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Author: Subject: Safety of ball milling commercial smokeless powder.
Katie
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[*] posted on 15-4-2020 at 12:03
Safety of ball milling commercial smokeless powder.


Would it be safe to run smokeless powder in a ball mill with lead media and a painted steel cylinder? I have a very fast burning double base (nitroglycerin and nitrocellulose) pistol powder. I would of course treat the ball mill as an explosive and start/stop the mill from at least 100 yards away and behind cover, but if it’s guaranteed or likely to explode, I’d rather not destroy my ball mill! I’m doing this to see if finely milled double base powder will detonate and how it compares to its active ingredients (nitroglycerin and nitrocellulose). If it works, I’d also like to experiment to see if the milled powder can act as a cheap, legal, easy to make, and widely available initiator/primer.

I’m new to the forum, so I’ll mention that I have some explosives safety training and lab experience, and I’m interested in the chemistry and engineering of energetic materials. I already went through my reckless “kewl bombz” phase when I was a kid!
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hyfalcon
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[*] posted on 16-4-2020 at 00:38


spark-less ceramic milling media. Lead media contaminates your product.
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SWIM
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[*] posted on 16-4-2020 at 09:53


Comes in different shapes and sizes, but I like the stuff that looks like marshmallows. (yum)

tumbling media.jpg - 156kB

It'll probably take that paint off your tumbler though. porcelain's pretty tough.

Can that stuff be ground wet?
Put it through something that functions like a quern, but mechanical?

Ha Ha, I got to use quern in a sentence.
Don't do that every day.




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[*] posted on 17-4-2020 at 12:41


I'd be a bit scared to ball mill NC in any way. Impact and friction sensitivity of it alone are high enough...add double base smokeless powder with NG? I'd advise against it, tbh. Just my two cents!
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[*] posted on 18-4-2020 at 00:41


@hyfalcon: Are you talking from experience or just guessing? Spark-free does not mean ignition-free, hit something hard enough and it will go off. And ceramics are hard...

Like most people here I don't know, so all I can do is speculate.
First off: NC is fairly insensitive to ignition. If we can ball mill black powder dry, why not NC? The problem is that NC is also very strong and flexible, quite undesirable properties for grinding. So ball milling with lead is probably going to be slow, and with heavy contamination. Brass or copper media (also safe for BP) might work better. Ceramics would also work better, but I don't know if it's hardness can cause ignition.
A quern/grinder would probably be more efficient, but I don't know if it would be safe. The design should prevent any contact between grinding surfaces at least.

Wet processing sounds like the obvious route for safety. As long as it's wet you can probably do whatever you like to it with no risk. The NC won't be affected, but I 'm not sure if the NG can be washed out somehow. I don't think so, but you should at least consider the possibility and handle the water accordingly.




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MadHatter
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[*] posted on 18-4-2020 at 06:34
Steel drum


This would make me nervous. Formerly, smokeless
powder was listed as hazmats 1.3 and 1.4. It's now
listed as 4.1. When I had my CDL w/hazmat, transporting
any class 1s(explosives 1.1 - 1.6) required them
to be in a non-metallic or non-ferrous lined area
for transport. I don't know what the problem with
iron is. Just a cautionary note. Paint scraping off the
cylinder would expose the smokeless powder to the
steel.

Katie, check out the burn speeds for smokeless powders
as of NOVEMBER 2019. Norma R1 is the fastest and may
be an adequate solution without grinding.

Attachment: burn-rate-color.pdf (418kB)
This file has been downloaded 245 times


[Edited on 2020/4/18 by MadHatter]




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[*] posted on 18-4-2020 at 07:00


Quote: Originally posted by Fulmen  
@hyfalcon: Are you talking from experience or just guessing? Spark-free does not mean ignition-free, hit something hard enough and it will go off. And ceramics are hard...

Like most people here I don't know, so all I can do is speculate.
First off: NC is fairly insensitive to ignition. If we can ball mill black powder dry, why not NC? The problem is that NC is also very strong and flexible, quite undesirable properties for grinding. So ball milling with lead is probably going to be slow, and with heavy contamination. Brass or copper media (also safe for BP) might work better. Ceramics would also work better, but I don't know if it's hardness can cause ignition.
A quern/grinder would probably be more efficient, but I don't know if it would be safe. The design should prevent any contact between grinding surfaces at least.

