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EAPyrotox
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SA (Ag2C2.AgNO3) - SENSITIVITY TO STATIC DISCHARGE
hello,
I just realized some sensitivity tests on silver acetylide, this compound seems safe enough to friction, impact (intervals of errors / margins). but
for Electrostatic / static discharge is a disaster, a simple spark lighter (piezo) set it off every time ..
Even if I use aluminum casing tube to counter the static, it seems scary...
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AndersHoveland
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Yes, it is an interesting phenomena that some explosives are particularly sensitive, some to static discharge, some to only to flame, and others
mostly to friction.
As an example, an interesting comparison can be made between nickel hydrazinium nitrate (NHN) and cobalt hydrazinium nitrate (CHN). CHN is more
sensitive to impact than NHN, the salts having drop height values of 59cm and 84cm, respectively. CHN also explodes at a lower temperature, 188degC,
compared to NHN at 219degC. From this information, one might conclude that CHN is more sensitive, but somewhat paradoxically, however, the CHN is
actually somewhat less sensitive to friction than NHN.
Possibly co-crystallization (a so called "clathrate") of the Ag2C2*AgNO3 with a nitrate ester, such as erythritol tetranitrate would reduce
sensitivity to static discharge, as nitrate esters are actually not reliably initiated by electrical ignition.
[Edited on 27-7-2011 by AndersHoveland]
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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Bot0nist
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Thanks for the warning EAPyrotox and for the data Anders. Have you tried taking advantage of "Faraday's cage" phenomenon in your cap design to help
protect from accidental static initiation?
Can you point me to the source of your data Anders Hoveland?
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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holmes1880
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The silver acetylide "revival" in amateur use is largely because people never bothered to test it for static sensitivity. SB15 did similar static
tests on SA few months ago, with same exact results- reliable detonation from a tiniest BBQ igniter spark. He wisely stopped using it and opted out
for a more friction sensitive HMTD.
I have looked before for SA static sensitivity figures, but found none. One insight that can be made, is that unlike most other primaries, SA readily
detonates in tiniest quantities from flame, without confinement. That in itself indicates its high sensitivity to flame. Fulminates are the other
primaries that have similar response to flame, and perhaps using those primaries as a benchmark, we can find approximate static figures for SA.
SA is a dangerous stuff. Vvideoupl on YT spread the rumor that it was safe, without ever fully testing it out.
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The WiZard is In
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Quote: Originally posted by Bot0nist | Thanks for the warning EAPyrotox and for the data Anders. Have you tried taking advantage of "Faraday's cage" phenomenon in your cap design to help
protect from accidental static initiation? |
What dobe the connection w/ a Faraday cage and static?
La cage is used to keep out EM radiation. Rub you rubber
soled shoes on a wool mat in la cage and see what happens
when you touch something grounded.
A ground strap works wonders for static electricity building
up - discharging from your person.
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holmes1880
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http://www.teledynerisi.com/products/0products_8td_page02.as...
That is 0.007J for LA, 0.0009J for LS, and 0.6J PETN.
Now, the question is what range of static discharge can a human body work up.
Quoting from "Capacitor Discharge Firing Systems" by Bob Dahlquist: "A human body carrying a static charge of 30,000 volts has only about 0.045
joule of stored electrical energy. Thus an accidental electrostatic discharge from a human body has less than 1/200 of the energy needed to fire an
uncoated resistor igniter. "
A hypothetic static discharge has therfore 6X the energy to initiate LA, while doesn't has less than 1/10th the energy to hypothetically ignite PETN.
I'm not even going to mention lead styphnate. And I do know silver acetylide is not nearly as static insensitive as LA.
From Static Electricity in Propane Industry by Ed Ferguson:
[Edited on 28-7-2011 by holmes1880]
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EAPyrotox
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Silver acetylide is a primary easily/fast made with basic ingredients, and I prefer it to an organic peroxide. I dont have large
knowledge of chemistry and materials for more complex primary (chlarates, tetrazoles).
So I use SA with gloves anti-static and electricity conductor cap case (al) to minimize the risk... but I heard about the primary 50/50 | SA/P(ETN)
probably more stable statics.
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holmes1880
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Even wearing a giant antistatic bag around me wouldn't make me feel safer. Just dumber. It just won't take very much to set off SA, assuming it has
similar properties to lead styphnate. It is probably even more sensitive.
