Smokeless powder not explosive, blackpowder is?


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akodo
September 7, 2007, 06:22 PM
Okay, this came up in a conversation last night, and I have heard some stuff along these lines on the highroad before.

Smokless powder does not explode, it just burns. Blackpowder, on the other hand, actually explodes.

What is the defintion of explode, what is going on that these things are different? How are other things, highly flamable things, classified. I have heard that gasoline doesn't explode, it only burns, is this true when it is vaporized? Sure, sitting in an open bucket, the top layer will burn, but what if you toss that bucket of gas onto a slowly burning fire...WOOF! is that an explosion or just a burn? What about dust particles in a grain elevator that 'explodes' is that really an explosion or just a burn?

Is there some reason a rapid burn is better/safer/more efficent than an explosion, especially as it relates to guns? Do you get less spikes in chamber pressure?

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strat81
September 7, 2007, 06:28 PM
What is the defintion of explode, what is going on that these things are different? How are other things, highly flamable things, classified. I have heard that gasoline doesn't explode, it only burns, is this true when it is vaporized?

DO NOT TRY THIS AT HOME: Fill a bucket with gasoline. Fill another bucket with kerosene. Toss a match into each. Observe. Black powder is to gasoline as smokeless powder is to kerosene. Pick up some smokeless powder at a gun shop and light some on the ground. It kind of just whiffs up (technical term). However, put that same powder in a brass case stick it in a gun barrel...

MaterDei
September 7, 2007, 06:37 PM
The following is my opinion only. I am not a physicist or chemist and I didn't stay at a Holiday Inn Express last night.

Things that burn will all explode when put into a confined space. Smokeless powder in a spoon or on the ground burns. In a cartridge in the bore of a gun it explodes.

Explosions are identified by a loud noise while burning is not. Some things burn so violently even when not enclosed that they create a loud noise and therefore 'explode'. Blackpowder is an example.

Myrdhyn
September 7, 2007, 06:48 PM
Explosive Material (http://en.wikipedia.org/wiki/Explosive_material)
Should answer your question (yes I spend too much of my work day on THR and wikipedia...I know). More specifically the sections on Low and High Explosives.

Also if I remember my highschool chemistry properly (we actually watched a video on this if I am remembering right)....both smokeless and black powders are low explosives and thereby only "burn quickly" and only "explode" under certain conditions (being confined being one of them) and do not technically "detonate" ever even though they can be made to produce effects that very closely simulate "detonation". The wikipedia article can, I do believe, confirm this.

Tommygunn
September 7, 2007, 06:53 PM
Blackpowder is an explosive.
Smokeless powder is a propellant.
They both will shove a bullet out a muzzle, but the chemistry is different.

As far as spikes of pressure, it's not only so much how high the spike is, it's how fast it's produced.
I'm not sure one is necessarily better than the other, but modern propellants generally contain more "umph" per volume and they do not produce as much fouling, which is really good when you're dealing with modern semiautos and other modern guns with closer tolerances.

esmith
September 7, 2007, 07:37 PM
An explosion is a unstable fast burn. It does not burn evenly. This is a common debate as to whether feul explodes or burns in a internal combustion engine. Powder burns quickly. This is what i was taught.

Car Knocker
September 7, 2007, 07:48 PM
Unique and Blue Dot, both smokeless powders, are labeled by the manufacturer as "Extremely Flammable and Explosive".

M2 Carbine
September 7, 2007, 07:52 PM
You can shoot or burn a can of smokeless powder and it will not explode.

If you shoot or burn black powder it will explode.

I have done both.

When my gun shop burned the top or bottom of the smokeless powder cans just popped off.
The couple black powder cans exploded.

The center cans are smokeless powder.
The two burst cans on the right are black powder.
The burst can on the top left is WD40.

http://img.photobucket.com/albums/v135/Bell406_206B/F_powder_cans.jpg

Officers'Wife
September 7, 2007, 08:00 PM
Smokless powder does not explode, it just burns. Blackpowder, on the other hand, actually explodes.


From the standpoint of high energy chemistry BP does not explode as there is no "detonation zone" except under highly unusual circumstance. BP deflagerates or burns quickly. Smokeless burns slows but has a detonatation zone when ... detonated.