Wet processing sounds like the obvious route for safety. As long as it's wet you can probably do whatever you like to it with no risk. The NC won't be affected, but I 'm not sure if the NG can be washed out somehow. I don't think so, but you should at least consider the possibility and handle the water accordingly.


Having done black powder in a homemade cylindrical ball mill made of pvc pipe, and milling for hours at a time. I've had no issues using ceramic media. If you have it running the right speed, it will grind. It shouldn't be running so fast as to run up the side of the wall and drop from a height. Fluidized bed effect is what you're shooting for.
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[*] posted on 18-4-2020 at 15:52


Quote: Originally posted by Katie  
Would it be safe to run smokeless powder in a ball mill with lead media and a painted steel cylinder? I have a very fast burning double base (nitroglycerin and nitrocellulose) pistol powder. I would of course treat the ball mill as an explosive and start/stop the mill from at least 100 yards away and behind cover, but if it’s guaranteed or likely to explode, I’d rather not destroy my ball mill! I’m doing this to see if finely milled double base powder will detonate and how it compares to its active ingredients (nitroglycerin and nitrocellulose). If it works, I’d also like to experiment to see if the milled powder can act as a cheap, legal, easy to make, and widely available initiator/primer.

I’m new to the forum, so I’ll mention that I have some explosives safety training and lab experience, and I’m interested in the chemistry and engineering of energetic materials. I already went through my reckless “kewl bombz” phase when I was a kid!


Again. I am confused as to what your goal is. Many have detonated smokeless powder with enough confinement. But it is not cheap.

How would it be an initiator? AutoStem is AN mixed with SP, FYI.

AN or AP explosives seem to make more sense.
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[*] posted on 21-4-2020 at 17:26


Quote: Originally posted by MineMan  
Quote: Originally posted by Katie  
Would it be safe to run smokeless powder in a ball mill with lead media and a painted steel cylinder? I have a very fast burning double base (nitroglycerin and nitrocellulose) pistol powder. I would of course treat the ball mill as an explosive and start/stop the mill from at least 100 yards away and behind cover, but if it’s guaranteed or likely to explode, I’d rather not destroy my ball mill! I’m doing this to see if finely milled double base powder will detonate and how it compares to its active ingredients (nitroglycerin and nitrocellulose). If it works, I’d also like to experiment to see if the milled powder can act as a cheap, legal, easy to make, and widely available initiator/primer.

I’m new to the forum, so I’ll mention that I have some explosives safety training and lab experience, and I’m interested in the chemistry and engineering of energetic materials. I already went through my reckless “kewl bombz” phase when I was a kid!


Again. I am confused as to what your goal is. Many have detonated smokeless powder with enough confinement. But it is not cheap.

How would it be an initiator? AutoStem is AN mixed with SP, FYI.

AN or AP explosives seem to make more sense.


Smokeless powders are produced in large particles and have additives designed to slow their burn rate. Double base contains nitrocellulose and nitroglycerin, so my goal is to see how finely milled smokeless powder compares to its active ingredients, as well as black powder and flash powder. I’d also like to experiment with possible extraction techniques to extract NG and NC from smokeless powder.

I’d love to make some NG to compare it to more accurately but I don’t have a lab vacuum to distill white fuming nitric acid.
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[*] posted on 23-4-2020 at 11:39


Quote: Originally posted by Fulmen  
@hyfalcon: Are you talking from experience or just guessing? Spark-free does not mean ignition-free, hit something hard enough and it will go off. And ceramics are hard...

Like most people here I don't know, so all I can do is speculate.
First off: NC is fairly insensitive to ignition. If we can ball mill black powder dry, why not NC? The problem is that NC is also very strong and flexible, quite undesirable properties for grinding. So ball milling with lead is probably going to be slow, and with heavy contamination. Brass or copper media (also safe for BP) might work better. Ceramics would also work better, but I don't know if it's hardness can cause ignition.
A quern/grinder would probably be more efficient, but I don't know if it would be safe. The design should prevent any contact between grinding surfaces at least.

Wet processing sounds like the obvious route for safety. As long as it's wet you can probably do whatever you like to it with no risk. The NC won't be affected, but I 'm not sure if the NG can be washed out somehow. I don't think so, but you should at least consider the possibility and handle the water accordingly.


