How to Tie a Bighorn CDC X-Caddis

Producer: Tim Flagler

The Bighorn CDC X-Caddis is intended to imitate the small black caddis that hatch out from late July into early September in significant numbers on Montana’s Bighorn River. While most anglers are drawn to the deeper runs and pools, the shallow riffles are where the action really takes place during this hatch. It’s amazing how so many large fish can take up residence in such skinny water. At the end of the day, don’t be surprised if you find your waders covered with the green eggs that were deposited on the water’s surface by this species of caddis.

Here, author, fly tier and blogger Matt Grobert is going to tie a Bighorn CDC X-Caddis on a size 18 TMC 100 dry fly hook. After loading a bobbin with a spool of black 6/0 Danville, he starts the thread on the hook shank, leaving a full eye-length space behind the eye. He then takes wraps rearward before snipping or breaking off the tag and leaves the thread hanging at about the hook point.

Amber Zelon is used to create a short trailing shuck on the fly. After cutting a strand free from the hank, Matt splits it in two to keep the shuck nice and light. Of course, both halves can be used and together will produce numerous flies. Snip one end of the Zelon off square and place that end on top of the hook shank. A bit of saliva will help to bind the ends together. Take a wrap over top of the material and then pull it rearward so the ends are about in line with the start of your tying thread. Take thread wraps rearward all the way to the hook bend, then forward to the initial tie-in point. End with your thread just in front of the hook point.

Gray olive Superfine dubbing is used for the body of the fly. This type of dubbing has very long fibers and Matt finds it helpful to first snip a clump into small segments and then work those segments together into a little pile. This allows him to have a bit more control with how much dubbing he puts on the thread at a time. Because of this, he’s able to build a very slender dubbing noodle on his tying thread, which in turn will allow him to produce a slim, tapered body on the fly. With the body complete, use your tying scissors to snip the Zelon shuck off square, about a hook gap in length.

The wing consists of two medium dun CDC feathers. It’s important to get their tips aligned and have the concave or backside of both feathers facing down. Give your bobbin a clockwise spin to cord up the thread. This will really help to grip the CDC and keep it from slipping. Lay the CDC feathers on top of the hook so their tips extend back about to the bend. While maintaining this position, squeeze them between the fingertips of your left hand and do a nice, tight couple of pinch wraps to secure them there. If the CDC does slip around the hook shank, it can be easily relocated back to the top and further secured with additional thread wraps.

Once you’ve got the wing looking good, pull the butt ends of the feathers up and back and build a thread dam in front of them to keep them pushed up slightly. While holding the fibers back, complete a 4 or 5 turn whip finish and snip or cut your tying thread free. Finally, get hold of the butt ends of the CDC feathers and snip them off square to form a small head on the fly.

And that’s the Bighorn CDC X-Caddis – simple and super effective.