Sciencemadness Discussion Board

ETN Stability as primary explosive

trevor - 7-1-2014 at 13:11

Hi all,
I have read many posts on this forum about ETN.. Unfortunately, as he said quicksilver for this type of explosive "There is a very small amount of Research Efforts made ​​with ETN." In the article "Characterization and Analys of tetranitrate Esters" There are some tests.
Taking into consideration the preparation of 'ETN via h2so4/nh4no3 lab grade and food grade Erythritol recrystalized via ethanol 95% (food grade) (almost pure final product) and using an EBW 4Kv 2uF with a small copper wire directly in contact with the ETN for detonation. Could be considered a relatively safe detonator (not counting the risks related to 'HV)?
Treated as a primary explosive and ignoring the low melting point can be Compared with LA for impact and friction sensitivity test?
There are studies about incompatible with metals and other materials?
Someone have any links to articles covering the ETN?
Thanks a lot

Ral123 - 7-1-2014 at 14:55

ETN is being compared to NG in a book I've read. MHN doesn't have the low melting point issue IIRC and should be expected to have a very low critical diameter at all times.
ETN being left all summer in the sun in black can didn't result much of decomposition signs except it became a melt in the first hot day. One year at room temperature, it looks good as new. Btw my well washed NG became rotten in two weeks because of the light.

trevor - 13-1-2014 at 13:15

Thanks for reply Ral123.
The ETN storage stability is indiscutible. A batch of ETN four years old have no decomposition signs.
But a ETN used as primary explosive [without other primaries] can be considered relatively safe to handle??
There are incompatible material to avoid?
thanks.

Ral123 - 13-1-2014 at 13:21

May be we can call it relatively safe while still fresh, stored at no more then room temperature. Aluminium doesn't seem to be a problem, at least short term. Why would you care about all that, making reliable ETN only initiators is quite hard.

trevor - 13-1-2014 at 14:17

Thanks for reply.
With a EBW system loaded at 4Kv @ 2uF do the trick.. In this way the ETN only initiators are 100% reliable... and i care about etn stability.. :)

Hennig Brand - 13-1-2014 at 17:40

Do you think the 4kV, 2uF charged capacitor is safer than a little primary? Serious question, I am interested in your answer.

Metacelsus - 13-1-2014 at 17:47

I would think that it is. You can charge the capacitor just before use, and even do so remotely. Furthermore, you don't have to deal with primary synthesis and (possibly) storage.

Hennig Brand - 13-1-2014 at 17:54

I see your point, but from where I'm sitting 0.1-0.2g of primary accidently detonating is not usually lethal, and that cap easily could be. HV capacitors make me nervous, but like anything else (including primaries) they can be handled safely.

Ral123 - 13-1-2014 at 23:48

Quote: Originally posted by Hennig Brand  
Do you think the 4kV, 2uF charged capacitor is safer than a little primary? Serious question, I am interested in your answer.

You can have 5g ETN booster and micro straw detonator with 200mg primary and let's say 100-200mg basecharge. If you don't hold the straw near the material, you'll be fine.

trevor - 14-1-2014 at 04:14

Quote: Originally posted by Hennig Brand  
Do you think the 4kV, 2uF charged capacitor is safer than a little primary? Serious question, I am interested in your answer.

In my opinion yes.
Although High Voltage is dangerous, effects and dangers associated with it have been studied for hundred of years. A well engineered and isolated EBW has a stable and repeatable behavior over time without unpredictable things. I'd rather have to deal with an explosive insensitive that requires considerable energy to be initialized. Considering the fact that once the EBW is tested and isolated I can decide when I load it, while a sensitive primary remains always SENSITIVE.

[Edited on 14-1-2014 by trevor]

Fuse - 14-1-2014 at 05:06

I set off a lot of charges with EBW (1uF 4kV) and 0,3g ETN.
Very reliable system.

Ral123 - 14-1-2014 at 09:21

How is all that energy transferred from the capacitor to the wire and what is it made of? How is that thing triggered? I feel that the system can fail on many levels. Also what do you use to cover the wire when it's sitting in the ETN. For short term storage, switching to MHN can marginally increase reliability.

