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Black Powder explodes by Shock ?


Pirotecnia

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Some people tells it explode by shock or friction, others not..

Whats the true?

 

Thanks

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It will not ignite by impact under normal circumstances. It may ignite from electric shock or by friction intense enough to cause it to reach ignition temperature.
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Some people tells it explode by shock or friction, others not..

Whats the true?

 

Thanks

 

I have rammed hundreds,just waiting to get the one that blows on me thats why I wear goggles cotton gloves and jeans!I also ram so it will go down in the ground I hope.Murpghys law mate get ya everytime.A skydiver knows hes one jump away from a no deploy on his chute, so hes ready when it happens!

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ive heard an instance where quickmatch was stapled with a staple gun to the rack and ignited causing a death.

not an evry day occourance but it still pays to protect yourself where you can, i would be more concerned about foreign material in the bp causing it to ignite than pure bp.

here is a video of some tests impact,friction

 

 

i would not trust anything i did not make, for example some quickmatch has metals, take no chances!

 

dan.

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You could probably put BP on an anvil and hit it will all your might with a 10kg sledgehammer without problems. Would it explode, it would be from metal-metal producing sparks, not from impact on the BP itself.
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a ball mill produces thousands of impacts during the making of the BP when it runs.

 

Why don't more of them blow? Sparks make BP blow, not impact.

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ive heard an instance where quickmatch was stapled with a staple gun to the rack and ignited causing a death.

dan.

 

 

I heard about this somewhere. The guy was a well know pyro. He was actually setting up a show ouside of a hotel for a public display when it ignited and a shell hit in the forehead. I can't remember where I read this but whoever wrote it had planned on meeting him about an idea for a show a couple hours after the incident.

Edited by busspuppy
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http://www.creagan.n...i_bulletin.html

 

Dan, I'd be interested in any reference or proof of commercial quickmatch containing any metals.

 

Warthog, it's also a matter of energy of impact. A ball mill has a large number of relatively low energy impacts. People have for instance milled whistle mix successfully before. Anyone can tell you it will go off with a harder impact. Just because it doesn't explode in a ball mill doesn't mean it will never explode. I do believe that BP has a measured impact sensitivity somewhere.

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I remember reading about the accident, the guy setting up the show shot a staple through the quick match and a 4" ball shell struck him in the forehead.

Speculation was grit of some type in the quick match caused ignition.

BP in dust form will ignite from an electric spark, but granulated is not so easy.

A guy on PF posted pics last year of electric current from his MIG welder running over 2FA granules without ignition

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There was a ballmill in a greenhouse in Florida a few years ago that popped, speculation was that the mill was under-loaded and a strike from the media pinched a particle of BP and ignited the jar.

 

"The "stoichiometric" ratio of 84:8:8... The ideal reaction is of 10KNO3 + 8C + 3S... Black powder is the safest of all explosives... It is insensitive to shock and friction or to electric spark. It must be initiated by heat or flame..."

-J. B. Calvert-

 

-dag

Edited by dagabu
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From what I remember reading that particular media caused more than one accident. Apparently it was some batch of ceramic media. There was also some postulation that the powder simply leaked out and was lit by the motor. I don't think there was ever anything definitive decided.
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yes the poor guy was hit by a shell in the forehead 3-4" it was said that grit and the staplegun was the possible cause.

the greenhouse incident was probably due to an undercharged jar with ceramic media, his tomatoes survived, the greenhouse did not. i think i read that the powder leaked aswell, the jar had wooden discs for endcaps that were both blown out iirc.

 

mumbles: i have a few short pieces of said quickmatch, how would you like me to confirm that it contains metal, most likely al there is also visible off white particles which could be sulfur or a coarse oxidizer, i can take a picture comparing it to regular commercial qm and my bm, side by side burn test? it is way more energetic than normal bm, acts like flying fish fuse when lit.

or is there a chemical test to establish its properties or which metal is used?

 

dan.

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I remember reading about the accident, the guy setting up the show shot a staple through the quick match and a 4" ball shell struck him in the forehead.

That was here in Las Vegas a few years ago, and I believe the shell was only three inches.

