Why are metal detectors almost always used to find weapons when sharp and strong objects can be easily made from plastic, glass, etc.?

Question

Why are metal detectors almost always used to find weapons when sharp and strong objects can be easily made from plastic, glass, etc.?

In: Other

Answer 1

While weapons *can* be made from materials other than metal, metal is easiest material to produce and maintain a sharp edge.

The other fact is that we don’t have ‘plastic detectors’ or ‘glass detectors’ (in the same function and form as metal detectors), so it becomes more time consuming to find these types of items.

Answer 2

Even though they *can* be made out of materials other than metal…they’re still almost all metal. 

Answer 3

Also guns are much more important than knives to be caught given the much higher lethality, and essentially all of those are made of metal.