Semperfli Nano Silk 50D 12/0
Nano Silk 50D 12/0 is widely regarded as the professional fly tyer’s go-to GSP thread—exceptionally strong, incredibly smooth, and available in a broad range of colors and deniers. Its versatility makes it suitable for everything from delicate micro-patterns to larger flies where minimal thread bulk is essential.
Ideal for smaller flies, the 50-denier (12/0) size provides outstanding control with virtually no risk of thread breakage. Despite its ultra-fine diameter, Nano Silk delivers remarkable strength, giving you total confidence at the vise. It is 10 times stronger than steel of the same diameter and can even be split further for ultra-fine dubbing applications.
Designed primarily for hook sizes #8 to #16, Nano Silk 50D is also fine enough for tying down to sizes #16–32 while still maintaining exceptional holding power. Its thin profile and perfectly flat lay mean no unwanted thread build-up—even after dozens of wraps.
Specifications
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12/0, 50-denier GSP thread
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Breaking strain: 1,900 g / 4.2 lb
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Perfect for hook sizes #6 to #16 (fine enough for #16–32)
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Lays perfectly flat with zero build-up
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Ultra-strong—10× stronger than steel of equal diameter
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Approx. 50 m / 54.6 yd per spool (100 m on black/white spools)
Pro Tips
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Rotate your bobbin anti-clockwise to untwist the thread and achieve a perfectly flat lay. With only a few gentle wraps, you can secure foams and other delicate materials without cutting them.
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Use white Nano Silk and color the final 4 inches (100 mm) to create custom-colored heads or hotspots.
Not all GSP threads are created equal. Independent strength tests show Nano Silk outperforming other brands thanks to premium materials and manufacturing standards that ensure a smooth, tangle-free, and incredibly durable thread in every size. (Search for the Global Fly Fisher Thread Chart for independent testing.)
Note: As with all GSP threads, always use a ceramic bobbin holder when tying with Nano Silk.
