A blasting cap is a small explosive device generally used to trigger a larger more powerful explosive such as dynamite.

Blasting caps come in a variety of types, some of which are: non-electric caps, electric caps and fuse caps. They are used in commercial mining and are set off by a dynamo device which generates a short burst of current in a line long enough to ensure safety,

The need for blasting caps arises due to sensitivity issues of an explosive compound. High explosives detonate, or instantaneously convert into heat and chemical by products. Each explosive has a certain amount of energy required to create detonation. If an explosive is too sensitive it may detonate unexpectedly. The most practical explosive compound is one that is safe to handle, and wont detonate if accidentally dropped or mishandled. A blasting cap provides the initial shock wave to start a detonation in a more predictable way.

Blasting caps contain what is called a primary explosive. A primary explosive is a high explosive compound that will explode from flame, heat or shock. A blasting cap also contains a booster - another explosive to make the cap more powerful, and thus, more reliable for detonating secondary explosives.

Common explosives used in blasting caps are mercury fulminate, sodium azide, lead azide, and tetryl, among others.

External links

• Blasting Caps