Detonating cord comes in many different colors, jacket material styles and thicknesses. It looks like safety fuse, but instead of a black powder burning core, it contains a white powdered PETN high explosive core. It comes in coils or on spools of various lengths. Its strength is measured in “grains per foot”. Grain is a term used in measuring powdered materials like explosives and pharmaceutical powders. 1 grain is approximately 64.8 milligrams in weight. There are 437.5 grains to the ounce. There are 7,000 grains to the pound. Manufacturers generally color the jacket material or on textile types they often wind a countering thread of a contrasting color around the outside, to identify the strength of the product. This is then compared against color images in sales literature or technical brochures and package/spool labels.
Detonating cord explodes down its length at the rate of about 7,000-8,000 meters per second, when initiated by the explosion of a detonator taped to it. The explosive shock wave also radiates outward as it travels the length of the cord. Any other high explosive material that the cord passes through or is in close contact with, will also be detonated by the travelling shock wave.
Securesearch sells a wide variety of inert products made for us by detonating cord manufacturers. The core material may be a fine powder, fine granular material, or textile fibers to differentiate it from live product. We also have x-ray correct inert detonating cord product; it is custom-manufactured for us for those training and test applications that require the detcord to look on x-ray imaging equipment, as if it is live product.
Detcord lengths can be connected by special detcord connectors, or detcord relays. Some are small devices made of plastic, that look bone-shaped, and have an explosive-filled cylinder inside to transmit the shock wave from the end of one length of cord through to the start of the next length. They have a set of locking device, 2 plastic cross-pins to prevent the looped detcord ends from slipping out of the connector. They come in different colors, to indicate different loadings or millisecond delay times. Other types are aluminum or copper cylinders, open at both ends and into which the detcord is inserted. A special ring-crimping tool locks the metal shell wall to the detcord jacket. They have a small explosive charge in the middle, and if there is a millisecond delay, the delay time is printed on the exterior.