Black Powder Explosions

[Old Ford2]

Not sure if this is the best place to post??
Does anybody have first hand information that caused explosions at black powder plants, other than smoking.
With today's modern equipment and safety standards, things should be better.
Fred

[Pukka Bundook]

I'd think static and dust would get the job done, Old Ford.
It can blow up flour mills, so a powder mill is likely easier!

[Bigmon]

Sometime back I read interesting story regarding the DuPont plants in the early days.  They made light roofs and a temporary type wall facing a stream in the otherwise heavy stone buildings.  When they had an explosion the damage was kept to a minimum that way.
If someone was lost, they referred to it as  "he went across the creek".
Explosions were an accepted part of the trade.

[bob in the woods]

As a side note...wasn't there a special construction specification for these buildings ?  I read somewhere about the wall boards only being fastened on the top edge so that an explosion would not be contained ie the walls would blow out easily.
Powder dust is my guess as to the main culprit , along with friction caused heat. Dampness is your friend when making B.P.

[Mad Monk]

Not sure if this is the best place to post??
Does anybody have first hand information that caused explosions at black powder plants, other than smoking.
With today's modern equipment and safety standards, things should be better.
Fred

This could take awhile!!!
The thing with black powder plants is that no modern design machinery can really replace ALL of the old standard machinery.  Only two exceptions of more modern machinery design that I am aware of.  The standard plate and frame powder press is one item where modern designs work as well and then only one plant made the change.  In the Swiss powder plant they built a roller powder press.  The powder from the wheel mill is spread out on a rubber belt that takes the powder under a large roller that compacts it.  When Hodgdon rebuilt a portion of the Minden plant they put a vertical vibrating screw conveyor in to feed broken up press cake powder up into the feed hopper for the corning mill.  Replacing a system that used a wide leather belt with leather buckets attached.  Mainly because these days getting somebody to make the belt and buckets is nearly impossible.

The first real danger point in the powder making process is when you have the three ingredients in the wheel mill.  When they lay up the charge they add the potassium nitrate into the mill pan.  Then lay on the mixture of sulfur and charcoal from the ball mill.  Then pour onto that 10 pounds of water for every 100 pounds of powder in the mill.  They may try to mix this up a bit by hand.  They must insure that the pair of wheels are not resting on the metal bottom of the mill pan.  Then starting up the mill and getting the rollers turning is critical.  If the wheel are on the metal mill pan they will simply slide and cause an explosion.  So the mill is started on a very slow speed.  This helps mix the water into the ingredients.  Then part of the way through the milling time the operator must shut down the mill to look at how moist the mix is in the pan.  Adding water if necessary.  If the mix gets too dry in the pan it will blow up.

Back in the old days the Germans would use sheep skins with the fleece side up on the floors of the wheel mill buildings.  Changing them once a shift to be washed.  Hob nail boots were out of the question in the powder plant.  They wore special foot gear.  Here in the U.S. most of the wheel mill houses, in the late 1800s, had special spark proof lineoleum flooring.

Going to take a break here.

Bill K.

[Mad Monk]

In my previous message I forgot to mention that all three ingredients were run through screens before adding them into the wheel mill.  And bits of tramp metal or stones had to be removed.  Any solid material such as bits of metal or stones getting under the wheels could cause an explosion in the wheel mill or later in the process during the corning operation.

When the wheel mill time was completed they had to clean the batch out of the wheel mill.  Using wooden scoops.  Brushes could not be used since brushing might create little static sparks that would ignite the dust.  Static sparks have little danger with finished grains of powder but when you have microscopic powder dust suspended in air the danger of a static spark ignition is real.

When the horizontal plate and frame powder press came into use in the early to mid 1800s there were a number of explosions.  The mill cake is broken up and laid up in forms that make up the frames in the press.  The plates and frames are then assembled in the press.  Hydraulic pressure is applied slowly.  If the pressure is applied o quickly you can get a heat ignition of powder in the press where bits of powder are trapped on the edges of the frames in the press.  The pressure creates hot spots that may get hot enough to ignite the bits of powder which would then ignite the greater mass of powder in the press.  Usually they watched indicators on the press frame to judge the right amount of compacting of the powder.  Some pressed until the pressure gauge stabilized at a certain pressure.  Once the desired degree of compacting was reached they released the pressure and began to remove the plates and frames from the press. 

Bill K.

