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KemiRockarFett
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Tried that very many times in the past. If same procedure was done with acetone peroxide it ignited directly , even with guncotton, but the silver
acetylide silver nitrate was hard to get going with a fire steel. But it was extremley sensitive to flame.
What do you think about the risk when the detonator is done and the primary is compressed on top of a compressed secondary inside a al-tube.
I think primarys are fun in small amount just as coriusity but dont recommend anybody to use them in playing with explosives. Bye a low inductance
capacitor and bulid bridge wire detonators to set of PETN or EN instead.
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EAPyrotox
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I think the spark generated by static electricity (piezo lighter) has nothing to do with the sparks of fire steel.
Sparks of fire steel are only a emission of hot particles in very short time (T° < SA Tmin Ignition) like when you put your finger over a flame,
below 2 seconds you do not feel any heat (the matter and its surface has a greater resistance until time Tmin).
When the spark comes from the static energy, there is a stimulating effect on the matter (one can perceive a mini shock wave that scatters the SA
crystals in the test piezo lighter), so the igntion come over the shock of the spark (regime DET primary).
I think we can define several types of sparks, especially |Shock vs. heat| and indeed the primary appear to be more sensitive in a short time to a
shock stimulus.
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KemiRockarFett
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Quote: Originally posted by EAPyrotox | I think the spark generated by static electricity (piezo lighter) has nothing to do with the sparks of fire steel.
Sparks of fire steel are only a emission of hot particles in very short time (T° < SA Tmin Ignition) like when you put your finger over a flame,
below 2 seconds you do not feel any heat (the matter and its surface has a greater resistance until time Tmin).
When the spark comes from the static energy, there is a stimulating effect on the matter (one can perceive a mini shock wave that scatters the SA
crystals in the test piezo lighter), so the igntion come over the shock of the spark (regime DET primary).
I think we can define several types of sparks, especially |Shock vs. heat| and indeed the primary appear to be more sensitive in a short time to a
shock stimulus. |
What you trie to say is namned "power" in physics and is measured in W = J/s = Nm/s = kg m^2/s^3
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EAPyrotox
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Yes I know, I dont have accurate measurements of my spark ignition test so I illustrate the explanations with some examples physically correct.
And accurate measurements are not very helpful, they are seen to vary from one batch to another and other variables.
If it stays on SA, its resistance to "POWER" as you say is very thin.
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KemiRockarFett
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Quote: Originally posted by EAPyrotox | Yes I know, I dont have accurate measurements of my spark ignition test so I illustrate the explanations with some examples physically correct.
And accurate measurements are not very helpful, they are seen to vary from one batch to another and other variables.
If it stays on SA, its resistance to "POWER" as you say is very thin. |
So how to increas its resistance to static electricity? Is it possible to deflegmatice it in some way not reducing initating properties to much ?
And is it necesarry to do so if the SA is in place and compressed in an detonator?
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quicksilver
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Gentlemen, we DO have some discussion on static testing.
Unfortunately one cannot "increase resistance" to static discharge initiation. The work that proceeded the joule-threshold initiation figures were
completed with a clean, well-synthesized sample; so some had thought that if the particulate were "coated" or in some manner kept from direct
discharge contact. They [had thought this] would raise the level of production cost (beyond reason), lower the effectiveness, & generally be
impracticable. This obviously will not succeed due to the need for complete shielding, the cost, & ruination of the material, etc. The concerns
proved realistic.
-> When a certain level of electrical energy has been reached; there is very little on can do to protect free accessed material! However the
"self-grounded detonator" and it's associated patents (there are several) appeared to make a marginal difference. A difference, such that, even today
certain production techniques of capsule-wall grounding have continued in certain production fields. A few of the patents with capsule-wall grounding
do promote a concept of returning the static to it's origin. However in studying these patents there have been comments from some electronic
engineering students that only certain conditions would it succeed in providing a margin of safety.
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User
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I have quite some experience with this substance.
What I believe is of great importance that it seems nearly impossible to produce this material twice and actually obtain the same material.
I know this there is no magic involved but it appears that there are a lot of factors that have influence on the final product.
Not only color but also physical appearance seems to vary every single time, even tough I paid a lot of attention to duplicate the synthesis.
I also found that temperature conditions have great impact on the final product.
When it comes to static discharge, either I have always been lucky or I actually never experienced any problems in this field.