Look at it from this angle- Composition 4 when lighted with a match will burn slowly giving off great heat. Add a #6 blasting cap with a tetryl booster and it detonates at a rate (I think- it's been awhile) of 800 meters per second. C4, even with it's slow burn rate, is an explosive.

Next time someone tells you smokeless is not an explosive consider this. Bullseye pistol powder is 6 parts nitrocellulose and 4 parts nitroglycerine plus trace amounts of various stabilizing agents. That makes it a 40% dynamite no matter how you look at it.

(One of the persons that homeschooled me was a chemical engineer and a blaster.)

Selena

M2 Carbine
September 7, 2007, 08:00 PM
black powders are low explosives and thereby only "burn quickly" and only "explode" under certain conditions (being confined being one of them) and do not technically "detonate"

Shoot a can of black powder and you will see this statement is wrong.
Using a .308 I shot a full one pound can and a can that had a half pound of black powder.
Both made a very impressive explosion and fireball. A detonation by anyone's definition.:D

I have also shot cans of smokeless powder. The cans may as well have been full of sand.

Sheldon J
September 7, 2007, 08:02 PM
Basically the higher the compression the faster smokeless powder burns, place it in a pile outside someplace safe and light it and you will see a real nice flame just like a rocket engine, but no boom, you could not make a firecracker with the stuff if your life depended on it

Black powder's burn rate is the same for any F of powder, very fast in the open or enclosed, so you put a big pile in the same place and light it and boom, the only factor affecting burn rate is the size of the granule Example F burns slower than FF and FF burns slower than FFF, you get the direction I am heading here.
Which brings us to the point of the OSHA rule that almost passed on smokeless powder being total Bull, smokeless will not explode in the can period.

adobewalls
September 7, 2007, 08:08 PM
Put a table spoon of smokeless powder on your driveway and light it off, it tends to burn, rapidly, but you can watch the flame "spread".

Put a tablespoon of blackpowder on your drive way and it tends to go up all at once with a flash.

Is the above scientific, no, but it made the point to me.

Officers'Wife
September 7, 2007, 08:11 PM
Hi M2,

Right idea, wrong premise. When an nc/ng propellant is "loose" i.e. without close physical contact, the detonation zone is disrupted and a true explosion cannot occur. If you were foolish enough- or stupid enough- which I'm sure you are not... to dissolve the propellant with a suitable solvent then allow the solvent to evaporate to leave a solid block of propellant then use the proper amount of pressure (a high velocity bullet or primary explosive) you will get an explosion even without a container.

Selena

Cosmoline
September 7, 2007, 08:21 PM
Unique and Blue Dot, both smokeless powders, are labeled by the manufacturer as "Extremely Flammable and Explosive".

True, and you can make a pipe bomb from Unique. But it's not an explosive in the same sense that BP is. It's a propellant. In everyday use this comes up with storage and shipping issues.

You can certainly make smokeless into an explosive by changing its physical structure or by forcing it to ignite in a very compressed area with no release, but in the can it's not going to blow up. The factory containers are all designed to prevent the buildup of pressure, because smokeless gets more and more intense as pressure builds. This is why storing smokeless in sealed non-factory containers is such a bad idea.

M2 Carbine
September 7, 2007, 08:31 PM
True Officers'Wife.
The only point I'm making is that smokeless powder when burned or even shot is reasonably safe but when a can of black powder is burned or shot there will be a dangerous explosion.
Maybe not a maximum possible explosion but pretty impressive none the less.:)


As I recall those two cans of black powder in my fire were sitting on a shelf in the open.
I knew when each went off. The explosion was not what a pound of black powder is capable of but still scary.:)

Wheeler44
September 7, 2007, 08:32 PM
From "Speer Manual for reloading ammunition" third printing May, 1962 page 20. article by B. E. Hodgdon "black (powder) is a low-explosive powder and should be respected as such. It burns just as fast without confinement as it does when used as a propellant.".....


Smokeless powder is progressive and confinement is necessary to obtain the characteristic of the desired powerful propellant.

Officers'Wife
September 7, 2007, 08:50 PM
Hi M2,

My bad, I was going by HEC standards and I see now the thread is legal standard. In the latter context, of course, BP is an "explosive" and smokeless only a propellant. Only in the minds of the great white father in Washington is a pyrotechnic mix more dangerous than a low velocity high explosive.

