A cap crimper, or more correctly a blasting cap crimper, is a dedicated tool or a part of a multi-function tool designed to crimp or attach a pyrotechnic type blasting fuse to a blasting cap or detonator. These blasting caps or detonators are then used to explode, detonate, or set off either commercial explosives used in mining and construction or military explosive charges used for demolition. A cap crimper is a tool specially designed and constructed to facilitate the connection of these fuses and caps in an efficient and safe manner. These tools are made of non-ferrous metals, which prevent sparking, and are designed to apply only sufficient pressure to complete the crimp without damaging the cap.
Most commercial and military explosives are designed to be inherently stable and immune to impact, heat, cold, and even fire. They can only be set off or detonated by the application of extreme shock such as that supplied by a blasting cap or being in direct contact with other detonating explosives. There are several types of blasting caps in use to facilitate explosive detonation, most of which are electrically operated. Pyrotechnic type fuses are still used frequently, though, and it is in these applications that cap crimpers are used.
Blasting cap crimpers are typically single purpose tools specifically designed to crimp blasting caps only. Several multi-purpose tools available include a cap crimping attachment among their features, however. Dedicated blast cap crimpers are similar in appearance and operation to electrical connection crimpers, and are typically constructed of a non-ferrous metal to prevent accidental spark generation. These crimpers operate by evenly applying a concentric or equal indentation around the hollow copper blasting cap that holds the fuse firmly in place.
Blasting caps designed for use in conjunction with pyrotechnic fuses are primarily used in applications where the danger exists of possible premature detonation of electric caps due to static interference. These blasting caps consist of a hollow copper tube closed at one end and filled with a small explosive charge. The tube is empty for a short distance towards the open end and it is into this cavity that the fuse is inserted and crimped into position with the cap crimper.
Pyrotechnic fuses are typically hollow plastic tubes filled with a combustible mixture that is ignited with a simple flame. These fuses provide the catalyst required to explode the blasting cap and in turn detonate the primary explosive charge. Plastic igniter cord (PIC) is a common form of pyrotechnic fuse and is widely used in mining and construction blasting operations.
Due to the fact that blasting caps contain an explosive compound, care should be exercised to avoid crimping the explosives when using the cap crimper. Blasting caps should always be held facing away from the face and body when using the cap crimper to prevent accidental injuries should the cap detonate unexpectedly.