Page 1 of 2 12 LastLast
Results 1 to 10 of 13
  1. #1
    Join Date
    May 2011
    Location
    Central Mississippi
    Posts
    912

    Default Failure of Carbon Fiber Knives to Pass Metal Detector Screening

    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.
    Last edited by Gabriel Suarez; 03-04-2018 at 08:33 PM.
    .
    Monte

  2. #2
    Join Date
    Nov 2010
    Posts
    443
    And........
    ...what many people erroneously call metal detectors are, in fact, backscatter x-ray machines. These will also detect non-metal objects.

    geezer john

  3. #3
    Join Date
    May 2000
    Location
    Beyond The Wall
    Posts
    44,770
    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.
    Gabriel Suarez

    Turning Lambs into Lions Since 1995

    Suarez International USA Headquarters

  4. #4
    Join Date
    Feb 2009
    Location
    Colorado
    Posts
    7,286
    Good thing my muscles are with me everywhere I go.
    Geek Warlord
    Dungeons & Dragons & Deadlifts

    Muscle Wizard Casts: Fist


    CRG-1 DPS
    CRG-2 CRG x 2
    SGF-1 Shotgun Gunfighting
    Trauma care under fire
    Spetsnaz Sniper
    HRO-5 Terrorist & Active Shooter Interdiction
    HRO-6 CQB: Fighting in Structures
    CRG-4 Force on Force
    HRO-5 Terrorist & Active Shooter Interdiction - 3 day
    TWOTU edition
    Trauma Medicine for the CCW Operator
    Pistol Ground Fighting (Taint Shooting Progressions)

    TWOTU since May 2015

  5. #5
    Join Date
    May 2011
    Posts
    8,482
    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.
    LIVING > FIRED > JAIL > DEAD

    DISCIPLINA EST LIBERTATEM
    KRG, HRO: Team Tactics 1/2, CRG, HRO: CQB/Team Tactics, Defensive Knife, TMCO


    T
    WOTU Since 2012


  6. #6
    Join Date
    Aug 2004
    Posts
    4,383
    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.

  7. #7
    Join Date
    Oct 2011
    Posts
    176
    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.

  8. #8
    Join Date
    May 2011
    Location
    Central Mississippi
    Posts
    912
    Quote Originally Posted by WinstonSmith View Post
    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.
    .
    Monte

  9. #9
    Join Date
    Mar 2011
    Location
    SWFL
    Posts
    708
    Quote Originally Posted by 5x5 View Post
    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.
    KRG-1: Kalashnikov Rifle Gunfighting
    HRO-5: Terrorist and Active Shooter Interdiction
    CRG-4: Force On Force Gunfighting
    CRG-5: Zero To Five Feet Gunfighting
    Red Dot Combat Pistol School
    HRO-6/HRO-7: CQB-Fighting in Structures/Team Tactics, Urban Warfare Weekend

    TWOTU since 2016

  10. #10
    Join Date
    Mar 2011
    Location
    Western WA
    Posts
    5,508
    I’ve flown twice now with the Crusader. Left it in a jacket pocket, they didn’t even ask me about it
    Brent Yamamoto
    Suarez International Tier 1 Staff Instructor

    Ready, willing, able. Bring it.

    Instagram: karate_at_1200fps

    Upcoming classes:

    Advanced Close Range Gunfighting - Nov 2-3 Mapleton, OR

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •