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View Full Version : Failure of Carbon Fiber Knives to Pass Metal Detector Screening



Monte
03-04-2018, 08:10 PM
Over the past 18 years as a knifemaker, non-metallic knives have been a primary specialty of my shop. Like many other makers, Carbon Fiber has been the material of choice for the majority of those blades. Carbon Fiber (CF) has proven qualities of strength, toughness, and cutting ability that exceed other non-metallic composites.
Many other knifemakers have used CF in building tools for non-permissive-environments (NPE). My colleauge Ian Wendt, of Special Circumstances Inc, is a notable example. We have all believed that, being non-metallic, carbon fiber was capable of passing through a metal detector without causing it to alarm.
Working together, Ian and I have recently discovered that we were all wrong. Carbon fiber knives CAN be discovered by a metal detector.

Between myself and the other makers working in this field, a reasonable estimate is that there are thousands of carbon fiber knives in existence, and being relied upon. That practice is no longer recommended, as clear evidence shows they are not suitable for NPE use.

How Does This Happen?
In the simplest of terms, modern metal detectors use electrical current, passed through a coil, to generate a magnetic field. When that field passes over a metallic (or conductive) object, electric current is generated inside that object which creates it’s own magnetic field, that is then received by the receiver coil in the metal detector. This causes the detector to alarm.
Although carbon fiber is truly non-metallic, it is a conductive material. Being made up of multiple layers of hundreds of individual conductive carbon fibers, often interwoven, this means that a magnetic field will induce Eddy Currents within a piece of CF plate, such as a knife. That in turn creates a return magnetic field, received by the detector and alarmed on.

jmoore
03-04-2018, 08:23 PM
And........
...what many people erroneously call metal detectors are, in fact, backscatter x-ray machines. These will also detect non-metal objects.

geezer john

Gabriel Suarez
03-04-2018, 08:32 PM
And for at least ten mikefoxtrotting years now I have been saying that the era of carbon fiber or zytel or whatever material knives is gone and that tje era of DUAL USE WEAPONS IS AT HAND.

Dual Use weapons are things that are notvweapons bu design but are other things that can be used as weapons

So WHEN THEY ARE DISCOVERED...not IF...You can explain them away as anything but a weapon.

The higher the degree of sophistication, the more the need for dual use weapons.

Sam Security with a wand? Polymer knives are fine...specially when disguised with other items.

TSA? Dual use all the way kids.

Dorkface
03-04-2018, 08:32 PM
Good thing my muscles are with me everywhere I go.

WinstonSmith
03-05-2018, 04:38 AM
Thanks for the technical explanation, Monte. I had heard this rumor for some time but nobody could explain the science behind it. Your explanation makes sense.

I also agree with Gabe. I have some edged weapons like this, but they are for very specific purposes and would never travel into a true NPE with me like the TSA checkpoint at the airport (well, not intentionally but that’s a story for another time).

I almost like a throwaway folder for this role. If found, you say “oh man, forgot” and they say “mine, mine, mine” and that’s that. That’s “if” it is found (luggage screeners are not perfect, let’s just leave it at that). If they find the polymer or ceramic blade, they assume much worse intent about you.

Gun Mutt
03-05-2018, 04:44 AM
Wore a Wilderness Frequent Flyer on a trip recently: zero issues at RDU, pulled for wanding after the buckle's mass set off scanner at IND, fwiw.

5x5
03-05-2018, 06:25 AM
The easy button for flying is a screw driver. I carry two, wrapped in hockey tape for a better purchase, in my carry on and haven't even been asked about them. In fact, I believe one of the members here carries one in a custom kydex sheath. There is a length limit, but they are specifically mentioned by TSA as being legal.

Monte
03-05-2018, 09:43 AM
Thanks for the technical explanation, Monte. I had heard this rumor for some time but nobody could explain the science behind it. Your explanation makes sense.


I can't take the credit. It's stolen from the web.

