The Semperfli Poly Yarn is a very high quality polypropylene cord with a consistency that makes it an ideal material for a myriad of uses. It has a lower density than that of water so it floats very well and tends to absorb and work well the Hunt's Original Up High silicone used to improve the floatation of the fly. It has a perfect thickness of the single fibre, does not curl and maintains its consistency after prolonged use of the fly. It is easy to divide into smaller sections to be used on various hook sizes, from large flies to very small flat-water midge.
Polypropylene, commonly called poly yarn, is one of the most important synthetic materials that has radically changed the world of fly tying in the last few years. The Semperfli Poly Yarn is available in a complete selection of colours that can be mixed to create unique effects and shades. It is the material par excellence in the construction of Parachute-style wings of dry flies, but is also widely used for sedge wings, stonefly and small chironomes.
Try it in combination with the Semperfli Superfine Dubbing to obtain almost unsinkable flies. The Semperfli Poly Yarn is also excellent for the wing bags of floating nymphs and nymphs, for bodies of dry flies and nymphs (flat or wrapped twisted to create a striped effect). If cut into small pieces it can be used as a dubbing. Its lightness characteristics (0.91 gr/cm3) make it ideal also as a tuft indicator for nymph fishing with strike indicator.
In the fly tying material market, Doug Swisher and Carl Richards made the first mention of poly fibre in their book entitled Selective Trout. They felt its specific gravity was extremely important for dry flies. It is a consideration that has been debated many times, and may or may not be true. We fully agree with them, no matter what others would say, but remember our words very well now: poly yarn tied on a hook has to be treated with a high quality floatant or the fly will sink easily when the poly catch water and the extra weight will pull a fly down rather quickly. Poly Yarn absorbs water extremely well so it also will absorbs a floatant real good what also easily makes it water resistant too.