Sciencemadness Discussion Board

Large rifles primer powder ignited Urea Nitrate + Al

aldofad - 7-9-2013 at 03:40

Success test completed!
I'll make a video next time to prove results
Extracted 2 grams of powder from large rifle primers, used to ignite 50 grams of Urea Nitrate.
Explosion happened 90 cm underground. No noise due to obvious absence of high frequency sounds cutted out by above earth. Low frequency sound udible and very funny without provoking foreign disturb.
Primer powder initiated electrically using a 30 m long wire, a 9V battery (but 3V is enough) and 1 cm 500W alogen resistance of 1.4 Ohms as heater for primer's powder.
Great safety due to primer powder, quckly scraped wearing goggles, much better than making AP.
Device was confined in a PVC tube.
Urea Nitrate was NOT purified with water to remove excess of Nitric Acid. Urea Nitrate was formed when adding Nitric Acid, then putted in ventilated oven 20 min to remove water.
10% of finely powdered aluminium was added to Urea Nitrate
I was always grounded electrically during all operations involving the initiator
The 2g of primer's powder may probably be reduced

Cheers!

Dany - 7-9-2013 at 04:20

how you are sure that the urea nitrate detonate? maybe the urea nitrate is scattered due to the explosion of the primer powder or urea nitrate partially detonate.
if you can put a steel (or aluminium) witness plate under the PVC pipe (pipe perpendicular to witness plate), so when the urea nitrate detonate it will leave a deep dent or a clear hole depending on the thickness of the plate. Judging only from sound is not a scientific way to prove a full detonation of an explosive charge.

Dany.

aldofad - 7-9-2013 at 04:32

Quote: Originally posted by Dany  
how you are sure that the urea nitrate detonate? maybe the urea nitrate is scattered due to the explosion of the primer powder or urea nitrate partially detonate.
if you can put a steel (or aluminium) witness plate under the PVC pipe (pipe perpendicular to witness plate), so when the urea nitrate detonate it will leave a deep dent or a clear hole depending on the thickness of the plate. Judging only from sound is not a scientific way to prove a full detonation of an explosive charge.

Dany.

Makes sense. I'm sure Urea Nitrate fully detonated. I'll provide evidence next time with a video

Cheers

[Edited on 7-9-2013 by aldofad]

Motherload - 7-9-2013 at 06:34

It is VERY likely that the primer ignited the mix .... As in Fuel (Al) Oxidiser (UN) mix and caused a deflageration.
Magnum Rifle Primer powder doesn't even detonate ETN. Not enough Styphanate an Azide in them.

Caps primers powder DOES NOT ingnites Urea Nitrate

aldofad - 9-9-2013 at 15:42

I've repeated the test I did initially paying more attention to any uncombusted powder, I must now admit that the loud boom was only provoked by the 2g confined initiator composed by primers caps powder and NO Urea Nitrate was ignited.
All your considerations were undoubtedly correct!

I'm preparing lead azide...

Dany - 9-9-2013 at 17:07

I recommend you to switch to steel pipe instead of PVC. Steel pipe tend to decrease the critical diameter of explosive materials (if all other material properties are kept constant). A hard confinement, will delay the arrival of rarefaction wave (Taylor wave) to the charge axis which lead to detonation wave being weakened. be careful of high velocity fragments from steel pipe. Ordinary steel pipe tend undergo what we call natural fragmentation which yield small and big dangerous piece of fragment. Be aware of lead azide, use dextrin (or polyvinyl alcohol) when precipitating lead azide. undextrinated lead azide solution tend to explode spontaneously on standing, avoid large crystal formation and perform the synthesis at small scale(<1 gr). use the plate dent test as a verification of full detonation.

Dany.

[Edited on 10-9-2013 by Dany]

Ral123 - 9-9-2013 at 22:28

Quote: Originally posted by Dany  
A hard confinement, will delay the arrival of rarefaction wave (Taylor wave) to the charge axis which lead to detonation wave being weakened.
[Edited on 10-9-2013 by Dany]

I don't get it, how can the hard confinement be a bad thing? You also said the speed of sound in the metal should be slower then the speed of the energetic material.

Dany - 10-9-2013 at 00:34

Ral123,

On the contrary i'm saying that the hard confining is a good material for explosive charge because i't will delay the arrival of Taylor wave at the charge axis. once the Taylor wave reach the axis center i't will made the detonation wave weaker. Suppose you have a cylinder of explosive, and you detonated at one end. as the reaction product begin to expand (so does the confinement material) a rarefaction wave is created that propagate to the charge center. a hard material will resist better the expansion (by inertia) and thus delay the formation of rarefaction wave and their time of arrival to charge axis. experiment shows, that increasing the thickness of the material provide better confinement but after a certain point (a certain thickness) no effect is observed (if for example we found that a 1 inch thickness of steel is the limiting or best confining thickness it is useless to increase the thickness of the tube beyond this value)

When i talk about sound speed, the subject was on liquid explosive that undergo low velocity detonation (LVD) and high detonation velocity (HVD). this is a special case of explosive materials in a special situation (explosive being near critical diameter or initiated with a weak detonator). yes in the case of LVD and HVD, experiement shows that unstable LVD can be created when the sound speed in the confinement material is lower than the sound speed in the explosive material whereas stable LVD is established when sound speed is greater in confining material because a precursor wave can be sent in the confinement leading to the creation of cavities in the liquid explosive which play the role of hot spot for explosive ignition. see http://www.sciencemadness.org/talk/viewthread.php?tid=20280&...

Dany.




[Edited on 10-9-2013 by Dany]

Bert - 10-9-2013 at 10:45

Quote: Originally posted by aldofad  

Extracted 2 grams of powder from large rifle primers, used to ignite 50 grams of Urea Nitrate.


Primers are an IGNITION product. They're designed to safely and reliably ignite (NOT detonate) propellants, some of which are, indeed, cap sensitive high explosives (fire a blasting cap in a bottle of Bullseye or similar powder if you doubt that).

So you disassembled enough primers to provide 2 grams of mixture? TWICE?! That would be well in excess of 100 primers AFAIK.

How many of them exploded during that process?

Farnsworth - 16-10-2013 at 23:15

By searching MSDS I found some months ago that some of CCIs rifle primers contain almost nothing but lead styphnate and some small amounts of barium nitrate. There's also a patent cited on here by me where larger amounts of styphnate (about 2 grams, coincidentally) in good confinement will make a nice DDT and initiate other explosives.

Not the best around, but pretty groovy for an OTC material.

doktor x - 16-10-2013 at 23:40

please dont dry urea nitrate in room or with ventilator in room be careful with tocsic nitric oxides from not washed urea nitrate,i have bad expiriences wiht this