How does C4 work?

C4 is an explosive compound known as RDX that is coated with a plastic binder. The plastic basically serves as both an protector for the explosive, and as an malleable feature for it.

Since the explosive has a coating of plastic over it, to set off C4, a blasting cap or wire is usually inserted into the explosive, and a jolt of electricity sent through it to set the RDX off.