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Author: Subject: DDNP & related compounds: The über thread!
roXefeller
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[*] posted on 5-2-2014 at 14:55



Quote:

AP can definitely detonate picric acid but it has to be a special configuration using generous amount of the AP used for the initiator. The configuration described worked with the ball of putty used to hot start and compress in situ the firing train. Without the AP / Bullseye putty for the top charge the device failed. But with that quarter gram as first fire, the device worked fine.


What is the function of the AP in this putty? Is the bullseye not sufficient as a first fire?
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Rosco Bodine
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[*] posted on 5-2-2014 at 16:12


AP putty made as described low order detonates on ignition, and in sufficent quantity would likely high order detonate without too much of a run up distance.
But it does shrink as the acetone evaporates so forming a ball or a short molded cylinder of the still soft material before it dries completely rock hard can be done to make this little "first fire" charge hammer for a 1.75 gram 3/8" diameter column of gently pressed AP crystals situated below, atop a 1.5 gram picric acid base charge. It should high order the base charge nicely if my test hold true.
Using the tetrameric variant of AP should even more greatly assure the desired result. However this kind of thing is in the realm of a ghetto improvisation, strictly low tech kind of near term use solution. Getting too involved with such a pursuit would likely turn out to be a short term activity for the recently departed, or the survivor called "Lefty" who uses a seeing eye dog.
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[*] posted on 5-2-2014 at 17:28


Just to be concise, you are saying that both the trimeric and tetrameric AP are storage unstable. I can read your statement both ways (trimeric stable/tetrameric unstable or both unstable). But I suspect, given the nature of AP, you are reaffirming both are storage unstable.

[Edited on 6-2-2014 by roXefeller]
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Rosco Bodine
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[*] posted on 5-2-2014 at 19:14


To be precise I said no such thing about either one. Both are chemically stable unlike HMTD which is not chemically stable. There is a high vapor pressure about acetone peroxide slightly lower for the tetramer but it puts the material in a state of constant recrystallization at ordinary temperature due to the continuous sublimation and condensation and crystallization of vapors where the container functions as a heat pipe with a random orientation, and the system is always in flux with recrystallization resulting in density change and larger crystals. It is not liable to just spontaneously explode in my experience, but the physical behavior is undesirable and even unnerving as a physical behavior for an explosive that seeks any crevice into which it may occupy and crystallize, which may include the threads of any container closure. It is like an accident waiting to happen. The vapor pressure is high enough that the material is used as a fumigant for extermination and/or repellent effect for insects in silos of flour or grain. But the vapor is also an added flame hazard where the flame kindled does not just reach and ignite a fuel but a flammable explosive that will do much more than simply burn when ignited accidentally, such as by static electricity.
All things considered it is the physical properties more than any chemical stability that is what is worrisome about AP. The ease and cheapness of making it also breeds complacency and carelessness about its handling which makes it seem less dangerous than it is. Eventually a handler of AP becomes clumsy or careless made more likely by the nature of the material which is a kind of insidious danger.

[Edited on 6-2-2014 by Rosco Bodine]
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[*] posted on 5-2-2014 at 19:34


Quote: Originally posted by Rosco Bodine  
However this kind of thing is in the realm of a ghetto improvisation, strictly low tech kind of near term use solution.


I apologize for putting words in your mouth. I read the above and that's what I concluded. It is exactly what you said in response that makes me question the necessity of AP in the putty. But given your tests, I would agree that it is needed as far as the parameters of your testing go. At least it is easy to create, but the short work in synthesizing it should allow for extra time for careful handling.

Why doesn't the in situ compression from this first fire overcompress the initiator to a dead pressed state?
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Rosco Bodine
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[*] posted on 5-2-2014 at 19:42


The volatility of the AP and the lack of storage stability for the putty would make necessary the near term use, for example a few days to a week or so, versus months later anticipated use of the assembled detonator, unless it was hermetically sealed. Not all initiators can be dead pressed and AP isn't one that is subject to dead pressing, which is a kind of misleading term anyway. A dead pressed initiator will no longer be able to ignite and make the DDT in the usual way from ignition, but will fail to ignite or quench after ignition. Even a dead pressed initiator will still assuredly detonate if it is initiated by even a portion of itself that isn't pressed so firmly. It becomes "dead" only in response to ignition, not "deactivated" in some magical way so that it won't detonate at all.