Primaries are for noobs. I am 100% confident there were accidents with SA, just those who had them never reported it.
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holmes1880
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To further make the case that SA is equally or more sensitive than lead styphnate, take their detonation/ignition temperatures. Vvideoupl via his
testing concluded that it was between 230C-240C. Assuming the higher range for SA, styphnate ignition temperature is 282C. This is highly relevant
because both chemicals respond similarly to flame, by detonating in tiniest amounts, unconfined.
This is a good indicator that SA is equally or more static sensitive than LS. Smallest spark can and will set it off, as further reinforced by the
piezoelectric lighter spark tests.
Based on patent, 5536990 on Piezoelectric Igniter(http://www.patentgenius.com/patent/5536990.html), it generates 0.25mJ or 0.00025J. This goes along with my assessment that SA is more static
sensitive than LS. Christ, an average static discharge from human finger packs 0.5mJ. I hope youngsters are taking notes.
[Edited on 29-7-2011 by holmes1880]
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EAPyrotox
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The key to a good pyrotechnician is in its primary.
So I will continue my research to a more stable and sustainable development.
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holmes1880
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A lot of good "pyrotechnicians" have less than 10 fingers and injuries. A kid named AnonymousUploads from YT had one with nitrotetrazole. Yet he still
chirps about how primaries are important. Consequently, he sounds like a fool. I have 2 more examples like that, but meh...
There is no safe primary alternative and never was. Dextrinated lead azide is the best thing available, but safe manufacturing requires very
meticulous control of the crystal size before and after recrystallization.
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Rosco Bodine
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@homes1880 How about you get off your little campaign of ignorance and stupidity regarding the danger of primary explosives since it has long ago worn
very thin. You don't have clue one what you are talking about so please stop teaching until you do have a clue. Tens of millions of ammunition
cartridges and other devices containing primary explosives as an essential component have
been handled correctly (not mishandled) without even one "just going off" unintentionally, but of course nothing is absolutely idiot proof since
always can be found the special idiot who is the exception.
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Rosco Bodine
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You are making the generalizations which are not reconcilable with reality and history. Mishandling of primary explosives is exposing them to stimuli
known to cause their initiation when that is not wanted. File that under operator error
and keep it filed there.
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holmes1880
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@Bodine Are you summarizing all primary explosives in one group? I'll assume commercially accepted. Yes, sure, proper production and handling is
always 99.9% safe, but new "pyrotechnics" often come in trying to replicate it, with rather sad results for them.
You can't possibly make an argument about primary's perfect safety after I showed with concrete facts that a strong static spark is enough to detonate
lead azide, with a healthy margin of mJ surplus. I'll give you plenty time to rebuttal, but I don't think you have anything concrete.
You've been around since mercury fulminate was a primary of choice, so I can't blame for you for being biased towards primary initiation.
EDIT: I would choose LA based detonator over NONEL, because the latter is an umbilical cord of an initiation. Expensive, and limiting in every way.
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holmes1880
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Quote: Originally posted by Rosco Bodine | You are making the generalizations which are not reconcilable with reality and history. Mishandling of primary explosives is exposing them to stimuli
known to cause their initiation when that is not wanted. File that under operator error
and keep it filed there. |
You are a Six Sigma type of person and that is commendable. But no commercial handling is error free. A simple Google search of blasting cap
accidents, will show a list of examples where some type of error resulted in lost fingers and injuries.
You would want to give some degree of safety to a detonator, not just go by "zero tolerance" approach.
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Rosco Bodine
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You have what you think is a "needed solution" to a mischaracterized problem,
but you fail to recognize that if what you regard is a problem is characterized accurately in the first place, then the dubious need for the problem
solution
to a problem that really isn't a problem can be recognized in a practical way
as being a need for a problem solution which does not actually exist.
I am not trying to redefine reality. You are.
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The WiZard is In
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Six-sigma? Sorry you worship a false God.
Extracted from —
Science 29 September 2000:
Vol. 289 no. 5488 pp. 2260-2262
DOI: 10.1126/science.289.5488.2260
NEWS FOCUS
SCIENTIFIC PRIORITY
CERN's Gamble Shows Perils, Rewards of Playing the Odds
Charles Seife
Igo-Kimenes is certain that even an extra month of experiments—
about as much overtime as LEP can get without triggering harsh
penalty clauses in builders' contracts—will not boost the data
across the threshold particle physicists use to separate true
discoveries from the chaff of statistical fluctuations: five standard
deviations, or five sigma. The LEP data are languishing in the
three- to four-sigma range, far short of what is needed to declare
a stone-solid discovery.
