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quicksilver
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The thing that nags away at me is the industrial accidents wherein metal picrates are formed within a large amount of picric acid and the whole mass
is popped.  Therefore it would seem that some method could be available but I
have been known for ideas that "seemed" to work but fell on their face 
Quite frankly, I d like to test it. (that's the whole reason for the thread on energetic test apperatus).....I also heard something about the
sensitivity of picrates being related to some element of their energy; however I don't know if it's brisance or what.....don't quote me but I believe
it's from a book published in 1918 on military explosives. One of the very first published by Wiley.
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Rosco Bodine
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I have tested the sensitivity of picric acid to initiation
by anhydrous crystalline normal lead picrate and
basic lead picrate , both with *negative results* in unreenforced detonators , where a 1.5 gram 9.5 mm
column of picric acid failed to be detonated by amounts
of the initiator increased even to 3 grams .... at which point I stopped the tests which appeared to be an exercise in futility . To secure reliable
detonation of picric acid from its normal or basic picrate used as initiator could possibly require even tens of grams , and strong confinement . In
any reasonable quantities as would be applicable in the size of a device acceptable for
use as a detonator , in an unreenforced configuration ,
the normal and basic picrates simply do not deliver
sufficient impulse to cause detonation of picric acid .
Perhaps for a 12.5 mm diameter column the threshold
would be crossed , or it could require even 19 mm or more , I am not really sure what would be the minimum
workable size .
Where a stronger confinement and larger amounts of materials is in play , then sure it is probable that the threshold amounts required are available
at some point
to secure reliable detonation , but it will be one big fat cap not nearly as efficient as such a device should be in
terms of size or utilization of energetic materials , aside
from safety concerns , all of which make this arrangement
a poor choice when better combinations are known .
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quicksilver
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Yep....it's funny that we do the same stuff. I was just doing something similar. I couldn't get that stuff to pop. I am getting quite a collection of
material, notes and 1st or sendhand experimental info that's quite accurate as well. After a period of calm testing and recording negitive results I
put down the note book and decided to wing it (albiet safely in small amounts). Well, I smacked it with a hammer, scrapped it accross various friction
bearing hard surfaces, & used a bit of basic lead picrate (some of the highest sensitivity I have worked with) .5gr....no go, full gram; no go, I
finally gave up as I could not get more into the capsule I had. I am wondering what azides might do but I bet it wouldn't be a simple .01 gram as with
ETN / PETN.
So I am thinking that the "accidents" that occur must be either large diameter column (as you suggest) or area in which a larger hot spot is created
than that which I am familiar. frankly, I think that all energetic materials should be respected deeply for their potential but it seems that some of
the horror stories that surround PA may be a bit inflated. I am certainly not suggesting that PA should be treated in a chavler fashon but it seems
tough as TNT. Actually in the typical in a 6mm column I would bet that it would need something mighty hot to pop.
I was suprised at the results....I even thought that perhaps I had a blend of di & tri nitrated material - [...Now I know I'm working with the
tri - nitrated material because I use a friend's mp machine and if I'm within about 3 degrees I think I have the real deal] PA is damn valuable stuff
but it's not a clear and present danger to the lab outside of it's toxicity and annoying stain-making qualities IMO. Frankly the best reason for
keeping it wet is to minimize the dust!
[Edited on 29-9-2006 by quicksilver]
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Rosco Bodine
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The first compound detonators which I ever made and tested were 1.5 gram picric acid base charges in a .25 inch (6.36mm) column diameter press loaded
in 3 sequential 0.5 gram portions at 8,000 psi , then topped
with 0.4 gram microcrystalline PbN3 press loaded in one
increment at 15% reduced pressure of 6,800 psi . The capsules were 1/32" wall aluminum . A loading block
holder was made from two blocks of phenolic bolted
together and bored along the axis of the clamped together faces , so that the holder could be separated
and the capsule could be freed from the holder after loading , since the pressure of loading had been found to expand the capsule sufficiently to make
it a nearly permanent assembly if held in a one piece tubular loading die .
