Improvised Munitions Handbook (Improvised Explosive Devices or ...

2. Cut 2 slots on opposite sides of the tin can at the line
farthest from the open end. Make slots large enough for
the flat stick or piece of metal to pass through.
3. Punch 2 small holes just below the rim of the open
end of the can.
4. Tape blue tip matches together in pairs.
The distance between the match heads
should equal the inside diameter of the can.
Two pairs are sufficient.
5. Attach paired matches to second and third
coils of the spring, using thin wire.