bombcb.txt
CARDBOARD TUBE BOMBS
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
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
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
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!
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