Why is detonaton by impact louder?

[mark]

Im rather perplexed. I just hit a bb sized quantity of ap with a hammerr, and my ears rang for a good minite. But when 10 times the amount of powder was put in a triangle cracker and wraped extensivley with duct tape, my ears didnt come close to ringing. I Was only about 5 feet away when the triangle went off too. Any ideas why this happened?

[CyclonitePyro]

Hey, I know waht you mean, I'm pretty sure that the stronger the confinement the louder the bang, well when you hit it, for that brief instant you are confining your Ap between two hard heavy surfaces, that acts like extreme confinement just long enough for it to detonate, I'm sure someone can better explain though.

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[mark]

That might be the answer, but I doubt it. It was a rounded hammer, so their must havve been some gaps between the hamer and the brick.

[Mr Cool]

If your triangle cracker was loose inside, or had a large fuse hole, then maybe a lot was wasted in the Def-Det transition? Or maybe it didn't even detonate?

[kingspaz]

maybe it is similar to implosion nuclear devices. the bullet types don't work so well because the energy released blasts it to bits as soon as the bullet hits so not much uranium is used. in the plutonium implosion devices explosives compress the plutonium so it stays at the supercritical (think thats the one) mass for longer so fission takes place for longer before it blows itself apart. anyway what i'm trying to say is when you hit it with a hammer maybe it doesn't have chance to throw itself apart so as it detonates it is getting compressed therefore reacting faster. that could be what happens but its only one of many possibilities. also the noise of the hammer could add to the noise.

[green beret]

I personaly agree with cyclonite pyro. For a very brief moment the AP is confined between two very strong metal surfaces. The fact that it is a round hammer shouldnt make that much difference.

[a_bab]

And the triangle cracker is made by several layers of paper, wich will absorbe much of the sound.

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[ALENGOSVIG1]

Also when initiated by flame some of the explosive deflagerates before it steps into detonation. i dont think this alone is the answer.

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[JB]

Is it possible that the sudden shock from the hammer impact breaks down the AP in a different way than when deflagration leads to detonation via fuse - so therefor if you put a small detonator of AP into the triangle cracker, detonating the triangle cracker of AP will produce a louder report than simply fuse ignition....if that made any sense

[PYRO500]

As I recal from the explosives and demolitions field manual that a booster charge when detonated detonates at a speed that can detonate the main charge, well I also think it said that the speed of the booster and main charge are added, I could be mistaken but that's what I think, the hammer detonates the AP, and the hammer's speed is added to the det. speed of the ap causing the AP to detonate faster than it normally would, I also recall hitting AP with a hammer and having it make a higher pitch POW than when detonated with fuse

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[Microtek]

In my opinion it is a matter of compression.
Most ( CHNO ) explosives detonate at a velocity that is approximately linearly dependent upon their density, and at a det-pressure that is linearly dependent on the square of the density.
For this reason, the habit many people have of simply packing the AP loosely into the container, causes the detonation to proceed at a much lower velocity, than if it was compressed.
On the other hand, when struck by a hammer the AP is compressed to a reasonably high density before it explodes, thus reaching a much higher velocity.
Finally, what makes your ears ring is the sharp spike in air-pressure resulting from a high-velocity detonation; not the slower explosion of larger amounts of AP.

[This message has been edited by Microtek (edited September 24, 2001).]

[mark]

Thanks everyone! I might try a detonator on my next device

[bangandow]

Microtek is right. When you hit it with a hammer you are basically compressing it till it can be compressed no more. Thus, the AP is at its highest density when it detonates from the hammer. Denser=higher velocity. Its as if you took the force of the hammer hitting the AP and pressed the AP with that much force before detonation. It still has the same effect.