It's best I bow out now before I get into primary, secondary and tertiary explosives and velocity differences.

Selena

LHB1
September 7, 2007, 09:24 PM
It's been a LONG time since I studied physics but isn't an "explosion" only a superfast burn rate? Technically don't all flammables, propellants, and explosives simply burn at different rates? As noted above, additional pressure can increase the burn rate of a substance/propellant.

Good shooting and be safe.
LB

SaMx
September 7, 2007, 09:26 PM
an explosion is technically just something expanding really fast. black powder burns really fast, so it expands really fast. Smokeless powder burns slowly in the open, but in an enclosed space it burns fast, and expands fast.

Stevie-Ray
September 7, 2007, 11:17 PM
Basically the higher the compression the faster smokeless powder burns, place it in a pile outside someplace safe and light it and you will see a real nice flame just like a rocket engine, but no boom, you could not make a firecracker with the stuff if your life depended on itAah, but break open a firecracker and light the middle and you get the same "rocket engine effect." Unless, of course you stomp on it quickly. Then boom.

We did this all the time. Never wanted to waste a dud firecracker.:D

Feanaro
September 7, 2007, 11:38 PM
Smokeless powder in a spoon or on the ground burns. In a cartridge in the bore of a gun it explodes.

It burns. When smokeless powder "detonates," it causes a severe pressure spike.

cnorman18
September 8, 2007, 12:00 AM
Modern smokeless powders are indeed "propellants". The point is not that they "explode", which they don't, but that they burn very quickly and produce enormous amounts of gas (which you can't see when you light it on a table). The gases, when confined by a cartridge case and a gun's chamber, force the bullet down the barrel and toward the target. When the rapidly expanding gases are released by the bullet exiting the muzzle, the pressure wave is perceived as a report.

Some powders burn faster than others. In a pistol, you want a fast-burning powder like Red Dot; the shorter the barrel, the faster the powder you need. If you have a lot of unburned powder residue in the barrel after firing, or a huge muzzle flash, your powder is too slow. A powder that is too fast, though, in extreme cases, can cause damage to the gun or even make it explode. That's why it's a very bad idea to use pistol powders in rifles.

Rifles need a slow-burning powder to make the pressure wave last as long as the bullet is in the barrel. If all the powder is burned before the bullet exits the muzzle, on the rest of its trip down the barrel the bullet is actually slowing down from the friction as the pressure curve drops off. This most commonly happens when a cartridge is underloaded--and the resulting low pressure as the bullet exits the muzzle is why underloaded cartridges aren't as loud. In extreme cases, the bullet will actually stick in the barrel, which can cause a subsequent full-power round to explode the gun. This often happens in pistols when a handloader tries to make low-power loads for a magnum handgun in order to reduce recoil and noise. I have personally seen a S&W .44 barrel sawn in half lengthwise to reveal six bullets lined up in the bore. If loaded with a full-power cartridge in this condition, the gun would have done a really convincing impression of a hand grenade.

Black powder works much the same way, but is a very fast-burning powder indeed, so fast that it is called an "explosive". Its burn rate can be crudely controlled by the fineness of the granules; the finer the grind, the faster the ignition. Thus, the fine-grained powder is used in pistols and the coarser-grained powders in rifles.

The chief advantage of modern powders is their stability. It's very hard to ignite smokeless powder without a primer, though an open flame will do it. I vividly remember watching my father stub out a cigarette in an ashtray piled with modern powder to illustrate that; he then touched a match to the pile, and it went up in a "whoosh" with very little smoke or ash residue.

Black powder, on the other hand, is scarily unstable. It can ignite (and when confined, that means "detonate") from static electricity, impact, or friction alone. More than one Civil War soldier was killed when his brass flask of powder blew up at his side when it was struck by a bullet--or while he was just running.

Many modern BP shooters prefer Pyrodex for that very reason--it's a modern compound that mimics the burning qualities of black powder, but is as stable and safe as modern powder. As a bonus, it leaves far less fouling in the weapon.

