megalomania
June 25th, 2003, 04:48 PM
outsider
Frequent Poster
Posts: 91
From:
Registered: FEB 2001
posted February 27, 2001 04:08 PM
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I need an explosive made of NM with a high velocity of detonation when used in small quantities and with low confinement, for use in small tubes as det. cord or frame shaped charges. Because the velocity of detonation decreases when explosives are used in small quantities. I experienced that when I made a frame shaped charge out of polyethylene tube (diameter 12 mm). It produced only a dent in the mild steel object is was put on while the main charge shattered the steel. I concluded that the amount of H.E. and confinement where to low to reach full velocity of detonation. This happens with all H.E.: below certain amounts (diameters) the velocity decreases (PETN in primacord: 6200 m/s while maximum VoD is about 8500 m/s). But maybe only a dent was caused because of too little H.E. in the tube (150 g/m) and the VoD was high enough (but not maximum). Can someone tell me? Does primacord shatter mild steel or also just produce a dent because of too low amounts and not the decreased VoD?
[This message has been edited by outsider (edited March 01, 2001).]
simply RED
Frequent Poster
Posts: 238
From: HELL
Registered: OCT 2000
posted March 04, 2001 08:13 AM
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Try nitromethane thickened with some nirocellulose or better with nitroglycerine smokeless powder. This must work well in small quantities. Also some powdered PETN, RDX, ammonium perchlorate could be added to sensitize the mixture. The PETN cord detonates at high velocity(BG army old standard DS-A, DS-B, DS-V has diameter 5-6 mm and detonate at 6500-7200 m/s. This is high enough and should work with shaped charges. Shaped charges are really effective when diameter more than 20 cm. I've tried 10 mm shaped charge with molten acteone peroxide(chrystaline form- the temperature in the synthesis bath increased and it melt ) and steel tin cone at 45degrees, 1,5 diameters to the target. It penetrated 2,5 mm stell.
outsider
Frequent Poster
Posts: 91
From:
Registered: FEB 2001
posted March 04, 2001 12:14 PM
--------------------------------------------------------------------------------
Thanks for the reply. I was thinking about thickening NM with NC but I can't get hold of it. So I tried thickening it with PMMA (see other thread) but didn't succeed. Maybe I will go and just buy 1,000 ping pong balls and try to gel NM with them. I know the VoD is high of those gelled NM mixtures even in small diameter tubes. But maybe the NM explosive I used had a high enough VoD but was just a too small amount for shattering the mild steel. That's why a want to know the effect of det. cord: if it produces also just a dent in mild steel I know the explosive I used had a high enough VoD.
By the way, for shaped charges (which is something different than frame shaped charges!) the VoD must be very high, and I wonder if the AP can reach a VoD high enough for a shape charge. That's why they use secondary high explosives for shaped charges because of the high VoD, high power and low sensitivity. And AP has none of those properties. And melting AP seems to me a very dangerous thing to do, besides that it doesn't have an effect.
[This message has been edited by outsider (edited March 05, 2001).]
[This message has been edited by outsider (edited March 05, 2001).]
simply RED
Frequent Poster
Posts: 238
From: HELL
Registered: OCT 2000
posted March 06, 2001 04:52 PM
--------------------------------------------------------------------------------
You are absolutely right! The AP can't evaporate steel plate and is absolutely unusable 4 shaped charges...but some of the explosive force is concentrated in the explosive center.....
outsider
Frequent Poster
Posts: 91
From:
Registered: FEB 2001
posted March 07, 2001 06:24 AM
--------------------------------------------------------------------------------
Yes, that's absolutely true also. When an high explosive (secundary or primary) has a V-shaped cavity the shockwaves meet each other and collide. And the resulting shockwave is focused and stronger. And this will happen with AP also. But it doesn't make it a Shaped Charge in the sense that it will penetrate thick steel (or create a fluid metal jet of the metal liner from the cavity). But the stronger shockwave may increase the power of the AP charge as a detonator: it may more easily detonate high explosives. By the way other shaped cavity's will also produce such an effect only not as effective.
ezekiel
Frequent Poster
Posts: 110
From:
Registered: SEP 2000
posted March 08, 2001 03:27 PM
--------------------------------------------------------------------------------
Well...
no.
shaped charges work because of constructive interference between the initial and secondary shockwaves produced as the explosive decomposes.
