View Full Version : Need info on CDC flies

09-17-2011, 09:24 PM
:confused: I am beginning to read about CDC flies and would like to find out from you guys who have used them ...how effective they are ....which patterns you like and don't like.....which streams have you used them on .....do you use the emergers ...drys or both.
I see LRO has a couple of patterns but one would think they would carry more .....

Sure would like to get some input from you guys. I've been at this sport for 50+ years and I am learning something new about every day.

Thanks for your thoughts........Bob

09-18-2011, 11:26 AM
I believe CDC it is one of the best materials for tying emergers and other flies. I had this excerpt saved in my fly fishing folder and I thought I would share it with you in hopes that it helps to address some of your questions. I had to break this up in to two posts due to size limitations.

Tying WITH CDC. By: Weilenmann, Hans. Fly Fisherman, Mar2003, Vol. 34 Issue 3, p38, 6p, 6 Color Photographs, 1 Black and White Photograph; Abstract: Examines the uses of 'Cul De Canard' (CDC) in fly tying. Description of CDC by Henry Bresson, a French fly tier; History of CDC; Discussion on the benefits of CDC in fly fishing; Types of CDC. Reading Level (Lexile): 1100; (AN 9016554)His website is www.danica.com/flytier/ (http://littleriveroutfitters.com/forum/www.danica.com/flytier/)

From midges to bonefish flies, cul de canard (CDC) is equally at home in dry, wet, nymph, and saltwater patterns.

THE DESCRIPTION “CUL DE CANARD” was reputedly coined in the late 1950s by French tier Henry Bresson for one of his patterns. The description has contributed to some confusion, especially when it was literally translated into English as “duck's butt” or “duck's arse” feathers. In fact, the preen gland is located on the back of the bird, a short distance up from where the tail feathers sprout from the skin.

Many birds preen, recondition, and waterproof their feathers with oil secreted from their preen (uropygial) glands. CDC feathers sit on top of the gland and the area close around it. While CDC is normally harvested from members of the duck family (“canard” is the French word for duck), other waterfowl such as geese offer feathers similar in quality. As the size of the bird increases, so does the size of the feathers.

Understanding CDC: WHILE THE NATURAL OILS in the feather assist in repelling water, the hydrophobic properties and the structure of the CDC feather are fundamental to its buoyancy. If the oil in the feather was solely responsible for making it float, dyeing CDC would prevent the feather from floating, but this is not the case—provided the dyeing process keeps the feather's structure intact.

Furthermore, CDC feathers don't float well when they are matted with water or fish slime. If the oil was the primary contributor to the feather's buoyancy, the collapse of the structure wouldn't matter, but it does.
If you can maintain the feather's structure, the surface area of the barbules in the film works to keep the fly afloat and the tiny air bubbles retained in the ribbonlike, kinked structure of the hydrophobic barbules hold up those barbules that have broken through the surface film.

A closer look at the makeup of a CDC feather shows why applying a liquid or paste floatant collapses the feather structure and ruins the characteristics that help it float.

For me, the primary quality of CDC is the mobility of the barbules, whether moving in the air currents above the water's surface or in the water currents in the film or subsurface. CDC wings positioned above the surface film do not contribute to buoyancy, but do offer a full silhouette without bulk and respond to the slightest breeze to suggest life. Submerged, the mobile CDC barbules respond to every shift in current, again suggesting life.

Natural and dyed CDC impart a built-in life to flies. This is where CDC shines and what makes it an excellent choice to feature in a broad range of patterns. CDC also blends in well with other materials, where the combinations of their respective properties complement one another for a more effective result.

With correct use of the material and treatment on the stream, CDC flies are among the most durable of patterns as well as some of the simplest to tie.

CDC Type: WHILE CDC FEATHERS are generally lumped together under the single umbrella called CDC, close examination shows distinct differences in their appearance, depending on where they are found in relation to the gland. Certain types of feathers are more suitable for specific purposes.
I designed and use a simple classification system to explain to other tiers the types of CDC most desirable for different patterns or functions. I categorize CDC into four distinct types (shown above).