Brightlightman
03-05-2018, 05:54 PM
The easy button for flying is a screw driver. I carry two, wrapped in hockey tape for a better purchase, in my carry on and haven't even been asked about them. In fact, I believe one of the members here carries one in a custom kydex sheath. There is a length limit, but they are specifically mentioned by TSA as being legal.

One of last flights they didn't give a crap about my screwdriver (sharpened for extra precision), flashlights, paracord wrapped cable pistol lock, or steel chopsticks. They were interested in my choirboy. Had to put it in luggage.

Brent Yamamoto
03-05-2018, 06:03 PM
I’ve flown twice now with the Crusader. Left it in a jacket pocket, they didn’t even ask me about it

MesserMan
03-05-2018, 07:42 PM
I had jury duty last summer at the county courthouse. Had to do the standard pocket dump into the tray and then walk through the detector. Had my Heretic (wrapped in paracord and everything) with me, it went into the tray with everything else. The officer working the checkpoint took special notice of it. The conversation went like this:

Officer (holding Heretic, looking closely at it): "What is THIS, is it a knife?"

Me: "Nope, bottle opener."

Officer (now with a big friendly smile on his face) : "Oh, haha, I used to carry one of those everywhere too. Don't do as much drinking nowadays though. Here you go" (handing it back)

Me: "Thanks, have a nice day."


I found that interesting, that even though he was immediately quite suspicious of it, all it took to make him accept it was stating matter-of-factly that it was a bottle opener. He didn't even give it second thought after that. Couldn't pull that off with a ceramic knife.

kabar
03-06-2018, 05:31 PM
I saw this article and immediately thought of this thread...

https://www.scientificamerican.com/article/stronger-than-steel-able-to-stop-a-speeding-bullet-mdash-it-rsquo-s-super-wood/

I'm not sure how pointy you could make this stuff, but I bet it would beat a #2 pencil by a good margin.

Maine1
03-14-2018, 07:55 PM
if we are reverting to wood...American Hornbeam is my choice.

once one opens their minds...everything is a weapon.

oldranger53
11-11-2019, 09:36 AM
if we are reverting to wood...American Hornbeam is my choice.

once one opens their minds...everything is a weapon.Roger that!
Everything is a weapon!

Sent from BlackBerry KeyOne

jesmith
11-11-2019, 11:02 AM
Get an old Bic fine point pen. The ones with the solid brass tip. Fill the barrel with epoxy glue. It will pass almost any search - and still write.

jlwilliams
11-11-2019, 07:59 PM
Non metallic knives are good for selling to guys who want a secret squirrel toy. There is nothing wrong with that. Lord knows I made a lot of cool stuff for guys who wanted it but were never going to use it. As long as you have buyers for carbon fiber letter openers, keep making what they are buying. It's good to be forthright and let people know that they don't fool a modern metal detector. Still, if you have buyers, make product.

The custom knife world has created all sorts of cool, multi use "EDC" type tools. Lots of church key/ bottle opener/ pry tools out there. There is still room for more and you won't go wrong creating tools that people can carry with the potential that they can be used to cause trauma. The market for quasi discreet personal weapon/ tools is vast.

boopee12
11-12-2019, 06:53 AM
The Scribe as sold at OST goes from here to Germany without a second look.

Mushinto
11-12-2019, 09:27 AM
I don't plan to board a plane or enter a courthouse with a purpose-built weapon. However, there are other places I go that have magnetometers where I do carry weapons if I can get away with it. For instance, they have elaborate screening at the local hospital where I sometimes have to go to visit people or pick up records. My retired Leo badge does not seem to impress them. They even temporarily confiscated my keychain knife.

This is good information.

The only penalty if caught, would be that they wouldn't let me in. My Cold Steel plastic balisong does not seem to alert them, and it is an awesome weapon.

--ML

OldLawman
01-16-2020, 02:31 PM
I recently started working as a regional sales rep for the largest metal detector company in the US. Walk though, hand-held and ground search. I have samples at play with.
I also have two of the Mad Dog Knives Frequent Flyer knives (both large and small sizes) along with their Kydex sheathes. No metal obvious, like rivets. Checked them both out - nothing. Nada. They could pass through anywhere that used this kind of detection. Now backscatter would be a different story. I have worn one or another going to various venues where I know they use WTMD, and nary a peep. Have not even tried airports, as the knives have too much market value to lose over an experiment.

