Black powder

[imray]

I kinda looked through the thread and didn't see it but you do know there is a hazard shipment fee required whether it is 1 lb. or 25lb black powder. I'm not exactly sure anyway its somewhere around $37 dollars a shipment. It could be more I'm not exactly sure what it is right now. best wishes, ray

[burnsranch]

I bought 14 lbs so it worked out to $17.00 a pound.

[Paddlefoot]

That electricity test was quite interesting! I have always operated under the idea that BP was easily ignited by static. I believe there was a notation on a Lee powder measure advising in Huge bold letters not to use BP in it because of the danger of static setting off the powder. Pretty sure I had seen that warning on an RCBS measure also.  Danged if I don't learn something new all the time.

[Mad Monk]

A little something for those who collect such information.  In two parts.

Blasters' Handbook
E. I. du Pont de Nemours and Company
15th Ed.
Wilmington, DE

Chapt. 3 Black Powder

Properties:

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 (572F.).
They should not be exposed for long periods of time at temperatures above 100 C. (212 F.)  Ignition can be effected by any flame, spark, hot wire or hot surface, and by blasting accessories such 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."


E. Ogre

[Mad Monk]

More on black powder

When you look at the data in this old paper consider the amount of electrical energy involved in igniting GRAINS of black powder.  Far beyond simple electrostatic energy discharge levels we deal with.


Chemical Abstracts
American Chemical Society
Eschenbach Printing Company
Easton, PA

Vol. 8
1914
Page 1670

Investigations On Electrostatic Conditions in the Sifting of Black Powder at the Kockelscheur Powder Factory.
J.P. Manternach. 2.ges.
Schiess-Spregnstoffw. 9, 41-45, 68-70.

As a result of two explosions which occurred during the sifting of black powder, an investigation was made to determine the intensity of the static charges generated in the process, the possibility of ignition of powder by such charges, and means of preventing this condition.  The electrometer of H.W. Schmidt was used in this work.  It was found that the condition of the air around the machine increased 3 to 4 fold while the machines were being operated, and that the conditions of the atmosphere were favorable for the formation of static charges.  Experiments showed that the explosive (grains of powder) could not be ignited by sparks up to 6 cm long from an electrostatic machine.  With induction sparks of greater intensity, no ignitions were obtained with a primary circuit of 1/2 - 7 amp. and 4 - 16 V., but with 8 amp. and 88 V. ignition of the explosive resulted.  Proper circulation of the air in the sifting room and effective grounding of all machines and appliances constitute the best means of avoiding conditions which might produce dangerous conditions.
(end of paper)


An important note here.
No ignitions with the "electrostatic machine".  I should point out that the electrostatic machine produces sparks with far higher energy levels that we humans can produce with movement and clothing.

The problem in the German powder plant sifting operation was the fine powder dust suspended in the air while the machinery was in operation.   The ignition of  grains of black powder require spark intensities far beyond what we are able to generate.  When you look at the voltage and amperage required in the induction coil discharges you are up there with high-voltage auto ignition systems.

In powder plant operations you have areas where near micron size powder dust particles are floating around suspended in the air where a spark through the air is able to ignite the microscopic particles of sulfur in the powder dust.  The same would be true of particles of charcoal.
But whole grains of black powder are nearly impossible to ignite with static discharge sparks because of the energy level required.

I should also point out that with the commercially available black powders we use the dust seen in most containers is excess loose graphite.  That does not ignite and begin to burn until you heat it close to 2,000 degrees.


E. Ogre

[Daryl]

It's a day wasted if you don't learn something - thanks Ogre. A pleasrue reading your stuff - always something to learn.

[Paddlefoot]

So the explosions at the powder factory were more related to the kind that happen at the C&H sugar factory on Maui or in a grain silo than to anything related to the powder itself. Very interesting.

[Mad Monk]

So the explosions at the powder factory were more related to the kind that happen at the C&H sugar factory on Maui or in a grain silo than to anything related to the powder itself. Very interesting.

When the black powder plants began to switch to electrical power it took them a bit to learn that electrical motors should be outside the building driving machinery with shafts through small openings in walls.

Whenever the subject of static ignition comes up in one of these threads I am reminded of writings by Lammot du Pont on his visit to various European BP plants at the opening of the U.S. Civil War.
He noted in the German federal powder plant that they laid sheep skins on the floors of the wheel mill houses.  Fleece side up.  Any dust from the mill would settle into the fleece and not be carried around in the air for any length of time.  At the end of each shift these were pulled up to be washed and fresh clean ones laid on the floor.  We always think of wool as being nearly ideal to generate static charges.

In English BP plants they used chutes made up of cotton muslin to drop in process powder from one building level down to the next lower level.  These would be removed periodically for laundering.

In the English plants there was a final step in the powder making process known as "reeling".  They had what looked like large fly fishing reels with cotton muslin inside.  Powder was placed in these "reels" and they were then rotated for a certain period of time.  As the powder grains tumbled in the cloth lined reel any excess dust and debris was polished off the grains.  These cloths also would be removed for laundering.

E. Ogre