Black powder has been around a long time. There are also many variations of its formula, each producing different results. In this guide I will cover the history of black powder, green mix, meal powder, pulverone, corned black powder, professional grade, and some different formula variations along with their purposes. The quality of black powder is determined by not only how fast it burns, but how much sparks are given off as a small pile burns. Also, how much residue left behind. The less sparks and the less residue, the greater the quality of the black powder. All images on this page are enlarged when clicked. Black powder is made by mixing Potassium nitrate, Charcoal, and Sulfur in a 75:15:10 ratio. The complete chemical equation of the combustion of black powder is unknown, but the products from the combustion are known:
Potassium Carbonate (K2CO3), Potassium Sulfate (K2SO4), Potassium Sulfide (K2S), Sulfur (S), Potassium Nitrate (KNO3), Potassium thiocyanate (KSCN), Carbon (C), Ammonium Carbonate ((NH4)2CO3), Carbon Dioxide (CO2), Nitrogen (N2), Carbon Monoxide (CO), Hydrogen Sulfide (H2S), Hydrogen (H2), and Methane (CH4)
Black powder is believed to have been invented in ancient china, around the 9th century (800-899 A.D.). Its discovery was unknown, but it appears to have been discovered accidentally like most things today. Some believe an alchemist was trying to find the potion to immortality. Around the 11th century, the Chinese military started using this material for rockets and bombs thrown from catapults. “The first reference to missile throwing weapons appears in 1259 when bamboo or copper tubes were used to launch baked clay bullets or shrapnel consisting of pebbles and small stones at the enemy." (Wikipedia). The use of this was spread throughout Europe and other countries from Eurasia (the huge landmass that consists of Europe of Asia). The Europeans were the ones that realized how important potassium nitrate was to the mixture. By the 15th century, the ottoman Turks knew what they were doing when it came to heavy artillery. They were able to construct a cannon with a 90cm bore, which could send a projectile weighing 320kg (705lb) over 1.6km (1mile).
Black powder was also used in mining, to blow up the bigger rocks. It was also used in engineering. Such examples include the Languedoc canal in southern France, the Erie Canal in New York and the Box Tunnel between London and Bristol. For more information on those, look them up in an encyclopedia. In the 19th century, black powder’s use as a blasting agent was replaced by nitroglycerin. Also, its use in firearms declined after the invention of nitrocellulose and smokeless powder. Today it is mainly used for pyrotechnics, muzzle-loading rifles, and war reenactments.
Green mix is the term used for black powder in which the ingredients have merely been mixed together. It is often inferior quality but can be used for a couple things. It is often used to prime stars as it will burn slow enough to give enough heat to the star. Green mix usually burns slowly giving off quite a bit of sparks and leaving a hefty amount of residue behind. Though minimal amount of work is needed to produce this; it is required to grind up the lumps of chemicals if there are any present. Green mix is often later turned into meal powder which is often more useful than green mix.
|Potassium Nitrate||Plastic Cup|
|Sulfur||Mortar and Pestle (or similar device)|
REMEMBER THIS RATIO: 75:15:10 (Potassium nitrate = 75, Charcoal = 15, Sulfur = 10)
Gather All your chemicals. From left to right: Potassium nitrate, Sulfur, Charcoal
Weigh out the potassium nitrate, charcoal and sulfur and place in plastic cup (or similar device). Remember that for ever 100g of black powder, use 75g potassium nitrate, 15g charcoal, and 10g sulfur. Dextrin is a binder that will hold this powder together if water is involved. It is necessary if you plan to prime stars, turn into filler pulverone (I'll discuss this later), or do anything else in which you want this powder to coat something. I did not add any to this batch for demonstration purposes, but I usually add dextrin to all of my black powder. If you need to, add 5% dextrin now. For every 100g of black powder, use 5g of dextrin (making 105g).
Pour all of this into a mortar and pestle. You can also use a plastic spoon with a bowl, but I like the mortar and pestle.
This is what the mixture should look like when all the lumps are crushed up and it’s evenly mixed. Note: Your black powder may vary in color due to potassium nitrate type. I used granular, which means its in big crystals (table salt size). If you use powdery potassium nitrate, your black powder will look grayer. As you can see, this makes a mess due to the charcoal. This green mix is ready for use.
