Classic Waxed Thread 18/0

Semperfli Classic Waxed Thread 18/0

Semperfli Classic Waxed Thread 18/0 is an ultra-fine polyester fly tying thread designed for very small flies and delicate tying where keeping thread bulk to an absolute minimum is essential.

At approximately 30 denier, it provides a remarkably fine thread profile while still offering a breaking strain of around 390g / 13.7oz. This makes it particularly useful for small dry flies, midges, emergers, micro nymphs and other patterns where neat proportions and precise thread control matter.

The lightly waxed polyester construction gives excellent material grip while the fine, lightly twisted thread can lay flat on the hook, helping produce slim bodies and very small fly heads.

Why Choose Semperfli Classic Waxed Thread 18/0?

• Ultra-fine 18/0 fly tying thread
• Approximately 30 denier
• Breaking strain approximately 390g / 13.7oz
• Approximately 220m / 240 yards per spool
• Lightly waxed for improved grip
• Fine polyester construction
• Lays flat to minimise thread build-up
• Suitable for very small and delicate flies
• Excellent for midges, dry flies, emergers and micro nymphs
• Ideal for approximately hook sizes 14–32
• Helps create exceptionally neat heads and slim bodies

Ultra-Fine Thread for Small Flies

When tying small flies, even a few wraps of a heavier thread can quickly create unwanted bulk.

Semperfli Classic Waxed Thread 18/0 allows multiple controlled wraps while maintaining a very slim profile, making it particularly useful when tying tiny dry flies, midges and delicate nymph patterns.

Despite its extremely fine diameter, the thread retains useful strength, allowing materials to be secured firmly without needing excessive wraps.

Flat-Laying Polyester Construction

The lightly twisted polyester construction allows the thread to flatten as it is wrapped around the hook.

This helps spread tying pressure across the material and produces smoother bodies, smaller heads and cleaner finishing work.

The light wax coating also improves grip, helping materials stay securely in place while tying.

Choosing the Right Classic Waxed Thread

For a slightly heavier fine thread suitable for a wider range of everyday trout flies, see our Semperfli Classic Waxed Thread 12/0.

For a stronger general-purpose option, see our Semperfli Classic Waxed Thread 8/0.

You can also browse our complete range of fly tying threads including waxed polyester, GSP, silk and specialist fly tying threads.

Specifications

Brand: Semperfli
Product: Classic Waxed Thread
Thread Size: 18/0
Denier: Approx. 30D
Material: Polyester
Spool Length: Approx. 220m / 240 yards
Breaking Strain: Approx. 390g / 13.7oz
Recommended Hook Sizes: Approximately 14–32
Finish: Lightly waxed
Packaging: Spool

Semperfli Classic Waxed Thread 18/0 is an excellent choice for fly tyers who need an extremely fine thread for small flies without sacrificing useful strength, grip or control.