How to Make Black Powder

How to Make Black Powder

(and other explosives)

Introduction

Black Powder, also known as Gunpowder, is an explosive that has been around, literally,

for centuries. The exact origins of the formula are lost in time, but it is known that the

Chinese used Black Powder in weaponry at least 1,000 years ago.

Technically, Black Powder burns by a process known as deflagration. This differs from

detonation in that Black Powder produces subsonic shock waves, as opposed to the

supersonic shock waves produced by explosives such as Dynamite, C-4 or TNT. This

means that Black Powder is better suited as a propellant (such as in fireworks, bullets and

cannons) than blasting (such as in construction or demolition).

Safety

Black Powder is dangerous!. The powder burns at a very high temperature, and is easily

ignited. (High grade powder doesn't even need a flame to ignite - it can be set off by

percussion, such as the firing pin of a pistol.) Basically, what I am saying is that if you

are not careful, you could land up with very severe burns, or worse. Some basic

guidelines to follow:

1) Always mix ingredients in small amounts. Do not try to make 10 Kg of black

powder (or any explosive) in one batch. Mixing small amounts of powder limits

the potential damage should an unexpected explosion occur.

2) Keep your workplace tidy. Always carefully clean up spilled chemicals. Some

materials can spontaneously combust when mixed (this is especially true of

nitrates and chlorates). For the same reason, use separate instruments (plastic

spoons, mixing cups, etc) for different chemicals. Label your instruments so that

you know what materials they have been in contact with.

3) Mix materials outdoors. Chemical explosives contain their own internal source of

oxygen, and cannot be smothered. If you start a chemical fire indoors, it can be

nearly impossible to extinguish.

4) Be aware of static sparks. Do not use metal instruments to mix or grind materials.

Do not store chemicals in metal containers. Use ceramics or plastics wherever

possible. Store chemicals and mixtures in plastic containers or ZipLoc bags.

5) Wear safety goggles. Should the worst happen, skin can be grafted. Eyes cannot

be replaced.

Ingredients

Black Powder has traditionally consisted of three ingredients: Potassium Nitrate (KNO3,

also known as Salt Peter), Sulfur and Charcoal. The Sulfur and Charcoal provide fuel for

the reaction, while the Potassium Nitrate provides Oxygen. By themselves, Charcoal and

Sulfur will burn, albeit very slowly. The addition of an oxidizer (such as KNO3) greatly

speeds up the burn rate of the fuel, resulting in an explosive reaction.

The traditional ratio of the ingredients is 15:3:2 of KNO3, Charcoal and Sulfur by weight

(not volume!). However, simply mixing the dry ingredients together will not give you

black powder. At best, you will get a green powder that will do little more than produce

vast quantities of smoke, and annoy your neighbors. In order to make high-grade powder,

a little work is needed.

Preparing the Ingredients

The quality of the resulting powder depends on a number of factors. The most important

of these is binding, which refers to how tightly the KNO3 is mixed in with the

Charcoal/Sulfur mixture. This is why a loose binding, such as a dry mix, produces a very

low-grade powder.

The quality of the powder is defined by its burn rate, usually expressed in cm3/s. A burn

rate of about 14 cm3/s or higher is required to use the powder as a propellant. (Also,

possession and manufacture of powder with a burn rate of 14 cm3/s or higher constitutes

a weapons violation under US law, unless you are also in possession of an ATF license.)

I will present two methods of preparing black powder here. The first produces powder

with a slightly lower burn rate, but is safer to prepare. The second can produce very high

quality powder, but contains an element of danger. The methods presented here will get

you a burn rate of 14 cm3/s or better, depending on how much patience you have, and the

quality of your ingredients.

The Charcoal/Sulfur mixture must be ground as finely as possible. Simply whacking

away at your barbeque charcoal with a hammer is not going to cut it. The charcoal must

be ground into a very fine powder. Commercial manufacturers use large machines known

as ball mills to crush the charcoal and sulfur. A ball mill is basically a large rotating drum

filled with charcoal, sulfur and a crushing agent, such as lead balls or heavy stones. The

mill is rotated at high speed for up to 48 hours or longer. The result is a very finely

powdered