Meal powder is just green mix that has been ball milled. The ball milling crushes up the ingredients as fine as possible and also integrates them better to produce a better black powder. This is actually the highest quality black powder (In my opinion) of all 5 mentioned on this page in terms of speed, sparks and residue. No, it is not as fast as pulverone or corned black powder, but when it’s properly milled it leaves no residue and almost no sparks come off of it when it’s burned. Pulverone and Corned black powder will leave a small amount of residue as water is typically involved which can change the size of the potassium nitrate crystals making them less efficient. There is a difference between milling all the ingredients separately and then mixing them compared to milling all the ingredients together. Milling them separately is safer, but the ingredients will not mix as intimately as when it’s all milled together.
|Potassium Nitrate, Charcoal, Sulfur OR Greenmix||Ball mill|
|Dextrin (optional)||Non-sparking grinding media (such as hardened lead balls).|
You do not have to make green mix in order to make meal powder. You can start from the chemicals and the ball mill will mix them up. I started with green mix for the purpose of this demonstration. If this meal powder is going to be used for pulverone, corned black powder, or used on stars then add 5% dextrin now. So for ever 100g of black powder, add 5g of dextrin (making 105g). I add dextrin to all my black powder.
Add your non-sparking grinding media to one of your ball mill jars. Note: In this picture is a 3lb ball mill jar filled with 100 hardened lead-antimony grinding balls. The media weighs 11.7g - 11.8g per ball. The correct ratio for ball mill jars is 50% by volume grinding media, 25% by volume black powder, and 25% by volume empty space. This will decrease the amount of time needed. I however do not use this ratio as I have limited amounts of grinding media.
Pour in the green mix or measured chemicals and dextrin if needed. The correct ratio for ball mill jars is 50% by volume grinding media, 25% by volume black powder, and 25% by volume empty space. This will decrease the amount of time needed. I however do not use this ratio as I have limited amounts of grinding media.
Seal the jar and place it in your mill then turn your mill on. Usually it only takes 2-4 hours to produce good quality black powder. When I ball mill, I turn it on at 8:00PM then turn it off at 4:00AM (8 hours). Then I turn it back on at 7:00AM and turn it off at 3:00PM (8 hours). The total is 16 hours with a 2 hour break in between to let the ball mill rest. Note: The model in the picture is a 6lb ball mill (dual 3lb jar) that is sold at firefox.
After the 16 hours, my meal powder was a very fine dust. It will gain in volume after the ball milling because the particles will be crushed finer. The clumps are only because it is so fine that it sticks together. These clumps break up without any force so don't worry if and when it happens to your black powder.
All pulverone is, is granulated meal powder. It is necessary to have dextrin in your black powder if you wish to produce pulverone as that is what holds the granules together. Pulverone burns much faster than meal powder because the hot gasses are allowed to shoot through the open spaces between grains. Filler pulverone can be made by granulating green mix with dextrin added. This will burn faster than green mix, but of course slower than regular pulverone. Some other common names for pulverone include "granulated black powder" or "granulated BP" (BP is a common acronym for black powder).
|Meal Powder w/ Dextrin added||Glass or metal bowl (no styrofoam and no plastic)Bowl|
|25% Alcohol Solution||Plastic spoon or similar device|
|20 mesh or greater screen. A window screen is between 16 and 10 mesh which is perfect.|
The 25% alcohol solution helps as the alcohol reduces the surface tension of the water. It can be made as follows:
For 100ml of a 25% alcohol solution, use the following ratios:
|95% Ethanol (Grain Alcohol)||74ml Water/26ml Alcohol|
|99% Isopropyl (Rubbing Alcohol)||75ml Water/25ml Alcohol|
|91% Isopropyl (Rubbing Alcohol)||72ml Water/28ml Alcohol|
|70% Isopropyl (Rubbing Alcohol)||64ml Water/36ml Alcohol|
|100% Methanol (HEET)||75ml Water/25ml Alcohol|
Here is 105g of meal powder along with a spray-bottle full of 25% alcohol solution. I will refer to this 105g as 100g since the dextrin doesn't really count.
Pour the 100g of meal powder into your bowl.
Now, you must make the meal powder damp, but not wet. I usually add 23-25mls of 25% alcohol solution to every 100g of meal powder. If you haven’t done this before, start at 20mls and work up from there. The meal powder will be crumbly but not shiny. If you accidentally add too much water, dry it in the shade or in doors. If you dry it in an oven, it could possibly ignite. If you dry it in the sun, the sun will dry up the top layer and seal all the moisture inside. For some reason, the texture didn't come out very well on my camera. It helps to turn down the brightness of your screen a little bit though to see it better.
Once it has achieved the right texture, prepare your drying surface and grab your screen. This is a 16mesh sieve used for cooking. I normally use a cardboard box lined with newspaper but I'm using a more flat surface for demonstration purposes. Lay out some newspaper on your drying surface to help absorb some of the moisture. As you can see, I used parade magazine to dry my explosives.
Pour your damp meal powder into the screen (don't worry, some will fall through) and use a pestle or similar device to push it through the screen. This will form small granules representing worms or terds. If they clump together, throw it all back in the bowl and add some dry meal powder to get rid of some of the moisture and try again.
