Black Powder

General Information | Low Order / Burst

AKA: Gun powder (in some circles), BP, "powder".
Appears: Black or very dark grey powder.
Formula: KNO3 + S + C
Stability: Moderately Stable
Sensitivity: Spark, Flame
Solubility: Partial solubility in water.
Velocity: N/A



Gun Stores
    Generally readily available. Brands include:
    Goex Authentic Rifle Propellant
 Hobby Shops, Department Stores
    Black powder (or a reasonable facsimile thereof) is used as the fuel in model rocket engines.


Potassium Nitrate 75
Charcoal 15
Sulfur 10
    Preparation of black powder is a heavily discussed topic, and there are quite a few methods and revisions of methods concerning the preparation of the stuff. For the most part, preparation methods fall under one of two schools of thought: The milling method and the precipitation method. The milling method will be discussed here. In order to carry out this process, one will need a ball mill and optionally a press.

    After measuring the ingredients they are mixed together and loaded into the ball mill. The total amount of powder you can mill at one time is dependent on the size and power of your mill, so no specific loads will be given here. As a general rule, the mill should be filled 2/3 of the way once the material to be milled and the milling media (balls) are loaded.
    Mill the ingredients for about six hours, or until you are confident that the mixture is milled to the finest power possible. At this juncture the powder can be used as-is, since it is quite intimately mixed, but others may desire to press and corn the powder to increase performance. If this is the case, the milled powder is loaded into the press and compressed to 1.7 grams per cubic centimeter (which can be easily calculated by dividing the total weight of your ingredients to the volume of the press after you've cranked it), then crushed into the desired grain size.


    Regardless of how you prepare it, black powder will ignite with a spark or flame, burning quickly with an orange flame and producing a fairly large quantity of grey smoke in the process. The burning speed of the powder will depend on how well it is mixed, the amount of moisture present, and the size of the grains (if it has been pressed and corned). Poorly prepared black powder will burn slowly or not at all. If your black powder burns slowly and produces molten balls of potassium nitrate as it combusts (called pearls) it is a sign that your powder either has too much potassium nitrate or the nitrate is not mixed with the powder well enough.
    Black powder has a multitude of uses, including burst charges, primes, pyrotechnic boosters, fuses, and igniters.


    Spark and flame sensitive. Avoid these dangers, and excessive heat.
    Explosive, flammable.
    Hygroscopic. Keep sealed during storage.
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