Indeed a good subject to touch.
Ironically I did have a little accident caused by friction.
A tiny sample (range of 5 mg) was mixed with MHN(mannitolhexanitrate) upon mixing the sample detonated probably by pressing too hard.
I was very well protected, no harm done.
Scared me though.
What a fine day for chemistry this is.
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quicksilver
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One complexity is the depth of the solution during exposure to acetylene gas. The deeper the solution within the container, naturally, the more
exposure to the gas. The vessel (it appears) ideally should be elongated for greater contact & consistent in it's (solution height) depth. When
examining the synthesis there are many variables; even the pressure of the delivered gaseous element plays a role as the higher pressure, the shorter
the exposure (faster "bubble rise"). Once upon the surface of the solution the actual contact is diminished, thus a very gentle introduction of gas
become a variable.
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holmes1880
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Has it been proposed to completely insulate the primary in a polyethylene or other static insulating materials?
http://www.waterfront-woods.com/Articles/Electricity/static....
Coating/wrapping the capsule in polyethylene would be highly problematic in amateur conditions, but sealing few mg of primary shouldn't be too hard
to manage. To help melt through the cover, an ignition mix of your choice can be used- black powder substitutes, DBSP, etc...
The time is not enough.
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gregxy
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Actually it is possible to greatly decrease the sensitivity to static. In smokeless powder they do it by forming the grains into small balls and
coating them with graphite. The current then flows over the surface of the grains without igniting them. Discharges of several joules fail to ignite
it.
I suspect the physical properties have a lot to do with static sensitivity. Materials with sharp pointed crystals, high melting points and low
ignition energy would be most
sensitive.
If the melting point is above the ignition temperature sensitivity is greater. Consider picric acid and picarate salts. The acid is not flamable while
the salts are, yet I would expect the salts to be more stable from a chemical standpoint.
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holmes1880
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Yes, but somehow they didn't bother to use that for primary initiators, so there might be some kink in this concept. I'd recommend testing primaries
in polyethylene for the simplicity/time sake, and then play around with coating small SA pellets with ground up pencil lead. I did not do much
research into coating methodologies, but I would assume a small spray on adhesive+ lead powder. That's just the first thing that comes to mind, but
research DBSP production process.
The time is not enough.
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AndersHoveland
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Perhaps treating the substance with graphite spray would help reduce sensitivity to static:
http://www.tedpella.com/technote_html/16051TN.pdf
http://www.aircraftspruce.com/catalog/cspages/drygraphite520...
I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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Rosco Bodine
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There are a lot of variables which apply to "static sensitivity", most notable would be the state of subdivison of the particles, their mesh size and
crystalline form
and the density of the particles in the "reaction zone" through which the static discharge occurs. A compressed pellet is expected to be less
sensitive to static discharge due to increasing compaction having the direction of dead pressing .
Dielectric stress then becomes operable as the concern. It is somewhat analogous to the situation where a cloud of coal dust or even ordinary flour
can be ignited by a small spark, which would have no ignition effect upon a lump of coal or a hardtack biscuit. Ignition requirement then becomes a
different order magnitude several times over due to the distribution and different relative concentration being lowered for the stimuli as an average
insult to each individual particle in the sample ....understanding of course that the chain reaction has to first begin with one particle with the
local reaction then progressing. Free moisture and high humidity are good for preventing buildups of static charges
because the moisture conducts and provides a bleed path for large potential differences to equalize. Where handling loose powders is a necessity,
high humidity, even misting the area with free water from a trigger sprayer can be
a wise precaution. Misting of the technician ankle and shoes and hair on the head
is not a bad idea either, as a bad hair day is better than a final day on the job.
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holmes1880
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Thanks for the find, Anders. I did not know there was a graphite spray. I guess the only variable is how to apply the spray- is it by coating an
primary, high density SA pellet all the way around it(assuming it can still ignite with a standard pyro mix) or spray the loose small pile and then
gently mix it around. I would go with the former approach because it seems more likely to get a seamless seal that way.
Some of the primary users need to definitely test this method for spark initiation. Spray can be bought cheap online. Since you'll be dealing with a
larger pellet size(100-200mg), take apart your piezoelectric igniter and use additional wiring as in this video:
http://www.youtube.com/watch?v=spT2vvOZlvc&feature=chann...
The time is not enough.