To physicists and astronomers, the five-sigma rule is the acid test
for judging discoveries and assigning credit. So why do the
physicists at LEP persist when they know they can't possibly make
the grade? Because they also know that reality is a lot messier
than theory. In practice, the five-sigma rule is far from golden.
Discoveries that seem statistically unassailable can vanish
overnight, while flimsier looking findings have entered the award
rosters and the textbooks without cavil. Qualitative factors, such as
the reputation of a team of scientists, whether a finding conforms
to prevailing theory, and how and why the team announces a
discovery, can determine whether it wins the Nobel Prize or
languishes as an also-ran.
Vanishing probabilities
To a statistician, such vagaries may seem absurd. On the surface,
finding a new particle should be little different from figuring out
whether a medication is effective or when a coin is biased.
Numerically, a five-sigma result corresponds to less than one
chance in 3 million that a sighting is due to chance (see sidebar).
Even a much weaker three-sigma result in particle physics means
that the scientists are 99.9% sure that their signal didn't appear
by accident. By definition, then, a mere one three-sigma result in
1000 results is wrong. Right?
Not exactly. “Half of all three-sigma results are wrong,” says John
Bahcall, a particle physicist and astrophysicist at Princeton
University. “Look at the history.” He's right: Not only do a
surprising number of three-sigma results vanish on closer
inspection, but an astounding number of five- and six-sigma results
have done so, too.
In the mid-1980s, for example, physicists at the Organization for
Heavy Ion Research (GSI) in Darmstadt, Germany, looked well on
their way to the Nobel Prize. Two separate experiments had found
peaks in their data, hinting at a new particle in the 600- to 700-
KeV (thousand electron volts) range. It wasn't predicted by the
Standard Model, but the signal was strong—more than six sigma,
corresponding to a one-in-a-billion chance of error. Today, the
mysterious particle is gone forever. “We have given up the
experiments,” sighs GSI physicist Helmut Bokemeyer. “We have
not been able to see what we had seen before.”
What went wrong? Bokemeyer thinks that the GSI experiments
were highly “optimized” to find the peak. In other words, change
the experiment ever so slightly, and the peak disappears, which
explains why the result is so difficult to reproduce. “Otherwise, we
have no idea what it could be,” he says. There are other possible
explanations. For instance, the researchers might have begun an
experimental run and looked for a growing peak to make sure that
the equipment was set up properly. If there was no indication of a
bulge in the data, they would change aspects of the experiment
and try again.
Some physicists believe that this habitual restarting of the
experiment may have introduced an unintentional bias into the
results. Subtle statistical effects like this, or problems with
equipment, or a slight error in calculation, or an overlooked source
of conflicting data, can throw off statistical calculations in a
tremendous way. “It's the systematic errors that kill you,” Bahcall
says. Bahcall knows that the perils of failure against the odds
stretch far beyond particle physics: Seven years ago he saw it
strike on a cosmic scale.
Vanishing planets
“It was the thing that one fears more than anything else in one's
scientific life, and it was happening,” says Andrew Lyne, an
astrophysicist at Jodrell Bank Observatory in Manchester, U.K. “I
certainly at the time thought that it was the end of my career.”
In January 1992, Lyne was celebrating a monumental discovery.
He and his team had spotted what appeared to be the first planet
circling a foreign star. Their radio telescope had found a pulsar
whose clocklike pulses sped up and slowed down in a way that
suggested it was being tugged around by an invisible orbiting body.
“Indeed, based upon a straightforward statistical analysis, the
effect was very highly significant—hundreds of sigmas, a
certainty,” Lyne says. “We did all sorts of tests on the data and
tried to think of all the possible ways we might be making a
mistake.” After finding their procedures sound, the team published
their discovery: the first extrasolar planet. “It received a lot of
interest, as you can imagine, from the media and others,” he says
.
Bahcall, then president of the American Astronomical Society,
called a special session together to discuss the discovery at the
society's annual meeting. But then disaster struck. “Ten or 12 days
before I was due to give that talk, I discovered the error and the
true source for the periodicity,” Lyne says. “It was rather subtle.”