[Edited on 6-2-2014 by Rosco Bodine]
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Hennig Brand
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[*] posted on 6-2-2014 at 11:57
Success


Picric acid (1.5g) was pressed into the ~7.6mm id aluminum arrow shaft with a lever press and an addition 0.5 g was pressed on top by hand. DDNP (0.5g) was pressed into a reinforcing cap (1/4" id) and an additional 0.5g, for a total of 1g of DDNP, was pressed on top of the picric acid. Care was taken to not overpress the DDNP. The reinforcing cap was then pressed into place in the detonator casing. Because of guesstimating, instead of measuring, the casing was just barely big enough and there was not enough room left to press in locking discs on top of the reinforcing cap. A bit of black electrical tape was used to hold a bit of black powder and the fuse in place on top of the cap. To summarize, 2g of picric acid and 1g of DDNP was used. DDNP ignites very easily so it was decided that a flash igniter was not needed. The DDNP used was not recrystallized, it was simply washed with small amounts of ice cold water after filtering, from the post reaction mixture, and then air dried.

The witness plate is 1/8" steel. The center hole was there before the blast and is the pilot hole from a hole saw.

A lovely sharp crack was heard at detonation and peering from behind cover a moment later a little puff of black smoke could be seen drifting away. A hole was punched through the witness plate. What a lovely scene.

The big thing with picric acid, as I am continually learning, is to not be stingy with the primary. It takes a considerable kick to get it going.


DDNP Unrecrystallized.jpg - 393kB Cap On Witness Plate.jpg - 471kB Top View.jpg - 489kB Bottom View.jpg - 468kB

Edit:
Just measured the steel witness plate today, with vernier calipers, and it is actually about 3mm thick not 1/8" (3mm is about 94% the thickness of 1/8").

[Edited on 7-2-2014 by Hennig Brand]




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[*] posted on 6-2-2014 at 12:30


Nice test mate. Why is the BP there, it can reach pressures witch can ruin the fragile setup. The visco can ignite dextrinated azide. The conclusion for me is if I'd use DDNP, it would be at least a few grams in 30.06 case for example with neck sealed well with epoxy, reaching beyond where the bullet seats. Otherwise I wouldn't consider the cap reliable enough to trust it expensive material. Witch is most effective primary: MF, SADS or DDNP?
I wonder how one detonates cast TNP? 40g caseless RDX booster or 20g maximum density tamped NG/NC 96/6 in a cavity at direct contact?
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[*] posted on 6-2-2014 at 12:44


Thanks, I used a bit of your routine of hand pressing the last bit of secondary for increased sensitivity. The hole through the reinforcing cap is only 1/16", so I put a little black powder on top just to make sure there was lots of fire ensuring ignition. DDNP behaves more like mercury fulminate, than lead azide, but according to all the literature I have seen it is much more powerful. So far I personally prefer lead azide over DDNP, but DDNP is made from picric acid and it also has some other qualities that actually make it superior to lead azide in some respects. Being able to make a primary from your secondary is very advantageous, especially when that secondary can be made from so many different things and is already so versatile as an explosive. It really isn't all that hard to make DDNP either. Once you have a good reducing agent, the processes involved are actually pretty straight forward. I know if done right it takes much less than a gram of DDNP to initiate picric acid, but even using a gram it's still a decent setup for the hobbyist. Also, I wouldn't mind storing a DDNP-picric acid compound cap for long lengths of time. However, I wouldn't want to store a cap with a peroxide primary for very long at all.


[Edited on 6-2-2014 by Hennig Brand]




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[*] posted on 6-2-2014 at 13:54


People bash lead azide's ~1500j/g. It's got more energy density and initiating power then almost all the common primaries(unless you can make trinitrotriazidobenzene?). It also decomposes to pure nitrogen and lead, so it's got absolutely flat decomposition curve(I suppose) and is so bad ass, it doesn't give a s*it about confinement. The undextrinated form seems very flame sensitive.
For me it's hard to trust DDNP more then well designed AP compound cap. I've had about two failures with AP - TNP in a straw and moist UN.
Do you have a convenient way to share your DDNP recipe?
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[*] posted on 6-2-2014 at 14:13


I love lead azide. I think in many ways it's the king of the primaries. In the "picramic acid from picric" thread I just recently gave a brief description of my process. From picramic acid to DDNP, I just used the process right out of the text "The Chemistry of Powder and Explosives". There are a few steps to the whole process, starting from picric acid, but none of them are particularly hard or time consuming. Getting a decent reducing agent is the only difficult part. Maybe you could get access to sodium or ammonium sulfide. Compared to acetone peroxide everything is hard, so I guess it's all relative.

