FIELD EXPEDIENT
PREPARATION OF BLACK POWDERS
Preparation of Black Powder:
Potassium nitrate black powder may be prepared in a simple, safe manner. The
formulation described below will result in approximately 1-1/2 pounds of black powder,
which may be used as blasting or rifle powder.
Material Required:
• Heat source such as a kitchen stove (or an open fire, if it is the only available
source)
• Two-gallon bucket (metal or plastic)
• Cooking pan or skillet; 4 quart capacity
• Flat window screen, at least i-foot square
• Large wooden spoon or stick
• Plain weave cloth sheet (at least 2 feet square)
• Measuring cup (8 ounces)
• Potassium nitrate (granulated)
• Powdered wood charcoal
• Powdered sulfur
• Rubbing alcohol (70% isopropyl alcohol) or wood (methyl) alcohol
• Water
Procedure:
1. Measure by volume, 3 cups of granulated potassium nitrate, 2 cups of powdered
charcoal, and 1/2 cup of powdered sulfur into the 4-quart pan (or skillet), and
moisten with 1 cup of water. Using a wooden stick or spoon, throroughiy mix the
ingredients.
2. Add 2 additional cups of water to the mixture and place the pan on the heating
source. Allow the liquid to come to a simmer with sufficient stirring to obtain an
evenly mixed blend. With vigorous stirring, rapidly pour this mixture into five pints of
alcohol contained in the two-gallon bucket.
3. After the alcohol mixture has been allowed to stand about 5 minutes, collect the
black powder by straining the entire contents through the cloth. Remove as much
liquid as possible by wrapping the cloth around the powder and squeezing the
resulting bag.
4. Spread the wet powder in a thin layer (1/2 inch thick) on a flat surface and allow to
dry to a slightly moist solid. Place the screen over the bucket which has been
cleaned and dried from the operation described in Step 2. Place a workable amount
of the moist powder on the screen and granulate by hand, rubbing the solid through
the screen. If the particles collected in the bucket appear to stick together and
change in shape, recombine the entire batch, redry, and repeat the granulation
operation.
5. Dry the granulated black powder by spreading on a flat surface in about a '/2-inch
layer. Sun drying is preferred for this step.