100% on this. Once when the boss was out of town, a few of us gathered the ingredients for gun powder together with the intent on making it for kicks. We had all the reagent bottles gathered, then one by one each of us recalled the various disasters we’d had in the lab and changed our mind. Like you, solkoe, the problem was with grinding the ingredients together. Having had a perchlorate go off in my hand, I really didn’t want any part of grinding an explosive. We did get a good thermite reaction started, but that doesn’t go boom unexpectedly, so we had it safely contained in a hood.
Crap! Even we would have started out with less than a gram. I hope you were wearing diapers.
I guess after 20 years, I just wanted to try something a little different. I feel very silly for not having calculated the risks a little better and very lucky that the young man did not get any burns.
I’m still interested and may continue this type of experiment by grinding the ingredients separately and lighting them in a paper towel as I did in the first few attempts. The students love it. If anything, this mishap gave them a healthy respect for explosives.
Still a very bad idea. As mentioned upthread, the burn rate is regulated by controlling the exposed surface area of the grain; finer grain sizes give faster and often uncontrolled deflagration. For commercial production of black powder and smokeless powders, the constituents are ground to a specific size, combined together in a mix bowl (which often looks like a small concrete mixer or industrial food mixer) in an alcohol slurry, rolled out onto a table and flattened to a consistent thickness, and then broken up by some non-sparking, low-impact process or pushed through a sieve to get a specific granular size. Mixing up a back of dry powder by hand has the potential for premature detonation through electrostatic discharge and incomplete mixing of components which may make some of the powder burn slowly or not at all and then another area burn energetically. And it should go without saying that you shouldn’t get anywhere near double-base smokeless powders without knowing exactly what you are doing.
Again, if you don’t have prior experience with pyrotechnics you should be very, very cautious about experimenting with it, and you definitely shouldn’t be supervising students messing with it until you have enough experience to know what is dangerous and what isn’t. If you elect to go ahead with this anyway, make sure you are wearing polycarbonate glasses or (preferably) face shield, cotton gloves and clothing, and no hair gel or other flammable products.
As the powder monkey who taught me how to handle explosives and set demolition charges used to say, “There are three things you need to know about handling explosives…” [Holds up thumb, forefinger, and stump of ring finger]
Hi. I read that OP, and can tell you solkoe, that you set yourself up for disaster. Gunpowder is “shelf stable” and yes, you do need a source of ignition, however you provided that ignition through the shock and friction of grinding it in a mortar and pestle-like situation. Granted, I wouldn’t do the same with C-4, but I know what I can cut with a knife and what I cannot. . .
Black powder is milled in factories, in a manner muldoonthief mentioned–usually a slurry. Other methods include grinding seperate components and then mixing later. Black powder can be wet down and rinsed, but when the water dries out, the residue is still black powder and is still dangerous. I take precautions when opening things just in case there’s a friction point where some residue may be (read unintended “BOOM!”).
Please do not take this as snark, but a friendly suggestion: You may be an experienced teacher, and yes, you need to have fun too, but have fun like this at your house and get some training with it before you expose other folks. 'Specially high school kids who now think it may be cool to replicate at home, who’ll end up getting hurt, or at the least set the dog aflame (which is always an awkward dinner table conversation). If you want to continue doing this in class, keep in mind you run the risk of “fragging” students. I’m uncomfortable with this thought. . .
Seriously man, black powder is relatively safe, but it ain’t that safe. The other comment I had have already been mentioned in this thread, but I will reiterate, you may want to teach about oxidizers and fuels in class, but can’t you come up with something safer (and less replicatable)?
Tripler
I remotely open everything I can for this reason. And I burning your dog too. . .
I used to work with a guy who said that as a teen he liked to make nitroglycerine. He’s make it cold, of course, and put it in little vials that he froze into ice cubes in an ice cube tray. Then he’d wait for a very hot Summer’s day and space the nitro vial-containing ice cubes along the street and wait for the ice to melt.
Not really. You don’t want to ‘crush’ the powder. I shoot black powder revolvers, not muskets or cannons; but the goal is to seat the ball ‘firmly’ onto the powder without really compressing the powder. You want to have enough air in the chamber for good and thorough ignition of the powder.
A friend of mine once did that when he was at school. He made the stuff and then thought, “what the heck do I do with it now?” He went outside to his garden, and poured the vial into the hole in the ground in which his mum’s whirligig rotary washing line thing went.
Of course, half an hour later he hears a boom and a shriek as his mum puts out the washing…
The importance of this is to insure that there is no gap between the powder and ball. Without raising the muzzle to vertical the powder wouldn’t fill properly without sufficient effort.
