Detonating High Explosives with a Flash Powder based Detonator

[D-Mendel]

As the title implies - is it really possible?

I've experimented latley with flash compositions (Based on Dark Al powder with KClO4 as oxidizer and small amounts of KMnO4 as a... "bonus" :p ), and it seems to be quite strong (or at least, makes a very loud bang).

I haven't experimented with high explosives, so of course I began wondering if a small metal tube containing this powder, placed the right way to a high explosive would set it off.

Actually, I know they differ in sensitivity, so the right question would be - what, of at all, high explosive will detonate in this method?

[Bert]

This is a common newbie speculation, a search will show you the information if you care to take a few minutes to UTFSE and read.

2 years + since you joined and your first post asks this question outside the water cooler???

[tomu]

Nitroesters like Nitroglycerin or Ethylenglycoldinitrate and PETN will detonate with this kind of low power initiation.

[festergrump]

Work the problem, D-Mendel.

First, what is the goal of your device? Stump removal? Shattering steel? Blasting apart a large stone mass?

Next, what's the best secondary explosive for this goal? What are the pros and cons of using this? Once you have this in mind you can move on to the next step...

What primary (and in what quantities) will ensure a complete detonation for the secondary I've decided upon?

More often than not, when you ask "...what, if any at all, high explosive will detonate with this method?" the problem REALLY to be worked is "How can I impress the fuck out of my friends with my Mad Bomb Skillz?!". You're working the problem backwards, man, and showing no real reason for any help from any member here.

I'm with Bert... UTFSE and READ...

[megalomania]

The theoretical possibility exists that under the proper conditions a high explosive could be initiated by a detonator of such feeble means. Achieving a reliable and consistent initiation is entirely another matter. It may work, but only if you get lucky on 1 out of 100 tries. As festergrump intimated, what the high explosive is, and under what conditions it is to be initiated will affect the outcome.

[nbk2000]

Most explosives sensitive enough to be detonated by the feeble shock of a flashpowder 'detonator', are sensitive enough to go off accidentally during production or handling (if you're not careful).

So, if you're not ready to make real detonators, you are most certainly NOT ready to be making such sensitive explosives.


How can I impress the fuck out of my friends with my Mad Bomb Skillz?!


Greater truth has never been spoken. :D

[D-Mendel]

Thanks for all the replies, but I really feel the need to explain why I was asking this - out of pure curiosity. I'm not in to (yet) high explosives, I deal with pyrotechnics as a hobby. A few days ago I had an accident that made something blow-up stronger then anything I've made before - so I wondered about its ability to detonate high-explosives, that's all.

[nitroso]

I'm with Bert... UTFSE and READ...

I'm with ernie and uncle fester... :rolleyes:

UTFWTFIMARUDE@$$H0lEWHOCANTANSWERASIMPLEQUESTION

++++++++++++++

Bert and Ernie from Sesame Street have manners, something this rude product of the modern State Sheeple Indoctrination Facility lacks, so bye-bye to UTFWTFIMARUDE@$$H0lEWHOCANTLOOKFORHISOWNANSWERS!. :) NBK

[crsk8andsno56]

As mega stated there is always the chance to be able to set this off, but I'm guessing you would need a lot of the low explosive (flash powder, bp, etc) to make this work. It would be much easier to just make a different primary such as AP, HMTD, MEKP or something else then wasting the expensive low explosive that would be the initiator.

Also WTF was that last post by nitroso? Pure spam or what?

[Bert]

It was more a kind of despairing signal to the NBK2000 that he realized his unworthiness and wanted to be put out of our misery... Some old, infirm or geneticaly inferior individuals will do this kind of thing, as they realize at some level that the only positive contribution they could make to the gene pool of their species is, paradoxicaly, a negative one.

[Shalashaska]

Also WTF was that last post by nitroso? Pure spam or what?

He was one of the people that decides to use their first post to either agree with the person that posted directly prior to him, or just a generic one line post consisting of, "Dude, you're so lazy, use the search."

The latter posts are unnecessary, since the mods will handle it how they see fit, and if the person that didn't search isn't banned, they'll know plenty well not to post without searching first.

[Rbick]

It's funny that I saw this post tonight, since today I tried this exact idea. Just out of pure curiosity I attempted to detonate a 100g charge of APAN with 12% AP.

The "initiator" was 6g of 3:1 flash using KClO4 and 600 mesh Al pressed into a 7mm expended rifle cartridge. Yes, it does make a loud bang, but no, it didn't detonate the APAN.

The 12% mixture of APAN is not fuse sensitive (in my experience), but still, if the flash can't detonate that, then it sure as hell won't detonate much of anything else. You're much better off making a 1 or 2 gram AP cap, which would successfully detonate 100g of APAN no problem.

++++++++++

Use paragraph breaks in the future, eh? NBK

[uniqueusername]

It seems like there should be a reasonably simple way to figure out any "will x grams of y detonate z" question. If the energy of detonation per mole for explosive y and the energy required for detonation of z is known all you would have to do is solve for x.
Ex. (all numbers made up no idea if any of this is right)
Energy release of APAP detonation = 100 J/mol
Energy required to initiate detonation of PETN = 1000 J

moles required for detonation of PETN using APAP =
x = (1000 J) / (100 J/mol)
This is basic algebra so I assume everyone can solve for x and cancel units. Just in case, J and J cancel leaving x = 1000/100mol, x= 10mol.

10 moles of APAP is required to initiate PETN detonation (made up numbers). I am pretty sure that all HE's are self sustaining and the quanity of PETN is irrelevant but I am not sure.

Does anyone know of any such formulas?

[Bert]

Do you know enough about the behavior of energetic compounds yet to understand how such factors as charge density and the related VOD bear on this question?

[uniqueusername]

Unfortunatly no I don't. I will read up on that.

[Alexires]

unique, that is like saying that 50,000 matches have the same energy as a blast furnace and that you should be able to melt steel by lighting them under it one at a time.

It has to do with energy yes, but it also has to do with how sensitive the recieving explosive is to energy, at what "rate" the energy is applied (is the impulse great enough?), etc. You could be best served looking at this (http://www.roguesci.org/theforum/showthread.php?t=6130&highlight=recommended+reading) thread.

I'm sure there are equations, or something at least giving a basic idea, but they are probably not going to be as easy as a+b=c.

[uniqueusername]

Haha I guess I should have thought of that. Thanks for pointing it out. That seem like it would complicate any equations quiet a bit. Hopefully I can find some time to read some of that material, however I am currently boning up on my organic chemistry in relation to drugs at the moment. So I don't have a lot of free time. Does anyone happen to know of a formula that is something like what I described? I would like to at least get a look at one if possible. Regardless of whether I can understand it or not.

[Bert]

uniqueusername, If you post something showing that you have UTFSE or done any experimentation, you might get something in return. Even an intelligently worded request for spoon feeding is still a request for spoon feeding. "I don't have the time" means you should be somewhere else.

