Anodizing

Tactical flashlights need to be tough.  Really tough.  This toughness requires that the outer surface be extremely hard to resist abrasion.  While metals in general are hard materials, aluminum is not a particularly hard metal and in its raw form it scratches and gouges easily.  Since the optimum material for a tactical LED flashlight is 6061-T6 aluminum (see blog post on Aluminum), a way to increase the hardness of the outer surface is required.  Tactical operations also demand that the body of tools such as flashlights be electrically non-conductive since contact with sources of electricity is possible.

So how does one reap the benefits of 6061-T6 aluminum while drastically increasing surface hardness and providing electrical insulation?  Anodizing is the answer.  But not all anodizing is the same.  A good overview of the anodizing process may be found on Wikipedia and other online sources and will not be repeated here.  Suffice it to say that cheap flashlights generally use Type II anodizing while high quality torches use thicker and harder Type III.  The difference between the two is tremendous.   While simple Type II anodizing quickly scratches in common use, Type III anodized surfaces boast hardness rivaling diamond.  Type III anodized parts easily resist abrasion from nearly all materials including hardened steel files.  The practical result is that a flashlight with mere Type II anodizing will quickly be marred and damaged to the point that large areas of bare aluminum is exposed which contributes to rapid deterioration of the device and the risk of shock should it come into contact with an electrical power source.  A flashlight with true Type III hard anodizing will withstand far more abrasion and abuse while retaining good protection of the underlying material and electrical non-conductivity (it will also continue to look good cosmetically).

While it is difficult to definitively identify Type III hard anodizing visually, there are several instances where its presence can be clearly ruled out.  Type III hard anodizing naturally produces a dark gray coloration which can only be dyed darker.  This allows for black, dark green, brown, and other dark colors but categorically eliminates light or bright colors.  Any flashlight that has brightly colored anodizing or a light shade such as desert-tan or “dark earth” is not truly hard and its finish can be expected to degrade easily.

Like so many important aspects of tactical flashlights, the features of the best models are not readily apparent and the benefits are not obvious.  Manufacturers do not generally acknowledge cost-saving measures and will often use ambiguous descriptions such as “Mil-Spec Anodizing” (military specifications include Types I, II, and III so such marketing hype is meaningless).  Such marketing hype does little to help consumers choose the best products that genuinely use the best technology available.  It is left to the savvy buyer to determine the products that are hard enough to endure hard core use.