Don’t know if I agree with Mr. L.A.,
With black powder a tight pack is fine IMHO, however those that use granulated triple 7 powder have to be much more cautious about how tight the ball is seated on the powder. I do not think it has anything to do with 02, but I have witnessed two times when someone was shooting next to me and had a squib with 100 grain of 777. The ball hit the ground about 40 yards from muzzle.
Let me just state that the ball should be slowly and firmly seated on the powder.
If you want to know why I state slowly, review this link and think about how this device and a muzzle loader are similar:dubious:
But gunpowder only explodes when it is confined. Wrapping it loosely in paper towel doe not confine it. Also, I could cut the batch size down to 1 g rather than ten.
Still, I appreciate your concern. I will probably not try anything like this again.
This is absolutely true. The reason that you don’t want the powder tightly packed is that combustion only occurs as the exposed surfaces. This has nothing to do with the presence or absence of air–the same would be true in a vacuum–but just the basic physical chemistry of deflagration. If the powder is compressed that reduces the surface area available for combustion, at least initially, until the compressed powder breaks apart, which may cause a sudden spike in pressure. Pressure also influences burning rate, so a pressure spike may cause rapid combustion, which in turn increases pressure, ad nauseam, which is undesirable; you’d rather have a constant pressure over a specified time interval.
With regard to the o.p., this is the type of thing that should be of interest when discussing redox reactions; the reaction rate and resultant products are not just based upon the theoretical stoichiometric combination of reactants but also the reaction rate, influence of intermediate products, thermodynamic effects, et cetera which may alter the resulting products or time-energy output of the reaction. A flash and bang might be “fun” but it is not especially educational from either a practical or theoretical sense.
Sorry, everyone. What Stranger said was what I meant to say (though he said it much better than I would have, and added some details that hadn’t occurred to me). I was posting on the fly. My point was that you don’t want to really pack down your powder.
Point well made. The gummy bear in the molten KCLO3 is definitely a better example of an oxidizing reaction. Fortunately or unforturnately, the gunpowder experiment will be the one they remember.
>Wrapping it loosely in paper towel doe not confine it.
Im guessing that paper towel + glass + synthetic fibers on students + walking around in woolly socks == static electricity. Enough to ignite a thin powder. I find women generate tons of static electricity because their clothes are more likely to be synthetic or rub against a synthetic layer (bras, tights, slips, undershirts, etc). Was this a female student or someone wearing a woolly sweater?
In a musket, the hard part is getting the round started down the barrel. The round (either a round ball or a minie ball, which despite its name is actually a conical bullet and not ball shaped) is just made out of cast lead and they vary slightly in size. You get one that’s just slightly big and it’s going to be more difficult to get it down the barrel. Black powder also tends to foul the barrel. The more you shoot, the more gunk builds up inside the barrel, making it harder to shove the round into the barrel.
Some folks actually get out calipers and measure their rounds and squish them down a bit if they aren’t right on spec. I’ve also seen people run cleaning patches down the barrel after every shot to minimize fouling. I personally use the old fashioned method of just giving it a bit extra oomph on the ramrod. It works.
By the time you get down near the breech, though, barrel fouling is at a minimum and if the round was a bit big it’s been squished down to size already (it’s just soft lead). Shoving it those last few inches all the way to the breech is usually the easiest part.
In Hollywood they always ram everything down. In the real world you just don’t want an air gap in between the powder and the round. That’s it.
A lot of my musket stuff is made out of brass just because of the danger of static and black powder. Static has caused grain silo and sawmill explosions.
Women are also significantly more likely to cause a gas pump fire due to a static discharge. Part of it is because of the clothing. Wool and synthetics are better at generating static. Part of it is also because women are more likely to get back into the car when it is cold, and sliding across the seat also builds up static.
Static electricity and Black Powder have long been a subject of caution and rightfully so, however there have been some extensive tests done in this area. This linkwill give you some idea of what I am talking about.
Granted this test is only with BP and I do not know what would happen with the substitute powders of today, and maybe the corned BP in use today is a much better conductor than the powder from the past?
The Minie ball was a french development that started with a cone shaped breach designed to expand the hollow based ball(bullet) upon loading by ramming the ball down against the cone that was long enough to have a load of powder already in place, Captain Minie’s design put that metal cone wedge with the ball instead of the barrel because of cleaning issues for starters. But the ball with minie’s wedge would be “Rammed” to expand the wedge thereby making it tight enough to seal the ball into the rifling’s.
Now the American version of the Mini’e ball eliminated the wedge and the gasses upon ignition would expand the ball therefore making this ball a “NORTON Ball” (Captain John Norton) “not” a Mini’e! Read this link.
The arrogance of the British caused Norton’s invention to fall:( and now even today we should be crediting Norton, but we don’t:mad:
Brass for the furniture I would think is more on ease of working and aesthetics.
But that is only my opinion for what few pennies its worth.