[Mad Monk]

When the press "cakes" were removed from the press frames they would simply be leaned up against a wall to "cure".  Now at that time the powder companies did not understand what was actually involved in this curing step.  Once the press cakes were exposed to air the moisture in them would start to evaporate.  This would cause the minute crystals of potassium nitrate to fuse together solidly.  Without this fusing the powder would have no mechanical strength and fall apart back to a powder if handled.  But once cured they large cakes would then be broken down into chunks for the corning mill.  The larger powder plants had a machine with two opposing rolls with spikes that would fracture and break up the cakes.  The operator simply passed the cakes into the pair of spike rollers and collect the chuncks in baskets.  In some small plants they simply broke up the cakes on a table with wooden mallets.  This broken up press cake had to be stored in such a way that it did not loose anymore of it's moisture content.

Bill K.

[Mad Monk]

The next step was to "corn" the powder into grains.  This corning mill was very dangerous.  Generally this is where most of the old plants had explosions.  Repeated corning mill explosions shut down a number of powder plants that never restarted.  Most powder plants had only one corning mill so an explosion in a corning mill shut down the entire works until it could be rebuilt and put back in operation.  Generally the corning mill explosions would occur just as the machine is being started.  Some were the result of bits of tramp metal or stones getting into the product being metered into the 4 or 5 sets of grooved rollers that broke the feed down into grains.  This was also a very dusty operation.  Usually the screening unit was located in the corning mill building so that oversize from the screens could go back into the corning mill for a second pass.  And it was not unusual to have about 1000 pounds of powder in the building during the operation.  So ignition of that 1000 pounds of powder in process insured that the corning mill and screening unit would be rubble after an explosion.

Bill K.

[D. Taylor Sapergia]

Thanks for this Bill...quite an education in powder production.

[Mad Monk]

The gaps between the corning mill cracking rollers could be set to give a predominance of a particular grain size.  The screening unit sorted the grain to specific size ranges which dropped into baskets for that size.  Screening step "tailings" were simply sent back to the powder press to be worked away in the next press batch.  If you look at the 4f out of the old GOEX Moosic, PA plant you see these screen tailings simply being packaged as 4f for flintlock pan powder rather than rework in the process.

The "grained" powder then went to the polishing barrel.  Individual sizes were polished rather than a mixture of grain sizes.  In the polishing barrel a large amount was tumbled in a horizontal drum.  With du Pont and then GOEX they blew heated air through the barrel while the mass of powder grains was being tumbled.  This both polished the grains and dried them down to a final moisture content.  That final moisture being about 0.5% moisture content.  It was also in this barrel where the glaze was formed on the surfaces of the grains.  A small amount of graphite would be added.  The graphite used to make the powder flow better through hoppers during the final packaging operation.  It provided no moisture protection.  Simply made the mass of grains flow through packaging funnels without bridging in the funnels.

Some plants used tray drying and tumbling to dry and polish the powder.  Power grains would be spread out on thin cloth on drying trays .  Into an oven for a few hours and then into the polishing barrels to be tumbled.  Accomplished the same end results but a good deal more labor intensive that the du Pont method of drying and polishing at the same time.  du Pont had developed these air fed polishing barrels originally for blasting powder to reduce production costs.  Generally. Explosions were very few in this part of the powder making process.  In British and European powder plants they usually "reeled" the powders before packaging.  Large frames that looked like a large fly fishing reel with cotton fabric suspended in the reel.  Powder added and then tumbled slowly for a short period of time.  Dust on the powder grains from previous processing steps would be collected in the weave of the fabric.  The fabric then being washed to recover the potassium nitrate in the powder dust.


This bunch of postings should give the reader an idea of just how much work goes into a pound of powder and where the dangers are.  And again.  No modern machinery has ever been developed to totally replace all of the "old" "dangerous" machinery.  And I should add that a lot of time and money has been spent by various powder companies to try and do so.  The most recent being back in the 1970s when they tried to produce black powder in what is known as the Jet Mill process.  When I read the patents on the Jet Mill process I just laughed.  That was about the time I was running a Jet Mill in a R&D group in another industry and found the results did not come anywhere close to the advertising claims.

Bill K.

[smylee grouch]

I have said it before but will repeat, thank you so much for your contributions Mad Monk. A lot of topics have what I would call information over load, more info than an average person needs to know to still be interested in the topic but this topic is not one of those. All this info is important to me as it gives me a better understanding of the topic. With all the work involved and danger involved I am amazed that we can still buy powder and don,t complain about the price to do so. JMHO

[Mad Monk]

Thanks for this Bill...quite an education in powder production.

