Making Black Powder (gunpowder)

I recently became interested in black powder rifles and pistols.  I fired my first BP rifle a few times and it is just plain fun.  Years ago I read a comment about black powder shooting and it went something like this; black powder; it's messy, smelly, dirty, hard to clean and goes bang when you pull the trigger...what's not to like?  Its a guy thing.  I finally understand what he meant.  It's love at first bang!

Having a day that we are home bound, I get to organize my work area in preparation to make some more black powder.  It turns out that we are unable to buy commercial black powder within a 4 hours drive.  I could buy and have bought black powder substitutes and that is OK yet I really want to use real black powder.

Since BP is an explosive there is risk involved with making it.  Even a small batch (7 ounces in my case) must be approached with care.  The process is not overly complicated and can be completed with simple tools.  To make commercial grade BP requires additional tools, time and care.

My first step in making BP is to obtain the ingredients; potassium nitrate, sulphur and charcoal. Charcoal can be made fairly easily and a number of web sites and videos are available to show you how.  Fortunately, all three items can be purchased on-line.  Having not made BP before I sought assistance from a friend who has a fireworks manufacturer license and makes fireworks grade BP.

After making a small batch under his direct tutelage I obtained the needed tools and chemicals then setup a work area.  I needed a space that I can keep clean, provides cool dry storage, and ample space to move around.  

Keeping the area clean is very important to me.  I read one guys post claiming that he used a vacuum cleaner to capture spilled chemicals.  My mind immediately went to the thought of a vacuum cleaner bag full of all the powder needed to make BP and an electric motor.  It may not cause an explosion but I have decided to not follow his lead.

The tools I obtained included:

   ball mill (rock tumbler)

   1/2 inch lead balls for the mill (non-sparking)

   stainless steel screens to mix chemicals and separate various sizes of BP grains

   an accurate scale (all chemicals are to be calculated by weight, not volume)

   various storage containers 
   a 6-ton press to make BP into a dense puck with the needed dies

The chemicals purchased were 7.5 pounds of potassium nitrate, 1.5 pounds of charcoal and 1 pound of sulphur.  This are enough chemicals to produce 10 pounds of BP.  That should be enough to run my BP firearms for a long time.  I will be making small batches and using them as needed.  That way I will not be storing large quantities of BP.  Since my scale is in grams I have chosen to make a 200 gram batch (just over 7 ounces).  The proportion of chemicals is 75% potassium Nitrate, 15% charcoal and 10% sulphur.

The weight of chemicals for each batch is:

150 grams potassium nitrate

30 grams of charcoal

20 grams of sulphur

You can find numerous methods to make BP on the web and the process I have decided to use is basically what www.skylighter.com has in their guides.  They are also a good place to buy chemicals.  A good site to see the process in pictures is http://www.brianredmond.net/dwilliams/blackpowder/blackpowder.html 

To begin I ball mill all three chemicals separately.  Each is weighed to the proper portion and then screened together several time to mix as completely as possible.  At this time we have black powder and it is critical to follow all cautionary procedures.  When the three chemicals are well incorporated the batch is then placed in the ball mill and allowed to run 6-8 hours.  Some people simply place all three chemicals in proper proportion into the ball mill to begin with.  I may try that later and compare each batch for performance.

To maintain safety during this process the ball mill is placed in a container located 100' from anything I am not wanting to be destroyed if a blast should occur.

After the final milling is complete, the very fine black powder is dampened with a 50/50 mixture of water and alcohol, placed in the 3" die in the press and compressed over a couple of hours until the BP is in the form of a puck.  The puck is then dried.

When the entire batch is formed into pucks (I like about 1/8" thick while others use 1/2" or more) the pucks are crushed into smaller particles.  The particles are then run through a couple of screens including a #8, 8 squares per inch and a #20 screen.  This separates the particles by size.  

The particles that stay on the #8 screen are crushed and re-screened.  Those particles that stay on the 20 screen are then placed in the ball mill again without any ball media.  This step is to "polish" the grains of BP.  The material that falls though the #20 screen are reincorporated in the another puck and processed again.

Each batch is re-screened.  The 20 screen particles are used as FF (rifles) while the 30 screen are used as FFF (revolvers).  I do not expect to add graphite to the tumbling process as would be done with commercial powder.  The graphite added to commercial powder helps the powder flow which is beneficial for reloading brass shells.

To avoid all of this process, simply purchase any of a number of BP substitutes.  Some of us just like to do things to understand a little bit more of what it would have been like in the American frontier.  I'm sure most just bought BP but some brave souls had to make it. 

I will discuss a simpler method in another post to make black powder that is not great for firearms but can be used in fireworks and possibly firearms in a pinch.