Here’s a youtube video where the guy makes a small bomb using stuff purchasable in airport terminals *beyond* the security checkpoint (however, he uses a few tools that would probably raise flags at the metal detector. The bomb is pretty simple: a lithium battery is pulled apart and wrapped around a tiny can of aerosol spray, and placed in a steel thermos mug; also placed in the mug is a condom partially filled with water and tied off. Shake, and the spraycan pops the condom; the water gets into the unwrapped battery and does an energetic little dance with the lithium, which burns through the aerosol can and ignites the contents… blammo. The mug, optionally, is wrapped with a magazine and dental floss; this adds *slightly* to the strength of the mug, allowing pressure to build a bit more and make a bigger bang.
The video is age-restricted, so you might have to sign in to see it.
[youtube TZ5a4ycwsig]
The guy behind this has a website and a number of such videos, showing different weapons you can make using stuff you can buy inside the airport.
The value of such demonstrations is not to teach nuts and terrorists how to cause trouble. No, it’s to show that “security through obscurity” is a thing of the past. People will be able to cobble together deadly weapons *anywhere,* so it’s best to deal with the mindset and the person, not the tools. Someone will figure out how to MacGuyver Nerf into a high explosive with razor-sharp edges using nothing more than a packet of peanuts and a lukewarm half-can of Diet Coke.
Personally, I’m always impressed when someone demonstrated this sort of cleverness. Granted, the “fraggucino” grenade isn’t that big of a bang, almost certainly wouldn’t blow a hole in a jetliner fuselage… but it’d cause a hell of a ruckus. And someone else *will* be able to figure out how to take the ingredients and turn it into a *real* bomb.