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a_bab
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@holmes
EBW was used for the nuke as any other approach would have been too far in terms of reliable TIMINGS (rather then risk) that were needed to properly
detonate the HE shell. Simply put, with any primary approach one cannot reliably initiate simultaneously some 20+ charges with a ns resolution.
It has been discussed before, but I'm too lazy to lookup.
"Conventional blasting caps use electricity to heat a bridge wire rather than vaporize it, and that heating then causes the primary explosive to
detonate. Imprecise contact between the bridgewire and the primary explosive changes how quickly the explosive is heated up, and minor electrical
variations in the wire or leads will change how quickly it heats up as well. The heating process typically takes milliseconds to tens of milliseconds
to complete and initiate detonation in the primary explosive. This is roughly one to ten thousand times longer and less precise than the EBW
electrical vaporization." - Yes, I know. Wiki.
As about SA, here you have it: more then 20 years ago I had about 0.5 grams go off accidentaly in a small plastic box. I tried to peel off a label of
that box when it went off. The resulted in some minor bruises and an eager need for a find another primary, less sensitive to static discharge.
Eventually LA was chosen.
BTW, still typing with 10 fingers.
[Edited on 31-7-2011 by a_bab]
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holmes1880
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Quote: Originally posted by a_bab |
As about SA, here you have it: more then 20 years ago I had about 0.5 grams go off accidentaly in a small plastic box. I tried to peel off a label of
that box when it went off. The resulted in some minor bruises and an eager need for a find another primary, less sensitive to static discharge.
Eventually LA was chosen.
BTW, still typing with 10 fingers.
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Definitely appreciate the info. It really validates TS's concern. I know it was 20 years ago, but you wouldn't happen to remember if you had a carpet
in your quarters, whether it was a dry time of the year, or other things that may have caused a build up of a strong spark? And yes, it was a clever
thing to have been keeping only 500mg. Many people mindlessly keep batches of 5-10g, and not even under isopropyl.
About atomic bomb, makes sense that timing could have been a big factor in choosing the initiation system. It was a win/win for them, because they
weren't risking cratering the whole project cite plus thousands people living there, and they got a initiation system that met the requirements.
Although, the EBW system was first pioneered by a Soviet Russian guy who was skeptical of primaries. MF was probably still used at the time, so I
don't blame him.
The time is not enough.
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a_bab
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holmes, there was no carpet as I was outdoors. I can't remember the clothing but it must have been cotton, so no static issues either. The plastic was
probably some PS as it broke in sharp shards. There was no serious damage besides the minor bruising. The hand did feel like being struck with a
hammer though.
PS plastic + rubbing = small sparks. The truth is, SA is so sensitive to static discharges that I bet ANY kind of spark should be able to set it.
Another fact was that the interior of the box was "dusted" with SA. Also, the SA was rather old (a week), thus grey in color. It was also very dry.
At any rate, I would not reccomend anyone SA for a primary.
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quicksilver
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Frankly - crushed carpet, low to no humidity (in certain altitudes as well) can yield up some serious static. Perhaps the worst I have personally seen
was a summer, zero humidity at above 4000-4500 ft elevation and heavy "older" compressed carpeting. One could SEE the spark from body to ground. In
conditions similar to those, there really isn't a method to "safe" the situation. Shoe soles could be either rubber or smooth leather: it doesn't seem
to alter it. I have no idea what the energy rate was (due to discharge variations) but I believe it would be possible to ignite high-end fuse grain
BP; it was strong enough to to make contact painful. Humidity could have an inhibiting effect but air-conditioning would ruin it.
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Rosco Bodine
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Quote: Originally posted by holmes1880 | It was a win/win for them, because they weren't risking cratering the whole project cite plus thousands people living there, and they got a
initiation system that met the requirements. Although, the EBW system was first pioneered by a Soviet Russian guy who was skeptical of primaries. MF
was probably still used at the time, so I don't blame him. |
You just keep harping on a matter where your ignorance is showing. Do you not know that electrical detonation of nitroglycerin predates the use of
the fulminate blasting cap for detonating NG and the use of primary explosives is the more modern method? Your continual harping on your obsessive
and disproportional estimation of the danger of primary explosives is a neurosis comparable to that pseudo debate which was Edison's tirade against
the use of alternating curent for commercial electric power distribution grids, simply because of Edison's vested interest or illogical preference and
misbelief that somehow DC was superior to AC.