Comparisons were made for caps loaded by this scheme
with both picric acid and styphnic acid used as base charges . The performance was very nearly identical ,
with the styphnic acid being estimated perhaps 3 % less powerful , but perhaps 20% more sensitive to initiation
by PbN3 . Threshold amounts of initiator for full detonation of the base charge in the unreenforced caps
appeared to be about 0.15 gram for the TNR and about
0.2 gram for the TNP . Reliable loadings providing some extra initiator for consistency of high output performance were decided to be 0.3 grams for
the TNR and 0.4 grams
for the TNP .
From my own tests with these and other materials loadings , charge geometry is important to performance ,
and the scaling up of the base charge also requires a
scaling up of the initiator accordingly . I know this
experimental finding contradicts the literature , and
I don't much care as I trust my own experimental
results more than the results reported by others where
such contradictions arise . I think the larger scheme
devices is where the general rule applies concerning
there being no benefit in using larger than minimal
initiator charges , but in the scaling up of a compound
detonator that more general rule simply does not apply .
Simply put , to get oversized base charges to go at
highest velocity like they ought to , you have to overdrive the shit out of them with what is a correspondingly larger intitator . On a number scale
I suppose the compound dets I have tested would
range from #12 to #30 , since I tend to have a pretty
liberal view concerning what is a " cap sensitive "
composition . I sort of figure at a point where most
folks would resort to using a small booster , my preference is to just use a bigger cap and get straight to business without any middle man .
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quicksilver
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I'd say .4 gr of PbN3 is a damn strong kick start! When I experiment with heavy weight & strong initators I have a tough time telling if I am
"getting my money's worth" from the base charge. But here we have a threshold amount of .15-.2 - Jeeze, it stiill seems like a lot from what I was
used to (my 1st was PETN based and a damn small bit of azide; I think .05)... That one appeared better than a commercial #8 from my limited
experience.
I take it that (your .4 azide) really DID overdrive and was satisfactory in proformance...? When I made a base charge of PA I used .8 fulminate and
got results that I felt were better than a commercial #8 but not by much.
I did notice that if one uses aluminum that is hard rather than soft the caps seem to have a wee better proformance. Arrows made by EASTON-AlCOA are
made of Al that is fantastic for caps! It is super brittle and shatters in a manner unlike simple soft Al tubing.
[Edited on 29-9-2006 by quicksilver]
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Rosco Bodine
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Generally what I would do is test increasing increments
of 0.05 grams until reaching the point of minimal amount for *consistently* producing a complete detonation with reliability .......and that is what I
would call " threshold "
rather than the lesser minimum which would only sometimes produce a complete detonation . Then I would arbitrarily increase that amount by 50%
usually
to feel comfortable with the figure as a " sure " loading ,
allowing headroom for degradation over time or whatever
" Murphy's Law " type factors might introduce .
1.5 grams in a 6.36mm column diameter is sort of a
tall and narrow column in a diameter that is near to the critical diameter for these materials , which causes an
unusual increase in the demand for impulse to sustain
a good detonation wave through the realatively tall
and narrow column of base charge , and using fairly
coarse crystals like I generally favor increases the
impulse requirement further . Both of these factors
being in play are further multiplied by the unreenforced
configuration which by itself can double the minimum
amount of initiator which is often stated in the literature
without regard to other factors , where the " bragging "
being done about how little initiator is required relates
to circumstances where *everything* has been optimized
in favor of minimum initiating charges , including the use
of reenforcing caps over the inititator , and particle sizes
for the base charge and geometry for the device that is
very different than what would be those parameters for
a * real world * device .
You have to write your own tables for the particular
device you have in mind and derive your own working
figures from experimental tests , because that is where
the transition from theory to reality occurs . The conditions which you implement in your own design
are not going to match the conditions for the tests
which were the basis for the figures given in the literature , so to an extent you can throw away the book and write your own , after discovering that
it is your
data that applies to what you are doing better than
anybody elses data which applied to their own design .