BTW, experimenting with drugs and explosives at the same time is a VERY bad idea.

[Alexires]

Personally, I don't know of any equations, but after running a search in google (string - initiator calculate explosive) I came up with interesting looking pages.


http://www.springerlink.com/content/xj4qm236165n011l/

An approximate method is proposed to calculate the impact sensitivity indices (critical initiation pressure and critical charge thickness) for solid explosive mixtures (explosive compositions and mixtures of an oxidizer with a fuel). The calculation is based on some model concepts of the physicochemical and explosive properties of reactive mixtures. Test calculations of the sensitivity indices were performed for mixtures of HMX and TNT and mixtures of ammonium perchlorate with polymethylmethacrylate (PMMA) and TNT, and the results are compared with data of laboratory experiments on an impactor.

http://links.jstor.org/sici?sici=0080-4630(19580729)246%3A1245%3C268%3ATIOEBS%3E2.0.CO%3 B2-7

A 'gap' test of the sensitivity of explosives to shock is described. An RDX pellet generates a shock in a metal wafer (the 'gap') which is in contact with the sample. A sharp dent in a steel bar at the other end of the sample signifies detonation. Sensitivity is determined in terms of the minimum gap thickness that inhibits detonation. The sensitivity of a mixture of explosives has been found to be simply related to the sensitivities and amounts of its components. Ionization probes and photography have been used to record the course of detonation; a hypothesis explains the observed facts. There is for each charge a critical initial shock velocity below which transition to detonation will not occur. The entering shock wave initiates reactions which release energy. The energy available from these reactions will counteract losses and, if sufficient, reinforce the shock which will then accelerate smoothly into a detonation. The probability that any test will result in a detonation is thus seen to be controlled by the balance of energy lost and gained by the shock wave.


http://egweb.mines.edu/faculty/vpetr/MNGN%20333_444/Class%20Notes/Handbook/Handbook%20for%20Explosives%20Engineering%20chemis try.pdf

Looks pretty good. If you download it, then go to section

5.3 - Real Physics of Detonation.

Real detonation is much more complex than either the CJ or ZND models which are described below. But these models do describe with some degree of accuracy what occurs in a detonation.


Now changing the syntax to "initiation calculate explosive" we get -

http://www.eng-tips.com/viewthread.cfm?qid=33615
http://flux.aps.org/meetings/YR97/BAPSSHOCK97/abs/S400.html
http://www.sms-ink.com/services_char_eval.html

http://www3.interscience.wiley.com/cgi-bin/abstract/109617768/ABSTRACT?CRETRY=1&SRETRY=0

Abstract: An approximate model for pressure buildup behind the front of an initiating shock wave is developed. This model leads to the widely used P2t initiation criterion, but the pressure index is not limited to a value of two. Expressions for wave run time and distance to detonation are also obtained. The use of the model is illustrated using explosives widely discussed in the literature. It is shown that critical shock initiation and run distance to detonation can be rapidly estimated to good approximation over a wide range of shock conditions from the results of one or two relatively simple experiments. The calculational method may be useful for various applications.

http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA149990

http://www3.interscience.wiley.com/cgi-bin/abstract/109740097/ABSTRACT

Abstract: The critical energy (Ec) criterion developed by Walker and Wasley for predicting the response of bare, heterogeneous explosives to flying-plate impact, is modified for application to flat-nosed rods and spherical projectiles. This modification redefines the shock duration term used in calculating Ec and implies that a minimum volume of explosive at a given shock energy is needed before initiation occurs. The modification also changes the L/D ratio of the projectile at which plate behaviour changes to rod behaviour from the currently accepted value of approximately 1/4 to 1/12. Comparisons between the modified criterion and published experimental data show that the same value of Ec can now be obtained from both flying-plate and more complex projectile impacts into the same explosive.

http://www.sms-ink.com/services_char_sens.html

http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PHFLE6000011000003000710000001&idtype=cvips&gifs=yes

Extract: This paper is devoted to the building of a model for the ignition and growth of a detonation in pressed solid explosives. The ignition model describes the various phenomena occurring at the microscopic scale during viscoplastic pore collapse. The growth stage is represented by a model combining inner combustion inside the pores and outer combustion on the surface of the grains. These microscopic models are incorporated into a macroscopic one. The macroscopic model reproduces waves propagation and takes into account the various couplings between the microscopic and macroscopic scales. Pores and grain size distributions are also considered. The governing equations are solved using a shock tracking high resolution scheme, in order to avoid numerical smearing of the shock front. The role of microscopic topology of the explosive is investigated. Results are validated on pressure gauge records and shock to detonation transition distance (Pop-plots).

http://www.intdetsymp.org/detsymp2002/PaperSubmit/FinalManuscript/pdf/HillGustavsen-129.pdf
Extract: We present a new methodology for fitting x-t shock initiation data
based upon extended detonation shock dynamics (DSD) theory.
Fits are generated by simple, analytic phase plane functions. We
demonstrate the technique using recent PBX 9501 and PBX 9502
gas gun data. The method enhances Pop plot and inert Hugoniot
accuracy, and provides extended DSD calibration in the initiation
regime. It is also useful for studying physical initiation mechan-isms.
We use it to evaluate the single curve initiation model. We
then develop an approximately universal fitting function for
reaction build-up, from which the c-j reaction zone thickness can
be estimated. Finally, we define a practical figure-of-merit to
quantify homogeneous/heterogeneous initiation character.

http://www.llnl.gov/tid/lof/documents/pdf/307704.pdf

If you can make head or tale of most of this, then you are doing pretty well.

[Boomer]

ROFLMFAO!

This is exactly the kind of reply such a thread deserved. After going through those, he will never again ask some "can I detenate this with that" questions.

On a sidenote, thanks for the literature. Will keep me busy for some time!

[uniqueusername]

uniqueusername, If you post something showing that you have UTFSE or done any experimentation, you might get something in return. Even an intelligently worded request for spoon feeding is still a request for spoon feeding. "I don't have the time" means you should be somewhere else.

BTW, experimenting with drugs and explosives at the same time is a VERY bad idea.

Sorry to bring back a dead thread but I feel I have to defend my self. First if you use " " marks make sure they are appropriate. I never said "I don't have the time" I said "I don't have a lot of free time". Second, I did UTFSE and did not find anything. Thirdly I wouldn't call what I asked for spoon feeding as no one was able to produce such a forumula, which leads me to believe that such a simple all encompassing formula does not exist. So in order to do what I wanted to do it would require a substantial amount of free time which I did not have at the time. Finally, when did I say I would be experimenting with explosives and drugs at the same time? I have an interest in both areas but that does not mean they occupy the same time windows. I make a point of being stone cold sober when working with anything potentially dangerous.

As a side note I apologize for some of my slopply worded responses in some older posts. I was operating on around 5 hours a sleep a night and indulging a bit in amphetamine in order to catch up with my classes. Thanks for all the links and info regarding the formula which I seek.

