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nitro-genes
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Hi Dornier,
Noticed the "melting whistlemix" thread but never saw you actually included picrates, I really need to search this forum better before adding a new
post! :-) Part of the brisance, as was mentioned before, is presumably from heating the mixture allowing the components to melt and partly overcome
the initiation energy needed to break the bonds within the fuel and oxidizer, allowing the DDT to occur more quickly. I didn't saw the complete
shredding of the alufoil like for silver/lead azide or the melted potassium chlorate +SP you mentioned, though I was still impressed with the brisance
of the composition. I have a feeling that as use for initiation of secondaries, these compositions can work but require a lot of confinement and
practically optimized cap designs. Planning on making a comparison between initiation of PETN or ETN with Leadazide and the k1k composition, never
hurts to give it a try...
I was just thinking, that formulation based on crackling microstars might be able to initiate PETN/ETN. This would ommit the melting step, as (primed)
microstars presumably work by ignition of the outer layer, melting of the inner star, after which they explode with great brisance. :-)
http://www.youtube.com/watch?v=3UcVMhWjc8c
http://www.youtube.com/watch?v=2zceUUs_R20
EDIT: Lol, just noticed the second movie was actually Dorniers! :-D
[Edited on 31-7-2014 by nitro-genes]
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Jimbo Jones
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In the past I’ve made (with various success) a “dragon’s eggs” formulations based on this mixture.
http://www.sciencemadness.org/talk/viewthread.php?tid=22599#...
After reading the post from Yamato71 I’ve tried to replicate his result, but with no luck. I have tried both ultra-fine flake and spherical (8 – 9
micron) aluminum. Cupric oxide and cuprous oxide. Homemade and commercial nitrocellulose extracted from civil pyrotechnics. No DDT or even similar
results as what Yamato71 describe in his post.
Anyway. The idea still deserve some attention.
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plante1999
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Lead picrate would probably make s good substitute to potassium picrate in the whisle mix comp. It is more sensitive, but nothing like a true primary
like silver azide. It would be worth a try I think.
I never asked for this.
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Dornier 335A
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Nitro-genes, what I have concluded from my tests is that the great rise in brisance comes from the fact that the mixture becomes
completely homogeneous, all the way down on a molecular level when it is melted. Only the picrate in the potassium chlorate / sodium picrate
mixture melts before ignition and that is likely why it doesn't always detonate violently when confined and heated. The higher temperature of course
shortens the DDT, but won't enhance the performance of an already going detonation by much.
I have the impression that picrate/chlorate/perchlorate mixtures are rather similar to DDNP in terms of DDT times and performance, so something like
Henning Brand's work could likely be used.
I doubt the dragon eggs formula can be used to initiate a secondary in amounts small enough to be useful. I concluded in my video you linked that the
commercial bismuth formula completely lacks brisance. Yamato71's results are interesting and I think Antiswat was able to replicate them to some
extent.
I considered making lead picrate, but I want to stay away from lead as much as possible.
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nitro-genes
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Magnalium would probably do much better with the CuO compositions, added benefit is that the MgAl alloy is mucht easier to tumble into a powder as
well (compared to Al or Mg alone). Lead tetraoxide is easily produced from lead + acetic acid --> carbonate precipitation --> Heating to oxidize
basic lead carbonate with O2 from the air, although I agree cumulative toxic compounds like heavy metal salts are best avoided.
@Dornier, agreed, the total enery release is not affected much by heating probably, though the ability of the shockwave to accelerate fast is THE most
important factor determining the initiating performance (brisance) on a weight basis for primaries used in blasting caps. Azides accelerate immensely
fast and single crystals can make DDT, while total potential energy release for leadpicrate/styphnate is probably higher. The only difference is that
the latter accelerate much slower and don't reach a high VoD in the small amount in which they are used. Most regular chlorate whistle compositions
example can reach 2500 m/s in bulk amounts and BC initiation, but in gram amounts and fuse ignition they only reach about 800 m/s or lower. Audibly
they may sound the same and could be definined as detonation as in faster than the speed of sound, though the former will be much more brisant.
Anyway, testing is the only way to find out, I'll give it a try...
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Dornier 335A
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Here's high speed footage (240 fps) from four tests:
Molten KClO3 / NaC7H5O2, 4 mg
Molten KClO3 / NaC7H5O2, 30 mg
KClO3 / NaC7H5O2 in powder form, 50 mg
KClO3 / KC6H2N3O7 in powder form, 50 mg
The two first were detonations. The two last gave very loud blasts and turned the paper tubes into fragments (on average 5 mm) but were not complete
detonations. Look at the flames shooting out. Last one also coloured the tape yellow.
[Edited on 3-8-2014 by Dornier 335A]
[Edited on 3-8-2014 by Dornier 335A]
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DraconicAcid
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Completely irrelevant, but I just have to come up with an assignment question that includes the line, "Professor Peter Piper precipitated a pound of
potassium picrate."
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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