Delay compositions are used to introduce a delay into the firing train, e.g. to properly sequence firing of fireworks, to delay firing of ejection charges in e.g. model rockets, or to introduce a few seconds of time between triggering a hand grenade and its explosion.
Typical delay times range between several milliseconds and several seconds.
A popular delay charge is a tube of pressed black powder.
The mechanical assembly prevents the outright detonation of the charge.
Typical materials used are: The burn rates are dependent on: [1] Examples of some compositions are: [2]