by Dick Talleur
Beads have changed not only how we tie many of our flies, but also the behavior of these flies...
The hole that is drilled through th center of a fly-tying bead is usually a little wider on one side than it is on the other. This feature serves a couple of purposes. It enables the bead to go around the bend of the hook, and it also covers and protects the finishing raps of thread.
Fly-tying beads usually range in size from 1/16 to 1/4 inch in diameter. Use 1/16-inch-diameter beads to tie small flies down to size 20 or so. (the exact size depends upon the style and brand of hooks used.) Beads really do increase the effectiveness of smaller patterns. Use the large-diameter beads for tying nymphs and wet flies.
There is a big difference in the weight of beads made of different materials. Most beads are made of brass, but tungsten beads are also available. A 1/8-inch-diameter tungsten bead weighs 2-1/2 times more than a brass bead. So, if you opt for tungsten, be aware that you're adding a lot of additional weight to the fly.
Beads come in a variety of colors. The four most common colors are gold, copper, silver, and black. There are also beads in enameled colors. These can be very effective in certain applications, such as imitating eggs. You can also use colored beads to tie a variety of unusual-looking wet flies and nymphs.
Another option for adding a bead to a fly is to use a glass bead. Glass beads do not add much weight to a fly, but it can give the fly a flash or sparkle. Beads come in many colors and sizes. In some cases, the body of the fly can be made entirely of glass beads.
Some fly tiers believe that a clear or opaque bead behind the eye of the hook represents an air bubble. This bubble is formed when the insect is preparing to hack.