Fuse - 14-1-2014 at 23:58

I use 50mt of multicore wire (alpha wire), it's diameter is 5mm.
I trigger capacitor using a diy trigatron.
The detonator is made using shielded cable inserted into heat shrink tubing, inside there is ETN, the other end is closed with cap.
I've used that detonators after 2 years of storage and they never failed. Believe me.

Is possible to attach a photo here?

underground - 15-1-2014 at 04:22

Quote: Originally posted by Fuse  
I use 50mt of multicore wire (alpha wire), it's diameter is 5mm.
I trigger capacitor using a diy trigatron.
The detonator is made using shielded cable inserted into heat shrink tubing, inside there is ETN, the other end is closed with cap.
I've used that detonators after 2 years of storage and they never failed. Believe me.

Is possible to attach a photo here?



It sounds really cool!! photo and scheme would be awsome!!
Yes it is possible to attach a photo here...
Also is it possible to replace the capasitors with some batteries and transformers to transmorm the low voltage to high voltage, so in case of missfire you can try again ?

[Edited on 15-1-2014 by underground]

Metacelsus - 15-1-2014 at 08:19

No, it is not possible. The capacitors are necessary to provide a high current pulse. If there is a misfire, the wire is probably burned out (it just didn't initiate the explosive). Thus, trying again is pointless.

Ral123 - 15-1-2014 at 09:47

Quote: Originally posted by Fuse  
I use 50mt of multicore wire (alpha wire), it's diameter is 5mm.
I trigger capacitor using a diy trigatron.
The detonator is made using shielded cable inserted into heat shrink tubing, inside there is ETN, the other end is closed with cap.
I've used that detonators after 2 years of storage and they never failed. Believe me.

Is possible to attach a photo here?

How big is the capacitor bank and at what wire length can it operate?

trevor - 15-1-2014 at 14:44

To work properly, you must have a minimum of 4 microwave capacitors in series / parallel for reach the 4Kv @ 1uF.
With this configuration eyou can reach the 30 meters of cable with no loss of reliability.
It 'important to remember that the member "fuse" was essential to achieve these performance.

Fuse - 16-1-2014 at 00:45

@underground
I've attached photos of EBW ETN cap. It is complete hermetic.



01.JPG - 87kB 02.JPG - 85kB 03.JPG - 68kB 04.JPG - 81kB 05.JPG - 78kB 06.JPG - 59kB 07.JPG - 99kB 08.JPG - 72kB 09.JPG - 135kB

underground - 16-1-2014 at 01:27

Fuse thanks a lot!!! i will try it!! Just awsome!!Some info more please, does the 2 wires are connected together with something at the No1 photo, or it is just a cut wire ? Also can you tell us the capacitors you use for detonation and how you trigger them in more details ? :)


EDIT:
I was thinking for that also, but i do not know if it is is possible. As i said before, use some batteries and transformers, but now to charge the high V. capacitors for multiple detonations, without charging and discharging the capacitors all the time, and do it remotely with a radio RC circuit and a relay!!

[Edited on 16-1-2014 by underground]

Krakermanworks - 16-1-2014 at 01:49

Hi, I've heard etn can be detonated reliably with just tinfoil/aluminium wrapper and rcandy (60:40 mix of kno3:sugar) has anyone had success with this method as the only primers I'm available to are tatp/hmtd which I'd rather not handle, thanks.


[Edited on 16-1-2014 by Krakermanworks]

underground - 16-1-2014 at 02:03

Quote: Originally posted by Krakermanworks  
Hi, I've heard etn can be detonated reliably with just tinfoil/aluminium wrapper and rcandy (60:40 mix of kno3:sugar) has anyone had success with this method as the only primers I'm available to are tatp/hmtd which I'd rather not handle, thanks.


[Edited on 16-1-2014 by Krakermanworks]



It looks that it works, check that video
http://www.youtube.com/watch?v=XVmMedPfKn4

Fuse - 16-1-2014 at 02:21

@underground

In the #1 image you can see the violet cable cut, inside it there are 2 wires: blue and white.
You have to cut about 5mm of the thin copper that you can see on the left part of image and solder between blue and white wire.