TACC
01-16-2020, 09:19 PM
That ain't getting through TSA , these people are checking anomalies foung in my collar and rolled up sleeves, much less something if real substance.

Sent from my SM-G965U using Tapatalk

Greg Nichols
01-17-2020, 06:32 AM
That ain't getting through TSA , these people are checking anomalies foung in my collar and rolled up sleeves, much less something if real substance.

Sent from my SM-G965U using Tapatalk

Yep, try flying with metal in you. The scanner almost always picks up something.

Gabriel Suarez
01-17-2020, 07:36 AM
So defining NPEs briefly. There are Level 1 NPE which are decided upon by the owner of a venue and carry no legal ramifications other than being denied entry or being asked to leave. Then there are Level 2 NPE which carry a legal standing but are in unenforced state...such as an official building of some sort without a scan or pat down needed for access. Finally there are Level 3 NPE which have security of some sort (Police, TSA, etc.) and may have serious legal repercussions if violated (airplanes as one example).

Now the reality of things. There are guys who have no physical strength, no ability to fight with their hands, and have lead soft and comfortable and well fed lives whose only source of self defense on earth is a pistol. That my friends is a horrible thing to be by choice. Your first line weapons are these. Physical strength and martial ability. You do not need to be a BJJ master or an MMA contender. You will not be fighting a "match" with another man of your age and weight and skill. Just needig to discuss this smacks of a naivette toward violence that some have. You need to have the ability to break a neck, a leg, or a head. You need the strength to pick up a man and throw him through a window, off a balcony, or into traffic. And you need the physical toughness and immunity from the sort of pain that would shut down the most vociferous dad-bod ber swiller. Having that is worth all of the dual use, and overt use weapons ever made.

Next is an understanding of the ground you fight on. Shades of Musashi's Book of Ground. What is the real likelihood that you will be in a life and death gun, knife or fist fight so crazy they will write a rock ballad about? In a Post Office? Hmm...possible...good active shooter target, and well...we can dispense with all the "Going Postal" jokes. Same goes for a school, a church, a library, a mall, and other similar venues. So yes...being armed there is a good idea. How about in a large sporting event where everyone is being scanned by off duty police prior to entry? Yeah...still, although not as likely. How about on an airplane? Much less likely.

The point is that you always have your first line warrior body and skills. Adding layers to this depends on the ground and the environment. In places with extreme high levels of security that the screening is well funded and the repercussions for being discovered in violation are high, you will not have any layers added. I can choke a man out in three seconds. I can knock him out by smashing his head against a wall. I have done these things. The skill and ability to confidently say, yes I can do that to him is more useful and valuable than trying to sneak a ninja knife past TSA, or the Deputy manning the scanner, that won't accomplish the mission any better or faster.

Now to those "other venues"...I will discuss later.

Brent Yamamoto
01-17-2020, 09:09 AM
The point is that you always have your first line warrior body and skills. Adding layers to this depends on the ground and the environment. In places with extreme high levels of security that the screening is well funded and the repercussions for being discovered in violation are high, you will not have any layers added. I can choke a man out in three seconds. I can knock him out by smashing his head against a wall. I have done these things. The skill and ability to confidently say, yes I can do that to him is more useful and valuable than trying to sneak a ninja knife past TSA, or the Deputy manning the scanner, that won't accomplish the mission any better or faster.


YES!!!

I remember a shooting session many years ago with a karate master. It was great fun for all, the Japanese don't get many opportunities to go shooting.

He had a great time and appreciated the experience (and he was surprisingly good at it). Afterwards over food and drink, we discussed training, karate, shooting, etc. To conclude the discussion he held up a fist and said "This...this is better than the gun. You always have it with you."

I think there's a bit more to it than that. But he wasn't exactly wrong either.