Harvesting CDC: THE BEST QUALITY CDC comes straight off the bird. The harvesting process is simple and swift and the average mature bird provides between 70 and 100 usable feathers.

Once you lift the cover feathers, you can easily locate the preen gland by feel as well as sight. The visible part of the gland shows up like a shiny pebble protruding from the surrounding skin and is capped by a clump of feather puffs (type 3 feathers, or oiler puffs) saturated with oil. On the illustration shown on the previous page, these feathers are darker and are just below the thumbnail. The larger feathers surround the gland and increase in size as they get farther away from the center. On a mature mallard the stem on the longest feathers that still retain the CDC structure may be close to 2 inches long. On a goose they may exceed 3 inches.
Store the saturated oiler puffs with the rest of the feathers and in a few days the oil will disperse evenly throughout the feathers, leaving the oiler puffs fluffy.

TYING THE CDC & ELK: 1 Select a properly sized (type 1) CDC feather. The longest barbule should be approximately two times the hook-shank length. Hold the butt of the CDC feather with the fingers/thumb of your left hand, and draw the feather between the thumb and index finger of your right hand toward the tip, bunching the tips together. Tie in the bunch, butt pointing backward over the hook bend. Tie the feather down with two tight turns of thread, slip a third turn under the tips to force them upward, and follow with a fourth turn over the tips, just forward of the third turn, to lock the CDC barbules in place. Spiral-wrap the thread forward to the eye, then wrap back one touching turn away from the hook eye.

2 Clamp the feather butt with hackle piters and wind the CDC feather toward the eye in touching turns. The rear half of the body resembles a dubbed body, but as you progress toward the eye free barbules will stand out. Stroke these back with each turn. With a little practice, you will learn to arrive at the hook eye with only the bare part of the stem left.
Tie off the CDC feather with one or two tight turns of thread and unclip the hackle pliers. Do not trim yet. Tighten with another two turns of thread. The CDC butt will move with the thread, tightening further at the tie-off point. Trim the CDC butt.

3 Take a small amount of straight, fine-tipped deer hair. I look for undamaged tips with distinct coloration (dark tips with a lighter colored band farther down the hair) and a fairly steep taper to the hair, which allows me to produce the distinct, rounded head on my CDC & Elk.
Even the hair tips in a stacker. Position the bunch of hair on top of the hook parallel to the hook shank. Measure the tips so the wing will be long enough to just reach the back of the hook. Trim the butts square (perpendicular to the strands) with the front of the hook eye prior to tying in the wing.
Tie down the wing with two tight wraps of thread over the hair stubs. Make a third wrap with the thread, through the stubs, at a 45 degree angle. A fourth wrap goes under the stubs. Complete the fly with a whip-finish under the stubs and a little varnish. Aim for a neatly rounded head.

09-18-2011, 11:31 AM
Here is the second part of the excerpt...

RECIPE: ONCE & AWAY: (originated and tied by Hans van Klinken)

HOOK: #12–18 Partridge GRS15ST.
THREAD: Black 8/0 Uni-Thread.
BODY: One peccary fiber or heavy thread, coated with varnish.
THORAX: Three strands of peacock herl.
WING: Four large type 2 or type 4 CDC feathers.
WINGCASE: Same CDC feathers as wing.
RECIPE: MP BONEFISH FLY (originated and tied by Marc Petitjean)
HOOK: #4–8 Tiemco 411S. WEIGHT: Medium lead wire (0.02”), five turns in the start of the bend.
ANTENNAE: Yellow Flashabou.
EYES: Monofilament.
HACKLE: Type 4 CDC, light yellow.
BODY: Yellow Flashabou.

Note: The eyes are formed by holding a short section of 30-pound monofilament with needlepoint pliers or tweezers and melting each end to a small ball. The resultant “dumbbell” is caught into a twisted piece of Kevlar thread, which is allowed to double back or furl into itself.