Check my videos on youtube, search "Exploding bridgewire detonator" and "direct detonation of ETN"
(There I've different name, it is "freepatentsonline")

underground - 16-1-2014 at 02:46

Thanks!!

Ral123 - 16-1-2014 at 08:57

Set off picric acid with that, and I'll expect it to be reliable with ETN/MHN. What's the purpose of the tiny capacitors?

Fuse - 16-1-2014 at 09:45

The purpose of tiny capacitors is simply to stop the pipe :)
With the cap I set off ammonium nitrate based mixtures.
AN/Al, AN/Al/Oil, AN/Al/ethylene glycol, and other with charcoal, sugar and sulphur..
All mixes detonated.

Ral123 - 16-1-2014 at 11:26

Quote: Originally posted by Fuse  
The purpose of tiny capacitors is simply to stop the pipe :)

Some man just want to watch the world burn.
Do you realise what a terrible inefficiency that is? I file down every last part of the millimetre of the wall thickness and bottom thickness and do all I can to add "inertial" confinement on the top.
Have you tried to initiate AN mixtures without Al/other sensitizer with that thing? I've seen quite and expensive charge fail, partially due to the detonator being sealed with epoxy at the bottom.

Krakermanworks - 16-1-2014 at 16:16

Quote: Originally posted by underground  
Quote: Originally posted by Krakermanworks  
Hi, I've heard etn can be detonated reliably with just tinfoil/aluminium wrapper and rcandy (60:40 mix of kno3:sugar) has anyone had success with this method as the only primers I'm available to are tatp/hmtd which I'd rather not handle, thanks.


[Edited on 16-1-2014 by Krakermanworks]



It looks that it works, check that video
http://www.youtube.com/watch?v=XVmMedPfKn4


Thanks looks a bit 'hit and miss' though ill try nitrate/al/sulfur as that will give of more heat than nitrate/sugar.

Fuse - 17-1-2014 at 00:02

@Ral123
The bottom is not sealed with epoxy.
The Heat-shrink tubing is heat up until she tighten to the capacitor.
I never tested AN without sensitizers.

Antiswat - 17-1-2014 at 03:15

http://www.youtube.com/watch?v=eGW_lKX3OV4

ETN set off with fuse, supposing its 2mm visco 1cm/s standard (1.8mm??)

when this is possible, then overkill as in rocket candy cast into thin plastic tubes should be quite reliable as long as fuse to rocket candy is ensured not to cause problems

not to mention i suggest that thinner layers of ETN packed in al foil is better compared to having one large blob of ETN, might be wrong..?

one thing tho: if using rocket candy you might want to add 0.5g ETN below the initiator, and not get the main charge above the initiator as this might cause problems with the rocket candy burning at approx 1500*C, considering some secondaries are quite flammable (KClO3 / sugar for instance, if anybody would ever attempt to initiate that?)

overkill is reliability

Daffodile - 11-3-2016 at 17:08

Okay so to see how stable ETN is, I melted some, poured it on a flat block, and left it outside in the sun for a month (sheltered from rain). About a quarter was uneffected, half turned yellow, and another quarter turned orange and crumbly. Some of the orange/ yellow stuff was actually really sensitive, and detonated in little pops/ snaps when I touched it with a match. The whiteish stuff was pretty normal and didnt seem effected. The changes are apparently from NOx related decomposition.

XeonTheMGPony - 13-3-2016 at 10:59

What is the longest etn been stored for in different forms?

Daffodile - 13-3-2016 at 11:17

Quote: Originally posted by XeonTheMGPony  
What is the longest etn been stored for in different forms?


Forms? I think its more about different levels of decomposition

XeonTheMGPony - 13-3-2016 at 11:31

Forms as in cast, plasticized, pressed, compounded.

