CAS TOPICS > The Darksider's Den

Scientific experiment w/ BP?

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Silver Creek Slim:
I remember a scene in a John Wayne movie where the Duke shoots a can of BP with his Colt and he gets a BIG explosion. So, I decided to see if what would happen in real life. My wife and me goes out to the back forty with a can of Goex FFFg and my trusty Marlin 39A. (Me wife went along for a witness and to rush me to the ER if need be). I put the can of BP in the middle to the field, backed up about 100 yards, and commenced to shootin' at the can. Once I finally got the range, I hit the can low where there should be powder and tipped the can over. No explosion, just BP pouring out of the hole.  :( Another Hollywood stunt debunked.

Slim(what's wanted to see flames)

Silver Creek Slim:
Tangle Eye posted this on TFS.

--- Quote ---When this post started, I sent an email with some BP questions to Maine Powder House to see what technical info they had. I got my response today. The guys at Maine Powder House apparently contacted Bill Knight (known as an authority on black powder science). Bill sent this reply back and it was forwarded to me.

This makes some good reading and makes sense. I can't verify anything in the response but this guy is well known in black powder circles, etc.

Here it is -- (excuse the funky email stuff still in it):

Regarding the questions presented in a message to you from Tangle Eye.

>Some have said that a spark isn't always necessary to ignite black
powder - that it can explode if it reaches its "flash point" temperature. Others say they have shot a can of black powder with a rifle and it exploded; others dispute that.<

That might best be addressed using information published by the E.I.
duPont de Nemours and Company in their 15 Ed. of "Blaster's Handbook".

Chapter 3, Black Powder

Sensitiveness: All black powders are relatively insensitive to shock and friction.

Ignition: Any treatment that produces a spark or quantity of heat of sufficient temperature will ignite black powder. Black powders will ignite instantly at about 300 C (572 F). They should not be exposed for long periods at temperatures above 100 C (212 F). Ignition can be effected by any flame, spark, hot wire or hot surface, and by blasting accessories as squibs, electrical squibs and igniters, electric blasting caps and detonating cord.

Velocity: Black powders do not have true velocities, whereas detonating explosives do. Their rate of burning is affected by confinement. In the open, trains of black powder burn very slowly, measurable in seconds per foot. Confined, as in steel pipes, speeds
of explosions have been timed at values from 560 feet per second for very coarse granulations to 2,070 feet per second for the finer granulations.

Glaze: Used where clean, free flowing and non-lumping is desired. Glaze is omitted when further processing is required. The glaze does not improve the efficiency of black powder nor does it provide water resistance.
In shooting at cans of black powder and ignition of the contents. This will depend on bullet velocities. High-velocity bullets generate a considerable amount of heat while traveling through the air from friction of the air on the bullet during its flight. If the velocity of the bullet is enough to heat the surface of the bullet to the ignition temperature of black powder you will see ignition of the powder. At low velocities a bullet simply does not generate enough frictional surface heat to heat the powder to its ignition temperature.
Going back to the latter-half of the 19th century; when duPont first wanted to ship kegs of black powder by railroad the railroads required that duPont build special box cars for this product. A regular box car was simply lined with an additional two inches of wood. The railroads were not too popular in most areas during what we now call the Robber Baron era. The common folk took a particular delight in firing shots into passing trains to damage goods being carried in the box cars which the railroad would then have to make good for. An additional two inches of wood lining the box cars carrying black powder would insure that a rifle round did not have sufficient heat to ignite the black powder in the car.
Tangle Eye mentions "flash point" of black powder. I had played with this in the lab. If I plugged in a hot plate and raised the temperature of the hot plate's surface to around 600 F I would see grains of black powder ignite instantly on contact with the top of the hot plate. If I took a little aluminum lab dish, added black powder, placed it on a cold hot plate and then heated it, the powder would not ignite. As the powder is heated there will be a series of events taking place. As the temperature of the powder rises above 200 F the sulfur will begin to volatilize, or turn to a vapor, and be carried off in the air. At this point there is a strong odor of sulfur. When the melting point of the potassium nitrate is reached the grains will begin to look like beads of liquid and then they will begin to bubble or foam. That leaves then what looks like bp bore fouling. But at no time did the powder grains ignite. The key here is that the powder first lost its sulfur. When the potassium nitrate bubbled it was loosing its source of oxygen. When the powder is instantly heated to around 575 F the three ingredients are able to react with each other in the combustion process.
Slow heating of black powder in a can may, or may not, result in an explosion. When the sulfur, in the powder, is heated to a temperature above 180 F it begins to go from a solid to a vapor without going through a liquid phase. Once the sulfur is changed from a solid to a gas it becomes highly reactive with the potassium nitrate - even if the potassium nitrate is not heated to its decomposition temperature where it would rapidly release oxygen. If the can allows most of the sulfur vapors to escape the powder would behave the same as it did in the hot plate experiments. If trapped in the can you would have the risk of the contents igniting at some point in the rise in temperature.
Tangle Eye writes:
>We're just trying to better educate ourselves and maybe learn to be safer with black powder too.<
Please keep in mind that 90% of the accidents involving black powder are related to careless smoking around black powder. That is to say accidents that involving the handling of the powder during storage and loading. The other 10% involve other forms of carelessness in handling.
--- End quote ---


Shiloh Sharpie:
I have a friend whose tent got hit by lightning while at Rendezvous.  A can of GOEX got perforated and was in the fire.  It did not explode.  He even got to use th epowder later.  Go figure.

A neibour was gon'a blast a rock using blackpowder.
The powder was wet and he tryed to dry it in a pan on
the stove :o
Almost burnt the house down and put himself in the hospital.
Stupid is as stupid does.

Shiloh Sharpie:
Qball - I'm still laughing about your neighbor.  Funny stuff (even though he is a knucklehead)  My buddy's tent story is great to listen to when he tells it.   Mostly due to the fact that all of them (he was not alone in the test) were three sheets to the wind at the time.  The goings on were hillarious.

Thanks for the laugh.



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