RECIPE: CDC PARA EMERGER (originated and tied by Gerhard Laible)

HOOK: #12–18 Tiemco 5230.
THREAD: Black 8/0 Uni-Thread.
TAIL: Brown cock hackle fibers.
BODY: Brown mink dubbing.
WINGCASE: Polycelon (color tier's choice).
HACKLE: Type 4 CDC fibers in a dubbing loop tied parachute-style.

RECIPE: CDC GREEN TRANSITIONAL CADDIS (originated and tied by René Harrop)

HOOK: #14–18 Tiemco 100.
THREAD: Olive 6/0 Uni-Thread. THORAX: Trico caddis émerger dubbing.
ABDOMEN: Green caddis emerger dubbing.
RIB: Gold wire.
LEGS: Brown mottled turkey hackle.
WING: Dyed gray mallard CDC barbules (type 4).
ANTENNAE: Tannish-yellow turkey hackle.
TAIL: Green caddis-emerger dubbing.

COC's history in fly tying and fly fishing begins in central Western Europa in the 1920s with the dry flies used by fishermen living in the Jura Mountains between France and Switzerland. These patterns, generally referred to as Moustique patterns, remained unchanged until well into the late 1970s. A generic Moustique pattern features a cock-hackle tail, a slender body of wrapped raffia or thread (later the patterns were tied with silk floss) ribbed with silk thread of a contrasting color, and a CDC collar.

In the 1980s similar flies continued to be tied and fished across Western Europe. Sometimes tiers would omit the tail, but they retained the CDC collar and at times combined it with a second material such as cock hackle.
In 1980 Marjan Fratnik, a tier from Slovenia, designed the F Fly. This simple, elegant, and deadly fly was a radical departure from how CDC was used. For this caddis imitation, Fratnik stacked two or three CDC feathers and tied them in at the eye of a thread-covered hook shank with the feather tips facing over the bend. He then trimmed the feather stems short at the eye of the hook and the wing length to the proportions and angle he desired. The F Fly triggered renewed interest for other uses for CDC in a growing number of European tiers.

Between 1985 and 1988, Gerhard Laible wrote a series of articles covering a range of techniques and patterns using CDC for the German fly-fishing publication Der Flisgenfischer. Laible complemented his articles with the first book focusing solely on this material, HOC Flies, published in Germany in 1993.

Dutch tier Hans vao Klinken (originator of the Klinkhamer Special) turned COG upright with his Once & Away pattern in 1988. The Once & Away has since spawned a host of patterns, generally referred to as Shuttlecock flies, which continue to be popular in Western Europe, especially with stillwater anglers. Shuttlecock designs are excellent ascending midge patterns for lakes and tailwaters.

While many European tiers contributed to the development of COG techniques, Fratnik, Laible, and van Klinken rank as among the first. Another European tier I place in this small group is Switzerland's Marc Petitjean, who is perhaps the best-known proponent of COG techniques and patterns today. Some of the techniques he either originated or made known to a wider audience are the use of a full GDC feather rolled into a noodle, tied in by the tip, twisted, and wrapped as a naturally tapered body (1985), his elegant and innovative use of GDG to make split wings, and in 1992 the mental leap to incorporate GDG in subsurface patterns. Since then the range of Petitjean's patterns has expanded to cover terrestrials, leeches, crustaceans, salmon and steelhead flies, and saltwater patterns.

By the late 1980s the first signs of CDC in North American contemporary fly tying became visible. In 1987 the English version of a French book by Jean-Paol Pequegnot, French Fishing Flies, appeared as the first book on the American market with references to CDG and GDC flies. It was followed by Darrel Martin's Fly-Tying Methods (1987), which devotes a half page to GDC, and Micropatterns (1994), in which a section on GDC provides the first indepth description of its properties, The book lists over a dozen patterns incorporating CDC, an indication of its growing popularity among tiers.
René Harrop's landmark article in the July 1991 issue of Flf Fisherman put him at the forefront of North American CDC proponents and helped popularize GDC in the States. A second prominent North American tier who has been developing techniques and patterns using CDC is Colorado tier Shane Stalcup. Between them, they have come up with a number of imaginative and effective patterns.

