Jacks Complete
January 4th, 2004, 05:20 PM
Haven't found this on the search.
I remember seeing a demo of this on Tomorrows World, back when I had TV. The way it was made was a couple of sheets of plastic, bonded together.
Basically, the trick was, to glue the two types of sheet so that the hard one was on the outside, and the soft was on the inside.
The bullet from the outside hit, and was distorted by, the hard outer sheet, which flexed the inner sheet, absorbing the energy. The shattered bits stayed in place, on the softer sheet, held by the glue.
Bullets from the inside hit the softer layer, and pushed through it, then shattered the hard outer layer, which was then pushed away from the glue and the softer layer, letting the bullet pass through. The hole would then shrink as the inner layer pulled back in, with the hard bits still glued to it.
Hence, one-way bulletproof glass. Obviously, it wouldn't be as strong as normal multi-layer polycarbonate and glass would, but it could be designed for the required threat level. Of course, you would need the occupants to be armed with something potent enough to pass cleanly through the outer layer, or you have one hell of a ricochet danger! It does, however, allow the option of shooting back, unlike the "fish in a barrel" approach otherwise employed.
Suggestions for the materials, anyone? I would think glass would do for the outer surface, and perhaps polystyrene for the inside, and some kind of superglue. Anyone know for sure? Any better suggestions?
I can't wait to make some! It is something I never got round to.
I remember seeing a demo of this on Tomorrows World, back when I had TV. The way it was made was a couple of sheets of plastic, bonded together.
Basically, the trick was, to glue the two types of sheet so that the hard one was on the outside, and the soft was on the inside.
The bullet from the outside hit, and was distorted by, the hard outer sheet, which flexed the inner sheet, absorbing the energy. The shattered bits stayed in place, on the softer sheet, held by the glue.
Bullets from the inside hit the softer layer, and pushed through it, then shattered the hard outer layer, which was then pushed away from the glue and the softer layer, letting the bullet pass through. The hole would then shrink as the inner layer pulled back in, with the hard bits still glued to it.
Hence, one-way bulletproof glass. Obviously, it wouldn't be as strong as normal multi-layer polycarbonate and glass would, but it could be designed for the required threat level. Of course, you would need the occupants to be armed with something potent enough to pass cleanly through the outer layer, or you have one hell of a ricochet danger! It does, however, allow the option of shooting back, unlike the "fish in a barrel" approach otherwise employed.
Suggestions for the materials, anyone? I would think glass would do for the outer surface, and perhaps polystyrene for the inside, and some kind of superglue. Anyone know for sure? Any better suggestions?
I can't wait to make some! It is something I never got round to.