Time
Bomb
One of the
more advanced properties of being an explosives specialist is the capability
to set off an explosive device exactly when it is required to detonate.
Hypothetically speaking a time bomb could be setup to explode after four
months during a change in season during which time the perpetrator could
disappear with very little evidence associating him with the device. The
science of time bombs is much more complicated than the use of conventional
explosives. i.e anyone could put a fuse in a pipe bomb and blow it up
but very few have the ability to control their explosions down to the
minute or the second hours after the device has been deployed in its place.
There are
two types of technologies associated with time bombs; The electrical deals
with the use of electronic circuits to time when the bomb will go off,
this technology is very accurate and could be used to control an explosion
down to the last second. The mechanical is the crude way of doing things,
it is less precise but can be setup a lot easier than by using an electronic
circuit. An additional technology is chemical which will also be discussed.
Mechanical
Fire plays a very important role in mechanical timed explosions. The very
simple example is the cigarette; a cigarette burning itself out also has
a moving flame, a fuse can be tied at the base of the cigarette where
the flame ends up and this fuse has a good chance of being lit once the
cigarette reaches that point. However with safety technology being applied
to cigarettes it is very likely this will not work very well, even if
the filter is removed to aid an air draft the heat of the cigarette will
find difficulty in lighting the fuse. A much better alternative is to
use a candle, simply a long candle placed flat on a non flammable surface
with a fuse intersecting it at it's base where it will ignite once the
flame reaches the fuse. A cigarette can usually take four minutes to burn
out and candle time varies from one type to another.
Electrical
Probably the best overall type of time bomb technology. The easiest way
to use this is to buy a time delay relay circuit from an electronics shop.
The relay controls the connection between a battery and the detonator
and the circuit controls the circuit. So if the circuit is set for one
hour once the hour is up the relay closes connecting the battery to the
electrical detonator causing an explosion. Only a basic knowledge of hobby
electronics is required for use of a prebuilt relay delay circuit. A technician
could also build a special purpose electrical circuit to this purpose
including safety devices and indicators to prevent accidents. An electromechanical
time bomb can be build using an analogue clock or watch; A small nail
can be punched into the face and when the minute or hour hand contact
the nail a circuit is closed between the axis of the clock and the nail
which when are attached to wires, battery and detonators can be an effective
and easy to contstruct time bomb.
chemical
Chemical delay initiators are very interesting and have their own special
uses. Once being they cannot be easily detected by electronic equipment
since they don't use a battery or emit any radiation and they are also
easily destroyed with the explosion preventing a forensics team from identifying
the initiator. The reaction between Perchlorate or chlorate and sulphuric
acid is explosive. if sulphuric acid is set to drip on aluminium foil
it will eventually eat through the foil and could be setup to drip on
chlorate powder on the other side causing an explosion on contact. Permanganate
and Glycerol also form an interesting combination, once glycerol liquid
is in contact with Pottassium Permanganate there is a delay of three minutes
before the compound bursts into flame.
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