Black powder is easy to make, and all of the ingredients can be purchased at drug or hardware stores. Invented by alchemists or (historically) the Chinese many years ago, black powder has seen many uses. It has been used in weapons, in fireworks and as a powerful tool for blasting away rock for road construction. It is also used as the charge to propel rescue parachutes and escape hatches in airplanes and ships.
Separate your ingredients. The recipe for black powder is 75 percent potassium nitrate, 15 percent charcoal and 10 percent sulfur. This is usually measured by weight: 75 parts to 15 parts to 10 parts.
Finely grind the ingredients. For safety's sake, grind them all separately and clean out the mortar and pestle thoroughly between crushings.
Mix all of the ingredients with a small amount of distilled water until the substance is the consistency of cookie dough.
Place small amounts of the mixture in a fine sieve and slowly pour small amounts of alcohol through them. This is a dangerous step; do not perform it near sparks or flame. This step can be skipped, but the resultant black powder will be of poor quality.
Hand-form the mixture into small, rectangular shapes. This is called "corning." Allow the shapes to dry thoroughly.
TL;DR (Too Long; Didn't Read)
This type of black powder is excellent for making model rocket engines.
Every step in making black powder should be considered hazardous.