Metal detectors - question

[dialex]

First, let me confess my complete ignorance. I don't have the faintest idea how this things work. I am wondering if they "sense" only ferrous alloys or even non ferrous like aluminum or copper, for instance.

Will they "sniff" a Tom Mayo TNT (Stellite blade, Titanium scales)?



<font color=blue>I'll be back!</font>

[Rex G]

Some, especially the earlier models, only detect ferrous metals, but the newer ones detect any metal, even things such as brass belt buckles. I would not try to get past one with any metal if there were legal consequences for doing so.

Edited by - rex g on 3/17/2003 9:06:02 AM

[Joe Talmadge]

Yep, any metal. Just a matter of how sensitive the thing is calibrated for.

[Sword and Shield]

Yep, definitely. I could go into how exactly they work (Think of a HUGE RLC circuit!), but I'll save that dry and boring conversation for another day. <img src="smile.gif" width=15 height=15 align=middle border=0>

Never underestimate the impossible.

[dialex]

Thanks a lot <img src="smile.gif" width=15 height=15 align=middle border=0>

<font color=blue>I'll be back!</font>

[Zrexxer]

Yep, I can't even think about getting through the ones at the airport these days without taking off my Texas A&M University belt buckle, and it's solid brass.

[MinalMinal]

There is one thing that I fuond that can get past the detectors, if you can find them and Yes I have one, it's called the Ti-Card. It is a solid piece of Titanium with and edge, Titanium isn't picked up by metal detectors, because it is a nonmagnetic metal. Being placed through a bag scanner or just keeping it in your wallet, it looks like a credit card, roughly the same size. They are actually really nice.

Nothing says "I Love You" like a knife!!!

[dialex]

How about those nylon knives? They say those knives cut pretty well. Some of them are even disguised as a hairbrush or a comb <img src="smile.gif" width=15 height=15 align=middle border=0>
I wonder how do they sharpen those things... Or are they single use only?

<font color=blue>I'll be back!</font>

[MinalMinal]

I dont know how well they keep an edge, but my Ti-Card is always on me in my wallet and constantly being used and it holds an incredible edge, and it is quick to sharpen on the Sharpmaker

Nothing says "I Love You" like a knife!!!

[sam the man..]

metal detectors!! aarrghh! well, late last year, when I boarded a flight to Brno in Czech Rep, my bone implant had triggered off the metal detector at the boarding gate.. then, the security dude used a wand on my left leg and asked me if I had something underneath.. Then I said : "bone implant" and he gave me a nod and said : "sorry, very sensitive detector, you can go.." man, these machines give me the creeps.. thank God the implant is out of my body.. <img src="smile.gif" width=15 height=15 align=middle border=0>

Sam

have scars will travel..

[Roshi]

Please be aware that even trying to carry a "plastic" knife, yawara stick, etc. on board a US aircraft will get you in trouble.

[Joe Talmadge]

<BLOCKQUOTE><font size=1 face=arial>quote:<hr height=1 noshade>
There is one thing that I fuond that can get past the detectors, if you can find them and Yes I have one, it's called the Ti-Card. It is a solid piece of Titanium with and edge, Titanium isn't picked up by metal detectors, because it is a nonmagnetic metal.
<hr height=1 noshade></BLOCKQUOTE></font><font face='Verdana, Arial, Helvetica' size=2>

MinalMinal: Obviously we all take our own risks. But there's one really glaring error above that you should know about: Metal detectors detect metal, not magnetism. All non-magnetic metals -- such as titanium -- are MOST ASSUREDLY detected by metal detectors. You could be slipping past because the metal detector is not set at a very sensitive setting. However, if for any reason you get wanded, in my experience the wands are always set super sensitive, and your titanium knife will get picked up quickly and easily. I've had the foil wrapper on half a pack of Certs get picked up!

Anyway, to re-emphasize: metal detectors detect metal, titanium is a metal, therefore titanium will be detected by any metal detector with the sensitive adjusted correctly. This is the guaranteed correct answer, it's not worth a felony sentence to test it!

Joe

[Sword and Shield]

OK, I wanted to avoid the physics of metal detectors, but the above confusion forces my hand. Sorry, all. Feel free to skip to the end. <img src="smile.gif" width=15 height=15 align=middle border=0>

A metal detector is basically a circuit with a capacitor, resistor and inductor. There is inherent in the system a net resonance derived from the resistance and inductance. When there is no metal in the loop, the resonance is constant, there is no current flow, and thus the buzzer doesn't go off.

If you step into the inductor loop with metal objects above a certain mass, you change the inductance, and by extension, the frequency. This change in frequency changes the current in the system, and the buzzer goes off.

Got it? Good. Now, in theory, anything conductive should set the detector off, such as a glass eye. The change in impedance for glass is so low that it is not normally measurable.

Now back to your regularly scheduled computing. <img src="smile.gif" width=15 height=15 align=middle border=0>

Never underestimate the impossible.

[Zrexxer]

Glass is conductive?

"We will not tire, we will not falter, and we will not fail." Oh well, I guess zero out of three isn't bad for Bush.

[reggie-ftw]

wow!! so glad to read this out of a message from Austin ! you just made my day .

[Sword and Shield]

Of course it is, Z. <img src="smile.gif" width=15 height=15 align=middle border=0> Ever hear of fiber optic communications, phone lines and such? Just a glass thread, is all. The resistance in a pane of glass is high enough to make it a near-insulator, but drawn threads work nicely.

Never underestimate the impossible.

[Knife Knut]

Huh?
Fiber optics are for "conducting" light.
<a href="http://electronics.howstuffworks.com/fiber-optic1.htm"> http://electronics.howstuffworks.com/fi ... ic1.htm</a>

As for the Nylon implements, I think that they would have verry poor cutting ability. They would be useful for thrusts (particularly the one based on the OSS spike dagger), or pressure points and pain compliance through concentration of force.



Knife Knut on a shoestring budget. <br>RKBA


Edited by - Knife Knut on 3/19/2003 11:25:44 PM

[dialex]

I have some metal teeth <img src="sad.gif" width=15 height=15 align=middle border=0> I guess they'd strip me and the darn thing will keep on buzzing <img src="tongue.gif" width=15 height=15 align=middle border=0>

<font color=blue>I'll be back!</font>

[Shiden]

Last summer I visited the Bundstag (the German parlement) in Berlin. We all had to pass through a metal detector, and bags and other stuff went through a Röntgenscanner (as on airports). My SpydeRench didn't trigger the metal detector. It surprised me, I'd loved to see their reaction. Probably the detector wasn't set very sensitive.

Shiden-Kaj

"Fear causes hesitation, hesitation causes your worst fears to come true." Neo, the Matrix