The veracity of your own tests is unimpeachable with
regards to its relevance to your own design .
These trinitrated phenols are quite sensitive to critical diameter versus particle size and column geometry
( height to diameter ratio ) and loading density and confinement values for columns in the range of diameters 6-9.5mm as would be found in detonators
, so they
are very good base charges for seeing the efficiency
differences of different initiators which may be tested .
Also any residue of undetonated material in a clean test chamber is easily revealed by misting with water spray
because the base charge is a dye , while the detonated
products are only a residue of soot in the chamber .
So you can quickly determine if a complete detonation occurred , simply by looking at the wash water  ,
no yellow ....lucky fellow , the initiator did the job .
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quicksilver
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Some damn good ideas there ("no yellow" was cute)...I know this is a bit OT but I have some fine methods of making and woorking with capsules but I
haven't found a method of making a re-enforcing cap....what do you use?
Going back to topic; I also use course crystaline material. Do you believe that the crushing of a compaction mechanism within the column has any
effect? by that I mean that IF the crystals were smaller could a greater pressure yield a higher preformance: other factors being equal? (would
crystal size ever have a bearing on preformance?)
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Rosco Bodine
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There certainly is an optimum mesh size and loading density for a specific column diameter . The work of
screening a dozen different mesh sizes and working out the loadings and output comparisons is more of the
task of a bean counter than I can stand . It is work that has probably been done by the commercial manufacturers
and is probably proprietary information what they have
developed as their own loadings , to wring out all the
efficiency which can be gotten with respect to the
economics of manufacture .
Actually it is my general practice of *not * using a reenforcing cap which has bearing upon my other
preferences and practices . The use of a reenforcing
cap when available enables a more efficient device to be made in terms of reducing the minimum loading for the
initiator . When a reenforcing cap is used , then the physical consistency of the crystals is less critical with regards to the crystals ability to
form a stable compressed pellet , since the compressed column of material will be mechanically locked into place by
the reenforcing cap .
In the absence of the reenforcing cap , then the physical considerations which govern a highly pressed loading are
similar as apply to press forming a clay nozzle for a
rocket motor , where an aggregate of material which
has sufficient grit is required to form a stable pellet
after compression , which will not slowly separate again
and crumble on storage . Indeed a stable loading is
the requirement which becomes the governing parameter
to the influencing of all the other considerations . This
is something which early researchers recognized and
there have been several patents concerning small percentages of additives and schemes for depositing
films of certain pressure flowable binders upon crystals
of lead azide , to greatly enhance its pellet forming properties as is particularly desirable in nonreenforced
detonators . I have not experimented with such binders
but have relied upon capsule geometry and crystalline
form of the materials as the easiest solution , although it
admittedly is not the most efficient solution .
In my experience the crystalline form has very definitive substantial bearing on the explosive properties of a material , even aside from loading
considerations for a plurality of crystals en masse , the crystal form being to the unit crystal , its own peculiar loading as a single crystal unit .
The sensitivity to initiation and critical diameter and detonation velocity are all influenced
by the crystal form and mesh size . There is something
of a compromise between mesh size and maximum possible compressed loading density which relates to the
amount of interstitial space which will remain in the mass
after compression into a pellet . The higher the density
produced for the pellet , the higher will be the possible
velocity .....but it will also become more difficult to initiate . So there are a set of compromises involved
in the design considerations for a detonator , whether
it is of an open topped column unreenforced design ,
or otherwise designed for added confinement . The reenforced cap is certainly a more advanced design
but is also more difficult to manufacture .
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Quince
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So to generate the optimal crystal shapes, what recrystallization procedure do you recommend?
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Rosco Bodine
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For a crude product that has been produced in high yield and purity directly from nitration , like the very light colored product which I described ,
and which ordenblitz
duplicated and described on page 6 , shown here in
one of ordenblitz's pictures .....
http://img58.imageshack.us/img58/634/dilutedandcooling4nd.jp...