[prometheus unleashed]

The problem with this flash powder is the products of the reaction as I found out looking at another thread.

2Al + KClO3 --> Al2O3 + KCl

Notice that there are no gas products released from the reaction only solids. Meaning that, while this type of flash is very brisant and will cause a lot of damage if confined, it does not have a high enough VOD nor does it produce enough heat to initiate a HE.

However, if you do have access to Potassium Chlorate or Perchlorate, I would suggest that you use some sort of fuel oil such as gas, diesel, or even nitromethane instead of aluminium.

For example:

3C12H26 + 37KClO3 --> 36CO2 + 39H2O + 37KCl

As you can see this reaction releases many moles of gas and might just be able to initiate a HE.

If I understand your affliction correctly, you wish to initiate a HE without having to deal with unstable primaries such as Acetone Peroxide or HTMD.

I myself have searched everywhere for literally months and months to figure out a way around these primaries and this formula seems promising. One thing I do suggest you do is convert your chlorate into perchlorate due to its greater stability and higher concentration of oxygen.

If you do try this be careful. All chlorates are sensitive to shock, heat, and friction.

[dbooksta]

Glad to see this thread picked up, Prometheus, but I believe your assumption is incorrect: Namely, that you need a reaction with gaseous products to trigger detonation.

If anything I would imagine that solid products would be more effective in triggering detonation since (in contrast to gasses) they are uncompressible. Heat of explosion may be a catalyst for some compounds, but we do know that reliable detonation can result from the impact of a solid with the secondary, as in slapper detonators (http://en.wikipedia.org/wiki/Slapper_detonator), or exploding targets triggered by high-speed bullets (http://roguesci.org/theforum/showthread.php?t=294).

Consensus seems to be that KClO4/Al FP has a reaction velocity around 1000m/s, which is around the speed of the fastest bullets. If that really translates to a 1000m/s shock wavefront then in principle it seems that FP should work for any compound sensitive to bullets below that velocity. (See Fedoroff, Encyclopedia of Explosives and Reated Items, volume 2, I believe under "bullets" for a table of these data.)

At this point it would be great if we could do tests to determine the minimum quantity and config of FP sufficient to trigger a given secondary. E.g., at a minimum, build a set of identical FP "detonators," fire one without any secondary, then fire others with secondary and look for explosions that are significantly bigger. I have seen some such (inconclusive) tests; the problem is getting a detonator that is sufficiently small to definitely tell the difference between the det and the secondary going off. That requires either very small dets or a very big test range so you can put a lot of secondary in the samples.

Or, if we can come up with reliable tests (http://roguesci.org/theforum/showthread.php?t=6438)this would be much easier.

[prometheus unleashed]

This information is certainly true dbooksta. However only a certain number of HEs are sensitive to a 1000 m/s shock waves. Tannerite is one I believe, HEs with very good oxidizers such as ammonium perchlorate, and perhaps some ammonium nitrate mixtures more sensitive fuels such as sulfur, carbon, or phosphorus.

These bond more readily with oxygen because they bond covalently and if my schooling and research serve me right, covalent bonds have a lower ignition temperature and are therefore easier to produce.

However, a flash powder detonator would never initiate a HE such as ANFO or Ammonal.

And you don't need a lot of gas to initiate a HE. However, once gases escape confinement, they expand at a greater velocity than any solid would and would therefore produce a higher shock wave velocity.

I certainly agree with you dbooksta, field experimentation is certainly in order.

[Positron]

Great thread.

1). As recently posted in a thread about Tannerite, a friend and I have had excellent success detonating the Tannerite material using small, 70:30 KCL04:Al "detonators". Each detonator was a brass tube, roughly 2" (5cm) long and 1/8" (0.3cm) in diameter. It was common consensus amongst us friends that the Tannerite detonated 100%.

2). The flash powder detonators described above were quite ineffective at detonating a homemade mix of 7% Ammonal (93:7 AN:Al). Much unreacted Ammonal was still "in the hole"...simply spattered around from the blast from the FP detonator. A flash powder charge of the same weight of the Ammonal mix was used as a reference, which created a nice "THUMP" and threw mud all over my friend's house. The 7% Ammonal failed to break the ground surface when buried to the same depth as the FP charge.

3). The Ammonal described above was used in a different test, where a 17HMR round was shot into it at approximately 2550FPS. Partial detonations were observed 3 times out of 3, but the bangs were significant enough to really tear the phonebooks up ; )

[bigkboom]

Hello I am a newbe to this site to have much hands on with binary explosives. (example flash) I also want to know what peak intensity and duration (energy) it requires to stet off binary compositions. example ANFO or nitormethane + eythylenediamide (PLX), ammonium nitrate+ Al or ammonium nitrate + nitromethane. Does anyone know??

[Positron]

If you are in search of the "perfect explosive combination" like I was when I clicked on this thread, I believe that I've found the combo. A flash powder "detonator", combined with a booster charge of Erythritol Tetranitrate (ETN), should do the trick. ETN is already discussed in good detail here on The Forum. Anyhow...this combo of FP det + ETN booster appears to be an excellent way to make the sleepy mixtures go boom...using off-the-shelf constituents. I can't wait to try it.

[Rbick]

As far as finding the energy required to set off a "binary composition", there are many variables to consider. Far too many to really make an accurate calculation of the primary needed, such as charge density, purity of explosives/components used, temperature, ect. I have found that experiments are the best way to determine the amount needed. Calculations will reveal valuable information, but real experience is where you will really make progress, assuming you dont lose your fingers first ;). A quick search of the forum will reveal the approximate amount needed for any of the charges you mentioned.

Not having enough time, I will tell you that flash powder is not a good choice for a blasting cap, nor a safe choice. The fact that you even considered flash would lead me to believe you should do a little more research on high explosives before you start your experiments. Good luck, and stay safe out there :)

[Charles Owlen Picket]

I saw an experiment with a "flash powder" detonator; utilizing a rather professional cap body (sealed) and professional Nonel initiation bridge-wire. The completed item looked like a mfg. electric cap and was placed in proximity to a chronograph. It was initiated by 50v @ 10 amps.

They got well over 3200fps from that testing medium; perhaps it could function as an initiator? This was not a sloppy situation however. The bridge-wire set-up was top drawer and professional as was the cap itself. The "flash" was more a chlorate-based explosive than pyro designed 70/30. What's more the initiation used was a real blasting box.

[Positron]

Not having enough time, I will tell you that flash powder is not a good choice for a blasting cap, nor a safe choice. The fact that you even considered flash would lead me to believe you should do a little more research on high explosives before you start your experiments.

Rbick, I was under the impression that replacing a sensitive primary explosive with flash powder, in a blasting cap, would be a very good thing if it gets the job done.

I do understand that these flash powder "detonators" are not going to initiate something like ANFO, but I must say, it does appear promising that they will fully initiate the higher-sensitivity secondaries!!

If there is something unduly dangerous about using flash powder in a blasting cap, please do tell, because I (we?) need to know. Thanks.