I removed the magazine since it was too small anyway. Here is 100g of pulverone sitting on my drying surface... drying. It looks clumpy which is excelent for me so I can tell you how to get rid of clumps..
To get the right pulverone, you must break up the clumps and sift through the powder. To do this (once its dry), pour all your black powder into a colander (or similar screen with 3/16" wide holes). This will separate the good stuff from the clumps. Once you have the clumps separated, pour them into a glass jar and close the lid. Give the jar a few violent shakes then look to see if most of the clumps are broken up. If not, give it another couple violent shakes. Pour this through the colander (or similar device) again. There should be very little amounts of stuff that stays on top. This you can break up with your hand or just pour into the black powder as it.
Now, pour your black powder into a 20mesh screen (some small sieves are about this size). You should do this in small portions, not one big portion otherwise it won’t be efficient. Save the stuff that stays in the screen. The stuff that passes through can be put in the ball mill with your next batch of meal powder to recycle it, or you can just burn it. From this batch, I only got 75g of good pulverone. It is not completely necessary to separate the smaller particles, but it will improve the performance of the bigger particles. Below is a picture of another batch of pulverone drying. It's rougly 2lbs.
Corned Black powder is similar to pulverone in the fact that it is little granules of black powder. It is made by compressing a cake of meal powder to its maximum density, then breaking it up and separating the granules. It is different as it provides a more even burn rate and just all out performs better. The only downside is that you need a hydraulic press to make it. These of course are fairly easy to make, but can be slightly expensive. I will provide a tutorial on making a hydraulic press once I make one.
|Meal powder w/ dextrin||Hydraulic Press|
|25% alcohol solution||Powder Die|
|Mortar and Pestle|
The powder die is the device in which the cake is actually formed. I will also provide a tutorial on this once I make a hydraulic press. I can not provide a pictorial on corning black powder as I have not done it, but I will give you the basics of how to do it and hopefully that will be enough for you until I do this.
Add 5-10% by weight of the 25% alcohol solution to your meal powder and mix it well, ensuring to evenly distribute the moisture. Then pour it into your powder die. You powder die should be able to accommodate at least 100g of meal powder at a time. Insert the piston (the part that actually does the crushing) into the powder die, and then place it in your press. Crank the press up until the black powder has reached a density of 1.8g/cm3. You can do this by marking the side of the piston at the place where there is only about 55-56cm3 of space inside (for ever 100g). Once you've done this, remove the cake from the die and set it out somewhere to dry (in the shade). When it is dry, tap it against some concrete. It should sound like china being tapped against concrete. Break this 'cake' up and break all the chunks up into smaller grains. This is your corned black powder.
Professional black powder is very high quality although the formula to some of the manufacturers is kept very secret. It is essentially corned black powder, but it's been polished. To polish, they just tumble the grains of black powder in graphite powder to give them a more black look and make them flow easier (as graphite is a lubricant). It is easy however for homemade black powder to be faster than commercial grade though. It all depends on the type of charcoal you use. Here is a table of the burn rates of black powders made with different wood charcoal.
Burn Rate in Ft/s
|Rock Mountain Willow||300|
|Silver Maple H||330|
|Red Adler (1)||410|
|Red Adler (2)||410|
(Taken from rec.pyrotechnics)
Here are a few tables to help you size up your corned black powder to commercial black powder:
(Taken from Alan Yates page)
Black powder has many formula variations; each producing a different result. 75:15:10 is actually not the optimal ratio, its just favored among pyrotechnicians and pyro enthusiasts. The correct ratio is actually 74.64% potassium nitrate, 13.51% charcoal, and 11.85% sulfur. You would see no performance gain with this compared to 75:15:10 however. Below is a small list of formula variations along with what it does compared to regular black powder. Most of these variations were taken from Alan Yates page.
|75% Potassium nitrate|
This composition can be ball milled which produces results almost exact to regular meal powder. The good part about this is that its tollerable to low quality potassium nitrate. It also makes a good rocket propellant, even if its not milled.
|60% Potassium Nitrate|
This composition can be ball milled which will produce a powder that is slower than regular meal powder. This makes a good rocket propellant and is still used today in most core-burner rockets.
|64% Potassium Nitrate|
This composition can be ball milled to make it burn faster. It is a slight variation of the 6:3:1 type. It can be used in nozzless rockets.
|73% Potassium nitrate|
The main purpose of this is for a prime where sulfur should not be present (on chlorate based stars). It burns quite fast but is harder to ignite than regular black powder. It can be ball milled for a better quality powder.
"Black Powder" Wikipedia: The Free Encyclopedia. 20 May 2006 <http://en.wikipedia.org/wiki/Blackpowder>
Composition Database. VK2ZAY's Website. 20 May 2006 <http://www.vk2zay.net/composition_index.php>