I think DDNP is very reliable, going on what is published in the literature. What was happening during my earlier tests was simply because there wasn't enough primary used. It can take a considerable amount to get up to full velocity, given that DDNP is a DDT (deflagration to detonation transition) primary explosive rather than a practically instantaneously detonating primary explosive, or as Rosco would say "unequivocal" primary explosive. When using 0.5g in the configuration I was using it either wasn't up to high velocity, or there wasn't enough primary left after it had gotten up to high velocity, to do the job of initiating picric acid. I would have to do more testing, but I imagine the amount of DDNP needed is actually closer to 0.5g than 1g. As an example, let’s say 0.3g is burned up getting the DDNP up to high velocity, well, that would mean that when using 0.5g only 0.2g is remaining to perform at high velocity and do the initiating. If 1g is used, that leaves 0.7g left to perform at high velocity. This is just an example, but it is likely something similar that is happening.

A reinforcing cap adds confinement which is meant to help these DDT type primaries get up to high velocity quicker, leaving more material to function at high velocity, thereby reducing the amount of primary needed.

[Edited on 7-2-2014 by Hennig Brand]




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[*] posted on 7-2-2014 at 11:00


You are gaining understanding. The literature figures tend to be a "best case scenario" about bare minimum quantities used under highly engineered test conditions. Your own results are likely going to vary by a multiplier that may even be a different order of magnitude which will appear that the literature is off by a decimal place. I have even laughed and thought this must be a misprint or an error by the typesetter for the older print literature. Look at their figures and then compare with your tests, and believe your own tests.

Don't underestimate the value of a fast DDT low order detonating flash igniter as first fire particularly for an unreenforced cap. That is an established technique that has been reported being observed has value, from the early literature and it has followed even to being included in modern devices, because it works well in those applications where a loose flash charge is permissable. Something like one of the 3 flash igniters based on basic lead picrate or loose lead styphnate or other similar flash charge that does low order detonate is what is needed and gunpowder doesn't have that intensity. In some cases like for the DDNP a progressive loading from dense to loose could be of benefit, where the same effect is provided from the one material.

One thing you could try WRT to the stepped loading of the base charge. Above the pressed 1.5 gram of picric acid, load a moderately pressed increment of 1/3 to 1/2 gram styphnic acid, which should initiate about 20% more easily and serve also to initiate the more highly compressed picric acid below.

It may also be that a similar arrangement where the diazo derivative of styphnic acid can also serve as an initiator of styphnic acid, and the greater sensitivity of styphnic acid along with the greater initiating power for some of the diazo derivatives may be even easier to achieve than is possible with the picric acid diazo derivative used for initiating picric acid. The same general theory may apply and be more easily implemented for styphnic acid.

See these links for the styphnic acid derived analogue of DDNP, hydroxy DDNP

http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...

credit to dave321 for pointing out the relevant patent US4246052
http://www.sciencemadness.org/talk/viewthread.php?tid=433&am...

[Edited on 8-2-2014 by Rosco Bodine]
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[*] posted on 7-2-2014 at 11:26


Do you recommend ball milled KClO4/activated charcoal as flash igniter? It looks very stable with good flame sensitivity, but it's slow mixture. Is it a good choice for flash igniter of lead azide? Also, in AP cap, we may want isolate the AP from the fuze by leaving it sealed and use the flash igniter to penetrate the seal.
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[*] posted on 7-2-2014 at 12:04


No I do not recommend that as an alternative. No it is not a good choice for a flash igniter. I specified what is and will try to find a link for the 3 basic flash igniters. Basic lead picrate is the first, lead nitrato-bis basic lead picrate is the second, and basic lead picrate - lead nitrate - lead chlorate triple salt / clathrate is the third.

Here is a link for a post with all three of the basic lead picrate type flash igniters. Other compunds may work as well but are not pyrotechnic mixtures. Some specialized pyrotechnics could possibly work but that would be less likely than chemical compounds that have the properties required.
http://www.sciencemadness.org/talk/viewthread.php?tid=389&am...

Lead salts have a disadvantage of toxicity, but that is offset by a desirable physical property involving the density of the lead atom that is beneficial in transfer of energy of the exploding material and dense vapors and also allows for a more compact charge since the salts of lead tend to have high bulk density. A dense vapor containing atomized lead and travelling at supersonic velocity has more kinetic energy when impacting a target material than does the vapor of an organic material travelling at a similar velocity. So the lead compounds that are energetic may pack a greater punch originating from a smaller more compact charge, than is possible from another similar compound having a different cation that is an atom less dense than lead.

