Aluminum is aluminum, or so many people assume. In reality, very little is made from pure elemental aluminum. Rather, when something is said to be made from “aluminum”, it is almost certainly made from an aluminum alloy. (An alloy is simply a metal that has been mixed with other elements or chemicals.) There are a great number of aluminum alloys available and the properties of these alloys are critical in choosing the best alloy for a particular application.
In the manufacture of tactical flashlights, the most important material properties to consider are heat conductivity, heat capacity, electrical conductivity, corrosion resistance, and strength. The values of these properties vary significantly between different alloys (specifications may be found in various materials handbooks and online). High heat conductivity ensures that heat generated by LED chips and circuit boards is rapidly moved away from critical components while high heat capacity allows the material to absorb heat with minimal temperature increase. High electrical conductivity provides efficient electrical current flow with minimal losses. High corrosion resistance keeps components from degrading over time, especially when used in harsh environments. High strength, of course, makes components survive heavy loads and abuse. A well-engineered product will be constructed from an alloy that best optimizes these properties.
With these factors in view, Elzetta manufactures flashlight components from 6061-T6 aluminum. The differences in material properties of this alloy compared to other aluminum variants are substantial. For example, 6061-T6 boasts 28% greater heat and electrical conductivity and 20% greater heat capacity than 7075-T6 aluminum with a tensile strength 28% greater than alloy 6063-T6. The “T6” portion of the material grade refers to the heat treatment and is a critical specification. Simply specifying “6061” is woefully inadequate as 6061-T6 has a yield strength four times greater than 6061-T0. However, a heat treatment identifier without an alloy grade is meaningless (“T6 aluminum” is not a valid specification).
Despite the importance of the specific alloy used in construction, most flashlight manufacturers do not publish the actual aluminum grade used in their products. Marketing terms such as “aerospace aluminum” or “aircraft grade” are meaningless jargon with no solid definitions and such descriptors should raise suspicions. Of course, if a company does specify a specific alloy grade, the legitimacy of the claim is only as good as the integrity of the manufacturer making the claim. It is nearly impossible to identify an alloy grade by visually examining a finished product. Therefore, it is important that a flashlight manufacturer not only state the particular alloy material but also have the established credibility to be trusted in their statement (overseas manufacturers are notorious for substituting inferior materials, especially when the substitution cannot be readily identified by consumers). A well-designed flashlight is distinguished from a mediocre one by small details and often-overlooked specifications. Spurious claims of “aerospace” aluminum may indicate that a product is not made of The Right Stuff.