Slow cooling undisturbed from a slightly less ( ~5% below saturation ) than saturated solution of the filtered and drained crude product in boiling
distilled water gives
a product which is exceptional from the first water
crystallization . The product will be an acicular mass
of elongated hexagonal blades .
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a_bab
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The pure (recrystalized from HCl iirc) TNP looks like white, transparent crystals. They will slowly become yellow, apparently under the effect of the
light.
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Zinc
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In the school lab me and my friend found a very old (the teacher said 20-30 years old) bottle containing picric acid. I have read on Megalomanias page
that it will form a very unstable crystalline structure after many years.
So is it safe to open the bottle?
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Rosco Bodine
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Yes .
Of course if you reveal being informed enough to know
that the public exhibition of " daring and heroic duty "
displayed by the local bomb disposal unit is nothing
else but a publicity scam ......then it may arouse curiosity
about where you get your information and why you would know better .
[Edited on 24-10-2006 by Rosco Bodine]
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Nitrojet
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Picric acid can be manufatured in laboratory scale via the following route:
Place 10 g. of phenol in a dry 750 ml. or 1 litre flat-bottomed flask and
add 23 g. (12-5 ml.) of concentrated sulphuric acid, shake the mixture
(which becomes warm) and heat it on a boiling water bath for 30 minutes
to complete the formation of the o-and- p-phenolsulphonic acids, and then
cool the flask thoroughly in an ice-water mixture. Place the flask on a
non-conducting surface (e.g., a wooden block or an asbestos board) in a
fume cupboard, and, whilst the phenolsulphonic acids are still a viscous
syrup, add 38 ml. of concentrated nitric acid and immediately mix the
liquids by shaking for a few seconds. Allow the mixture to stand;
generally within 1 minute a vigorous but harmless reaction takes place
and copious red fumes are evolved. When the reaction subsides, heat
the flask in a boiling water bath for 1.5-2 hours with occasional shaking ;
the heavy oil, initially present, will ultimately form a mass of crystals.
Add 100 ml. of cold water, chill thoroughly in ice water, filter the crystals
at the pump, wash well with water to remove all the nitric acid, and drain.
Recrystallise from dilute alcohol (1 volume of alcohol : 2 volumes of
water) ; about 110 ml. are required. Filter off the recrystallised material
and dry between filter paper. The yield of picric acid (yellow crystals),
m.p. 122°, is 16 g.
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Aqua_Fortis_100%
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Warning
Today I tried the usual procedure, wearing gloves and goggles:
100mL 98% sulfuric acid,
20g ASA
50g KNO3
I started adding ASA slowly on sulfuric acid, while heating it on a oil-bath.. Then after 30-40 min the mix was pratically black.
So removed the mix from the oil bath , let some more time and started to add the KNO3 very slowly to avoid NOx and overflow of foam..
After all, the mix was clear-red and bubbling , because of the CO2 .. So I let this some more time bubbling and put again on the oil bath... After
this the mix appeared clear orange/almost yellow..
I then removed of the oil-bath and let cooling slowly..
After some hours I came back and look a big mess on the floor.. The TNP crystals have ppt on the mix and for some reason the crystals increased
greatly the volume of the mix and part of this go to overflow and did the mess... Was a big mistake I did, because I didn't used a larger vessel for
the reaction..
So wearing new latex gloves and goggles I removed most of the "saved" material and with difficulties put on 500-600mL of ice/water. The yellow
material ppt instantaneously , but some of it splashed on my arms (not due to heat, but improperly pouring the mix on the ice-water)...
After I washed my arms and other parts like a manic , but the yellow stain still seems to be unaffected..
I wish to dont have severe poisoning of picric/picramide or other nasty stuffs forming inside my body..
Has anyone similair misfortune?
Any words of what really happened to this mix?
The lesson I learned today is to use a large vessel to hold any overflow and to use proper gloves/safety wear before even thinking in play with this
stuff..
[Edited on 19-1-2008 by Aqua_Fortis_100%]
[Edited on 19-1-2008 by Aqua_Fortis_100%]
"The secret of freedom lies in educating people, whereas the secret of tyranny is in keeping them ignorant."