Hope this helped.

ky_man
September 8, 2007, 12:06 AM
Static electricity will NOT ignite Black Powder. It is not a chemical compound, rather a mixture, and has no flammable vapors (no appreciable vapor point) to combine with atmospheric oxygen into a flammable mixture. Carbon is a great conductor of electricity, to boot. More energy needs to be supplied before the powder will self-ignite.

Static electricity has basically no current. I've tried to get it to ignite with a spark, no dice. A MIG welder WILL ignite it, but that's a heck of a spark (with lots of heat produced)

This guy has also tried it:
http://www.ctmuzzleloaders.com/ctml_experiments/sparks/sparks.html

BigBlock
September 8, 2007, 12:33 AM
This is just a ridiculous matter of semantics.

The definition of explode:
to expand with force and noise because of rapid chemical change or decomposition, as gunpowder or nitroglycerine

Both black and smokeless powder fit that description.

Officers'Wife
September 8, 2007, 12:37 AM
OK guys, do me a favor and find a copy of Tenney's "Chemistry of Powders and Explosives." It will ease your minds quite a bit and relieve you of a lot of misconceptions many of you seem to have. Don't let the title throw you, the math is minimal and gives a great deal of information on the subject of BP and other pyrotechnic mixtures as well as their properties.

Another reference though more concern with manufacture is Weingards' "Pyrotechnics." Although it goes into great detail on the office of surface area to pressure. Again the math is minimal and the writing is presented in such a way to be interesting.

As for smokeless there is a military training manual from the 1940's called "Military Explosives" that not only defines detonation v deflag but describes in detail the diff between the detonation of a high explosive and a so- called explosive mixture. However, I don't reccomend it for light reading.

Item last... The "carbon" in BP is charcoal. Charcoal is NOT repeat not a good conductor of electricity. It's the sulphur in the mixture that lowers it's flash point. Static discharge "can" cause the stuff to flash but not necessarily will. When pyrotechnians build devices (such as Roman Candles) they wear a grounded cuff on their arm to prevent static discharge. Of the pyrotechnical compositions Nitrate based mixtures (such as BP) are considered the safest to manufacture.


Selena

ky_man
September 8, 2007, 01:11 AM
It's true that the "carbon" in BP, being charcoal, is not as good a conductor of electricity as pure graphite. However, modern BP is "glazed" or coated with graphite, or a graphite-like allotrope of carbon to improve pour, moisture absorption, flash time, etc. This graphite is very conductive (i.e., not resistive).

Homemade powder or scratch made pyro powders are different altogether. And yes, safety should be a primary concern. When loading BP, if you happen to have something more sensitive on your bench when you get a spark, that means trouble!

cnorman18
September 8, 2007, 01:19 AM
If a spark can't ignite BP, how does a flintlock work?

ArmedBear
September 8, 2007, 01:23 AM
Note that a flintlock produces a pretty massive spark, and the powder in the pan is 4F (really fine grain).

People fought whole wars with the stuff, and hunted for their dinner daily, without blowing themselves up very often.:)

But it IS explosive, and it does ignite easily.

BP substitutes are propellants, however. Pyrodex is not classified as an explosive, for example.

Officers'Wife
September 8, 2007, 12:08 PM
IIRC the graphite coating is actually to help prevent ignition by static via the Faraday cage. When an object is surrounded by a conductive surface the charge doesn't penetrate the surface as well as to make the mix less hydroscopic. Also (again IIRC) the graphite coating is not industry standard. Please note that BP is a stochiometric mixture and the addition of inert matter such as graphite decreases the heat available and adds to fouling so the benefit is a matter of argument.

Again, Tenny discusses coating in great detail in his "Chemistry of Powders and Explosives." Most college campuses with a Chem Eng dept has a copy though on the "restricted" shelves. I know Purdue will allow you to read it in library.

Selena

cnorman18
September 8, 2007, 01:27 PM
You're right on the semantic problems with the word "explode". Something can "explode" without being an "explosive".

If you put an unopened can of beans in the microwave, it will "explode". That does not make beans an "explosive".

(I had a roommate once, though, who often proved that beans can be a deadly weapon for chemical warfare...)

ky_man
September 8, 2007, 04:25 PM
In the pan of a flintlock, the flint scrapes off steel (not the other way 'round), making a "spark" which is raised to incandescent heat by the flint/frizzen friction. These hot metal pieces are what ignite the powder. They are in no way similar to electrical "sparks".