Herr Haber - 13-3-2016 at 19:30

Quote: Originally posted by Daffodile  
Okay so to see how stable ETN is, I melted some, poured it on a flat block, and left it outside in the sun for a month (sheltered from rain). About a quarter was uneffected, half turned yellow, and another quarter turned orange and crumbly. Some of the orange/ yellow stuff was actually really sensitive, and detonated in little pops/ snaps when I touched it with a match. The whiteish stuff was pretty normal and didnt seem effected. The changes are apparently from NOx related decomposition.


Couldnt the colors be juste related to how the ETN recrystallized?
I've been using hemolisis tubes as containers (intent: blasting rock) and the procedure was:

- Put ETN in
- Press ETN
- Put in boiling water.
- Repeat until desired load was attained.

I noticed at the beginning some recrystallized parts were clear, some were some kind of pink and maybe a darker color that I wouldnt go as far as to call orange in the upper part of the tube.

Since I had to repeat the process to add more ETN and reach the desired load I noticed the colors and Crystal shapes changed quite a bit (as the cast ETN was melted again).
That last part might be because after all the ETN was molten I tried once to leave it in the hot water until it was cold (which seemed to give large crystals as one would expect).
Remove from the hot water and let it cool naturally and finally remove from the hot water and put it in the fridge.

In any case, I've left enough space to add some powdered ETN to ensure detonation. Holes were made through the caps and straws with one end closed were hot glued in place to accomodate the detonators.

The idea of rapid cooling occured to me because it seems that for many explosives, smaller crystals are easier to initiate. Perhaps I am mistaken on that point.

Anyway, now the hard part will be to find a rock and drill 15mm wide holes in it for my tests.

ETN Stability

Brightthermite - 31-5-2020 at 11:55

Hate to bring this back up from the depths but I could not find a thread just on ETN storage stability and I wanted to report some findings.

I synthesized 14 grams of ETN using sulfuric acid ammonium nitrate method. 7 grams of this was well washed but not recrystallized. It was then placed in an air tight pill bottle for 20 days. Opening that bottle (safely) thick orange brown gas was released, I assume this is from nitric acid left over destroying the ETN. Only 2 ish grams of material was left. Interesting enough the material that was left was all completely white and did not appear to have sublimed any. It performed well as if it was new. This being said, it seems un-crystallized ETN even if well washed is not able to be stored.

XeonTheMGPony - 2-6-2020 at 05:15

And water is wet!

That is sort of a well understood fundamental, very un wise and dangerous to store ANY compound made via mixed acids to not be well washed and recrystallized.

Follow Up

Brightthermite - 2-11-2021 at 12:18

ETN made using AN/SA, over 1.5 years old, both from the same run. The one that is showing signs of decomposing was actually recryst twice using acetone. I remember reading somewhere on here that if sodium bicarb is left in it can cause your ETN to decompose, I wonder if that is what's going on here since the gas it not really a dark orange. Two recyst would have the ETN in contact with twice as much bicarb so..

And as XeonTheMGPony claims above, what actually makes decomposing explosives dangerous? In the case of ETN all I have seen it do is destroy the product, make it under perform, and harder to set off. Are there some mixed acid made explosives that become more sensitive with acid left in the structure?

IMG_1758.jpg - 3MBIMG_1757.jpg - 2.6MB

Bert - 2-11-2021 at 16:58

Quote: Originally posted by Brightthermite  
what actually makes decomposing explosives dangerous? In the case of ETN all I have seen it do is destroy the product, make it under perform, and harder to set off. Are there some mixed acid made explosives that become more sensitive with acid left in the structure?


Yes, quite some. Self catalyzing decomposition processes leading to thermal runaways and kaboom.

You might want to research the history of the beginnings of modern explosives, the origins of scavengers for NOX such as urea, diphenhydramine or centralizes being added to smokeless propellants, carbonates being added to dynamite "dope" and such.

That history includes the formation of several craters where explosives magazines, arsenals or manufacturing plants once stood. The odd USA battleship blowing up. Austria banning all production of smokeless powder for a few decades. Subtle hints at what large quantities of acid tainted, decomposing high explosives might do.

Download Tenney Davis' Chemistry of Powder and Explosives from the SM library and do some research.

http://library.sciencemadness.org/library/books/the_chemistr...

