Black Powder
It is
critical that a pyrotechnic learns to make quality black powder.
Commercial muzzle loading BP can be bought for ~$20/lb in most areas,
and is usually suitable for use in fireworks. However, BP made properly
at home can far exceed the burn rate of commercial, and only costs
~$1/lb if chemicals are bought fairly. At that price difference, buying
the equipment pays itself off very quickly. Read the Safety/Legal page before beginning.
Equipment Needed:
Digital Scale
- As with all compositions, an accurate scale is the most important
tool. With only a scale, if your chemicals are already in fine powder
form it will at least be possible to make hand mixed BP called
greenmix. The burn rate of greenmix is rather slow, too slow to break
shells, but it may lift them if an excess amount is used. Without a
scale, it will be impossible to make consistent BP at all, or any other
composition for that matter.
A good pyrotechnic scale should be accurate to at least 0.1 gram, and a
load capacity of at least 500 grams. I use and much prefer digital.
These can be bought many places, both online and are also commonly sold
at health stores. The intended use for them is to measure jewelry or
nutrition food products.
Ball Mill - This is the most expensive tool needed for making
black powder, but it is well worth it. Ball mills are extremely useful
not only for BP, but for all BP based compositions and the individual
chemicals of many others. There are many stars that will not function
at all if some or all of the composition is not first ball milled.
Other methods of grinding such as by hand with a mortar and pestle are
not capable of achieving what is needed for good BP.
A good ball mill can be bought for well under $100, though even that is
often more than a starving pyrotechnic can spare. As a result, many
have resorted to Building Their Own Mill.
Rock tumblers have also been used to some success, but they require
much longer runtimes to achieve the same result as a proper mill.
Whether you decide to go the route of buying or building a mill, you
will need media to use in it. Lead is by far the most common since it
is readily available in 50 caliber muzzle loader balls, is heavy, and
is non-sparking. Brass is the other semi common media because of
similar properties. One of these two medias is a must. Using media such
as glass marbles or the like will result in disaster. Stick with what
is known to be safe. Mills can be bought at a variety of pyrotechnic
suppliers online.
Screen or Pasta Strainer - This is merely for granulating the BP once it has been milled. Any large mesh screen or pasta strainer will do fine.
Getting To It:
The first step of making good black powder is found in the chemicals used:
| Black Powder: |
| Potassium Nitrate |
75 |
| Charcoal |
15 |
| Sulfur |
10 |
Potassium
nitrate is usually quite pure from any supplier and very suitable for
BP. Sulfur, if bought from a pyrotechnic supplier is also usually pure,
but if bought as the garden store variety contains about %10 clay. When
used in BP that evens out to be a %1 clay addition to the mix, meaning
the BP will still preform fine for just about any purpose, but will not
be quite as fast as it could be.
Charcoal is the real deciding factor. The wood the charcoal comes from
plays a large part in the burn rate of BP. Some woods that are
particularly good for fast black powder include: Willow, Buckthorn,
Balsa, and I have also had great success with White Pine. Other
charcoals made from mixed hardwoods as you would buy from most pyrotech
suppliers will work suitably well for BP, but as with sulfur, not as
well as they could.
The process used for making black powder is rather simple once all the
equipment and chemicals are purchased. The proper ratio of each
chemical is weighed out and placed into a ballmill jar with 50 cal lead
ball or brass media. It is not at all likely that the BP will combust
in the mill, but as a safety precaution always let it run outdoors or in a detatched structure from any occupied area.
For best milling the jar should be filled halfway with the BP
composition, though if it is slightly over filled it will only take
more time to properly mill. The milling time is dependent on many
factors, but as a rule of thumb: More milling time = faster BP. Between
8-10 hours is as long as needed.
Eventually, the Bp will begin to stick to the walls of the mill if left
in long enough. This is fine, but it is not necessary to wait quite
that long for your result to be adequately fast. If the Bp sticks to
the walls before 8 hours of milling has passed, it is possible that one
of your chemicals (probably potassium nitrate) has to much moisture in
it. This can be solved by placing your nitrate on a tray in the sun to
dry before using it for your next batch of BP.
When the milling is completed, screen the media out of the composition
by dumping the contents of the milling jar onto a heavy screen or pasta
strainer, allowing the composition to fall through onto newspaper or
into a large bowl. Place the media back in the jar for later use
milling BP type compositions.
The BP now made is in the form of what is called meal powder, and is
perfect for coating rice hulls for break. However, for lift the BP must
be in granulated form. To achieve this, begin to dampen the BP with
water in a bowl until it forms a solid clay mass. As water is added,
mix in a tablespoon of liquid laundry starch per 100 grams of BP.
Be careful to not get the BP so wet that it turns to a soup. It should
be a fairly dry clay.
Now force the composition through the strainer or screen and it will
come out granulated on the other side. It should be granulated upon
sturdy kraft paper or another surface that will not rip when
damp. Newspaper is too flimsy for this. When all the BP is granulated,
allow it to sit outside to dry. When the paper it is sitting on is no
longer soft from the moisture and becomes crisp, the BP is dry and
ready for use.