The only success I had with an AP cap I already reported was using AP putty for a first fire and there was no isolation or blow through partition or flash igniter but it was a ball of AP putty ignited directly by the fuse that worked.
Likely other configurations can work but I am not going to explore designs of detonators based upon AP. I was simply reporting an experiment that showed it can occur that AP will detonate picric acid under certain conditions. Inferences about that can be drawn and applied to other scenarios involving other materials but I really don't want to explore all the nuances of various possible improvisations using AP. Anybody who wants to delve into that kind of interest is welcome to go there but I am not going to go there because AP does not interest me as having practical value beyond being a curiosity having short term improvisational use similar to HMTD. The properties of AP make it unsuitable except for a very limited kind of niche application that is not my interest.

[Edited on 7-2-2014 by Rosco Bodine]
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[*] posted on 7-2-2014 at 14:00


Thanks, between your posts and the text "Primary Explosives" by Matyas, I am starting to understand this initiation business a little better.

The only things in the detonator capsule above were picric acid and DDNP. The black powder was placed on the outside surface of the reinforcing cap just to insure a good flash at the end of the fuse so that the DDNP would be reliably lit through the small 1/16" touch hole in the reinforcing cap. DDNP is very easily lit, so a flash igniter is not needed in that respect, but you could be right about the other benefits of using a good flash igniter.




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[*] posted on 7-2-2014 at 14:44


Quote: Originally posted by Hennig Brand  
I am starting to understand this initiation business a little better.

I think we can all thank the complexity of initiators that kept most people with simple binary base charges away from the initiators they needed most of all. It probably save me from myself when I was a kid, and does still. A person has to reach a level of understanding like you guys are demonstrating, before doing more. Obviously exceptions are too be found, but simple caps and simple base charges would make for an unpleasant world.

Hennig Brand, I saw your attempts at basic lead picrate that were linked above, from last year and before. But you've also used some as a first fire recently. Any update on your methods to overcome the hurdles for basic lead picrate synthesis?

[Edited on 8-2-2014 by roXefeller]
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[*] posted on 8-2-2014 at 00:15


What complexity? It's just that we're enthusiastic to make cool things. Most people use HMTD in paper tube or AP in syringes. SADS in a straw, taped together with ETN in another straw.
http://www.inertproducts.com/inc/sdetail/250/8687
I wonder if AAA batteries make good cases.
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[*] posted on 8-2-2014 at 01:53


Quote: Originally posted by roXefeller  

Hennig Brand, I saw your attempts at basic lead picrate that were linked above, from last year and before. But you've also used some as a first fire recently. Any update on your methods to overcome the hurdles for basic lead picrate synthesis?


If you go to page 4 of the azo-clathrate thread, you will see that with high certainty I was getting basic lead picrate. The lighter color of my basic lead picrate, compared to some samples, was the result of smaller crystal size. A very good example of this is DDNP actually. Grow DDNP crystals large and the material can be a very dark brown. Keep the crystals very small and the material is closer to a yellow color.

Something to keep in mind, according to "Primary Explosives" by Matyas lead picrate forms several basic salts with varying lead content. There are other, older, references stating the same also. The amount and quality of reactants as well as the process used were very carefully controlled for my experiments (especially the later ones), which was a strong indication that crystal size was the reason for the difference in color. Reasonably high yields were also obtained. Microscope pictures of the basic lead picrate are also shown, in the azo-clathrate thread, showing well formed crystals of uniform type.

In general my fine crystalline basic lead picrate did not detonate unconfined in small quantity when lit, however even extremely weak confinement would cause it to detonate when lit. As an example, a small sample wrapped in a single fold of filter paper would detonate when lit. The darker colored samples with larger crystals would detonate, with less or even no confinement, in small quantity when lit however.

[Edited on 8-2-2014 by Hennig Brand]




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[*] posted on 8-2-2014 at 09:33


When you drop a test sample amount below the critical mass minimum for self confinement of loose crystals, governed by the conditions, then ignition will not provide a DDT to low order detonation. Likewise if you pour the loose crystals into incrementally decreased diameter holes bored in a wood block, a critical diameter will be found below which the loose crystals will only deflagrate without making transition to low order detonation showing the two factors combined at work which are interactive and are critical diameter and critical mass and additionally confinement of a one open ended tube for that particular test. But simply for a mound of loose crystals on a paper plate touched by a glowing splint, at a certain weight there will be a DDT to low order detonation for all three of the flash igniters, including basic lead picrate and it is probably lowest in its vigor for self confining DDT of loose crystals meaning the critical mass minimum trends higher than example for the chlorate containing or nitrate containing complex salts. Lead styphnate also has a low critical mass for loose crystals making the DDT to low order and if further several grams excess lead styphnate is present in the 4-5 gram range for example it will accellerate to high order and show its full potential.

critical mass and critical diameter and confinement and bulk density and crystal form and crystal mesh size are all interactive parameters .......which makes things get complicated fast for testing and comparing one sample with another. If any parameter is different it will skew the test results for sample A versus sample B and for different tests using any variation on the test conditions involving any even slight change of even one parameter. There is a precision involved about every tiny detail and aspect where even temperature and humidity can have bearing.

