Fly-fishing-line. Copolymers, flurocarbon, co-filament and thermally fused lines.

Until the advent of the Industrial Revolution fly-fishing-line was made from the most readily available materials, which usually meant horse-hair or silk thread.

However, the industrialization of the 1850’s brought mass production techniques that completely changed how fishing-lines were constructed.


Those early lines were all constructed from naturally occurring materials. There was nothing else. But today lines are made almost exclusively from man-made materials such as nylon and polyethylene.

Nylon monofilament, so called because it consists of a single strand, is the most common type and is favoured by the majority of anglers. Most brands of monofilament are indistinguishable from one another though there is some variation in the density of the materials used. The lighter, less dense fishing-lines are ideal for float fishing and the denser line is suitable for leger fishing.

New materials are constantly being developed though whether they will ever completely replace nylon remains to be seen. Copolymers which are mostly made in Japan and flurocarbon are examples of these.

The last few years have seen the introduction of even more exotic fishing-lines. Braided fishing-lines, where several strands of material are wound around each other, plus co-filament and thermally fused lines. The latter sometimes referred to as ’super lines’. They are much stronger than the monofilament lines that they have replaced.


Construction of a nylon fly-fishing-line is a pretty standardised affair. A single strand of nylon monofilament is encased in a plastic sleeve, usually PVC. The sleeve is waterproof and also protects the nylon against abraision.

To increase buoyancy air-bubbles are introduced into the PVC coating. Without this extra buoyancy it would be extremely difficult to produce floating fly-lines. Sometimes silicone is added to the PVC which acts as a lubricant.

When a fish bites and takes off on a mazy run through the water you may find that the amount of fly-line on your reel is insufficient. To avoid running out of line a secondary line of braided Dacron or some similar material is attached to the butt-end of the fly-line. This secondary line is called ’backing’.

At the business end of the fly-line you will find the leader (a tapered length of monofilament to which the fly and hook are attached). The leader gets progressively thinner towards its end section which is called the tippet.

So, a fly-fishing-line consists of three parts, the backing, the fly-line and the leader.

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