I put a lot of researching of old powder plant records and thinking in that work.  Every time one of those old powder plants were shut down the records quickly got lost.  A classic example in this was the old C&H (ICI) plant in Scotland.  Shut down around 1972.  Equipment quickly dismantled and shipped off to Germany. Plant records lot in a fire or simply trashed into a landfill.  In 1996 there was a fire in the office building at the old GOEX Moosic, PA plant.  All of that companies records were destroyed.  These old powder plants quickly become some unknown thing from the past in local mythology.  As I developed all of my information I passed it on to the Hagley Museum in Delaware where it would be safely kept for future historians. 

Bill K.

[Mad Monk]

I have said it before but will repeat, thank you so much for your contributions Mad Monk. A lot of topics have what I would call information over load, more info than an average person needs to know to still be interested in the topic but this topic is not one of those. All this info is important to me as it gives me a better understanding of the topic. With all the work involved and danger involved I am amazed that we can still buy powder and don't complain about the price to do so. JMHO

You may note that message board threads involving powder prices I tend to avoid.  When it comes to black powder still being produced we have the military to thank for that.  In certain applications it simply cannot be replaced though they have tried to do that.  It is used as an intermediate primer in a lot of artillery and tank cannons. 

Prices have been driven up excessively in all of the anti-terrorism nonsense.  Then here in PA we have the state Department of Environmental Resources getting into it with licensing, inspections, etc.  Production costs at the factories have been dwarfed by the government regulations telling the public it is for their protection.

In my work I was somewaht blessed.  A high school education dating to 1959. I was able to wade through the old writings.  Work out what they were trying to explain.  Then work through it with my industrial background in compounding rubber and plastics.  Same basic physical and chemistry principals.  And then with a limited vocabulary in $20 words explain it in terms the average shooter can understand.

Bill K.

[Daryl]

Bill - tks for this 'work' on powder manufacture. Hopefully all read it through and especially in the part where you state graphite does not aid in moisture protection.

That old wives tale of graphite lending moisture protection will not die, it seems.

[Mad Monk]

Bill - tks for this 'work' on powder manufacture. Hopefully all read it through and especially in the part where you state graphite does not aid in moisture protection.

That old wives tale of graphite lending moisture protection will not die, it seems.

The point they miss is that the graphite does not form what is known as a continuous film, or skin, on the surfaces of the grains.  In the air you have the moisture as individual molecules of H2O that pass between the particles of graphite on the grains.  It offers a little protection against liquid water as you see when you place the grains in a glass of water but it offers no protection against individual molecules passing through what is a porous film of graphite.  Or small agglomerations of water molecules at higher relative humidity.

Some years back WANO experimented with adding an acrylic latex into the polishing barrel to see if a thin coat would offer protection.  Nothing ever came out of that. With moisture in the air and black powder the key to a powder not effected by moisture in the air involves the use of a charcoal with a very low ash content and a high-purity potassium nitrate that is unaffected by moisture when the relative humidity is below 92%

I got into this graphite thing with Elephant.  If they did not add graphite to the grained powder before screening their screening rates were way down.  The graphite helps to increase screening rates in terms of pounds per hour processed.  Then on two runs they placed the screened powder in a polishing barrel with pieces of cotton muslin to remove any powder dust including most of the graphite.

In effect.  Graphite was often used to hide the enhanced hygroscopic behavior of powders prepared with inferior raw materials.

[Mike from OK]

Sometime back I read interesting story regarding the DuPont plants in the early days.  They made light roofs and a temporary type wall facing a stream in the otherwise heavy stone buildings.  When they had an explosion the damage was kept to a minimum that way.

That is correct. When I worked for DuPont we sat through a presentation about the company and its history. I believe the original powder mill site is still in Wilmington, DE along the banks of the Brandywine.

DuPont was an innovative company for its day. Safety was a big deal... Of course that had more to do with preventing costly damage and downtime than it did with preventing loss of life. But if stuff didn't blow up then the employees benefited as well.

Mike

[Mad Monk]

Sometime back I read interesting story regarding the DuPont plants in the early days.  They made light roofs and a temporary type wall facing a stream in the otherwise heavy stone buildings.  When they had an explosion the damage was kept to a minimum that way.

That is correct. When I worked for DuPont we sat through a presentation about the company and its history. I believe the original powder mill site is still in Wilmington, DE along the banks of the Brandywine.

DuPont was an innovative company for its day. Safety was a big deal... Of course that had more to do with preventing costly damage and downtime than it did with preventing loss of life. But if stuff didn't blow up then the employees benefited as well.

