The fire piston is a unique method of producing fire. In spite of the
appearance of needing higher technology to invent and construct a fire piston,
it is indeed a primitive technique.
Fire pistons rely on the principle that when air is compressed, it heats up
(this is the same principle that is used in diesel engines). If you compress air
enough, it will heat up enough to ignite tinder.
A fire piston consists of a cylinder and a plunger that fits into the
cylinder with a nearly air-tight seal. A tinder material is placed into the cylinder
and the plunger inserted a short ways. Then the plunger is suddenly and quickly forced
the cylinder, compressing the air and raising its temperature quickly and igniting
the tinder. The plunger is removed and the tinder carefully dumped out into a
larger tinder bundle and then blown into flame. Tinder
fungus is an excellent natural tinder to use with fire pistons.
Three fire pistons are shown here on this website, with pictures, a movie of
each, and descriptions.