[Lewis]

How about the fact that good flash is just as sensitive as the bitchiest of primaries, is much more reactive to contaminants, costs much more, has regulated ingredients, and on top of that has terrible initiation properties?

Seriously, just give it up, I think we're all sick of hearing about this.

[Hinckleyforpresident]

Positron: Getting flash to detonate reliably is quite hard in comparison to a primary.

In order to get high order detonation you've got to have a powerful shockwave travel though the secondary. Flash just doesn't make a strong enough shockwave most of the time.

True, you may get partial detonation on something like ETN or picric acid, but you won't get full det. In order to get a full det you have to be using a secondary that is nearing primary in sensitivity, like nitroglycerin. Hopefully you aren't talking about setting off mass quantities of NG with flash though.

Why not just make a primary? Peroxides are very easy, and some of the others aren't that bad either. Thats what they're meant for, detonators. Flash is meant for firecrackers and such.

[dbooksta]

Lewis, we (Positron and I, at least) are talking about KClO4/AL flash powder, which in my tests has proven nowhere near as sensitive as conventional primaries. Nobody's going to lose fingers packing it into a cap. It's stable, easy to make, and costs less than $15/pound.

The FP itself won't detonate from an electric match, but if it can start a detonation chain in ETN, tannerite, or something similarly more stable then we have achieved a safe and easy detonator, which is certainly one of my first objectives for continuing research in this area.

[Charles Owlen Picket]

No flame; no bitch, but I consider myself to have an open mind and I just don't understand the actual NEED to detonate a material with flash. I am convinced that (the point is moot) NG could be shot with a small electric squib of sealed flash (if it's seriously high end flash & a little glass test-tube of NG). However the point just doesn't resound with a "need".

I think that's where others are questioning this enterprise. If it's an intellectual exercise; all well and good. But you end up looking at the same issues. Unless the secondary is sensitive you are stuck using a large amount of flash in the hopes of communicating shock. Thus there is no "pay-off" in using it. It is NOT so stable from static/shock influences that it is "safe", etc, etc. In terms of it's abilities, it's weak. Outside of an intellectual exercise, I just don't see the reasoning here....(?)

What's more, I would take issue with the statement that "nobody's going to lose fingers packing it into a cap". Any state of mind that allows an individual to have a comfort zone with any energetic material is the doorway to new a typing style. That is a time honored phenomenon. More people have lost fingers to flash (in the west) than any other material. Think about it. The facts are that (per)chlorate flash is the most common experimental material of what is known as the "Kewl" (sp?).

[Positron]

Charles Owlen Picket, thanks for your civilized and constructive response. The intent with using these FP "detonators" is indeed to start a detonation chain, and to do it minus the use of the comparatively much-more-sensitive primaries.

Point taken though. Using a "flash cap" is probably something that would be more useful to the noobs. This is where the "need" is, to have something that's safe, simple, and that works. This combination could potentially open up the "energetic materials" World for a lot of people.

Any idiots/kewls using it in ridiculous ways for ridiculous purposes would be a separate issue.

I have found that:

1). Mixing up a batch of KCL04/Al flash is far safer than synthesizing and handling the typical primary explosives. Could a person lose fingers/hands/life from using flash powder? Yes, but I believe that dbooksta made his point.

2). A flash powder detonator is extremely effective for fully detonating at least one type of binary explosive mixture. I imagine that there are more.

3). Small quantities = low cost.

4). Syntheses are eliminated that would probably require ice baths, glassware, volatile liquids, filtering, time, etc.

5). Flash has very good storage stablity, unlike many primaries.

6). KCL04/Al flash doesn't smell. ; )

Negatives:

1). It's slow (borderline low-order), which limits the range of explosives that it may initiate.

2). Still requires good handling practices for safety

[-=HeX=-]

Tonight I tested out the 'Flash powder used as a detonators base charge'
theory. I used several different explosive charges of varying sensitivity.
I used the exact same detonator in each.

I tested the following explosives (Some as benchmarks of sensitivity) :
1. Pure, Dry, Ammonium Nitrate (100 grams, confined)
2. ANFO (5% Diesel, 4 kilograms, confined)
3. Picric Acid, pure (50 grams, confined)
4. R.D.X. Pure (50 grams, confined)
5. Nitroglycerine (25 millilitres, confined)
6. Pure Acetone Peroxide (150 grams, confined)

The 'Flash blasting cap' that I used was an aluminium tube, sealed at one
end with epoxy resin, with 10 grams of KClO4 + Al flash powder, with 1 gram of
Black Powder and an Estes Solar Igniter as the Igniter.

The confinement was sealed tube of 2 millimetre thick PVC, Schedule 40.

The Results:
1. Ammonium Nitrate- no detonation
2. ANFO- no detonation
3. Picric acid- no detonation, deflagrated ant ruptured container
4. R.D.X.- no detonation, but the container had a crack in it
5. Nitroglycerine- detonated, possibly low order though, no container left
6. Acetone Peroxide- detonated fully, vapourised the container.

This test concludes that flash powder is unsuitable for use in detonators.

[Charles Owlen Picket]

This is well trodden ground but just from an intellectual standpoint let's have this discussion. Back in 1993-4 when I was a PGII member there was a bit of study as to whether flash detonates. Shimizu found that given the correct initiation flash DOES shoot faster than the speed of sound (using a #6 cap). But he also found that given the point of self-containment (at about 50 grams) flash, initiated via flame or spark shoots faster than at lower levels.

Thus at a point of LARGE volume, we may get a blast wave. It is within the realm of possibility that given a large enough volume of flash that it may initiate a sensitive secondary (PETN, etc). But this defeats the purpose of a "cap". It places us in the position of (1.) studying the composition for higher sensitivity levels {no longer 70/30 flash*} (2.) defining what containment, if any, is necessary for the communication of blast initiation. We arrive at a physically big detonator. This is not the end of the discussion however.

Flash communicates a large amount of heat, oxygen, & airborne byproducts (smoke). This issue complicates the initiation of certain secondaries that are sensitive to these complications. Blast alone does not initiate. It must be "focused" and "clean". The use of a cap allows for this to take place. IF we have an enormous blast; shooting heat and smoke in all directions, we have a mess.

This is the reason for the development of differing detonators in the early 20th century and the utilization of the "squib". Squibs are not all manufactured for use with BP. They also have smaller focused elements that serve as "smaller than #6 caps" (which are no longer manufactured). If a "squib" could be made to direct blast from the containment of a chlorate composition (flash, etc), it could initiate a higher level of explosive composition. Here we enter into explosive trains built upon the use of NG, etc. The question of cost and worth become too significant to ignore, unfortunately. Now we see clearly that this whole issue really becomes just an intellectual/engineering trifle and cannot be reasonably put to use. The size and design prohibit it. - --- Just my opinion


* Konski's stuff dealt with flash sensitivity report level and tone....NOT the "power" level of flash composition (1994) - Shimizu's flash was 64:23:13 and that was what he was working with during his experiments.

