Before we get started on thread differences, let's talk wax. Almost all tying thread comes from the factory waxed, and if you want unwaxed thread you'll have to use silk, GSP, Kevlar, or a specialty thread like unwaxed 3/0 Danville's Monocord. Waxed thread is not a substitute for dubbing wax, and is applied to the thread in the manufacturing process merely to keep the thread from fraying and unwinding wildly when it breaks. Size is another major source of confusion for many consumers. Historically, fly-tying thread was sized using the archaic aught system that came originally from sizing silk surgical sutures, and is still used today for that purpose. Using a zero as a baseline and additional zeros to denote smaller sizes, the aught number described relative size based on a range of diameters and worked nicely in an age of organic materials where exactness was not always possible. Many tying threads are still measured this way today, as an example, 000000 or 6/0 (six aught) being smaller than 000 or 3/0 (three aught) threaThe Danville Chenille Company used this system for tying thread for 50 years with no issues, but in the 1990s, UNI Products entered the tying market. While UNI also used the aught system to distinguish its larger and smaller threads, the company used a different baseline diameter, and that's where everything went to hell. Using the aught system, tiers assumed that the new 8/0 UNI-Thread was smaller than 6/0 Danville's. And 6/0 UNI-Thread seemed much stronger than 6/0 Danville's. Despite the numbers on the spool, those comparisons weren't fair because the two threads aren't the same size at all. Wapsi Fly Company moved away from the confusing and archaic aught system when it introduced UTC Ultra Thread, and used the thread industry denier standard of measurement. Denier is the weight, in grams, of 9,000 meters of thread. It's a physical actual weight for a length of thread. It says nothing of the thread configuration, material, or strength. UTC Ultra Thread comes in 70, 140, 210, and 280 deniers, and simplified thread sizing to a significant degree. It's pretty simple math to figure out that 140-denier thread is twice as heavy as 70-denier thread, 210 is three times as heavy, and so on. Using the denier system retroactively tells us that 8/0 UNI-Thread is 72 denier, 6/0 Danville's Flymaster is exactly 70 denier, and surprisingly, 6/0 UNI-Thread is 135 denier—no wonder it seemed so much stronger; it's almost twice as heavy!

There is no constant baseline used by all manufacturers to clearly and accurately label their threads. As tiers, we should all know that 70-denier UTC Ultra Thread, 6/0 Danville's Flymaster, and 8/0 UNI-Thread are all about the same weight, but we should also know that these three threads are still very different because of both the materials used to make them, and the configuration (round or flat when viewed in cross section). The uses of wire and tinsel are closely related. The most notable use is that it adds "flashy color" to the fly. Any fly or lure to catch fish can often be upgraded with a bit of flash. The flash is attractive to fish. Maybe it just catches the fish's attention. Or it might be the flash mimics movement and adds to the life of the fly. In the case of a wet fly some will argue that the flash gives off the appearance of bubbles along the fly body which are often seen in emerging insects. Whatever the case...flash can help your fly. You will see flies with a lot of flash or just a touch of flash. This is up to you, what you are trying to imitate and the conditions of the water or sunlight available.

Another use of wire and tinsel is to create a segmented appearance on your fly. As we discussed in the Lesson 2 : Working with Thread, segmentation adds to the natural imitative property of the fly as well as the appearance of depth.

A third use of the wire and tinsel is to reinforce the construction of the fly. A wire rib or tinsel rib makes it difficult for a fish's toothy mouth to tear apart the fly and can be used to help hold other materials in place.

Wire and tinsel can also serve the purpose of adding weight to your wet fly. The more you put on your fly the heavier it will be. If you want a fly that sinks readily, select a heavy hook and wire body. If you want a wet fly that sinks, but not too deep, choose a lighter wire hook and add just a rib of wire or tinsel. It is all good! Let me reiterate the motto "Tying with a purpose". Think of your purpose for adding the wire or tinsel ahead of time and select the method and material to get you there.