Mike

The original powder mill is still there.  Between 1980 when I first visited it and roughly 2000 the historic site underwent extensive reconstruction by a man by the name of Rob Howard.  He and I became friends as he got into that work.  Then the management at the Hagley Museum changed and they then concentrated on the people that operated and supported the original operation and downplayed the powder manufacturing and how it was used in the field in the old days.   Given those days in that facility they showed a lot more care and concern for the overall well being of their employees than was seen in our coal mines and railroads here in Eastern PA.  If because of a work-related injury you were unable to do your pre-injury job they set you up with one you could handle.  Other industrial employers simply cast you out to the wind.

Bill K.

[Old Ford2]

Thank you for the information and education! Much appreciated.
Fred

[Natureboy]

  Speaking of Dupont:


free image sharing

[Smokey Plainsman]

Mad Monk, you are a TOP powdertician, and a wealth of knowledge.

[yulzari]

Thank you Bill. You are an irreplaceable fund of knowledge.

[Hungry Horse]

Hey, Natureboy, I was told that the cans like the one shown, that do not say made in USA on the back were produced before WWII. Do you know if that is true? I have some of both, and they are identical except for the legend on the back.

  HungryHorse

[Mad Monk]

If any of you out there have  good interest in Du Pont you might want to look on Amazon.
Lammot Du Pont and the American Explosives Industry, 1850-1884
May 1, 1984

Bunch of hard cover copies and I saw one listed at $13.45.  It is a very good book.  A lot of information.  A few historical gems.  During the Civil War Du Pont sold very large amounts of 1F musket powder for use in the std. .58 caliber rifled musket.  At the close of the war Du Pont purchased every pound of powder that the govt. sold at surplus auction.  That 1F musket powder was then run back through their corning mill to break it down into 2F which was then sold back to the govt. for use in the .45-70 GOVT cartridge.  Then once that was gone they sold the govt. 2F rifle type powder without telling the govt. arsenals about the change.  That was OK until those loadings' hit the troops out West.  They then suddenly had all sorts of fouling problems in the .45-70.

Also in the book was portions of how Du Pont forced a lot of other small powder companies out of business in the anthracite coal mine areas here in Eastern, PA.  Lammot was the guy who developed the polishing barrel that also dried the powder while being polished.  He also perfected the horizontal plate and frame press for pressing the powder.  He developed the sodium nitrate based powder for coal mine blasting work.  All of his developments were directed at greater production per man hour of labor and reducing production costs.

The book is well worth the cost and the time to read it.  Very educating on how that powder business operated at that time.

Bill K.

[Mad Monk]

Another historical gem from the book on Lammot Du Pont.

One day I listened to one of the Civil War authenticity experts talk about burlap not being authentic for the Civil War.  That thinking based on the fact that the ability to machine weave burlap, in India, did not start until after the U.S. Civil War.  Then in the book we see Lammot Dupont in England at the start of the war purchasing over 1 million pounds of raw India saltpeter to be shipped to the plant near Wilmington, DE.  Packaged in the burlap bags in India.  Once Du Pont emptied those bags they had plant worker's wives wash the bags and recovering saltpeter from them.   The washed burlap bags then sold off to anyone willing to buy them for reuse.  And that was just Du Pont.  The other powder companies were also buying India Saltpeter shipped in burlap bags.

The book also mentions that when Lammot had visited other English and European powder plants on his tour at the start of the Civil War he saw the powder being packaged in tin cans.  Once back home he set up to use tin cans for powder packaging.  Last time I was down at Hagley we went into what was Lammot's office in the powder plant.  Sitting on a cabinet was a lead powder container as described in the Lewis and Clark writings.

[Mad Monk]

Du Pont and the other powder companies purchased raw sulfur, mainly from Italy.  To purify it they would carefully melt it and pour it into tall cylindrical molds and allow it to cool.  While cooling and solidifying the impurities would rise to the top.  They would then open the mold.  Then take a saw and cut off the brown portion of the sulfur.  That was mainly arsenic.  Which would then be sold off as a byproduct to companies making lead arsenate orchard bug sprays.  U.S. orchards used this lead arsenate bug spray for almost 100 years.  Now we have large areas that were once fruit orchards with ground contaminated by the lead arsenate spray.  Which the alleged scientists claim was contaminate by lead shot used by hunters over the years.  When the wife and I did our long bicycle rides on the Western Maryland Rail Trail a section of it went through such an area fenced off against trespassing.  The critters that lived off the vegatation in that area cannot be eaten because of the lead arsenate.  Which goes right up through the food chain.  Lammot was smart enough to sell powder making byproducts for added income to the company.

Bill K.