[Positron]

Hmm. Alright. Based on what was stated, I'm not even sure if experimenting to try to get PETN, ETN, etc. to fire using these FP det's is worth it any more ; ) Futile though it may be, I am probably still going to try. Thanks for the free info c o p.

HeX, I can appreciate the real-World data, but your test did not prove that flash powder is "unsuitable for use in detonators". In fact, it proved exactly the opposite, if the definition of "detonator" is taken literally. Your generalization was far too broad.

Anyhow...HeX...is there any way that you could add ETN (Erythritol Tetranitrate) to your list?? I would be *very* interested to know the performance of this compound when initiated with a FP cap. Are there any other mildly-sensitive secondary explosive compounds in your arsenal that you could cook up and try?

[totenkov]

I think you may have a shot at detonating ETN with flash if you can get it to go off with .2 of a gram of AP. However there is a boundary between low explosives and high. You may get a partial det, but as previously stated, you need the shock wave sent out by high explosives, you will not get this from Al based flash powders.

[-=HeX=-]

Sorry for the delay in posting a reply. I also apologise for my oversight and blatant generalisation about it not being a 'detonater'.

I just got back from testing 50 grams of ETN, confined in the same way, a 2mm PVC pipe.

I used the same type of 'flash detonator', and the pipe went kaboom! I assume it was a full det as it was instant and very powerful. However I have fears that it could have been deflagration as it burns very violently in burn tests, but I believe that it was a full det.

I also tested 50 grams of waste HMTD and it also (obviously) detonated fully. Therefore flash can have some initiating properties.

However IMHO a 5 gram AP cap is much better, albeit riskier, but it IS better from a reliability point of view.

Over the coming weeks I intend to test some 15 gram caps so if you have any requests for tests to be done on any explosives I will try to make some to test the caps on.

[Hinckleyforpresident]

I also tested 50 grams of waste HMTD and it also (obviously) detonated fully. Therefore flash can have some initiating properties.

However IMHO a 5 gram AP cap is much better, albeit riskier, but it IS better from a reliability point of view.

Over the coming weeks I intend to test some 15 gram caps so if you have any requests for tests to be done on any explosives I will try to make some to test the caps on.

I would recommend using the minimum amount of a primary as possible. If you have ETN you should be able to make .5g AP/2g ETN blasting caps. Those are a lot more powerful and safer than just 5 grams of acetone peroxide.

Also, I would not consider flash useful as a detonator for primaries (like HMTD), considering that they are fuse sensitive.

I would see flash initiators as a novelty, I don't think they have any practical purposes. This is considering that flash is only capable of reliably detonating primaries, and primaries don't need flash to detonate, fuse can be used for that.

[Rbick]

Its not so much a question of whether flash will work, it is a matter of asking why. Primaries can be created for much less than what you would pay for the components of a flash mixture. Especially considering the components needed for high end flash, such as potassium perchlorate (KCLO4) and german dark Al, which are both quite expensive.

So I see testing flash as a meaningless pursuit, unless you really are just that curious. And of course they are fun on the 4th of July for salutes and whatnot. Aside from this, I wouldn't understand why one would consider the use of flash in the realm of high explosives. Its just too expensive, and dangerous.

Realizing how useless flash was when I did first begin this hobby, I got rid of it by placing the 1 kilo (approx) I had left under 8 liters of gasoline. Now that was something, and I made good use out of otherwise useless flash :D

[Charles Owlen Picket]

I absolutely agree. I just don't understand why the pursuit of flash as an initiator when other, safer, more productive materials exist. HOWEVER....if your point is to experiment with what level of blast (in any explosion, per se') would start a secondary -> check out the old Nobel experiments with squibs of BP to start NG. There is a wealth of material available.

[Smokey0541]

Hey my brothers,,,,,,,,,Before I say anything else here. PLEASE keep this in mind. It is never my intention to offend anyone here. I have to much respect for all of you. And this web site. And yes I am a NEWBIE. I have read a lot of postings here. And I must say you all have given me much to think about.

But as far as detonation is concerned... I have had very good results using simple fireworks with extended fuses. M-80s. I would not B.S. any of you here. It takes a little time to make up the extended fuses, but it's worth it. I try to help out guys who spend their week-ends with their family's prospecting. I have spent the better part of a day drilling a face and using a V cut or a burn cut and load the round with a prepared batch of ammonia nitrate that I have made anhydrous and 25% to 35% powdered aluminum and nitromethane. Like I said, for detonation I used M-80s or something similar and run the extended fuses through heat shrink and loaded the detonators in the back of the holes. NOW, the reason I have gone into all this detail is to show how this could be applied to other things besides busting rock. The most I have ever blasted was appx. 280lbs. And I had 100 % detonation. I do recommend adding the nitromathane to the mix just before you are ready to do whatever.

[ChippedHammer]

http://www.trickz.co.uk/flash-demo.wmv

Thats some damn powerful flash powder, if anything would work it would be exotic mixes like that.

[dbooksta]

Sheesh... and if anybody's going to lose a finger it's somebody lighting a pile of flash powder with such a short fuse. But in the video I don't see any notable difference versus standard KClO4/Al flash.

Smokey0541, do you just pour the AN/Al/NM into the open holes? And when you said you did 280 pounds is that with a homogenous mix? I can't imagine spending $1500 on Al and NM for a single blast, or do you have some special source for those ingredients?

Maybe we should start a thread on black-powder detonators.

[Charles Owlen Picket]

Once you have an effective explosive train the end-chain can contain simple, pure AN! That is the composition of standard military AN/TNT cylinders & saves money. That is also the end result of large scale bore-hole ANFO blasts. I just can't see it being a homogeneous mix. But then, perhaps he has money to burn.....

[Rbick]

The most I have ever blasted was appx. 280lbs. And I had 100 % detonation.

I want to see that video! That is huge, and I hope you video taped it. If you didn't, then what the hell is wrong with you?

About the ANNMAl mixture being detonated by flash; It would seem probable that it would work a good amount of the time. Ammonal itself is quite sensitive, especially with activated AN. It is common knowledge that this is used in tannerite exploding targets. So if a bullet from a long distance can initiate it, it makes sense high quality flash could as well. Again, for the reason of money, and since I set off more than ANNMAl charges, I opt to stay with primaries such as HMTD. Not to mention the recent bans placed on oxidizers such as KCLO4...

[nbk2000]

http://www.trickz.co.uk/flash-demo.wmv

Thats some damn powerful flash powder, if anything would work it would be exotic mixes like that.

What's the formula for that flash? I can't see the site (doesn't allow directory listing!) to find it.

[ChippedHammer]

A member of the UK pyrosociety posted it as a warning to new users, ill see if I can get the formula as it would be interesting to know. I'm willing to bet its a combination of kclo4, sb2s3 and magnesium.

[ChippedHammer]

Just got the formula, was not as exotic as I thought.