Ultimately where your tirade against the evils of primary explosives is leading is to the abolition of all firearms using
ammunition cartridges which could just "go off" unexpectedly, therefore only battery powered rayguns
will be allowable for citizens, while doubtlessly all the cops and soldiers and other government agents will be staying
with the old fashioned weapons which work very reliably and safely just as they always have.
Really I do not want to hear any more shit from you holmes1880 .....go spread your ignorance elsewhere
with your sweeping general condemnation of primary explosives as being some unacceptable danger which must be eliminated ......because the snake oil
you are selling here in this forum is a damn lie.
http://www.youtube.com/watch?v=0R_XMQTOcg8 Pipeline
Knowledge has been put in the pipeline .....open the valve and get wet ......or get lost
[Edited on 31-7-2011 by Rosco Bodine]
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KemiRockarFett
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Quote: Originally posted by Rosco Bodine | Quote: Originally posted by holmes1880 | It was a win/win for them, because they weren't risking cratering the whole project cite plus thousands people living there, and they got a
initiation system that met the requirements. Although, the EBW system was first pioneered by a Soviet Russian guy who was skeptical of primaries. MF
was probably still used at the time, so I don't blame him. |
You just keep harping on a matter where your ignorance is showing. Do you not know that electrical detonation of nitroglycerin predates the use of
the fulminate blasting cap for detonating NG and the use of primary explosives is the more modern method? Your continual harping on your obsessive
and disproportional estimation of the danger of primary explosives is a neurosis comparable to that pseudo debate which was Edison's tirade against
the use of alternating curent for commercial electric power distribution grids, simply because of Edison's vested interest or illogical preference and
misbelief that somehow DC was superior to AC.
Ultimately where your tirade against the evils of primary explosives is leading is to the abolition of all firearms using
ammunition cartridges which could just "go off" unexpectedly, therefore only battery powered rayguns
will be allowable for citizens, while doubtlessly all the cops and soldiers and other government agents will be staying
with the old fashioned weapons which work very reliably and safely just as they always have.
Really I do not want to hear any more shit from you holmes1880 .....go spread your ignorance elsewhere
with your sweeping general condemnation of primary explosives as being some unacceptable danger which must be eliminated ......because the snake oil
you are selling here in this forum is a damn lie.
http://www.youtube.com/watch?v=0R_XMQTOcg8 Pipeline
Knowledge has been put in the pipeline .....open the valve and get wet ......or get lost
[Edited on 31-7-2011 by Rosco Bodine] |
The primary in firearms are well protected. Therefore how big is the risk of static to initiate Ag2C2.AgNO3 compressed in a sealed al-capsule above
compressed PETN?
As I see it the risk for static to set it off is zero here. Wrong?
The risks are as I can se it under the manufacturing of the cap.
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Rosco Bodine
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People can be careless and stupid at doing anything, ignoring the known risks and taking their chances with consequences, but that doesn't make the
argument that their ignorance somehow translates to an unpredictability about about
the currents in the water where they are drowned, or the gasoline that burns them to death. People do encounter "anomalies" that are one in a million
.....
but that doesn't mean that all wells or streams drown people or that every fuel pump is a land mine. There needs to be a sense of proportion applied
by holmes1880 to inject some realism and reality into his perspective so that he may join the rest of us on earth instead of whatever planet it is on
which he resides where all primary explosives are somehow dangerously unpredictable. I have many boxes of strike anywhere matches. None of them just
independently strike themselves.
http://www.youtube.com/watch?v=PvTnu5-V_YI Games People Play
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holmes1880
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Well, a dry day provides good medium for a spark to travel through. I don't know if scratching off a label on a rigid plastic box is the same as
rubbing a plastic bag, but if they are similar, the voltage worked up can be up to 20,000. Considering that only 3,000V equates to .25mJ of energy,
there was probably spark 3-5 times that, which would be enough to initiate lead stypnate or SA.
@Bodine. Are you taking all the necessary precautions with your keyboard today? I hope you sprayed your hair and feet to prevent static discharge
before sitting down to type at your trolling station. You've been a useless troll in most threads EXCEPT for your beloved primary synth threads, so
you should go back there where you can put your time to better use. Pal, we are not running a perfect factory here, so people will get a bit relaxed
from time to time doing their amateur testing. Here is a clear example of a primary that is dangerous, both on paper and we now know in practice. This
was just one report from Energetics section member. There are many more unaccounted reports we'll never hear about. I didn't say every primary was
terryfing-lead/silver azide and maybe DDNP are acceptable for amateur use. LA is the most time-friendly to make and has a static threshold 7-10X that
of SA. Someone ought to do piezoelectric spark test on LA, I'm about 99% sure it won't initiate.