The explosive itself has NO EFFECT apart from the shock wave production (now don't anybody go start trying to be clever saying that that could apply to every instance - coz in most situations the gas produced and abrasion are primary factors).
Any explosive - primary, secondary, tertiary - will work. As lnog as you can get it into the right shape you are fine.
High vdet xplsives are best as they tend to have the most forceful shockwaves.
the shape is more imporatant than the explosive in alot of cases. Different shapes achieve different tasks.
Tubes, cones, semi-spheres and hollow cylinders are most common.
Try and guess what is best for what.
Acetone peroxide makes an excellent charge if mixed with an oxidising agent and catalyst (NH4NO3, NaClO3, Al, FeO2 etc etc).
------------------
Ezekiel
'Things bad begun make strong themselves by ill'
PHILOU Zrealone
Frequent Poster
Posts: 479
From: Brussels,Belgium,Europe
Registered: SEP 2000
posted March 15, 2001 07:48 AM
--------------------------------------------------------------------------------
The diameter and the container of the detonator device (the det cord)and the quantity/m have an effect on the VOD.
So detonation in a 5mm diameter is not the same as in a 10mm (you have to be over the critical D to get a detonation).And a paper pipe is different than a plastic pipe itself different than a glass pipe or different than an iron steel pipe....
------------------
"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"
Jhonbus
Frequent Poster
Posts: 347
From:
Registered: SEP 2000
posted March 20, 2001 12:58 PM
--------------------------------------------------------------------------------
A furrow is a dent in the shape of a line, like in a ploughed field.
Frequent Poster
Posts: 91
From:
Registered: FEB 2001
posted February 27, 2001 04:08 PM
--------------------------------------------------------------------------------
I need an explosive made of NM with a high velocity of detonation when used in small quantities and with low confinement, for use in small tubes as det. cord or frame shaped charges. Because the velocity of detonation decreases when explosives are used in small quantities. I experienced that when I made a frame shaped charge out of polyethylene tube (diameter 12 mm). It produced only a dent in the mild steel object is was put on while the main charge shattered the steel. I concluded that the amount of H.E. and confinement where to low to reach full velocity of detonation. This happens with all H.E.: below certain amounts (diameters) the velocity decreases (PETN in primacord: 6200 m/s while maximum VoD is about 8500 m/s). But maybe only a dent was caused because of too little H.E. in the tube (150 g/m) and the VoD was high enough (but not maximum). Can someone tell me? Does primacord shatter mild steel or also just produce a dent because of too low amounts and not the decreased VoD?
[This message has been edited by outsider (edited March 01, 2001).]
simply RED
Frequent Poster
Posts: 238
From: HELL
Registered: OCT 2000
posted March 04, 2001 08:13 AM
--------------------------------------------------------------------------------
Try nitromethane thickened with some nirocellulose or better with nitroglycerine smokeless powder. This must work well in small quantities. Also some powdered PETN, RDX, ammonium perchlorate could be added to sensitize the mixture. The PETN cord detonates at high velocity(BG army old standard DS-A, DS-B, DS-V has diameter 5-6 mm and detonate at 6500-7200 m/s. This is high enough and should work with shaped charges. Shaped charges are really effective when diameter more than 20 cm. I've tried 10 mm shaped charge with molten acteone peroxide(chrystaline form- the temperature in the synthesis bath increased and it melt ) and steel tin cone at 45degrees, 1,5 diameters to the target. It penetrated 2,5 mm stell.