 

I would question, what was the QM made of? It's been discovered lately that some Chinese quickmatch tests negative for nitrates, which means it's probably made with perc or chlorate. I don't recall if anyone did an analysis of the match they were using

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...

mumbles: i have a few short pieces of said quickmatch, how would you like me to confirm that it contains metal, most likely al there is also visible off white particles which could be sulfur or a coarse oxidizer, i can take a picture comparing it to regular commercial qm and my bm, side by side burn test? it is way more energetic than normal bm, acts like flying fish fuse when lit.

or is there a chemical test to establish its properties or which metal is used?

 

dan.

 

So, in other words you were speaking purely on speculation? A microscope should tell you. Metal particles are....well, metallic. Some quickmatch is purported to be made from a perchlorate composition, and resin bound. Encased this stuff burns very rapidly. It can be used to prime AP go-getters. I've never really burnt any outside of the casing. Some have postulated that is a toned down whistle mix, similar to some burst mixtures.

 

There are chemical tests, but it's hard to recommend something without knowing generally what is in the comp.

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i know it contains metal no microscope needed you can clearly see it shining at ya, its certainly not bp, likely a perc comp of some sort as you say.

i cant tell you how suprised i was to learn this, after cutting it with scissors.

 

 

dan.

 

 

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  • 4 weeks later...
I think BP can be ignited from shock, though very much energy is needed to do it. Sulfur is the main sensitizer here. Normally this energy isn't obtainable in normal conditions, but I suspect it could happen even in some amateur cases, for example when you have a very sharp end (small surface) hitting. The pressure could be high - for example a sharp spindle of a rocket tooling.
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At a certain point, the "shock" becomes friction and heat causing the burn. If one were to use a hammer, you can get anything that burns to start on fire. I was beating down a willow twig decades ago to make fletching for a blow gun dart and the small pile of fine wood fragments that I made smoked a time or two as I pounded the anvil with a #3 sledge. I didn't get a fire but the potential was there.

 

I really don't know how to create or measure shock so I had to take data from others with a bunch of letters after their names instead.

 

-dag

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A hammer strike may detonate the potassium nitrate itself if hit hard enough. In addition, you've got what Dagabu likely experienced which is pressure induced heat, such as what is created in a diesel engine. Overall, however unlikely an ignition is, it's not a great idea to use unnecessary impact around any pyro comps.
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[citation needed]

I should have emphasized 'may' in that sentence. I have no occurrence to cite, it is simply a conclusion through a string of logic. Potassium nitrate is capable of detonation, detonation can be initiated by energy transferred through impact, therefore, there is potential for potassium nitrate to detonate from a hammer blow. The chance may be so low that it may have never happened in all of history, but the potential is there.

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I should have emphasized 'may' in that sentence. I have no occurrence to cite, it is simply a conclusion through a string of logic. Potassium nitrate is capable of detonation, detonation can be initiated by energy transferred through impact, therefore, there is potential for potassium nitrate to detonate from a hammer blow. The chance may be so low that it may have never happened in all of history, but the potential is there.

 

Potassium nitrate has a heat of decomposition of +75.5 Kcal/mole, meaning it takes a constant source of energy to keep decomposing. Potassium chlorate on the other hand has a heat of decomposition of -10.6 Kcal/mole, so once it begins to decompose, the energy released is enough to keep it decomposing without any external source of energy. Compounds like potassium chlorate are able to detonate for this reason. Potassium nitrate will not.

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The only nitrate that might detonate on impact is ammonium nitrate. No metal nitrate will detonate on impact.
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The only nitrate that might detonate on impact is ammonium nitrate.

No "might" about it - ammonium nitrate only detonates from shock. Interesting compound, every one of its constituent elements is a gas and it decomposes with an excess of oxygen. Exploding ammonium nitrate without a separate fuel component, eg dark aluminum, is a waste of a good resource. As others have said, straight potassium nitrate will never explode from shock under any circumstances. When it's compounded with charcoal and sulfur, however, it doesn't take a lot of friction heat to light it.

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  • 1 month later...

I've tried igniting blackpowder with a hammer and anvil before, it didn't work. I did ignite a small amount of GOEX blackpowder for fun by placing it in a sparker (one of those things used to light a blowtorch or bunsen burner) and it took a few tries.

 

I'd be more careful with static or metal to metal contact because you can create sparks this way. I am thinking mounting quickmatch with a staple gun is not such a good idea...

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