Insofar as you're talking about wet milling, then I'd likely have no qualms. But the idea of NC being fairly insensitive to ignition I very much disagree with. It may be insensitive to ignition relative to a lot of the high explosives people mess with on here, but make no mistake, NC IS very much impact, friction, and ESD sensitive. Not to mention the inherent instability as it decomposes over time without stabilizer.
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[*] posted on 23-4-2020 at 13:09


Well, any energetic compound will display some level of sensitivity to initiation. That being said, NC is pretty darn insensitive compared to most high explosives. I've played with "artillery powder", hollow sticks of NC appr. 6-8mm in diameter and 20cm long. You can hit those with a hammer or tape a No8 blasting cap to the end without setting it off.

Also, if you read my post a little more carefully you'll see that I was comparing it to BP, which is a helluva lot more sensitive than NC to pretty much anything. And that is routinely ball-milled without incident.

You are right in that NC is inherently unstable (even with stabilizers it will eventually degrade), but here we're discussing commercially produced NC powders that should be as stable as can be.




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[*] posted on 23-4-2020 at 20:24


Quote: Originally posted by Fulmen  
Well, any energetic compound will display some level of sensitivity to initiation. That being said, NC is pretty darn insensitive compared to most high explosives. I've played with "artillery powder", hollow sticks of NC appr. 6-8mm in diameter and 20cm long. You can hit those with a hammer or tape a No8 blasting cap to the end without setting it off.

Also, if you read my post a little more carefully you'll see that I was comparing it to BP, which is a helluva lot more sensitive than NC to pretty much anything. And that is routinely ball-milled without incident.

You are right in that NC is inherently unstable (even with stabilizers it will eventually degrade), but here we're discussing commercially produced NC powders that should be as stable as can be.


I too would have to disagree with the sensitivity of NC. You can hit a pile of gunpowder on a steel anvil as much as you want-nothing. If you try the same with a piece of flash paper or flash cotton you get a flash and a loud bang.
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[*] posted on 25-4-2020 at 13:27


To be fair, the term "NC" is too inaccurate for this discussion. My apologies for that. My arguments have been based on "gelatinized NC-based gunpowder",raw or untreated NC is another animal indeed.



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[*] posted on 25-4-2020 at 20:49


I still struggle with the why of this...
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[*] posted on 26-4-2020 at 00:50


What's so hard to get? He wants to test how milling changes it's properties, I think that's a completely reasonable experiment. Unless you KNOW what the result is going to be, I don't see why you have to be so negative.



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[*] posted on 26-4-2020 at 18:48


Quote: Originally posted by MineMan  
I still struggle with the why of this...


I’m interested in this for two reasons. First, curiosity. I’d simply like to know to what degree smokeless powder additives reduce the reaction rate of NC/NG detonation/deflagration because I have an interest in energetic materials and chemical engineering. Two, I think it’s worth doing because if a finely milled smokeless powder is indeed somewhat comparable to pure or relatively pure NC/NG, it would be an easy and convenient OTC source of energetic material for those times you need an energetic for some kind of task and don’t have time to synthesize something more powerful. I’m hoping to at least see more power than black and flash powders.
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[*] posted on 28-4-2020 at 08:54


Quote: Originally posted by Fulmen  
Well, any energetic compound will display some level of sensitivity to initiation. That being said, NC is pretty darn insensitive compared to most high explosives. I've played with "artillery powder", hollow sticks of NC appr. 6-8mm in diameter and 20cm long. You can hit those with a hammer or tape a No8 blasting cap to the end without setting it off.

Also, if you read my post a little more carefully you'll see that I was comparing it to BP, which is a helluva lot more sensitive than NC to pretty much anything. And that is routinely ball-milled without incident.

You are right in that NC is inherently unstable (even with stabilizers it will eventually degrade), but here we're discussing commercially produced NC powders that should be as stable as can be.


I hope I'm not being considered hostile. But smokeless powder is typically using higher N-content NC (13%+) with NG. I work with NC a lot, both lacquer grade and propellant grade and the sensitivity difference once you hit the 13%+ is night and day. Ball milling wet definitely mitigates the risk, but if you mill it dry I give it a pretty dang good chance of going off.

That being said, @Katie, the fibrous nature of NC seems to lend itself to being more energetic. Lacquer grade NC is very powdery, whereas propellant grade NC is typically very fibrous like wood pulp. By milling the smokeless powder, I would predict you will see an overall decrease in performance. If you're set on testing this out, I highly recommend wet with water or ethanol. Dry is just a chance I wouldn't risk.
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