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quicksilver
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Well you know what happened and why so there is no need to re-write what you know. However a clean up of a lab accident is an important issue in
itself.
It seems that haste in a clean up can make a mess - into a problem. Nitrated benzenes are absorbed through the skin and they are toxic. Next time have
a plan in place as to HOW to clean up in case you need to do more than simple carry on.
One thing that may help is to look at the synthesis and determine that if the procedure calls for 100ml of fluid and an additional fluid level or
expansion, to think that the minimum container would be 25% larger than all concerned. Prior planning prevents poor performance. A lab coat is really
an important part of general safety equipment, goggles should be of a quality that prevents fogging, gloves should be available in large amounts so as
to be able to change into new ones to prevent contamination of product as well as personal contamination.
Benzenes are toxic to liver / kidneys and that may have a cumulative effect (just ask Mr Hurst). Single-level exposures are not that significant
unless it's on a large level.
You know all this, I'm sure but what you said in the description is the MOST important...."After some hours I came back and" Personally, I don't leave
experiments alone....especially of the type you describe!
[Edited on 20-1-2008 by quicksilver]
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Leander
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Could it be possible to produce a PBX containing picric acid?
Low sensitivity to initiation IMO doesn't immediately means it couldn't make a good plastic explosive. As far as I know, the key factor to a powerfull
PBX is not meanly sensitivity or raw power, but having a small critical diameter.
When using pure, fine meshed picric acid, and a percentage of inerts below 10%, with additionally some MHN or PETN, I think it's definitely with a
try.
Has anyone of you got any experience with this?
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Rosco Bodine
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It should be possible to make a gelled nitromethane containing perhaps 75% of picric acid as a colloidal jelly
and it would be cap sensitive , and certainly would have
adequate brisance for shaped and cutting charges .
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a_bab
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Actually it's a known odd fact that NM dissolves TNP like crazy.
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rbick
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Actually, the patent 5140908 goes into depth about sensitizing NM with picric acid.
It also mentions the addition of water to the mixture in some cases. The ratio added was up to 50% TNP 50% NM, although different percentages were
tested. It is described as cap sensitive and quite powerful. Take a look at the patent, as they have tables describing results of various TNP
percentages.
[Edited on 26-2-2008 by rbick]
p=plenty
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grndpndr
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Aqua fortis, rest assured, I witnessed a indivdual accidentaly contaminate himself (TNP)several times over a period of several months some 6-8 years
ago and hs liver function tests reman normal at age 50.At least his product ws of his product was of high quality!LOL
I assume TNP and lead azide are compatible in a compound det?Approx how much lead azide is needed to RELIABLY detonate the TNP(1-2gr,1/4-3/8 al
tubing.Thanks much!
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Rosco Bodine
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For TNP at 1/4" column diameter and a charge of 1.5 grams compressed in three half gram increments at 8,000psi , in an unreenforced configuration,
0.25 grams
of Pb(N3)2 compressed at 6,800psi is about the minimum
for initiation, at the medium to high velocity transition threshold. For a practical loading having guaranteed reliability at that diameter and
compression, 0.4 grams
will do the job. For TNR you can drop that to 0.3 grams.
The pellet geometry of the loadings has great bearing on how small charges like detonators perform, more than initiator weight being any linear
increase for larger diameters and/or heavier base charges. So to keep the performance on larger diameter columns of base charges, the initiator will
have to be geometrically increased accordingly, in my experience. For reliability, the initiator
should be heavy in order to overdrive the shit out of the base charge, to guarantee it goes at highest velocity.
