The Igniter
An igniter is a device used to ignite a rocket engine.  In Estes rocketry, an igniter element is a strip of resistance wire with a coating of pyrotechnic material on it. In the system it performs like a resistor in an electrical circuit. As electricity passes through micro-clips connected to the igniter, the igniter begins to glow and give off heat. The pyrotechnic material coating is ignited and is the last step in the ignition. Igniters must be installed so that the coating is touching the dark-colored propellant grain. If the igniter is not touching the grain, this could cause a misfire. Heat created by the igniter is not great enough to cross a gap between the igniter and propellant grain -- There must be direct contact between the igniter and the propellant.
 
Figure 1 Figure 2
How to use:
First, separate the igniter you are going to use from the other igniters by tearing or cutting the paper between any two igniters. Do not remove the paper from the igniter as this may result in cracking the pyrotechnic coating.  Now take the igniter and insert it all the way into the nozzle of the engine, making sure that the igniter is touching the propellant grain. For some engines you may have to push the igniter a long way down, as when using a C5 type engine, so push down gently until the igniter will go no further. Make certain that the igniter’s leads are not crossed. If the leads are crossed, this can cause a “short” in your launch system and thus a misfire. Place the igniter plug in the nozzle of the engine and press down firmly. Bend the igniter leads as shown to the below.