The following instructions explain how to make a pyrotechnic device that
makes a hell of a lot of smoke and noise, yet emits only a relatively
minor amount of shrapnel.
The best size of cardboard tubing to use for this device is from 1/4"
inner diameter to a maximum of 1/2" inner diameter. The walls should be
about 1/10" to 1/4" thick.
Tools
safety goggles
hot glue gun
power drill or dremel tool
drill bit to fit your fuze wire
knife
ceramic coffee cup
Materials/Supplies
Pyrodex RS or Pyrodex P gun powder
green hobby fuze wire
thin cardboard tube (less than 1/2")
hot glue sticks
scotch tape
SETUP
Put on your safety goggles. Do not proceed any further until you have
some kind of eye protection available.
Lay out a clean work area, and protect the surface you're working on with
either newspapers or old sheets.
Plug in the hot glue gun and set it somewhere to warm up safely.
Pour out a small amount of powder into the coffee cup. You want to keep
this amount as small as possible, in case of accidental detonation.
CONSTRUCTION
You are now ready to begin making bombs! For starters, I recommend 3" to
4" of cardboard tubing. Use a knife and make a CLEAN cut at both ends of
the piece of cardboard. My favorite cardboard is that found on some
brands of clothes hangers. You can use other rolls.
Using either a drill or a dremel tool, drill a single fuze hole exactly
midway down the tube. This hole should fit as tightly around your fuze
wire as possible, so depending on the size of the fuze wire, use an
appropriately sized bit.
Cut a length of fuze wire (4 inches is usually sufficient). Place just
the first 1/10" inside the fuze hole. Using the hot glue gun, carefully
squirt a small bead around the fuze right up against the fuze hole. This
is to seal the fuze hole, as well as to firmly attach the fuze to the
device. When you have squirted the little bead in place, twist the fuze
around, slowly sliding it into the case while continuing to twist it.
This will tend to draw the glue into the case, which will make a very
solid fit and good seal.
When the fuze is all the way in (pressed against the far side of the case
opposite the fuze hole), it's time to begin charging the device. Put a
little piece of scotch tape over one end of the tube (doesn't matter
which). Make sure no powder can leak out past this tape, and then pour
powder into the open end. Make sure the powder is able to fall past the
fuze wire sticking through the tube. Fill the tube completely.
When the tube is completely full of powder, tap the tube to allow the
powder to settle a little bit. When it has stopped settling, carefully
pour out a little bit of the powder. The amount of space you want free at
the top of the tube should be approximately 2 or 3 times the diameter of
the tube. Any less than this will not allow for a strong end seal.
Sticking the nose of the glue gun into the open end, squirt in enough glue
to fill the end, stopping when you have a blob of glue sticking out the
previously open end of the device. Before going any further, you must
wait for this glue plug to cool and solidify. I find this is a good time
to start working on my next device, and I tend to round-robin two or three
of them, so that I have no waiting while the glue cools.
When the glue has cooled, turn the glue end down and carefully peel back
the scotch tape. At this end you want to repeat what you did before,
pouring out enough of the powder to accommodate a glue plug.
When the second glue plug has cooled and solidified, you now have a
completed device! For grinners, you can dip the thing into paint, or
spraypaint it. If you want additional water-resistance, dip the device
into a thick enamel paint, or some of that liquid rubber/plastic tool
coating stuff.
DETONATION
The most dangerous parts of this device are the two glue plugs at each
end, as they can fly off with incredible force. Make sure you and others
are protected from this type of shrapnel.
If you have water-proofed them with a thick enamel paint, you can even
toss these devices into swimming pools once the fuze has been lit.
Good things to launch skyward with these devices include aluminum cans,
hubcaps, empty paint cans, old shoes, feisty cats, and anything else you
can fit one of these babies underneath. Have fun!
