Titanium and metal detectors

[InfernoMDM]

I forgot about this little bit of information, and thought I would share it. A long time ago probably before my initial sign up on this forum I was looking for the perfect dive knife. I use to swim extensively in the ocean and have nearly drowned from drifting shrimp nets and ropes around docks. Well as you all know rust is the killer of steel and even high quality steel, and even tenifer(coating on glocks might have misspelled the word) coated steels aren't a match for the ocean salt water.

While in my travels I came across a titanium folding knife. I will see if I can find it again but the company was oceanmaster or seamaster I believe. Around the same time I also began to play with the idea of defeating metal detectors. Well I had a chance to run my own titanium knife and a few others claiming to be titanium through the metal detector. Needless to say it didn't set of the metal detector after I removed the metal pocket clip. The test was more to see if metal detectors in airports, and other higher security areas would detect the knife itself, and they didn't. That said other knives claiming to be titanium didn't pass through, and were subsequently researched that a few were covered in, or only partially made of titanium.

I thought I would share that with you guys, although I know many of you know that from pure scientific fact this to be the case, but sometimes its nice to test things.

[Grapes Of Wraith]

Have you looked into the idea of a carbon fiber knife I know you can buy them and that they can't be detected. What I do not know is thier resistance to water, I would guess that it would be impossible for the blade to rust or dull in watter.

[InfernoMDM]

Have you looked into the idea of a carbon fiber knife I know you can buy them and that they can't be detected. What I do not know is thier resistance to water, I would guess that it would be impossible for the blade to rust or dull in watter.

Yes but Carbon Fiber knives that are generally found really have no edge. The best thing they have is the ability to pierce.

Also a note on sharpening titanium. Do not use any metal based sharpener as it will magnetize the titanium enough to set off the metal detector.

[Match]

Have you looked into the idea of a carbon fiber knife I know you can buy them and that they can't be detected. What I do not know is thier resistance to water, I would guess that it would be impossible for the blade to rust or dull in watter.

Carbon fiber is a mix of a carbon fiber (usually in bands) and a resin, it would be like trying to make a knife out of fiberglass, It has a high tensile strength, but it's not hard enough to cut anything. Although you could make a knife out of carbon fiber as long as it something hard for the blade.

Ceramic, flint, plastic, are all plausible for a edged weapon.

As for getting past metal detectors, I've *accidently* brought a pocket knife and multi tool, each with a blade long and sharp enough to scare sheeple into submission. I was unaware that they were in my carry ons. Airport security is a joke.

[Grapes Of Wraith]

best thing they have is the ability to pierce.
I just thought I'd mention that because they can still be used as a lethal weapon, and can be snuck onto a plane or other high security place.

http://i10.photobucket.com/albums/a139/maxdal/cfk.jpg

[InfernoMDM]

As for getting past metal detectors, I've *accidently* brought a pocket knife and multi tool, each with a blade long and sharp enough to scare sheeple into submission. I was unaware that they were in my carry ons. Airport security is a joke.

All metal detectors are calibrated to detect certain levels of metal. That being said this calibration is done by people and can error on the side of good and bad. However the ones I tested were set so very low as per the sites needs.

GoW - I agree although a edge is usually a lot easier to play with.

+++

Don't quote whole posts. NBK

[Jacks Complete]

As pointed out, that nice looking carbon fiber knife wouldn't carve wood for more than 5 seconds. It would also snap if used to pry anything. And a real knife would cut right through it.

Titanium is a great metal. With the right heat treatment of the cutting edge it can be hard enough to cut well, whilst still having a tough core that won't snap or shatter. It is (and I'll have to google this to make sure) paramagnetic, so it acts to reduce the effect of a magnetic field through it, and is slightly attracted to the magnet. Steel is highly magnetic (ferromagnetic) and so has a much breater effect on the AC magnetic field of a detector. Some stainless steels are paramagnetic, so some stainless knives may also be fine for walking through detectors. However, use of a demagnetiser would be a good idea, since the stroking of the blade whilst sharpening will set up a magnetic field in the material. Note that any repeated chopping or sharpening will magnetise a metal blade to some degree, even just chopping at a hardwood.

