOWEVER scaling up or down may NOT maintain the same levels of acids (in nitrations) or reagents & this is where knowledge of the final material
can help. Generally you just need to read up on the synthesis a hell of a lot & not blow off "plant-level" synthesis as often a lot has been
worked out when scaling up is in place that helps in smaller level labs (strange but true).
[Edited on 3-7-2009 by quicksilver]
|
|
|
grndpndr
National Hazard
Posts: 508
Registered: 9-7-2006
Member Is Offline
Mood: No Mood
|
|
It had been at least a year since I last did a lab.But before i puy everything away for a move i prepackaged the amounts normally used for the lab.I
also used some left over H2SO4 drain cleaner left at the rental.To rid it of a slight discoloration I tried the H2O2 method. A sure thing Synthesis
was a Complete failure! could have been any one of the mentioned preps.The H2O2
cleaning,neglecting to be sure the Rooto was concentrated.
Or even ensuring the dry precursors that were hygroscopic hadnt absorbed excessive moisture.I payed the price for the rush, a waste of time and
materials but a lesson learned.
Its no waste of time to ensure the suitability of your precursors even if its seems a routinely successful synthesis.
Safety being paramout and i got careless.Thankfully the failure was harmless but on the other hand it could have been catastrophic.It goes to show me
at least no matter the # of times ive successfully done the same lab it can turn to shiy in a heartbeat.
[Edited on 3-7-2009 by grndpndr]
[Edited on 3-7-2009 by grndpndr]
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
I just got my first full positive result with Picric Acid in a compound cap, and there was no doubt about it. Even from one gram there was a pretty
big cloud of black smoke, and much more noise and violence than from the HMTD alone. I used one gram, made from ASA and recrystalized twice, and one
gram of HMTD. I know it was maybe a bit dangerous, but I use the stuff all the time to play tricks on people, kids and adults love the little
torpedoes and other novelties made with it(Silver fulminate). I made a little pocket with thin waxy tissue and a pinch(probably less than 0.05g), then
put this around end of fuse to protect and provide separation from HMTD. Just the gram of HMTD probably would have done it(my last failure only used
0.5g HMTD), but I wanted to get the most out of my 1g and get the HMTD up to velocity quickly. In the future I will use Silver acetylide nitrate
instead, but this was what I had on hand. I have been using the same batch of Silver Fulminate for over a year now(less than 1g) and it is still good
and doesn' t seem that sensitive(every batch is different). Both TNP and HMTD were pressed to around 1.5g/cc, or there abouts. It was truly awesome,
and gratifying. This has been in the back of my mind for the last couple of years, with experiments off and on. I would get discouraged, but always go
back to it again eventually. I used stightly smaller than 3/8" diameter semi-soft aluminum tubing from old heating radiator or something, with wooden
plugs epoxied in, making sure end with the TNP was good and solid(thick). I pressed so hard that the tubing was doing a lot of swelling(should have
some kind of support I quess for best pressing). So instead of a yellow cloud, and yellow on the ground, I got a big black cloud, and great report
The large piece of shale rock I had it sitting on was cracked in several places, which AP or HMTD alone failed to do in those quantities. The nearby
rocks had little gouges out of them as well(aluminum shrapnel?). There was no yellow residue or powder from unreacted TNP, only black soot on the
broken pieces of shale. I also didn' t find any metal fragments from the cap this time, and every other time I did after the failed attempts.
[Edited on 4-7-2009 by Hennig Brand]
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
A handy method for making detonator capsules from tubing is to use one of those tubing cutter tools which
has a cutting wheel bearing against the tubing which rests upon rollers within a C-clamp sort of frame where
the cutting wheel depth is advanced incrementally by
turning a knob which has a threaded shaft operating
to move the cutter wheel, like a micrometer. If the
pressure on the cutter wheel is kind of median and time
is extended to maybe a dozen revolutions for completing the cut, the tubing will be deformed at the
cut, crimped slightly as well as cut so that a ledge is
formed towards the inside, leaving a circular bur on the
inner wall of the tubing at the cut. Generally the most
convenient approach is to start with a piece of tubing that is twice the length of the desired capsule and having clean cut ends which have been saw
cut, and then use the wheel cutter in the middle to produce
two pieces, each having a clean opening as the top
and a chamfered cut end which will be the bottom closure end, closed by a disc which has been punched from sheet stock using a hollow punch and a
hardwood
cutting block for the punchings. Very thin aluminum capsules can be made having the end closure discs
epoxied to seal the disc against the inner chamfer, using a dowel inside to tap the disc securely into place. The disc will be actually a slight dome
shape, and the slight flattening of that dome as it is tapped will expand and
secure it mechanically at the end. These aluminum capsules may be used as liners placed within stronger
outer capsules of brass or stainless steel made in a
similar manner but having their end closure discs silver
soldered. The laminated capsule liner within an outer capsule can be made secure and permanent by using a thin liquid epoxy such as is used for
coating tabletops,
placing one or two drops inside the outer capsule at the bottom, inserting the liner capsule and slowly and firmly
pushing it to the bottom, the liquid epoxy will ooze upward to force the air from the slight gap between the capsule liner and the outer capsule. The
liner capsule
should be a few millimeters longer than the outer capsule, and the excess epoxy extruding from the
gap during assembly can be wiped away with a rag.
