Gatecrasher™

PDF icon

Download the Gatecrasher™ Datasheet

Theory

In rock blasting and building demolition, shot holes are drilled precisely where explosives will have their maximum effect – spread out throughout the rock with the explosives packed into the centre of the rock. Unfortunately, in breaching this is not possible and the explosive must be applied to the outside of the target.

If a lesson can be learned from rock blasting then it is that it is better to spread your explosive across the area where you want to make a hole in order to shape the final hole rather than using the same amount of explosive in a big lump in the middle. If a single lump is used, the final size of the hole depends on how much explosive you use and to make a large, man sized hole, you need to use much more explosive than you would if you placed the explosive in the shape of the hole.

Even if you spread the explosive out in the right shape, the laws of physics dictate that most of the energy of the explosive escapes backwards into the air behind the charge. This is because as the explosive turns to gas, the gas will always try to find the easiest route of escape and going back into the air is much easier than going through a wall. This is the reason we use tamping which is effectively replacing the air behind the charge with something denser and heavier – water. Even though the water is not as thick and dense as the wall it still slows the escape of the gasses by a few miliseconds and even that short time is long enough for enough extra force to be directed towards the target to effectively double the force of the charge. If you use less water, the effectiveness is less and you can never really have too much tamping material.

After conducting our own trials we came up with the dimensions of the Gatecrasher™ which strike a balance between effectiveness of the charge against size and weight (amount of water).

Key Features

  • Water-Tamped
  • User-Filled
  • Variable Load – 300g – 3kg
  • Usable with a wide range of explosives – detcord, sheet, bulk
  • Central channel gives an optional kicking charge for use on thicker targets in order to clear the centre of the hole
  • High Performance – 19 inches successfully breached