Black powder is also commonly called gunpowder or lifting powder. It is not as powerful as flash powder and has a pushing power instead of a blasting powder. It is a low explosive which is commonly used in fireworks to propel shells or rockets into the air. It is not very suitable powder to use to explode things, but it can be done.

INSTRUCTIONS:

MATERIALS:
Potassium Nitrate
Charcoal (pure charcoal is best, although you can use barbecue charcoal)
Sulphur (pure sulphur is best, although flowers of sulphur can be used)
Water

EQUIPMENT:
Metal tin (cleaned cat food tin, spaghetti tine etc)
Grinding equipment (ball mill, mortar and pestle, or even a hammer)
Heat source without flame(camp stove with block of concrete on top, oven, hot water cylinder, or even the sun)
Stirring device (eg wooden stick)

METHOD:

1. First you need to weigh out the chemicals. The weight ratio between the three ingredients is 75% potassium nitrate to 15% charcoal to 10% sulphur. If you don't have accurate scales, you can use the formula 3 parts potassium nitrate to 2 parts charcoal to 1 part sulphur. This is obviously not as precise as using a digital balance, but makes a pretty good mixture of black powder.

2. You will need to make sure the chemicals are finally crushed, especially if you are using barbecue charcoal, which comes in a big lump. Black powder is special in the way that it is very insensitive to shock and therefore can be grinded without the worry of it going of. Trust me, I've placed a pile of black powder on concrete and hammered it with a mallet and nothing happened. This is an exception to most pyrotechnic mixtures so do not try this with other mixtures. An easy way to grind the chemicals is to put the potassium nitrate, charcoal and sulphur in a seal-shut plastic bag, place it on concrete and hammer it until it turns to powder. If you are more fancy you can use a mortar and pestle or even a ball mill for optimal results. Once the chemicals are all crushed, mix them all together in the metal tin.

3. Now slowly add water to the mixture while stirring. We do this because water helps improve the burn rate of black powder by allowing the molecule of potassium nitrate to be absorbed into the gaps between the molecules or charcoal. Keep adding water until the black powder turns into a very wet, black paste.

4. Now we need to evaporate the water as fast as possible, preferably within the hour. This is to stop the particles in the mixture clumping together and crystallizing, which would slow down the burn rate. The best method I have found is to use a camp stove and a block of concrete. The metal tin must not come in direct contact with the flame so I have found if you place a block on concrete on the camp stove you can heat the concrete up un till it become hot to the touch, turn of the flame, and then place the metal tin on the top surface of the concrete. Concrete keeps its heat for along time, therefore it should stay warm for hours, supplying a steady supply of heat to the black powder in the metal tin to evaporate all of the water. Stir the mixture every ten minutes or so while its drying to keep the chemicals well mixed. Also make sure the water does not start to boil, if so immediately take it of the heat and let the concrete cool down first.

5.As the black powder starts to dry off it should start to stick together. Keep stirring until the black powder comes dry to the touch. It is now a good idea to heat the concrete up once more again to drive of the very last of the water. Be wary that the black powder in its relatively dry state is sensitive to heat, so as a precaution in helps to not heat the concrete up as much as before. Remember to take the tin off the concrete while the camp stove is heating it up, because the hot air rising is much hotter than the concrete and can heat the tin up so much it sets the black powder inside on fire.

6. Now the black powder is really dry, scrape it out of the tin and grind it a final time to remove all the lumps. Store it in a well labeled air proof container away from heat and flame.