It is worth the effort to make up a batch of these capsules of maybe a dozen at a time, using materials
whose diameters are found convenient and will match up with whatever igniter squibs or fuse holders or closures are intended to be used later for
actuating the device.
The base charge range for TNP which will be most useful
will be from 1.5 grams to 2.5 or even 3 grams, the heavier
loadings (of course) being my own preference as these
will directly initiate even relatively insensitive main charges
like urea nitrate, without the need for using a booster,
since the cap is big enough to do the job reliably. I would
much prefer to have confident certainty at the expense
of doubling a loading, than to have to use less reliable and more troublesome "extra steps" to get the job done.
If you are press loading at high enough pressure that capsule expansion is occurring, this may make it difficult or impossible to remove the loaded
capsule from the holder block if it is a one piece bored holder. A laminated block
holder which is held together with bolts and has the cavity
then drilled and centered of the seam where the halves
bolt together can be used to remedy that problem of an expanded capsule which has gotten stuck in a one piece holder. After loading expands the
capsule, the bolts can be
loosened which secure the halves of the holder block together, and the halves separate easily, allowing the loaded capsule to be removed.
[Edited on 5-7-2009 by Rosco Bodine]
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
Nice ideas! I think a good dense piece of hardwood, cut down the middle first, then made to be held together with bolts and wing nuts or something
might work for me. The bore holes could be carefully drilled, perfectly centered on the join between the two halves of hardwood(starting with small
drill bits and working up to size of the cap you wish, for better control of accuracy). When starting with smaller bits first, their is room for
corrections, when right, larger bit will easily follow smaller bore mostly(depending on bit and material) . The two block halves should of course be
held tight together, in the right position before drilling. Drill press would be ideal, but can be done without. Good idea, do you think hardwood
would be ok? I think I saw you refer to phenolic resin at least once before, but hardwood should work right?
I guess it is pretty important, though I don' t know much about it, to have thin endcaps when using TNP as an initiator. My big thick epoxy and wood
endcaps, give good confinement, but how much less effective is my weight of charge at initiating in this arrangement? How much inferior is it to use
wooden endcaps, normaly? I tried soldering an aluminum plug in my aluminum tubing, but had no luck getting the solder to stick. I found with a little
research that choice of aluminum and solder and process control are all very important with aluminum soldering. Brass solders very easy usually
though. I have never had much luck soldering steel either. There are many techniques and specialty solders, and I have only tried a few common ones. I
think the chamfered ends and disks looks like a good solution, thanks. The idea is to have the initiator as close to the secondary as possible, while
still having a strong enough cap to fulfill the needs of the primary and/or intermediate, right?
Lots of good ideas thanks. I will try to do some of them justice.
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
A 96/4 Sn/Ag soft silver solder using a liquid flux like
alpha metals or "ruby fluid" will stick to stainless steel
or plain steel or to brass even better. There are supposedly some aluminum brazes / quasi soft solders
but I haven't tried them.....more trouble than it's worth
when epoxy works fine as basically a seam sealer.
If a thick end cap is used then I would position the cap laterally in the insertion into the main charge since there
is a "projectile" having a disruptive effect coming off the end of the det.
Hardwood is okay for the blocks, or structural plastic, or aluminum, or fabric reenforced phenolic, or you could even probably cast the blocks with
chopped fiberglass reenforced resin. A drill press should be used for the
boring of the mated blocks, unless you work out some sort of casting scheme for making a shell holder which
can be separated.
For a TNP base charge it is probably essential that the
initiator be in actual physical contact compressed directly onto the column of TNP so you want something chemically compatable. With more sensitive
base charges like PETN, actual physical contact is not required
with the initiator, where sympathetic detonation or
flyer fragment impact initiation by flying particles of a granulated partition material can be exploited. But TNP isn't that sensitive so it would
require a pretty huge scaleup to exploit that sort of scenario, which really would not be practical for TNP except in a large ordnance.
Polypropylene culture tubes actually make decent capsules,
but off course it is probably an unauthorized off label use
if you really worry about such polite manners and all, not
wishing to so rudely and abruptly end the existence of labware It's definitely
a short goodbye for that culture
tube being so horribly abused in such an uncultured way
However, when must needs be, the time may come when some sacrifices are just plain necessary.