I also have a theory that there is a reflected wave sympathetic detonation somewhere intermediate in the column when a heavy initiating charge is
used, which basically makes the middle of the column do a similar thing as the meeting opposing waves in det cord loops when the Dautriche method is
used for calculating velocity in stick charges. You should see the hot spot signature
develop in the column of base charge on witness plates
at some point in the incremental increase of base charge
well above the amount required for ordinary mode initiation, at which point you have a "special" engineers cap . A 2 gram TNP base and that configuration will
make urea nitrate and probably a few other relatively insensitve secondaries which might more usually require a booster, go high order just fine from
the cap alone, if it is inserted deep in the charge. A #12 cap maybe, but hey,
it works for me
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grndpndr
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Thanks Ive always felt caps that would seriousy overdrive the intended HE best, feeling a weak cap could waste much larger qantities of HE.Aprox.
comm. equivalet of .4-.5 lead azide/1gr TNP -2gr TNP?In a 3/16 soft AL tubing w/epoxed end caps.
At the time what i saw used- FM, approx .5/.75gr pressd to ahieve somewhre round 4500mps and 1-2gr TNP with similr al tubing the results were as one
would expect.Very litte doubt of detonaion unless problems were encountered with the main charge.By themselve thrown in a pond they made a satisfying
thump in 6-8ft of water and rocked the dock.Unscientific to be sure but little doubt as to effectivenes.
[Edited on 25-5-2008 by grndpndr]
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grndpndr
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Hs anyone ever investigated concave detontor end caps hopefully to achieve a SC effect for the longer stick and rectangular mil TNT/C4 demolition
block charges.FM5-25 has exellent cutaways of compound det to scale using lead styphnte as an ignitor and lead nitrate as the primary2.350 length x
.241 OD M7 special military though wieghts arent mentioned and the lenghth is designed for fused use with near 1/2 the lenghth designed for the
fuse.RDX is the base taking the vast majority of room.
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Rosco Bodine
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| Quote: | Originally posted by grndpndr
Thanks Ive always felt caps that would seriousy overdrive the intended HE best, feeling a weak cap could waste much larger qantities of HE.Aprox.
comm. equivalet of .4-.5 lead azide/1gr TNP -2gr TNP?In a 3/16 soft AL tubing w/epoxed end caps.
At the time what i saw used- FM, approx .5/.75gr pressd to ahieve somewhre round 4500mps and 1-2gr TNP with similr al tubing the results were as one
would expect.Very litte doubt of detonaion unless problems were encountered with the main charge.By themselve thrown in a pond they made a satisfying
thump in 6-8ft of water and rocked the dock.Unscientific to be sure but little doubt as to effectivenes.
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There's no way I would drop below 1/4" diameter for a compressed charge with good confinement for TNP or TNR because of critical diameter coming into
play. A column diameter of 5/16" would be better actually for the base charge, but of course that also increases the initiator weight requirement
geometrically to maintain the same performance.
Do you follow what I am telling you about the geometric increase? I mean it is not a matter of a linear increase of 25% more initiator being needed
when the diameter increases 25% from four sixteenths to five sixteenths, but is the volumetric increase required for maintaining the same relative
heights of the compressed initiator pellet to the
compressed base charge pellet. Call it Rosco's rule for microcharges and no you
won't find it in the books, like a few other of my observations, but you can try it and see
some experimental verification for charges in the near regions of critical diameter and critical mass where overdriving is required to reach maximum
velocity in the
relatively short distances involved.
To illustrate Rosco's rule for microcharges in play, let's take
the case of the increase in column diameter from 1/4" to 5/16" which is a 25% diameter increase. You have to look at the area increase on the "end
disc" of the column which is defined by pi times the square of the radius, so the area
increases by 56.25% as a result of that 25% diameter increase, and that's the amount of increase you have to apply to the weight of the initiator used
for the increased
column diameter to maintain the geometry of the charges.
It's a common misunderstanding for people who would think,
well I have increased the column diameter by 25% so then
I should increase the initiator weight by 25%, when that will give a deficient amount, the increase actually being 56.25%.
So if 0.4 grams of Pb(N3)2 is the sweet spot loading for the
1/4" diameter, then going up by 25% diameter to 5/16", will require bumping up the initiator weight to 0.625 grams.
And to all the naysayers, try it and see if it doesn't work out that way for smaller charges that are in that region where
critical diameter becomes an influence on velocity.
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