Phokin Naoum Nitroglycerin and Nitroglycerin Explosives also has basic information on neutralization, degradation and stabilizers.

http://library.sciencemadness.org/library/books/nitroglyceri...



[Edited on 11-4-2021 by Bert]

XeonTheMGPony - 3-11-2021 at 03:51

How clean was your Acetone? Any thing I use for my production is cleaned and distilled, I hate variables so I kill off as many as I can so I have a known state to go back to if things go wrong, Acetone is very good at striping oils and such, so if you didn't buy lab grade (I sure don't) I can tell you it had contaminants in it!

Next as Bert mentioned, very few things escape the notice of entropy, all ways use a scavenger. I use 3% by weight of urea for ETN.


katyushaslab - 3-11-2021 at 04:53

As Bert mentioned, decomposition can be self catalysing.

A few years ago I had a bunch of commercial "flash cotton" (nitrocellulose) stored damp in a cupboard, ignored for a few months. When I eventually went to check on it, a good amount of it had turned into a kind of goop, there was a strong stench of NOx from it, etc.

I figure a small amount of it degraded, and started taking the rest with it - as more NOx is released, more acid can form, accellerating the breakdown of the material. If this process generates sufficient heat... bad things happen.

Brightthermite - 3-11-2021 at 18:00

Thats interesting, so the danger lies in the generation of heat. Not the acid some how making the explosives more sensitive.

My acetone is from the hardware store, so as clean as that is. Ill make a habit of distilling it from now on. Im also interested in using a scavenger and doing some more 1 year plus testing.

Does anyone have any methods for telling if there ETN is pure and acid free. I have in my notes that the sample that is decomposing appeared to be completely pure, it obviously is not. It frustrates me I was not able to tell. Maybe my recyst method is not great?

Dissolve in acetone, dump in water with about 5 percent bi carb.

Microtek - 4-11-2021 at 02:57

I would suggest you do this instead for recrystallizing:

- Dissolve in acetone

- Add solid bicarb or possibly aqueous ammonia to the acetone and stir for at least 10 min.

- Crash in ca. 5% aqueous urea soln.

Fulmen - 4-11-2021 at 11:32

@Brightthermite: To be precise it's a runaway reaction driven by both heat and NOx. Short story:
Certain nitrate esters (like cellulose nitrate) are inherently unstable, very slowly decomposing to water, CO2 and NOx plus heat. The initial rate in pure samples is completely negligible, however heat and NOx promotes further decomposition (evolving more heat and NOx). In small, properly stored samples the heat and NOx will diffuse out too fast to do real harm. But in large amounts (and sealed containers like ammunition) the process can reach runaway conditions. And even if it doesn't self ignite it can cause erratic performance in munitions.

I can't recall any cases where sensitivity was greatly affected, but you should always assume the worse.

Brightthermite - 4-11-2021 at 12:21

@Fulmen thank you clearing up that it doesn't necessarily make the material more sensitive. I could see how a run away producing heat in a sealed container with fully crystalized explosives could be dangerous.

@Microtek I believe ill try the ammonia, the problem with bicarb in acetone is the solubility is very low. So I think this makes it hard to get the bicarb in contact with the acid. Is there a specific pH you go for when using ammonia? Is the solution of urea how you introduce the scavenger like mentioned above?

Herr Haber - 4-11-2021 at 13:43

Take advantage of the water left after filtering. Dont dry unless you really want to know your yield at that stage. You are getting it wet again soon enough.

Microtek - 4-11-2021 at 13:58

You should only aim for pH 7-7.5 otherwise you risk hydrolysis or other reactions (if you go to higher pH). The intention with the urea is to include just a very small amount in the crystals to scavenge small amounts of NOx (in order to break the autocatalytic feed back loop).

Brightthermite - 4-11-2021 at 17:58

@Herr Haber are you suggesting not to dry in hopes that water will help dissolve the bicarb?

I hope all this helps me get consistently more stable products. I have some samples that are 2 plus years old and showing no signs of decomposition and others that are a half a year and smell of acid. Very frustrating.

Also pure ETN dissolved in any solvent should have a pH of around 7 correct? looking for more way to test purity besides smell.