outsider
Frequent Poster
Posts: 91
From:
Registered: FEB 2001
posted March 04, 2001 12:14 PM
--------------------------------------------------------------------------------
Thanks for the reply. I was thinking about thickening NM with NC but I can't get hold of it. So I tried thickening it with PMMA (see other thread) but didn't succeed. Maybe I will go and just buy 1,000 ping pong balls and try to gel NM with them. I know the VoD is high of those gelled NM mixtures even in small diameter tubes. But maybe the NM explosive I used had a high enough VoD but was just a too small amount for shattering the mild steel. That's why a want to know the effect of det. cord: if it produces also just a dent in mild steel I know the explosive I used had a high enough VoD.
By the way, for shaped charges (which is something different than frame shaped charges!) the VoD must be very high, and I wonder if the AP can reach a VoD high enough for a shape charge. That's why they use secondary high explosives for shaped charges because of the high VoD, high power and low sensitivity. And AP has none of those properties. And melting AP seems to me a very dangerous thing to do, besides that it doesn't have an effect.
[This message has been edited by outsider (edited March 05, 2001).]
[This message has been edited by outsider (edited March 05, 2001).]
simply RED
Frequent Poster
Posts: 238
From: HELL
Registered: OCT 2000
posted March 06, 2001 04:52 PM
--------------------------------------------------------------------------------
You are absolutely right! The AP can't evaporate steel plate and is absolutely unusable 4 shaped charges...but some of the explosive force is concentrated in the explosive center.....
outsider
Frequent Poster
Posts: 91
From:
Registered: FEB 2001
posted March 07, 2001 06:24 AM
--------------------------------------------------------------------------------
Yes, that's absolutely true also. When an high explosive (secundary or primary) has a V-shaped cavity the shockwaves meet each other and collide. And the resulting shockwave is focused and stronger. And this will happen with AP also. But it doesn't make it a Shaped Charge in the sense that it will penetrate thick steel (or create a fluid metal jet of the metal liner from the cavity). But the stronger shockwave may increase the power of the AP charge as a detonator: it may more easily detonate high explosives. By the way other shaped cavity's will also produce such an effect only not as effective.
ezekiel
Frequent Poster
Posts: 110
From:
Registered: SEP 2000
posted March 08, 2001 03:27 PM
--------------------------------------------------------------------------------
Well...
no.
shaped charges work because of constructive interference between the initial and secondary shockwaves produced as the explosive decomposes.
The explosive itself has NO EFFECT apart from the shock wave production (now don't anybody go start trying to be clever saying that that could apply to every instance - coz in most situations the gas produced and abrasion are primary factors).
Any explosive - primary, secondary, tertiary - will work. As lnog as you can get it into the right shape you are fine.
High vdet xplsives are best as they tend to have the most forceful shockwaves.
the shape is more imporatant than the explosive in alot of cases. Different shapes achieve different tasks.
Tubes, cones, semi-spheres and hollow cylinders are most common.
Try and guess what is best for what.
Acetone peroxide makes an excellent charge if mixed with an oxidising agent and catalyst (NH4NO3, NaClO3, Al, FeO2 etc etc).
------------------
Ezekiel
'Things bad begun make strong themselves by ill'
PHILOU Zrealone
Frequent Poster
Posts: 479
From: Brussels,Belgium,Europe
Registered: SEP 2000
posted March 15, 2001 07:48 AM
--------------------------------------------------------------------------------
The diameter and the container of the detonator device (the det cord)and the quantity/m have an effect on the VOD.
So detonation in a 5mm diameter is not the same as in a 10mm (you have to be over the critical D to get a detonation).And a paper pipe is different than a plastic pipe itself different than a glass pipe or different than an iron steel pipe....
------------------
"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"
Jhonbus
Frequent Poster
Posts: 347
From:
Registered: SEP 2000
posted March 20, 2001 12:58 PM
--------------------------------------------------------------------------------
A furrow is a dent in the shape of a line, like in a ploughed field.