Perhaps it is time for a little music to go along with my sample X amount of candidate energetic test compound y.....

......It just won't pop blues :P


<iframe sandbox width="640" height="480" src="//www.youtube.com/embed/3EVBhtkwszk?rel=0" frameborder="0" allowfullscreen></iframe>

[Edited on 8-2-2014 by Rosco Bodine]
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[*] posted on 8-2-2014 at 12:08


Yeah, I could have actually measured the amount of BLP lit unconfined from the above post I guess. It was more of a rough qualitative test. LS really does take very little to self confine and DDT.

Something else from chapter two of "Primary Explosives" by Matyas; "Both DDNP and LA show a performance relatively independent of specific surface with the best performance around 4,000 cm2/g. The behaviour of MF is however quite different, as its minimal necessary amount continually increases with increasing specific surface (decreasing crystal size)."

There are several lovely graphs, illustrating the concept, before the above statement was made in the text. The graph relating to DDNP is attached as a jpg below. From the graph it can be seen that even for very fluffy material, once compressed, performance is not dissimilar from much coarser material.

So, in the case of DDNP maybe all that time spent recrystallizing is for limited benefit.

DDNP Initiator Efficiency Versus Particle Size.jpg - 73kB

[Edited on 8-2-2014 by Hennig Brand]




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[*] posted on 8-2-2014 at 13:03


DDNP has properties which make it behave in peculiar ways that may cause undesired but foreseeable issues which are however not insurmountable. Used alone as an initiator it can be more difficult to achieve the performance desired for DDNP than is true for mixtures that have been found to provide improved performance. But used as a single substance, neat DDNP is sensitive to crystal form and density and to loading density, and of course to critical diameter and confinement, and those factors must be taken into account. DDNP presents a situation where used alone it is somewhat marginal as an initiator. Yet certain optimized implementations using it can be workable and reliable. The navy has used detonators that were standardized but used significant loadings of the DDNP to initiate a base charge of progressive density loaded PETN, and used the DDNP as a chlorate enhanced and sensitized mixture 75/25 at a large diameter of nearly 3/8" with a DDNP loading of about 3/4 gram. So it is easily seen how a gram of DDNP for a far less sensitive base charge like picric acid is not surprising. Instead of being too impressed by R&D figures reported for a substance that is being "sold" by its inventors and investors, trust that the navy was reporting a more pragmatic approach to real world use of the technology in the field that is the theory reduced to actual practice, and that required a generous multiplier for the laboratory test results.

Urbanski reported quote:

"In Smolenski and Plucinski's opinion dinitrodiazophenol alone is not suitable as an initiating material for detonators since it requires too long a path for burning to change into detonation, hence it is necessary to add another initiating substance e.g. lead azide. Nevertheless it is suitable for filling caps."

Special techniques are required for practical use of DDNP.



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[*] posted on 8-2-2014 at 13:12


Lead azide and DDNP are apparently incompatible, but yeah giving it a little jump start from a lead azide type explosive would solve the biggest problem with DDNP.



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[*] posted on 8-2-2014 at 14:02


I read about that incompatability also and wondered if silver azide would be better.

There is a chart which I have been trying to locate and I think it is in PATR which shows the initiating power of mixtures of lead azide and lead styphnate. I know the chart is also in the Matyas book, but there is an older black and white chart I'm sure I have somewhere and wanted the different context article that goes with the chart. Such binary mixtures for initiators are not uncommon. Anyway I have seen it stated also that lead azide is not compatible with lead styphnate but I do not believe that is true because of the ASA composition widely used.

[Edited on 8-2-2014 by Rosco Bodine]
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[*] posted on 8-2-2014 at 15:07


Quote: Originally posted by Hennig Brand  
Both DDNP and LA show a performance relatively independent of specific surface


Taking note of that same graph, there is a strong sensitivity of the minimum amount with the density of packing, small density changes produces large drops in performance. And given a material with high specific area, in order to acheive that higher density by pressure alone will confirm the optimal packing pressure shown by your earlier graph (https://www.sciencemadness.org/whisper/viewthread.php?tid=43...). It confirms too much pressure causing reduced performance.
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[*] posted on 8-2-2014 at 20:36


Factors Affecting Initiating Efficiency of Detonators

R. L. Grant , J. E. Tiffany
Ind. Eng. Chem., 1945, 37 (7), pp 661–666
DOI: 10.1021/ie50427a017
Publication Date: July 1945



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