I have found that 4F is not any better in the flashpan than 3F or 2F. The main charge powder works just fine in the flash pan, try it. If there's a difference, it's negligible.

Another benefit of using a larger granule is less surface area and a slower rate of moisture adsorption in humid environments. "Charcoal" is porous, where graphite is not.

... as well as to make the mix less hydroscopic.

You meant to say hygroscopic.

Officer's wife is right about BP being a near-stoichiometric mixture, but the graphite "coating" is just that, a very thin coating on the surface of the powder grain (e.g., GOEX powder); however, the graphite is in no way incorporated into the mixture. After mixing and processing, the powder grains have a very uniform composition. There is no EXACT stoichiometric mixture of C S N and O in BP, because the exact ratio for complete combustion in the "system" of a rifle barrel must vary with pressure, temperature, volume, etc. Plus, you never get complete combustion with BP in a rifle.

When a granule burns, it absorbs heat energy by convection from a neighboring burning granule. In a closed system, this process happens very quickly. The amount of graphite on a granule is so small (negligible) the amount of heat it absorbs before itself burning is negligible; however, it should contribute a positive enthalpy to the overall combustion reaction. I might even hazard to say that the addition of graphite would help to control the initiation of combustion at the granule surface, as pure graphite or one of its allotropes have uniform physical characteristics. Plus, the addition of graphite cuts down on dust production.

BP burns relatively slowly in STP conditions [standard temp (72F), pressure (1 atm)] but when it burns in an enclosed system, it generates heat and pressure rapidly. These increases accelerate the velocity of the reaction close to "explosion" speed.

Thus, speaks the rifle.

Here are some other great books on the subject:

A Treatise on Gun-powder; a Treatise on Fire-arms, by Alessandro Vittorio Papacino d'Antoni (1789)
http://books.google.com/books?id=ThzZFyQ9FpAC&pg=PA10&dq=gunpowder+date:1720-1805&as_brr=1&ei=zfniRoyXK4i67gLj6pCrAQ#PPA16,M1

Officers'Wife
September 8, 2007, 08:40 PM
Hi KY

You meant to say hygroscopic

No, I meant to say hydroscopic and have forgotten the nom. is all. I deserved that though and apologize for being so patronizing.

Just for giggles and grins take 70 gr (50 cal rifle) of BP and damp mold it into a charge matching the caliber of your rifle with a cone shaped cavity about 3/4 of the length. You will discover the ball velocity is quite higher than loose powder. The reason- as the powder is burned inside the cavity the surface area increases along the length of the burn. Fasinating stuff.

Selena

Kentak
September 8, 2007, 09:14 PM
An explosive will cause an explosion even if detonated in an unconfined situation. A stick of dynamite will explode if detonated while lying in the open. A pile of gunpowder will explode if ignited.

A pile of smokeless powder will only burn rapidly if ignited unconfined.

But, smokeless powder can cause an explosion if ignited in a confined space such that the pressure of the resulting gasses exceeds the ability of the container to, umm, contain it. Smokeless powder could be used to make a pipe bomb, for example.

I don't think it would be too much of a stretch to call the detonation within the cartridge case and bore an explosion--one in which the energy is directed along the bore of the gun. In other words, smokeless powder is not an explosive, but can be used to cause an explosion.

K

Cougfan2
September 8, 2007, 09:27 PM
I used to work for Hodgdon powder company.

DOT defines, or used to, smokeless powder in containers of 8 lbs. or less as Class A flammable solids. Black powder of any weight, or smokeless powder in containers of more than 8 lbs. are classed as Class B explosives.

Black powder burns at the same rate whether confined or unconfined. This is the definition of an explosive. Smokeless powders are progressive burning and burn at different rates when confined or unconfined. Stick powders for large case rifle calibers tend to have slow burn rates while ball and flake powders tend to have faster burning rates.

Pyrodex, the black powder alternative, has the fastest burn rate of any progressive powder. Thus, it's transfer and storage is the same as smokeless powder according to DOT and BATFE.

Kentak
September 8, 2007, 09:55 PM
Some explosives will detonate without burning at all.

