How Aluminum Changed Fly Fishing Forever
July 16, 2015
When you're onstream, casting dry flies to rising trout, it seems like you're alone in the wilderness, a million miles from the demands and detractions of technology. But the fact is that fly fishers are "early adopters" who have been quick to adapt the best in materials and processes to develop better equipment to use on rivers, lakes, saltwater flats, and wherever our adventures take us. It's a simple premise: the less we worry about or gear, the more we can enjoy the fishing. And while our rods, waders, and fly lines have certainly come along long way, the machined aluminum reels we enjoy today may be the most enduring innovation our generation of fly fishers will ever experience.
Charles F. Orvis is widely credited with designing, manufacturing, and popularizing the first American-made fly reel. Its two round side plates were made from brass sheet material, with pillars riveted to each side to hold the structure together. The plates were heavily ported to save weight, and while "airy" ventilated design eventually became iconic in the world of fly fishing, brass sheet and later steel sheet materials were too malleable and heavy to make a truly functional fly reel. An idea was hatched, but it was never fully formed in Orvis's lifetime.
By the 1950s, the aircraft industry had settled on 6061 aluminum alloy as its primary construction material due to its impressive strength-to-weight ratio and corrosion resistance. As American production capacity increased, aluminum found its way into the world of sports and recreation, with aluminum tubes being used for everything from bats, tent poles, and bicycle frames.
Almost all fly reels produced today are also made from similar aluminum alloys but they are not all created equal. Most inexpensive reels today are made through injection moulding, where molten aluminum is forced into a cavity, then cooled and released to produce both the spool and frame.
This casting process is superior to the sheet metal design of the original 1874 ventilated Orvis reel, but pales in caparison to the best of what modern technology has to offer: fly reels machined from solid bar stock 6061-T6 aluminum. First, the machining process produces much more exacting tolerances than any casting process, which means parts like the spool and frame fit together better without the burrs, bumps, and irregularities you sometimes find in mould-produced pieces. More important, 6061-T6 alloy (containing silicon, magnesium, and other elements) used for the best fly reels is a precipitation hardening alloy.
Sometimes called "age hardening" this tempering process takes a naturally soft element like aluminum and produces a durable, light, yet incredibly strong block of alloy that has no equal. The best reel manufacturers in the world use this 6061-T6 bar stock, and a computer numerical controlled (CNC) lathe to machine the spool and the frame from a single block of material.
The final step is anodization of the reel surfaces, an electrolytic process which greatly increases the thickness of the aluminum oxide layer on the exterior. When exposed to air, aluminum alloys passively develop a very thin layer of aluminum oxide, but by passing a direct current through a solution of sulphuric acid, and using the reel part as the anode of an electric circuit, the layer deepens to 0.0005" to 0.006" thick, and seals up the naturally porous aluminum, making it even more corrosion resistant, more scratch-resistant, and creates a much better surface for adhering paint. This smooth, durable finish is part of the reason why the reels we have today aren't just engineering feats that can smoothly slow the run of a tuna or marlin—they are also family heirlooms that will never "wear out," and can be proudly passed from one generation to the next.