[Note: Marc Petitjean, a CDC aficionado and one of the key people in modern development of CDC flies, conducted much of the research into the early use of CDG. His research and that of other angling historians and tiers, as well as over 100 CDC patterns from several continents, has been published in Tying Flies with CDC: The Fisherman's Miracle Feather by Leon

Links (Stackpole Books, 2002).]

Fresh CDC feathers are mostly free from vermin, but to be safe put the container with feathers in the freezer for at least two days to kill any mature bugs. Some eggs may remain intact, so remove the container from the freezer for a day or two to allow any surviving eggs to hatch, then put it back in the freezer for two more days to finish the process.

CDC & Elk EVERY FLY FISHERMAN has to believe in something. For me, enticing fish to take a fly hinges on the concept of triggers. Offer a fish the appropriate positive triggers and it is more likely to think “food!
Based on this philosophy, I designed the CDC & Elk in 1992 and it has become my staple dry fly. In this pattern, I combine the proven wing silhouette and buoyancy of Al Troth's Elk-hair Caddis with the lifelike qualities of a type 1 CDC feather wrapped around the hook shank. The CDC body and the straggling filaments suggest anything from sprawling insect legs to trailing nymphal shucks to crippled wings.

Over the past decade, the CDC & Elk has taken fish consistently on many waters and several continents. It is a pattern deceptive in its simplicity and versatility. From its beginning as a modified Elk-hair Caddis, it slipped into the slot as my go-to fly for a multitude of mayfly hatches, a general search pattern to cover hatchless periods, an emerger pattern, and a wet fly.

Tips and Tricks With CDC
Bleaching natural dun-colored CDC feathers in a mixture of equal amounts of 3 percent hydrogen peroxide and household ammonia results in a wonderful, warm, light-amber color. The timing is not critical and may range from several hours to an overnight soak. Rinse the feathers in fresh water and let them air dry. The resultant feather stem remains pliant and the bleaching process appears to leave the feather structure mostly intact. The hydrogen peroxide and ammonia mixture gives off unpleasant and unhealthy fumes, so do this in a well-ventilated area.

Barbules broken away from the stem make nice dubbing material. Use them alone or mix in other natural fur or synthetic dubbing.

Roll a type 2 feather on a sheet of firm foam. Press the feather down with your fingertips and roll perpendicular to the stem. Start from the butt and work up toward the tip. Once you form the “rope, you can tie it in by the tip and wrap it around the shank for a buoyant and naturally tapered body. Many of Marc Petitjean's patterns feature this style of body. Including the stem makes these bodies virtually bulletproof, without the need of a reinforcing rib.

When you cut CDC with scissors, you get an unnatural-looking square edge. Tear away the excess length of the barbules for ends that resemble the natural tips.

I prefer to dry my CDC patterns using amadou. I have experimented with other drying agents such as Shimazaki Dry Shake and Frog's Fanny, but it appears that once you use either of the two on a pattern, the buoyancy only lasts one fish before the drying agents need to be reapplied. Flies dried with amadou can be fluffed up by blowing air on them or with several false casts.

Zooming in on the CDC feather structure, the stem shows, besides the barbules, jagged protrusions. The barbules in turn sport ribbon like twisted barbs. Flattened barbs maximize the surface area. In the surface film, a larger and water repellent surface area assists floatation of the dry CDC pattern.

09-18-2011, 11:41 AM
Thanks Shawn, I knew if anyone could give me some insight into CDCs it would be you. I'll digest all of this info. I don't tie anymore but I enjoy reading the info.


Dancing Bear
09-18-2011, 06:27 PM
I like the CDC and Elk in tan for spring and summer and ginger for the fall. Tie the ginger on a #12 for the October Caddis. It makes a very "buggy" looking fly and it is easy to tie.