Chemistry & Science
Experiments

- Black Powder -
Granulated Black Powder and
Meal Coated Rice
Hulls

Black Powder is the backbone of pyrotechnics.
After all,
it's Black Powder that gives fireworks the smell we all love so much.

Black Powder Basics

Black Powder is
also known by a couple of other names. The most common, is Gun Powder. Black
powder is produced in large quantities commercially, and sold in small 1 pound
containers, mainly for use in antique Black Powder guns. It is also normally
sold in different granulations, and they indicate how fine the Black Powder is
granulated by how many "F's" they put on the container. Coarse granulations are
called "FG or FFG" (aka "1Fg" and "2Fg"). Finer granulations are "FFFg and
"FFFFg" (aka 3Fg and 4Fg).
The more "F's", the finer the Black Powder... and
the finer the Black Powder is, the faster it burns.
Small (fine) granulations
burn faster and are used in small bore guns, where larger (coarser)
granulations, are used for larger bore guns & cannons... and for launching
Aerial Shells out of mortars. Using a finer granulation for these jobs puts too
much strain on the gun (or shell or mortar) because the powder burns much faster
and creates a fast pressure increase that could damage whatever you're trying to
launch, or the gun/mortar itself.
Coarser, granulated Black Powder that is
used in mortars to launch shells, or in Roman Candles to shoot out stars, is
sometimes called "Lift Powder".
When Black Powder isn't granulated, and is in
a super fine powder state (similar to that of Talcum Powder) it is called "Meal
Powder".
Just to confuse things even more, any granulated Black Powder is
also sometimes called "Grain Powder".

Smokeless Powder
(Pyrodex, etc.) is not to be confused with Black Powder. It is actually
Nitrocellulose, and cannot be used in place of Black Powder.

Now, why
they needed 5 names to describe one substance is beyond me, but just keep in
mind that Black Powder, Gun Powder, Lift Powder, Grain Powder, and Meal Powder
are really all the same material. 20 years ago (when I was 13), I sat picking
the raisins out of Oatmeal because I thought Meal Powder was just finely
powdered Oatmeal. Needless to say, the rocket engine I was building didn't work,
as Oatmeal doesn't have quite the kick that Black Powder does. On the other
hand, Black Powder makes a terrible breakfast.

Anyway, as far as
fireworks are concerned, Black Powder is used both in its finely powdered form
(Meal Powder) for coating starts and for mixing in other pyrotechnic formulas,
and in its granulated form (Lift Powder) for launching shells out of a mortar,
or stars out of a Roman Candle.

The formula for
Black Powder is 75% Potassium Nitrate, 15% Charcoal, and 10% Sulfur, and like
all formulas, it is measured by weight only.

However, unlike many
pyrotechnic formulas, you just can't mix these chemicals together and expect to
have Black Powder. The mixing process for Black Powder is just as important as
the formula. Black Powder MUST be made in a Ball Mill to work
properly.
A Ball Mill is a rotating drum with dozens of lead balls
inside. The 3 chemicals are loaded into the Ball Mill, along with the lead
balls, sealed shut and allowed to rotate for anywhere between 1 hour and 24
hours. As the Ball Mill rotates, the lead balls will crush the chemicals
together, forcing some of the Potassium Nitrate into the pores of the Charcoal
and Sulfur. At the same time, the entire mass will be reduced to a super fine
powder. The longer the Ball Mill runs, the stronger the Black Powder will be. A
general rule of thumb for all pyrotechnic mixtures is " the finer the powder is,
the faster it will burn ".
ONLY lead balls can be used in a Ball Mill
as they are completely non-sparking. ONLY Black Powder can be mixed in a
Ball Mill. Other pyrotechnic mixtures such as Flash Powder, etc. CAN NOT,
as they are too sensitive and will explode. Individual chemicals however, can
also be Ball Milled into a fine powder, but the mill must be cleaned before this
is done.

Once the mill has
run for a while, it can be opened and the lead balls separated from the fine
Meal Powder.
As we'll show you below, this Meal Powder can now be used to
make all the other forms of Black Powder for use in fireworks.

Black Powder vs. Flash
Powder
A lot of people
ask which is stronger, Black Powder or Flash Powder... or if Black Powder can be
used in Salutes (exploding fireworks).
In short, there is no comparison.
Flash Powder is a high explosive, a shattering explosive. It converts to a gas
so fast, that objects near it, and containers that hold it cannot move out of
they way (or vent) fast enough to release this gas, so they are destroyed into
fragments.
Black Powder is a low explosive, a heaving explosive. It converts
to gas much more slowly than Flash Powder, and generally pushes things as
opposed to fragmenting them. If Black Powder is used in a small Salute like an
M-80, it will just make a loud "pop", and push out the end plugs.
Flash
Powder in an M-80 will make a loud explosion and fragment the tube into small
pieces. Flash Powder burns so much faster than Black Powder that in larger
Salutes, it doesn't even matter if you've got end plugs on the tube at all, it
will still detonate and fragment the Salute, even with 2 open ends.
You can
NEVER substitute Flash Powder for Black Powder or vice-versa. If you were
to use Flash Powder to launch a shell out of a tube, or a bullet out of a gun,
it would barely move the shell or bullet, and completely destroy the mortar or
gun, most probably injuring the operator.

Black Powder Manufacture