Luminosa ( Full of light )
http://www.youtube.com/watch?v=djw1Oa8yg70&fmt=18
[Edited on 5-7-2009 by Rosco Bodine]
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
You know another score for TNP in the teaching department. I find you can get away with just about anything with the more sensitive and easier made
explosives (esp nitric esters), and still get a descent initiation. The TNP really forces one to hone their skills, especially when used in small
quantities, because if off by very little from what is best there is a very good chance it will not work at all. Most of these lessons might never be
learned at all, with say the dynamites, because (I believe) the differences are usually not perceived in those cases, whereas with Picric Acid if one
plays with it long enough, the best practices will be made apparent. These leasons could have great value when trying to get the most out of other
energetic compounds(I would think).
Thanks for the advice on the support blocks and stuff. What is your preference Syphnic Acid or Picric Acid? Or what do you usually prefer using? Not
to be a bother, but you seem to have quite a bit of experience working with both.
I know they are too small for TNP really, but have you seen the plastic tubing that is used for airbreaks sometimes. It must be tuff stuff for sure.
It would probably take one hell of a slapper or exploding bridgewire detonation system for Picric Acid alright. Haven' t really heard of that
particular flying fragment detonator you mentioned. I do have some really big capacitors, 25uF @ 2000V, that should make a bridge wire explode! I find
I am a bit reluctant to play with them, as capacitors like that make me more nervous than primaries in some ways. A good charging/discharging and
safety system could make it very foolproof if care was taken. I have quite a few of these capacitors, as I took them out of electrical assemblies that
were going to be tossed by salvage place. They were part of a military vehicle, but I don' t know what for. Are these suitable as an exploding
bridgewire capacitor?
|
|
|
Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
Member Is Offline
Mood: analytical
|
|
Picric Acid is generally what I have used because it is cheaper and completely OTC, and its derivatives are also very useful. However, as a base
charge Styphnic Acid appears that it would perform nearly as well and would be more easily initiated for being a bit more sensitive. The crystals of
styphnic acid are distinctly harder material
than picric acid, forming from boiling water crystallization
more easily a precipitation of uniform sized hexagonal plates about the same mesh of table salt, giving a free pouring material which press loads
beautifully. Styphnic acid is IIRC a higher density loose poured and it compresses to a pellet smoothly. I haven't really done
tests of the styphnic acid dets for comparison of the
performance against picric acid, but the witness plate
evidence indicates that styphnic acid would do the job almost as well on a weight basis as would TNP, and
perhaps on a volume basis for the combined base and initiator column may even do better. So styphnic acid is no slouch either as a base charge, but
is of course more
expensive and the precursor is less convenient. In certain configurations however it is possible that styphnic acid could be technically superior.
That is a
range of experiments which I haven't really investigated.
But it appears that styphnic acid being more sensitive to initiation would perhaps not require an initiator to be press loaded, but could probably be
topped with an aqueous dextrine solution dampened putty made of microparticulate lead azide and lead styphnate, allowed
to slowly air dry to a hard pellet in a firing squib later
inserted against the base charge, or perhaps simply
depositing the damp putty directly directly onto the
the compressed base charge and letting it air dry in place. Styphnic acid is distinctly more sensitive to initiation and indicates having a smaller
critical diameter
would be probable although I haven't checked this.
|
|
|
grndpndr
National Hazard
Posts: 508
Registered: 9-7-2006
Member Is Offline
Mood: No Mood
|
|
Im sure you have far more experience here but are you sure a reinforced cap is really nescessary?I havent heard of any complaints from plain AL hobby
tubing cut with the obligatory tubing cutter and epoxied wood dowels.As for pressing a small 4in vice(to small!) and dowel seemed perfectly adequate
except in the case of max density for mercury fulminate which apparently didnt matter nor did a bit of tissue/etc seperating the primarys and TNP.A
test similar to davis chem of powder and explosives IIRC revealed a textbook result,Hole punch in the bottom of the witness plate and no bulging of
the detonator with the TNP pressed to near max density and apparently very brisant compared to commercial #6-#8 and more akin to a military engineer
detonator.I made dozens without failure electric and fused.The tubing was both 5/16 and 3/8 for the larger caps 2-3 gramsTNP .I also subscribe to the
more is better approach for inexpensive materials when detonating a potentially expensive labor intensive energetic.Regards,no disrespect intended
.Though ive made more than I can recall I certainly realize Im no expert(as my failed lab reveals)and Appreciate
your input.Regards.
Safetys sake a large sandbag was always placed over the pressing op and detonator.
My apologys for all the edits but it occurs to me condenser coils/tubing is nescessarily much softer than the hobby tubing.
[Edited on 6-7-2009 by grndpndr]
[Edited on 6-7-2009 by grndpndr]
[Edited on 6-7-2009 by grndpndr]
[Edited on 6-7-2009 by grndpndr]
[Edited on 6-7-2009 by grndpndr]
|
|
|
| Pages:
1
..
11
12
13
14
15
..
31 |
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