Unlike you at your keyboard, I tested 7 pyro-based blasting caps yesterday, 1 was with a 20g kinepak charge underwater. The 6 caps were tested in an
empty plastic gallon can filled with sand because I do testing in a fire exit stairwell. All were successful in either shredding apart a 357 Mag brass
cartridge tied to the cap or initiating the kinepak. DDT concept of dense plug formation is very much real.
The time is not enough.
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Rosco Bodine
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The safety troll certainly isn't me but displacement is a common symptom of a neurosis. And with regards to the perfect factory example, you simply
underscore the point that a relaxed song in the head approach instead of a practical situational awareness is what kills people, whether they are
crossing at a crosswalk or doing anything else where a misadventure may occur. Amateur is just that ....amateur...in knowledge and in
practices....but not all amateurs are equal in their recklessness or ignorance. It is ultimately Darwinian, you place your bets based on what you
think is smart, and roll the dice hoping you were right.
Having ten fingers, eyesight, and a life in this world when you pick up the dice, doesn't mean the same math will be your blessing when the tumbling
dice stop rolling. All your tests don't amount to shit if you can't objectively interpret your
own data within the experiment as well as in perspective of the larger knowledge of the art. You have tunnel vision which you mistake for panoramic.
You can pull loose a sparkplug wire and set aflame a piece of paper with it by putting the paper in the arc path. That doesn mean that every book on
every library shelf is at risk of ignition when you do your little experiment. The locality of the specific reaction zone and the condition operable
there is highly specific and qualified,
and so is the susceptiblity of various things to ignition by electric discharge.
Even stadardizing of a test to fit a particular model would be somewhat an abstraction. Aircraft are regularly struck by lightning, even aircraft
that are armed warplanes, but it a rarity that a lightning strike would cause an aircraft to explode in midflight. How would you reconcile that with
your theory of susceptibility
to unitended detonation? There has been no argument from me that there are different mechanisms and pathways to detonation and this has been
discussed for years without missing any substantive "discovery" on which you seem to have assigned yourself a mission to enlighten us. You are simply
biased and you let that bias cause conclusions which are without validity. Maybe you are seeking to make amateur experimentation with energetic
materials "idiot proof" .....well good luck on that.....but bad information is not helpful. There is also a lot of gray area which is a matter of
interpretation for tests and models being translated to guidelines for actual handling procedures. Truly the idea that chemistry, particularly
chemistry involving energetic materials, is something so simple that any idiot can safely do it, is an illusion that will continue delivering painful
lessons
with missing fingers, eyes, and lives which are witness to a different reality.
Not everyone is fit to be an aircraft pilot either, or a hunter, or a soldier or
many other specialized pursuits and the truth is that some people are not temperamentally or intellectually suited to such pursuits. Not everyone is
even fit to be behind the wheel of a car, but ask a lot of them and they would be the first to say it is so simple any idiot can do it, even if they
could not pass a driving test.
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holmes1880
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I agree 110% that very few people have the right demeanor and situational IQ to work with HE. Anyone under 20 should postpone testing of energetics.
Age isn't a qualifying safety requirement, but teenagers tend to underestimate the severity of consequences of dangerous acts and overestimate their
own judgement and abilities.
Quote: | Do you not know that electrical detonation of nitroglycerin predates the use of the fulminate blasting cap for detonating NG and the use of primary
explosives is the more modern method? | .
Liquid blasting cap sounds like a one shitty idea. It probably made MF seem like a safe alternative. Bhahaha. Hey, BP blasting cap used to detonate NG
also predates that. They were messing with a lot of impractical things back then, what else is new...
The time is not enough.
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Rosco Bodine
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There was no liquid blasting cap used, just two wires to a spark gap and I think it was a Wimhurst machine with Leyden jars ....they zapped the crap
out of the NG and bingo! That'll do it ....and still does actually, if anyone cares to try it...but I'm not going to lay out a step by step and
haven't tried it to confirm. I have misplaced my Wimhurst machine and Leyden jars. Now where are they.
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