The Casual Dress is a Polly Rosborough pattern that requires only two materials, is a pleasure to tie and does a remarkable job of attracting trout.
For a hook, a Dai-Riki #710 in size 12 is just about perfect. Start by mashing the barb and getting the hook firmly secured in the jaws of your tying vise.
For thread, you’re going to want something that’s easy to split, like UTC 140 Denier in black. Start your thread on the hook shank leaving a 2 eye-length space behind the hook eye and take a few wraps rearward before snipping off the tag.
The value of having a fly shop in the town where I live cannot be overstated. Although both they and I were out of muskrat on the skin, they were able to dig up some decades old stuff from a rarely opened drawer in the back. Once again, thanks guys.
For the tail of the fly, use the tips of your tying scissors to separate out a small clump of muskrat fur and snip it free from the hide. Then, remove most of the fluffy underfur but don’t throw it away. Instead, set it aside in a safe place as it will be used to dub the body of the fly. Get hold of the remaining clump of fur and guard hairs with the fingertips of your right hand. Measure to form a tail about a hook shank in length and transfer that measurement rearward to the start of the hook bend. Start taking wraps of tying thread to secure the fur to the top of the hook shank, back to the start of the bend. With the tail in place, advance your tying thread to about the hook point.
Pick up that small clump of underfur you set aside and mix it up a bit to separate the fibers and basically turn it into dubbing. Pull down on your bobbin to expose 4-5” of thread. Then, use the muskrat underfur dubbing to create a fairly long, slender noodle on your tying thread. If you can add a bit of taper to it, so it’s thicker at the bottom, so much the better.
Now, here’s a little trick that will help to tighten up the noodle and create a segmented look to the body of the fly. Begin by taking a few wraps so the dubbing starts right at the base of the tail. This will also anchor the end of the dubbing noodle. Give your bobbin a few real hefty clockwise spins, which will not only cord up the thread but cord up the dubbing noodle as well, spinning it into a tight little rope. When you go to take touching wraps with the rope, you should notice that the body of the fly looks segmented. This isn’t essential on a Casual Dress but I think it looks good. Once the body is complete, you’ll need to give the bobbin a counterclockwise spin to uncord and flatten out the thread.
For the fly’s collar, snip a slightly smaller clump of muskrat free from the hide. This time don’t pull out the lower underfur. Instead, snip a large portion of it off square to leave a small slip of guard hairs and just a bit of fur. Set this on the edge of something for easy access.
Use your bodkin to further flatten the thread and then split it in half. Insert the index finger of your left hand between the strands to hold them open and then pick up that slip of fur and place it between the strands, up by the hook. Once again, give your bobbin a healthy clockwise spin to cord up the thread and trap the fur. You should end up with a short, full, fluffy segment of dubbing rope. Take wraps with the dubbing, pulling back as you go, to produce a somewhat wild-looking collar on the fly. To me, this is what really sells the Casual Dress.
To provide a little contrast in color, snip a single strand of black ostrich herl free from the stem. Cut off the very butt end of the herl and then orient it so the flues are pointing up and the stem is pointing down. Maintaining this orientation, use your tying thread to secure the herl to the hook. Make sure that it’s locked down really well. Pull up on the herl and begin sweeping the flues rearward as you would a soft hackle. You should notice that when you begin wrapping the herl, the stem side will be to the front while the flues slant back. Take wraps with the herl all the way up to the back edge of the hook eye. This is one of the few cases where you don’t really need to leave room. Secure the herl with 2 or 3 turns of tying thread and then snip the excess off close. If there are any wayward flues or fibers, now’s a good time to trim them out. Do a 4 or 5 turn whip finish to build up a small head on the fly, seat the knot well and then snip or cut your tying thread free.
Add a drop of head cement to the thread wraps to make sure they don’t come unraveled and your Casual Dress is complete. You can use them any day of the week, not just on Fridays.