70 kmno4
30 1 micron atomized aluminum

I have no idea where one would buy 1 micron aluminum powder, the closest I could find was 2 micron at firefox-fx (useless as no one can buy) and some 3 micron on eBay.

http://cgi.ebay.com/6-6-lbs-d50-3-21um-ALUMINUM-POWDER-99-5-FAST-SHIP_W0QQitemZ200173546671QQihZ010QQcategoryZ3258Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Positron]

Smokey0541, thanks for your post.

I'll never use a sensitive primary explosive if I have the option to use flash powder instead. Flash is infinitely safer. If it's possible to construct a relatively small booster, that is capable of fully detonating substances such as ANFO, using nothing more than a flash powder initiator...then (for my use) I see no reason to use primaries. Furthermore, I'd be THRILLED if I never had to synth one again.

If the secondary explosive is hammer or heat-sensitive, I have to believe that flash will set it off in some form or fashion.

Whether or not the detonation of the various secondary explosives would be incomplete/low-order/high-order, must be tested.

[Charles Owlen Picket]

I'll never use a sensitive primary explosive if I have the option to use flash powder instead. Flash is infinitely safer.
Could you please expound on why you think "Flash powder" is safer?

[Positron]

Compared to primary explosives such as AP, HMTD, and MEKP, my experiences with 70:30 KCL04/Al flash powder has been that it (flash) is:

1. A Hell of a lot (+ or - a few percent) less shock-sensitive

For my use, a substance's sensitivity to shock is probably the most important aspect to its "overall safety rating", because that's probably how I am going to screw up. I'm much more likely to drop the substance, drop something ON the substance, crack glass near it, etc. than expose it to a heat source or pop it with a spark.

[Lewis]

Positron, the only primaries you listed were dangerously reactive peroxides. This is not a fair comparison.

Honestly, I'm starting to think that many posters' reasons for wanting this to work is sheer laziness. If you have access to powerful fuels and oxidizers, you should be able to synthesize a decent primary in stead.


1. A Hell of a lot (+ or - a few percent) less shock-sensitive

:p

[Positron]

Quote from Lewis:Positron, the only primaries you listed were dangerously reactive peroxides. This is not a fair comparison.

Well shit, why didn't someone tell me!! IT'S SOMEONE ELSES FAULT NOW! :D :cool:

Seriously, instead of asking a question like "Which primary explosives are reasonably insensitive?", I think I will delve back into Tenny Davis' book. It sounds like I just need to obtain a wider range of chemicals, and do some more of my own research trying to find the apparently elusive (to me) "perfect primary". Specifically, I need to look up some good hammer-drop test data.

[-=HeX=-]

Sorry for the late reply, i am also sorry for the confusion hinkleyforpresident but the use of flash based dets was for scientific purposes, and testing sensitivity and for the possibility of its use for others (I'll stick to my AP), not for my practical field work in the use of explosives.

I prefer to use straight AP dets for my work as they are easy to make, reliable and I keep my ETN for shaped charges, which I detonate using the 5 gram AP dets, however I see your point and accept that it is very valid. However as I mass produce AP dets (20 at a time from one 100 gram synth) I find them easier for me.

My offer still stands and if you want anything tested, just ask, as I have a lot of HE going to waste and 27 flash caps left.

[Hinckleyforpresident]

However as I mass produce AP dets (20 at a time from one 100 gram synth) I find them easier for me.

*Ring ring ring, ring ring ring* :p.

Sorry, I couldn't resist.

Are you doing single 100 gram batches?! Or are you talking about more several more reasonable, say 20 gram batches? I love AP for detcaps, but I would never dare to do a single batch like that.

[VasiaPupkin]

The detonator type is discussed is exist. Its NPED detonator "non-primary explosive type detonator" used in mining industry.
The aim of pyrotechnic charge is only to quickly ignite the main charge of high explosive like PETN.
And HE when ignited in tight metal case tend to deflagration to detonation transition (DDT).
Therefore pyrotechnic charge is a fine thermite charge, not flash powder charge. Mixtures like flash powder has a great blast effect and detonator case is
crushed before DDT to be carried out. BTW check my post in http://www.roguesci.org/theforum/showthread.php?t=4484&highlight=NPED&page=2
You'll find it useful.

[Positron]

Hell yeah, that's what I'm talking about.

Vasiapupkin, can I get your thoughts on the following detonator:


l --------------------------------l
l ~~~~~~~~~~~~~~~~~~~~~~~/ /~fuse~~~~~~~~~~~~~
l [PETN] [Fuse-sensitive thermite] l
l --------------------------------l

---------- = tight metal case

I'd imagine that the hole for the fuse would result in the device being a low-pressure rocket combustion chamber (ignition of thermite in a small confined space), so there will probably not be much pressure on the PETN. But considering what Vasiapupkin is saying, the PETN doesn't NEED pressure to detonate.

The fuse-sensitive thermite would be a 1:1 mixture of 3-micron aluminum and Fe2O3. I HAVE tested this to be ignitable with a standard butane-lighter flame, but I have NOT tested it to be fuse-ignitable. Yet.

EDIT - I added the following:
Maybe the high-energy flash powder mentioned in the above-linked thread would be better to use than this thermite, to increase the pressure, and hence the thermal energy imparted to the PETN per unit time. I dunno. Gotta test it.

Anyhow, for this device to properly work, it must reliably and fully initiate "sleepy" secondary explosives such as ANFO, and the detonations must be confirmed to be high-order via standard testing.

[Charles Owlen Picket]

ANFO typically is detonated via a Booster (or a Gain if European). However, if the ANFO is prepped in a very specific manner it may be detonated via a cap but the cap usually needs to be the equivalent of the "SSS" DuPont seismic type. Using a home-grown, certain things need to be in place. The density of the base initiator (the PETN / RDX at the bottom) needs to be quite high. There is an enormous difference between a well compressed base charge and one that has merely been tamped down. So much so, that one can discern the difference in density levels right away.

DDT had been investigated at length by various authors. This may be where ETN may pay off. I have a few doubts that this could be accomplished within a 6mm cap body however. If the "flash" is in too close a proximity to the initiator secondary, the whole of the cap may explode without a proper detonation.

[Positron]

Press to maximize VoD. Definately.

I agree, the metal case failing before DDT would render it useless, but the nice thing is that the yield strength of the metal cylinder will go up tremendously with added wall thickness. After that, the next issue would become keeping the ends of the tube intact while everything happens. If one of the ends blows out before the transition to high-order is made, then the VoD would suffer?

Threading the ends/welding in a plug/crimping the end could become necessary. Hope not.

BTW, there is a lot of information pertaining to NPED's (Non Primary Explosive Detonators) on Page 11 in the Erythritol Tetranitrate thread. There are some great bits of info around pages 9 - 12, and maybe others.

http://www.roguesci.org/theforum/showthread.php?t=3132&page=11

Damn, I hope I can get one of these FP-initiated ETN detonators to work. They would be safe, cheap, easy-to-make, and powerful. Great for an amateur such as myself.