The following is presented for informational purposes only. Do not under any circumstances do any of the following.

Preparation of nitrogen triiodide.

Nitrogen tri-iodide is a chemical that is extremely unstable. Once prepared, the slightest disturbance will cause the compound to revert to it's components rapidly, those being nitrogen and iodine.

The preparation of NI3 was described to me by my high school chemistry teacher. I will not say if I have ever prepared any, because that would have been an irresponsible thing to do.

The preparation is pretty simple.

Obtain some elemental iodine. No, not the dark brown liquid that is used for disinfection, elemental iodine. It's a silvery gray crystal compound. At room temperature, you can usually observe a purple haze of heavy iodine vapor forming over the crystals. Solid iodine sublimates directly to vapor. In other words, it doesn't melt to a liquid before vaporizing when heated. If gently heated, the purple vapor will condense to silvery crystals on any cooler surface it comes into contact with. But, I digress.

If one were to do something so foolish as to prepare NI3, he would put a small amount of iodine crystals (let's say 1/4 teaspoon) in a cupped dish. He would then cover the crystals with a quantity of ammonia solution. The higher concentrated laboratory solution is preferred, but household ammonia will work. He would use plain ammonia, not the kind that has soap mixed with it.

Stir until all the iodine crystals have been converted to a fine, dark powder than settles to the bottom of the container. If not all the crystals convert, pour off the clear liquid and add more ammonia. The ammonia is the nitrogen source for the final compound.

Pour the contents into a funnel lined with a piece of a coffee filter. The compound is relatively stable while wet. Open up the filter with the NI3 in it and place it on some newspaper away from any air currents. Let it dry.

Detonate the NI3 by touching it with something. Anything. A stick, a straw, a feather. The slightest touch will cause it to decompose and release it's nitrogen with an energetic "snap." Also observe a purple cloud of iodine vapor and the purple iodine stain on the filter paper.

I have heard rumors of the following things being done with NI3. Many small quantities being prepared and laid out on the floor to dry. An unsuspecting roommate enters and gets startled sh**less as he hops around setting off little land mines. Packing wet NI3 into a door lock to dry. Best used against the same roommate.

Also heard of a bunch of college kids that foolishly prepared a large quantity of NI3. They became scared, and put the wet pile of NI3 under a tree in the yard to dry. Legend has it a loud explosion was heard much later. Upon investigation, bits and pieces of a tree squirrel were observed in many different locations around the yard.

That's an explosive.

K

Kentak
September 8, 2007, 10:03 PM
That's right, something that is not an explosive, by definition, can still cause an explosion.

Gasoline is flammable, but not explosive. An open container of gasoline will burn rapidly, but won't explode. However, should gasoline spill in a confined space, like a garage, it's vapors may mix with the air until an explosive mixture is formed. An ignition source, like Bubba lighting a cigarette, causes the mixture to burn rapidly producing hot expanding gasses. The pressure of these gasses will likely exceed the ability of the walls of Bubba's garage to contain them and will rapidly deconstruct themselves.

K

EOD Guy
September 9, 2007, 12:17 PM
If you want to get into the legal definitions for the transportation of explosives, you need to go the the hazardous materials table in 49CFR.

Smokeless powder for small arms is classed as a Division 1.4C explosive material. For domestic shipment only, it can be reclassed as a Division 4.1 flammable solid if packaged in containers of 100 pounds or less.

Black powder is classed as a Division 1.1D explosive material. Again, there is a domestic shipment exemption. Black powder for small arms packaged in conductive plastic or metal recepticals with a net capacity of 1 pound or less can be reclassed as a Division 4.1 flammable solid as long as no more than 25 recepticals are packaged in one fiberboard box. No more than 100 pounds total can be on any one vehicle.

Cartridges for small arms are classed as a Division 1.4S explosive material but may be reclassed as ORM-D material for domestic transportation if packaged in quantities of 66 pounds or less.

These definitions are for transportation and do not conform with the chemical definitions which have been covered in previous posts.

JoeG52
September 9, 2007, 03:23 PM
If a spark can't ignite BP, how does a flintlock work?


It depends on the type of spark.
http://www.brimstonepistoleros.com/Articles/staticelectricity.html

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