With a carefully tuned system, you still might get found out. Generally, however, it wouldn't be an issue. If a few experiments were run, the answer could be found easily and rapidly. Stainless steels such as those used for revolvers might also give interesting results.

[deaddwarf]

That carbon fiber knife is still an effective weapon and if you know how to utilize it effectively then it serves it's purpose (Think a scumball crackhead with a toothbrush shiv going as hard and fast as a singer sewing machine). A utility knife could be crafted if needed, the idea of this knife is purely combative.

I'd trust it over titanium due to the reasons stated, the metal can still acquire a faint magnetic field, that could be enough to get you caught out.

[nbk2000]

I'm sure most people interested in the plastic knives and such has heard of ones like the CIA Letter Opener and Delta Dart.

What I've heard, though have no way of proving myself, is that such knives, manufactured after about 2000, actually have a detectable metal content, either dispersed metal or a metallic insert.

RTPB: Trust but verify (that any such weapon actually IS non-metallic)

[inventorgp]

How bout' a ceramic knife made of zirconium dioxide?.
http://en.wikipedia.org/wiki/Ceramic_knife

Oh and just to let you a point of interest, Howa firearms are making barrels out of carbon fiber.

NBK's right on the metal content part, I read it some where and its in the link above.


EDIT: I saw this on another thread http://datacenter.ap.org/wdc/fbiweapons.pdf

[InfernoMDM]

If I get a chance to play with a hand held metal detector again I am going to see if I can snatch up a few of the plastic knives. I did a search on the net and didn't find any evidence of these plastic wonders having metal of any type in them. The only plastic knives with metal apparently is on page 35, 48 of inventorgp's link. Page 73 states a metallic construction of the "Titanium Charge Card" but doesn't state if the it would be picked up by the metal detectors.

I also have debated the ceramic knife idea, but I don't know much about the design features, and which may have metal reinforcements. I do know that any twisting or bending stress on the blades is likely to shatter them, which is why we don't see them as self defense blades.

[Frunk]

How bout' a ceramic knife made of zirconium dioxide?.
http://en.wikipedia.org/wiki/Ceramic_knife

Oh and just to let you a point of interest, Howa firearms are making barrels out of carbon fiber.


McMaster (Passivation) sell technical ceramics like zirconium oxide. 10 pounds of zirconium ceramic casting compound will cost you 115$. You can always go for silica and save 30$ or you can buy small blocks of them and machine it to a knife shape with diamond tools. Technical ceramics are really hard, normal machining tools are actually tipped with them, an example being silicon carbide tools. If you're rich and/or intend to make a large batch, pay 85$ for 5 kg of silicon carbide ceramic, buy some carbon fiber rods as an armature for the blade and practice your woodworking skills for the handles. You might be able to make some good ceramic knives after a few tests. You will probably need a small 400$ technical ceramic kiln form Ebay, I doubt these are chemical setting ceramics.

I suppose you could always use some super plastics like Lexan to make plastic knives... just buy a sheet, cut it up and try to sharpen it. Any plastic, wood, ceramic or glass pointy object could pass a metal detector and be used as a knife.




Carbon fiber barrels for firearms must absolutely have steel inserts. Bore size is everything and whatever plastic resin is used in carbon fiber would melt or at least warp if if was rubbed by an accelerating bullet.

[Skean Dhu]

Why go through all that trouble of finding a premade knife that will elude metal detectors, or making your own ceramic cast machined knife when the technology to do so has already been invented and exists for millenia?