[VasiaPupkin]

"But considering what Vasiapupkin is saying, the PETN doesn't NEED pressure to detonate."

First of all I wished to tell that the aim of thermite is quickly ignite PETN. The pressure is very important because DDT is
impossible without pressure. But the right way would be that the pressure would rise from PETN burning not from pyrotechnic charge.
Its because the PETN ignition is carried out not suddenly but in some time delay after heat influence.
This delay is enough to crush the case by pressure peak from flash powder burning.
Therefore you need first to ignite PETN by thermite as quick as you can. And preferably ignition stage would be without pressure peak.
The next idea would be to combine ignition with pressure rising. For example using 2 pyrotechnical charge:
the first charge is thermite to ignite the PETN and the second charge is a flash powder to rise the pressure for more quick DDT.
But its seems that the time of DDT has a sufficiently weak influence from initial pressure and the pressure peak from flash powder will crush the case.
PETN charge would be a low density charge ~1.1-1.3g/cm3 because good DDT is possible only at low density. Thus you need 2 PETN charge with low and high density.

The scheme is almost right. But I think ignition would be on borderline between PETN and thermite. Thermite is possible to granulate with NC. And it seems this thermite is not fuse-sensitive. You need gaseless ignition charge for thermite ignition.

[Smokey0541]

dbooksta
To answer your questions. I don't know where you got your prices from. I think I have $62.00 invested in the 150 pounds of AN I have in my stash. It used to be available at the rural ag supply for 0.004 to 0.007 cents per pound. And as for the AL. Just go behind any good sized machine shop and you can sort out the AL fines in the scrap barrels. Sometimes you need to run it through the mill to reduce it to a finer mix. As for the loading of the drill holes. I use a 6 foot length of 1-1/2 inch diameter PVC pipe with a 7 foot length of 1 inch PVC pipe with a PVC cap screwed on to one end for a plunger. In other words one big hypo. Fill the pipe shove it in the hole and push the plunger and pull the pipe at the same time.

Positron,
Let me make sure I didn't misstate something here. It would be very hard to live with if someone got hurt as a result of something I posted.
When I make the AN anhydrous, I do so by soaking the prill in denatured alcohol. I then separate the AN alcohol mix. At this point I reduce the prill to the consistency of a medium sand. Next, in a low temp oven at a temperature of 150 degrease or below" I dry it out very well. I also use a small fan to remove the alcohol vapors. Next mix in the AL.
Do this while the AN is still warm to the touch. Just above body temp. This helps keep out the moisture. Seal it up as quick as you can. It's very safe at this point. Just prior to use, add the nitromethane. It's still very safe as long as you don't get careless.

The reason I didn't video what you referenced is really quit simple. I've been doing this for 20+ years. And I do it often. Most of the time it's done underground. The next time I have an open face blast I will try to do a good video of it.

[barrydbryson]

I once stumbled upon a rather subjective measure of the force of Al flash powder while making kraft paper salutes. A 50-grain load of Al/KClO3 in a hard paper tube, 1" dia. X 3" long with a .50" dia. center hole was fired while lying on the surface of a foot-square bridge timber in the back yard. It left a permanent depression about 0.1 inch deep in the wood...definitely plastic deformation; although it would take more science to back out any kind of VOD. Interestingly enough, a like volume of HMTD fired in the same type tube did not do any more damage to the timber; and the loudness of the report (very subjective) was not any greater than with the FP. The HMTD was not compressed but was confined by the heavy tube and arbor-pressed, tapered hardwood end plugs. Maybe a lead expansion or ballistic pendulum test is in order to rate the ultimate strength of a flash powder cap. Flash powder does seem to blur the line between low and high-order reactions.

[-=HeX=-]

Yes Hinckleyforpresident I do make single 100 gram batches, the method used is Arthis's one. I am going to test some Thermite-ETN caps tomorrow and I will post results soon.

[Rbick]

The HMTD was not compressed but was confined
That is the very reason it did not perform. Even the higher performance explosives will do poorly when not pressed, or may not even detonate at all. Missing max density by even a few tenths of a g/cm3 can decrease performance by as much as 88%. Point being, HMTD is far superior to FP. It was actually considered for commercial use, and may have been used if it weren't for its instability.

Flash powder does seem to blur the line between low and high-order reactions.

This is true to an extent, as far as VoD when in the proper enviornment. But, FP lacks one property that is essential to a true explosive. This property is the production of gas upon detonation. No gaseous products result from the FP reaction. All of them are solids, as seen below. Some don't even classify it as explosive at all.

Al + KCLO4 ---> Al2O3 + KCL (not balanced)

The products being aluminum oxide and potassium chloride, both of which are solids.

It will still produce a shockwave from the amount of heat energy produced, but it will not be substancial in most cases to reach activation energy required to set off most secondary explosives. Don't get me wrong, it can be powerful indeed, especially in large quantities. I remember years ago when I detonated at 2.5kg charge of FP and it knocked dishes off my neighbors shelf :D

[Positron]

Hi All,

Just a quick post to report the results of a recent experiment. The idea for our experiment today was to make one of the previously-discussed "flash powder detonators".

A .30 caliber rifle cartridge was used as the detonator body. The primer-end of the casing was drilled completely through with a 1/8" drill bit, thus removing the primer in the process. A 1/8" Visco fuse was then pushed into the end, and secured in place with a little hot glue on the outside.

KCL03/Al flash powder (Chlorate, not Perchlorate) was added until the casing was approximately 1/2 full, then Erythritol Tetranitrate was used to fill the empty space. To finish the detonator, the lead bullet of a new .30 cal round was flipped around backwards, and pressed into the open end of the casing. The spherical ball end of the bullet was pointing toward the fuse-end (previously the primer-end).

It was basically a backwards-loaded bullet, loaded with flash and ETN, with a fuse sticking out the ass end :) We didn't have a lot of time.

RESULTS:

The fuse was lit, the cap placed in a shallow hole in the backyard, then a metal plate thrown over the hole. After the loud metallic "CLANG!!", the remains were inspected.

Well, we couldn't find anything. The brass casing was pretty much gone, the metal having been shattered into tiny pieces by the force of the explosion. After much time was spent picking through the remains, we finally found a piece that was larger than the rest; it was about 3/16" across.

I'm not saying that this is a high-order detonation just yet, BUT IT SURE LOOKS LIKE ONE TO ME!!!

In the near future, I plan to further test these devices for brisance and repeatability, while improving manufacturability. I'm after a cheap, easy-to-build, safe, powerful, non-primary-explosive detonator, that can be made with readily available ingredients.

Thanks to my friend for sharing his knowledge, and the use of his kitchen, chemicals, and backyard "test range".

[-=HeX=-]

I tested the ETN Thermite cap. I was not impressed. 10 grams of ETN and 5 grams of CuO/Al thermite, in a 3mm wall thickness steel tube an unmeasured length, capped with epoxy. The det went off, but not as well as a normal ETN charge of the same size. I think it was Deflagration overpresure. Any thoughts/ comments?

