Sunday, April 12, 2015

Schrade Color Shift

There was a car called the Crocodile, so the old vaudeville joke went.  It was touted to have Detroit’s newest safety device.  One side was painted blue and the other red.

What’s so safe about that?  You ask.

Well, in itself nothing, but if you were in accident it sure left the witnesses with conflicting statements. 

I did think it was funny the first time I read it, but I was 12 at the time.  Since then I have seen color shifting paint.  The most impressive were gun safes at the SHOT Show.  The colors shifted from red to blue as you walked by them.  It was very impressive.

the Schrade color shift knife
Yes, the handle looks black, but note the waffle-like depressions

Schrade has released a color shifting knife with the imaginative name of Color Shift.  I got one so let’s take a look at it.  And despite my first thoughts that’s this is really cheesy, it does change between reddish purple and greenish blue.  I even got a flash of gold once, but I have never been able to reproduce that relationship between eye/knife and illumination source.
  
The 2.9 inch drop point blade is made of 8cr13MoV steel from Ahonest Changjiang steel in China.  This is a high carbon steel similar to AUS8 made by Aichi Steel Corp of Japan. 

The blade is black coated and I don’t know the Rockwell hardness.  If I had to guess I would suspect it’s in the 56 to 58 range.  It’s not a bad steel for an everyday carry knife.  But it’s the handle that’s so interesting.

The 3.75 inch handle is aluminum with a pocket clip set up for tip up carry but you might be able to find someone who could drill and tap the metal in another position if you wanted it bad enough.  The really interesting aspect of the handle is its coating.

up close look at the pigment in the handle
The small white particles are at different depths in the clear handle material

The casual examination shows a waffle like surface pattern.  I suspect it’s a big part of the color change.  Let’s get up close and personal.

Color shift pigment
The particles have different thickness, shape and orientation in the handle material, the depressions helps insure the particles are at different tilt angles

The coating on the knife has little whitish flakes of material in random directions and depth.  If we move in even closer we can see the flakes.  They look like defoliated mica to me.  

There is a surface treatment used on pigments called ITT.  It stands for a chemical, specifically Isopropyl Titanium Triisostearate.  Minerals can be reacted with compounds like ITT which allow the surface to refract light like an oil slick on water.  Oil slick colors (no, don’t worry, I’m not going to draw charts and write equations as much as I would find that fun) are formed by the very thin layers of oil refracting specific colors of light.  The organic coating formed by ITT works the same way.  Add the cone-like depressions from the waffle pattern and you get color. 

Does it work?  The difference in colors is significant in terms of when the colors are in the spectrum.  The knife handle would be more impressive if the colors lived next to each other like yellow and green.  

The Schrade Color Shift Knife at one angle 
















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The same knife at a different angle


Still, if you want a flashy knife for EDC, look into the Shrade Color Shift (SCH106ALC).  I understand an assisted opening is now available.

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