For about 2 hours of your time and 5 USD in parts you could manufacture your own knife that will pass through metal detectors and rivals any surgeons scalple in keeness. The skill of knapping could be mastered in a weekend of diligent practice. Glass bottle bottoms, window panes, chert, quartz, obsidian, and even porcelain(ie; toilet resevior covers) can be made into effective knives.

literally so easy a Caveman could do it.

http://www.sterlingsculptures.com/Resources_folder/Knapping_folder/Knapping_2.htm
http://www.onagocag.com/knapping.html

I've even heard the leg bones of large animals can hold a reasonable edge. The Host of 'Survivor man" used an 'elk leg bone' knife when he was in the arctic, but for the life of me I can't find anything on the internet on using bone as the blade material. For stabbing Steak bones, antlers, toothbrushes, and wood have all been used for the task.

If you're dead set on buying a knife look into these: http://www.englishrussia.com/?p=590

[akinrog]

..............obsidian.......

This natural volcanic glass is so sharp, it's used not only by natives / cavemen of the past but also even by surgeons of modern age to make surgeries.

It's said the edge created by the shaped shard is so thin it can directly go through in between cells :eek: and the healed wound leaves very little scar marks.

If I could get them, I would use them, since in ancient times this material was very precious, because of its unique sharpness and shapeability (sp?). Regards.

[Too Coolio]

Hi Guys,
I was a member here a few years back but forgot my old username.Think it was Ragnar57(or something like that).

Anyways.A Carbon fibre knife designed to the effect of a Fairbairn-Sykes Shanghai dagger would be the way to go in my opinion.The F-S knife that I have doesn't really have much of an edge to begin with.Although it will easily cut bare skin,slashing through clothing like even thick cotton wouldn't be very effective especially with the edge closer to the tip.

The original shanghai was designed as a stabber.Focusing on this "point" as the main design criteria would seem to be the way to go.
I personally would prefer a robustly made Shiv over a knife that sacrifices toughness as a trade off only to achieve an easily damaged sharp edge.

That sapphire knife is pretty neat tho

[Jacks Complete]

They are sharp but brittle. Eye surgery in the Soviet Union was carried out using these blades, rather than the lasers we now use over here. The Russians still operate "eye hospital ships" in various places, they drop anchor someplace and for a small fee (far less than lasik!) they will sort vision defects.

The way it works is the crystalline fractures are clean, and this leaves an almost nanoscale sharp edge, unlike a metal, that deforms and smears. Take a look at the difference between a bee sting and a hypo under high magnification, and you can see the difference!

The issue is that if you hit something hard, it will fracture the edge. A steel blade would shear your ceramic one easily. Also, any force on the side of the blade would snap it, in the same way as a badly heat-treated knife will snap, rather than bend a little.

Tungsten carbide tools are now quite cheap. They are also technically illegal in the UK! But then, so is nearly everything.

[prespec]

Kyocera makes ceramic knives ,of the kitchen variety, as well as mobile phones. A small boning or paring knife would serve quite well as an easily concealed weapon.

[bookwurm99]

How bout' a ceramic knife made of zirconium dioxide?.
http://en.wikipedia.org/wiki/Ceramic_knife

Oh and just to let you a point of interest, Howa firearms are making barrels out of carbon fiber.


Carbon Fiber barrels start out as a high quality regular barrel. they then turn them down and wrap them in carbon fiber. they end up larger than the barrel started out as. they do carbon fiber barrels because they don't heat up as fast and cool better than fluting the barrel. (fluting: cutting grooves to increase surface area that also lighten the barrel) carbon fiber barrels are also ALOT lighter than traditional barrels. they are used mostly in lightweight hunting guns and in varminting.

[Jacks Complete]

Carbon fibre cannot be used alone due to the heat from a round burning it, the high pressures breaking it (think thermal shock and the different strengths and expansion rates of the carbon fiber and the glues - you want dimensional stability), and the friction wearing the surface away in a few rounds.

The US Army put millions into aluminium/carbon composite barrels, but never managed anything that worked. The OICW has a titanium barrel for the low pressure grenade launcher barrel.