[Positron]

Thanks for your post, HeX. Please clarify, you do not think that the ETN contributed at all to the explosion? Did you happen to fire it in a hole, and look to see if there was any undetonated ETN left over? Were you able to find the steel tube after the bang? If so, what did it look like?

I think that a good test would be to construct two identical ETN caps; one in which the ETN is initiated by "X" quantity of flash powder, and the other's ETN initiated by the same quantity of a primary explosive. I'd like to see how large a hole each could knock in 1/8" sheet aluminum.

[mil&co]

@Positron:
Blowing up bullet cartridges is no real conclusive test to check the primary capability's of your composition, FP alone should be able to completely shatter a casing on its own. You should do some plate-dent testing, one casing with FP+ETN and one with double salts+ETN.

@Rbick:
But, FP lacks one property that is essential to a true explosive. This property is the production of gas upon detonation. No gaseous products result from the FP reaction. All of them are solids, as seen below. Some don't even classify it as explosive at all.
Sure, for the same reason silver acetylide isn't considered an explosive, but still it does a hell of a job as a primary.
PF indeed doesn't leave any gass after detonation, but don't forget that during detonation oxygen is released (allbeit almost immediately consumed by the aluminium) and rapidly heated, creating some sort of shockwave comparable to normal high explosives. FP also has to be loosely packed to detonate properly, so there is some air present in the mix which also is heated in a very short time, expands very fast -> shockwave.

But still, I don't think FP will make a good primary explosive. It's more unstable than the most common primary's, and it wont be able to "overdrive" the secondary explosive, so the secondary has to do the transition from low-order to high-order detonation on its own.

[Rbick]

Good point, I never even really thought about that :)

I'll be the first to tell you FP has a shockwave, like the one I felt deep in my chest when I detonated 1.5kg of KCLO4/Al a few years back buried about 20cm underground. I have a video, although of poor quality which I will upload soon.

Regardless, like you said, it doesn't make a good primary. It is fun to experiment around with though...

[Positron]

FP alone should be able to completely shatter a casing on its own.

It most certainly does not. I've used flash in many brass cartridges over the years. It (flash) does NOT have the ability to shatter the highly malleable metal. I've found that the most damage that flash will do to a casing is "flower" it out, sometimes turning it completely inside-out. In every instance though, the metal remains largely intact.

The brass after our experiment looked like someone sprinkled gold glitter in the hole. Measured with calipers, most of the fragments were less than 1/16" on the longest dimension. That is what leads me to believe that the ETN detonated at least partially.

You should do some plate-dent testing, one casing with FP+ETN and one with double salts+ETN.

Agreed. Would you have any recommendations on plate thickness, and/or construction of the detonators?

I do realize that it is important to keep variables consistent between the two test detonators. Ex. ETN loading density, detonator physical construction, weight of FP and double-salt, etc.

It's more unstable than the most common primary's

"Most common" is a highly subjective expression. The most common primaries for me are AP, HMTD, and MEKP. 70:30 KCLO4/Al flash powder possesses excellent stability compared to these compounds. (EDIT: the stability of MEKP is indeed very good. Whether or not FP is better, I don't know.)

it wont be able to "overdrive" the secondary explosive, so the secondary has to do the transition from low-order to high-order detonation on its own.

Excellent point, though there seems to be many pros and cons in the FP Vs. primary-explosive discussion.

Gotta test it.......

[mil&co]

It most certainly does not. I've used flash in many brass cartridges over the years. It (flash) does NOT have the ability to shatter the highly malleable metal.
Excuse me then, my experience tells me something else. But our flash isn't the same (KClO4/GD), so that could explain a lot.
Agreed. Would you have any recommendations on plate thickness, and/or construction of the detonators?
I make my dets from alu tubing, 6mm ID, bentonite end-plug.
http://pyroforum.nl/index.php?act=Attach&type=post&id=2471
http://pyroforum.nl/index.php?act=Attach&type=post&id=2472
http://pyroforum.nl/index.php?act=Attach&type=post&id=2525
But I don't think you would be able to fit the proper amount of FP in such a small ID, so you'd have to go for something like 10mm ID or bigger. Getting a consistent density will require an press.

The witness-plate schould be at least 4mm thick, and marked on the place the detonator was placed, to show the transition between the FP denting and the damage caused by ETN.
The weight of FP and DS shouldn't nessisarily be equal, their power isn't the same, and you're only looking at the damage caused by ETN, so why bother?
"Most common" is a highly subjective expression.
Excuse me for the misunderstanding, I reside mostly on a foreign forum where nearly everyone uses DS, lead azide or azo-clathrates. In the quantity's needed to detonate for example MHN these primary's are much safer than the amount of FP needed to detonate MHN, regardless of their sensitivity.

[Pine Cone]

Tried twice with CO2 casing filled with 70/30 flash, taped to a 12" pc of "primer cord", I did not have success, the blast only shredded the outer covering.

Pine Cone

[armchairsapper]

I tried a Potassium Chlorate, not perchlorate, and Bullseye mixture with a very small amount of 5m AL powder in a 1/4 X 2" AL tube. I wasn't expecting much. I thought that it would "fizz" and maybe pop. I was quite shocked! The report sounded like a .38, made a hole that was about 1/4-1/3" deep, and I couldn't find any of the casing.

------------------------------------------
PC,AL,Bullseye Bullseye
------------------------------------------

[Charles Owlen Picket]

This discussion should start to center on the concepts of what detonation and initiation are contingent on. We certainly have observed the explosions with (per)chlorate based materials yield a great deal of intensity; however, the intensity of an explosion is not what preforms an initiation. Even less than one tenth of a gram of the appropriate primary can set in motion a base charge and that is preformed via shock/speed.

"Our subject is the propagation of the fully developed, macroscopically steady plane detonation wave." This is a near quote from Fickett & Davis and indicates a clearer understanding of the subject than what was once taken as gospel from smear photography and molecular break down. We have learned that it IS possible to accomplish this (wave) with materials that were once thought to be "non-initiatory" primary explosives, but the concept is fraught with misconceptions and specifics.

There are certain base charges that can be brought to high-level output via simple shock (NG, etc) and they may be used to enhance this from a big picture perspective but generally the demand is met with materials that break down in structure because, simply by doing so they impart a shock wave that can be consistently manipulated.

Greene (1950) had developed a plane wave model that usher in a generation of examination of this in a gaseous & thermodynamic model that can still be used to examine the implementation of the use of composition mixtures to accomplish initiation.
For those who really want to learn about this behaviour there is the writing and work of B. T. Chu who Shimizu drew some of his material from. (1956) Gas Column Activity Behind Strong Detonation Wave; Northwestern University Press. Not an easy read..... but directly applicable to this discussion and has BOTH - models and empirical examples. I am starting this and (for me) it's damn fascinating