The Vanilla Iso began as an attempt to create a more subtle version of the “Iso Iso Baby”, a pattern I’ve had success with the last couple of years. In the end, however, it’s basically a just parachute iso with a somewhat funky post and tail.
I start with a size 12 or 14 Dai-Riki #300 dry fly hook. After mashing the barb, get the hook firmly secured in the jaws of your tying vise.
For thread, I’m going to go with wine colored UTC 70 Denier. Start your thread on the hook shank, leaving an eye-length space behind the eye, then take a few wraps rearward before snipping or breaking off the tag. Relocate your tying thread so it’s 2 full eye-lengths behind the back edge of the hook eye.
I’m really starting to like soft foam parachute posts for a lot of things, here, medium size in white. Measure to get a shank-length long segment and then transfer that measurement forward to the tie-in point. Take two loose collecting wraps with your tying thread around the foam and the hook shank then pull down to close them. Follow this with a couple more wraps to really lock the foam in place. Then, start taking wraps rearward, securing the foam to the top of the shank. When you’re sure it’s not going anywhere, reach in with your tying scissors and snip the excess foam off at a shallow angle. Continue taking thread wraps down to the hook shank.
The tails of the fly are formed from another one of my favorite materials, centipede legs from the Montana Fly Company. These are mini sized, in speckled grey. Cut a single strand free from the hank and then fold it in half. This will be enough material to make 2 flies. Snip the loop to form two roughly equal length segments, then fold one of these segments in half. Place the loop end at the tie-in point and take thread wraps to secure it to the top of the hook shank, all the way back to the start of the bend. Then, work your thread forward to about the hook point. Get hold of the small loop and, while pulling it straight up, snip it off close. You should be left with 2 nearly equal length tails that splay outward, as they do on the naturals.
For the body of the fly, I like rabbit fur dubbing and have my own custom iso blend, but use whatever you’ve got, anything between a dark brown and a burgundy is just fine. Get hold of an ample pinch of dubbing and use it to create a thin, tapered noodle on your tying thread about 2” in length. Take wraps with the noodle so the dubbing starts right at the base of the tail and then continue taking touching wraps forward, up the hook shank, to form the abdomen of the fly. Ideally, the dubbing should end with a small space left behind the post. Wrap your tying thread forward to in front of the post and take a few wraps to jam it up to nearly vertical. You can post as you normally do here, but I like to create a small loop with my tying thread by doubling it over and taking a few wraps to lock it down. I’ll then insert the hook of my whip finish tool into the end of the loop and use it to make wraps up the post. The combination of the doubled thread and the rotating handle of the whip finish tool makes the job quite easy. When you’re satisfied with the posting effort, secure the remaining loop with a few wraps of thread and then snip that loop off close.
For hackle, a medium or dark dun is a good choice. Select a single feather with barbules that look to be about the right length. It’s always a good idea to double check the length on a quality hackle gauge before you commit to pulling the feather free from the hide. To prepare the feather for tie-in, hold it with the shiny side facing you and snip off the lower webby section. Then, pull down and strip off a 1/4” of fibers from the top side of the stem and just slightly more from the bottom. This will help the hackle to wrap correctly. Lay the bare stem against the near side of the hook so it’s end butts up against the return on the hook eye. Take wraps of tying thread to secure it really well. Continue wrapping all the way back to the base of the post. Then, lift the feather to vertical, up the post and take thread wraps to secure it there. Make sure you lash it all the way up to the point you posted to earlier. Take wraps back down the post and then end with your tying thread behind it. Now get hold of another small pinch of the same dubbing and once again create a thin but shorter noodle on your tying thread. Use that noodle to build up and fill in all the space behind the hook eye and back to the start of the abdomen. End with bare tying thread on the near side of the hook in front of the post.
If your vise allows, rotate the fly about 45 degrees away from you, this will enable you to better see what you’re doing when wrapping the hackle. Get hold of the hackle feather and begin making touching clockwise wraps down the post, 3 to 4 turns is usually plenty. When you’re done, keep pulling on the feather’s tip and take a few thread wraps around the base of the post to secure that tip. Once it’s really locked down, reach in with your tying scissors and snip the excess off close.
Pick up your whip finish tool and do a 4 or 5 turn whip finish around the base of the post. Make sure to seat the knot really well before snipping or cutting your tying thread free. I like to trim the post so it’s about 1/2 a hook shank in height. It’s not really supposed to represent a wing or anything, it’s more for angler visibility than anything else. If you want, clean up any wayward bits of dubbing or errant hackle fibers. Although not essential, a small drop of head cement applied to the thread wraps at the base of the post will ensure things don’t come unraveled.
I’ve only fished this pattern a couple of times but have done remarkably well with it, despite very tough low and clear water conditions. It floats like a champ, and the vanilla post, I mean white post, is quite easy to see even in low light conditions.