Slide the bead on, mount the hook, and start thread.
Tie in two brown goose biots at the bend, forked, about half a shank length.
Wrap the copper wire body in tight, touching turns to the 60% mark. Every wrap should click against the last with no gaps. Wire shows every flaw; make every wrap count.
Tie in a strip of Thin Skin at the front of the wire body, pointing rearward.
Twist 3 peacock herls into a rope and wrap the thorax.
Add a few brown hen fibers on each side as legs, swept back.
Fold the Thin Skin over the thorax, tie down, then dome the wingcase with a drop of epoxy or UV resin. That glossy bubble is the pattern's signature.
Whip finish behind the bead.
Substitutions
Body instead of Copper wire: Red wire — Red Copper John, top variant, very popular; Chartreuse wire — Chartreuse Copper John, great attractor; Green wire — Caddis imitation color; Black wire — Subtle, good in clear water; Gold wire — Flashier than copper
Wingcase instead of Thin Skin with epoxy: Thin Skin with UV resin — Faster to apply than epoxy; Flashback tinsel with UV resin — Extra flash under the resin; Black Scud Back with epoxy — Darker wingcase
Thorax instead of Peacock herl: Peacock Ice Dub — More durable, same color; Black dubbing — Simpler, dark thorax
Tail instead of Brown goose biots: Brown turkey biots — Cheaper, similar look; Brown hackle fibers — Quicker to tie
Bead instead of Gold tungsten: Copper tungsten — Matches copper body; Black nickel tungsten — Sleek modern look
Other versions
10 more in the app: Fischer's Flies, Barr's Original with Epoxy Wingcase, Fly Fish Food Tie, Barbless Beadhead, Chartreuse: Classic Recipe, Chartreuse: Classic Recipe (2), Red, Black, Rubber Legs Beadhead, Beadhead.