Carbon Fiber Defeats Metal Detectors? Think Again.

Ian Wendt of Special Circumstances and Morgan Atwood of BFE Labs just released a Youtube video about how electromagnetic (EM) Eddy-Current metal detectors can in fact react to carbon fiber. In simple terms, the vast majority of metal detectors used in the United States work by producing EM fields–and anything that disturbs that EM field sets it off. It doesn't have to be very conductive either; even though titanium is non-ferrous it still disturbs an EM field, for example.

Special Circumstances released the following statement:

To: All Special Circumstances customers with ceramic and carbon fiber laminated blades,
CC: Anyone who owns/carries carbon fiber knives for carry beyond metal detector-equipped checkpoints (wands or walk-through)

Subject: Eddy current-based metal detectors and carbon fiber

Announcement: It has come to my attention in the last few days that despite popular belief and the complete lack of any mention in available literature, carbon fiber can be detected by metal detectors that rely on eddy current detection. This includes the vast majority of modern security wands and walk-through metal detectors.

Even though carbon fiber is devoid of metal, there is a risk of detection based on factors described by me and Morgan Atwood of BFE Labs in the video below.

This discovery has put me in a very uncomfortable position, given that much of my business revolves around carbon fiber and ceramic laminated knives. However, I consider the implications and risks to be great enough that I believe it important to inform the community at large about this issue.

In short, if you carry one of my carbon fiber and ceramic laminated knives, you are at risk of detection by modern metal detectors. If you carry a carbon fiber blade from any other manufacturer or knifemaker, you are at risk of detection.

Therefore, I will no longer make any carbon fiber and ceramic laminated knives unless the customer SPECIFICALLY requests that construction and states that they accept the limitations of that material choice. Any existing, unfinished orders in my queue will be completed with G10 composites.

There is no impact on my carbon fiber and titanium laminated knives, or my plain titanium knives, as they were never intended for carry beyond modern metal detector-equipped checkpoints.

Police Magazine published an article detailing this back in 2006, but the information still remains widely unknown. Many who purchase and obtain CF knives and other tools do so with the belief they will be able to easily pass through a metal detector or pass physical wanding, but as Wendt and Atwood detail, that is simply not the case. There is some nuance regarding individual detectors and the grain orientation of the carbon fiber itself, as you will see in the video below.