When timing signals that come from pulsars, astronomers have to
correct for Earth's motion around the sun, which introduces a tiny
periodic distortion in the signal. To save computer resources,
Lyne's group used an approximation of Earth's orbit for the
preliminary calculations. For a more detailed analysis, they
planned to switch to a more accurate model and redo their work
from scratch. Unfortunately, with one of the 200 or so pulsars that
they looked at, they forgot to perform the more accurate
calculation and based their conclusions on the rough
approximation. “The full high-precision analysis was not carried
out,” Lyne says. The slight inaccuracy in accounting for Earth's
orbit led to a periodic signal that mimicked a planet around the
pulsar. Hundreds of sigmas crumbled to dust just before Lyne was
to present his findings.
Lyne gave a presentation anyhow—a retraction. “It was an
extremely difficult time,” he says. “It was a large audience of
extremely eminent astronomers and scientists.” But at the end of
his presentation, the audience broke out into a long, loud round of
applause. “Here I was, with the biggest blunder of my life and …”
Lyne pauses, gathering himself. “But I think that many people have
nearly done such things themselves.”
Lyne's reputation didn't suffer; other planet hunters weren't quite
so lucky. Peter Van de Kamp of Swarthmore College in
Pennsylvania will always be known as the one who found the planet
around Barnard's Star. It was a planet that made it into the
textbooks, even though it didn't exist.
Vanishing chances
As in the heavens, so, more subtly, on Earth. Going by statistics, if
physicists discovered a new five-sigma particle every day,
mistaken sightings ought to turn up about once every 10,000
years. In fact, the history of high-energy physics is littered with
five-sigma mirages. One was the “split A2,” an unexpected double
peak that, in the 1960s, seemed to signal the existence of two
particles where only one was expected. “It was believed by
everybody,” Bahcall says. But as scientists made more
measurements, the two peaks filled in, and the mysterious second
particle vanished. The story replayed itself in the early 1980s,
when physicists at Stanford, at DESY in Hamburg, and elsewhere
found something that looked remarkably like a Higgs boson at an
energy of about 8 giga electron volts (GeV), well short of the 114
GeV where CERN's current Higgs candidate lurks (Science, 31
August 1984, p. 912). The discovery, dubbed the zeta particle, had
a five-sigma significance, but it didn't survive for long. “They kept
measuring, and it disappeared,” SLAC's Riordan recalls. Physicists
on the zeta particle team still suffer from the memory.
Decades of such reverses have taught experimental physicists that
five-sigma rules and one-in-a-million errors are not to be taken
literally. “[The statistical analysis] is based upon the assumption
that you know everything and that everything is behaving as it
should,” says Val Fitch, who won the 1980 Nobel Prize in physics
for discovering charge-parity violation in K mesons. “But after
everything you think of, there can be things you don't think of. A
five-sigma discovery is only five sigma if you properly account for
systematics.”
"Lies, damned lies and statistics."
djh
----
"It is essential that persons having explosive
substances under their charge should never
lose sight of the conviction that, preventive
measures should always be prescribed
on the hypothesis of an explosion."
Marcellin Berthelot - 1892
Explosives and their power - Page 47
Attachment: Six-sigma.pdf (164kB) This file has been downloaded 637 times
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holmes1880
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Quote: Originally posted by Rosco Bodine | You have what you think is a "needed solution" to a mischaracterized problem,
but you fail to recognize that if what you regard is a problem is characterized accurately in the first place, then the dubious need for the problem
solution
to a problem that really isn't a problem can be recognized in a practical way
as being a need for a problem solution which does not actually exist.
I am not trying to redefine reality. You are. |
No, but you are redefining complex and compound sentence structure. Reality is that accidents happen because primary explosives can't tolerate too
much error. Why do you think the Manhattan project engineers went with EBW? Oh oh.
Hey, WiZ, you don't happen to know about accidents related to static electricity? I remember you posted in the ETN accident thread about detonators
going off when being tested with volt meter.
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Rosco Bodine
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It is possible that an automobile driver can fall asleep while driving, so according
to your logic every automobile should therefore be equipped with optional countermeasures to address that foreseeable danger. It is also conceivable
that an automobile driven by someone who falls asleep at the wheel could go off a cliff and freefall for a thousand feet before striking the ground,
therefore should all automobiles additionally be equipped with automatic ejection seats and parachutes to address the foreseeable need? Of course the
logic for safety is flawless in its indifference to costs and complexity and practical need which is precisely the kind of "counterfeit intelligence"
which motivates so many social and political agendas. But do not pretend that such "engineering" is science, when it is only salesmanship and politics
and deception.
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The WiZard is In
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Quote: Originally posted by Rosco Bodine | It is possible that an automobile driver can fall asleep while driving, so according
to your logic every automobile should therefore be equipped with optional countermeasures to address that foreseeable danger. It is also conceivable
that an automobile driven by someone who falls asleep at the wheel could go off a cliff and freefall for a thousand feet before striking the ground,
therefore should all automobiles additionally be equipped with automatic ejection seats and parachutes to address the foreseeable need? Of course the
logic for safety is flawless in its indifference to costs and complexity and practical need which is precisely the kind of "counterfeit intelligence"
which motivates so many social and political agendas. But do not pretend that such "engineering" is science, when it is only salesmanship and politics
and deception. |
Well... the Eco Nuts are against transport of nuclear power
reactor waste in well tested containers on account off ....
a truck may fall off a bridge onto a train carrying the
cannisters rupturing them.
djh
----
The Religion of
Global Warming
is not happy.
New NASA Data Blow Gaping Hole
In Global Warming Alarmism
http://news.yahoo.com/nasa-data-blow-gaping-hold-global-warm...
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holmes1880
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Poor, poor analogy. A more appropriate analogy would be why cars are designed to crush as a way to reduce the impact on the driver and why every
automobile now has airbags. Airbags quite significantly upped the costs. You'd think the seat belt is enough!
So far, you've ducked my question of why EBW was used for Manhattan Project and whether lead azide is susceptible to static inside a blasting cap. You
gave no response to that because you know you can't debate it.
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Rosco Bodine
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I know but like some other things I know it is not something I care to discuss.
Your problem is you know just enough to mistake what you think for what you know for sure but not care there is a difference and you will argue
forever anything you "think" but don't really know, as if there is a debate where there really isn't and you are simply the last one to know.
EBW and "safety detonators" are absolutely nothing new, but after you made your first one and it worked now you are the forums self-appointed expert
on safety who like most self-appointed experts don't really know as much as they pretend to know or even may have convinced themselves they know.
Go back to the ETN accident thread and see what you did after the forum owner asked you not to keep posting there ....you just don't know when to shut
up.
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KemiRockarFett
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The most primaries will be possible to set of with a static electricity spark. SA will not ignite so easily by a fire steel:
http://en.wikipedia.org/wiki/Swedish_firesteel
So how is the risk than the Ag2C2 . NO3 is pressed and in place in the detonator inside a Faraday cage on top of a secondary.
As I see it the risk is almost zero to get it go from static when charged in the detonator ( not if fuse are going to be inserted afterwards),
otherwise tell me why its still a danger. Compare to electronics that is much more sensitive in this ESD bags...
[Edited on 29-7-2011 by KemiRockarFett]
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holmes1880
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Have you tested it with that firesteel or that's just your assumption?
[Edited on 30-7-2011 by holmes1880]
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holmes1880
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@Bodine
Not this sh*t again. No sources, references, and subliminal condescension. Try harder, David.
I have made 1 practical, non-primary detonator that works on par with any commercial ones in terms of performance, dimensions, and strength. I don't
think you can brag that. In fact, for someone who chooses the keyboard route to experimentation, you are not the person to truly discuss safety.
Keyboard doesn't blow up, unless you spill coffee on it.
Just to review your input on static sensitivity of silver acetylide and primaries, here is what you provided us with:
Quote: | Your problem is you know just enough to mistake what you think for what you know for sure but not care there is a difference and you will argue
forever anything you "think" but don't really know, as if there is a debate where there really isn't and you are simply the last one to know.
|
and this,
Quote: | You have what you think is a "needed solution" to a mischaracterized problem,
but you fail to recognize that if what you regard is a problem is characterized accurately in the first place, then the dubious need for the problem
solution
to a problem that really isn't a problem can be recognized in a practical way
as being a need for a problem solution which does not actually exist. " |
and this revealing piece of information,
Quote: | How about you get off your little campaign of ignorance and stupidity regarding the danger of primary explosives since it has long ago worn very thin.
You don't have clue one what you are talking about so please stop teaching until you do have a clue. | .
Spoken like a chemistry keyboard safety expert.
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