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The pro´s and contra´s of Nylon, Fluorocarbon and UHMWPE

Fishing lines used to be made of natural materials; silk, gut and different kinds of twine where used up until about 1940. The line was generally knotted together to achieve the length required.

The very first synthetic thread was made in 1935, it was a polyamide thread (abbreviation: PA). It was patented by Dupont and introduced to the market in 1939. Nowadays it’s better known as Nylon (Du Pont), „Perlon" (I.G.Farben) or „Dederon“ (GDR brand name). This thread revolutionised angling from this point onwards, it was now possible to use a knotless fishing line of pretty much any length with a tensile strength above anything that had been available previously. Astonishingly, even today, the most commonly used base material for making fishing lines is Nylon! When it comes to making fishing lines Nylon has a huge range of favourable attributes and nothing else could replace it for making a high quality line for any and all applications.

Another base material has been used for making fishing lines since 1972, it is known as Fluorocarbon. of the chemical is Polyvinylidenfluorid, otherwise known as PVDF. Other trade names are „Kynar“, „Dyneon“ and „Solef“. Fluorocarbon´s original euphoric reception has somewhat cooled as it does have a lot of drawbacks; however, there are niches where this material proves very useful. zwar eher begrenzt, hat aber dennoch seine Vorteile bei ganz bestimmten Einsätzen.

In the past one has used materials such as cotton, silk, Dacron, Kevlar and polyester, to name but a few, for manufacturing multifilament fishing lines, some of these are still in use today. However, the breakthrough only really occurred when a fibre called „Ultra High Molecular Weight Polyethylen” (abbreviation: UHMWPE) became available. This fibre, otherwise known as Dyneema, has had a somewhat similar effect on sport fishing as did the introduction of Nylon, certainly had a lasting effect on some sectors of the sport. Dyneema is the trade name owned by the Dutch chemical company Royal DSM N.V. The same fibre is manufactured in Japan under license by the Toyobo Company who also uses exactly the same production methods as do DSM. The largest quantity of UHMWPE is produced in Greenville in North Carolina, USA by DSM. Honeywell sells its UHMWPE fibres under the trade name of „Spectra“. Other manufacturers are Quadrant EPP Inc., their trade name for UHMWPE fibres is „Tivar“ and Röchling Engineering Plastics use the name „Polystone-M“.

Back in 1999 the Japanese Toyobo Company presented the world with a new super fibre. The company called it Zylon. Zylon has a higher tensile strength than UHMWPE. The name reflects on the similarity to Nylon. At the time Toyobo thought they had a found a fibre that would have similar revolutionary influence on the market as did Nylon. Hence the name Zylon, Z is the last letter of the alphabet and the name seemed appropriate for such a revolutionary product being introduced at the end of the Twentieth century and at the threshold of the twenty-first. But alas, “what is in a name”? Zylon has one big disadvantage and that is it is sensitive to light; the tensile strength of the fibre decreases rapidly upon exposure to light, so that it is not a viable product at the moment. However, we are running experiments with this material, for example a “hybrid fibre” consisting of UHMWPE and Zylon, but we don’t have a usable product as yet.

Hence we will describe and compare the characteristics of Nylon, Fluorocarbon and UHMWPE.

Tensile strength

When the first Nylon monofilament fishing lines came on the market several decades ago, anglers were very impressed by the tensile strength, although those lines were much weaker than those available today. These days the best Nylon lines are manufactured utilising additives, such lines are known as Copolymers. Other processes that take place after the line has been extruded such as stretching, heat treatment and tempering, selectively improve certain qualities. Over the years these procedures have been refined, so that certain characteristics can be achieved with great precision. As a result it’s now possible to manufacture Nylon fishing lines with previously unheard of tensile strengths. Regarding multifilaments, UHMWPE is unbeatable. Below we compare the qualities of fishing lines of different materials that have a diameter of 0.18mm.

Dry un-knotted
In this case multifilaments beat Nylon monofilament hands down, at least they do when they’re made of high tech UHMWPE fibres. The newest UHMWPE fibers reach tensile strengths of up to 450 kg/mm² (as a single fiber under laboratory conditions) and when manufactured into tightly braided multifilament line they can still attain 300 kg/mm². See also: What are the maximum breaking strengths that can be achieved with UHMWPE fishing lines? A 0.18mm diameter line made from the best UHMWPE fibers and closely woven can achieve a linear load capacity of up to 7.63 kg. The highest quality Nylon monofilament of this thickness can achieve a maximum breaking strain of 3.6 kg. The very best Fluorocarbon reaches a maximum breaking strain of 3.1 kg. In this case UHMWPE is the obvious frontrunner, followed by Nylon that holds just about half as much. Fluorocarbon manages about 90% of Nylon.

Dry with knotted loop
This test shows some interesting tendencies. The breaking strain of 0.18 mm UHMWPE with a knotted loop is only 4.2 kg, that’s about 57% of its original un-knotted breaking strain. Nylon achieves a breaking strain of 3.5 kg which is a pretty impressive 97% of its un-knotted breaking strain. Fluorocarbon manages 2.4 kg, that’s 77% of its un-knotted breaking strain.

Wet un-knotted
This is where UHMWPE and Fluorocarbon really score. Fluorocarbon only absorbs about 0.01% water even after it is immersed in a bath of water for several hours. UHMWPE absorbs even less; about 0,002 %. As a result the suppleness, hardness, elasticity, and of course the braking strain are hardly effected. Nylon absorbs comparatively more water (4% - 10%) which has advantages and disadvantages. The advantages are obviously apparent for the angler whose line has been in the water for a while, it’s smoother, softer; slips nicely through the rings and generally fishes better. The disadvantage is that it also becomes somewhat weaker; this is due to the amount of water that it absorbs. However, one can reduce this tendency by technically tuning the line during production. Pressure-tempering the line reduces the water absorption, which helps maintain the tensile strength of the line, which is the case with STROFT GTM, STROFT ABR und STROFT Fluor. After being immersed in water for a period of 5 hours, a high grade Nylon retains a tensile strength of 3.4 kg, which is 94% of the dry tensile strength. UHMWPE and Fluorocarbon retain practically 100% of their comparative dry tensile strength.

Wet with knotted loop
UHMWPE and Fluorocarbon don’t change much in this case either (not measurable). They achieve the same breaking strain as when dry. That is 4.2 kg and 2.4 kg respectively. Nylon weakens somewhat to 3.0 kg which is about 83% of its dry un-knotted tensile strength. However, the actual breaking strain of Nylon is even now better than Fluorocarbon which is 2.4 kg.

Summary (tensile strength)
Knots are apparently the point of weakness for Fluorocarbon and UHMWPE. However, even though the knot strength of UHMWPE with the above mentioned knot is only 57%, the actual braking strain is still impressive and more than adequate for the majority of situations. Also, the actual knotted strength of Fluorocarbon, with the above mentioned knot, is at 77% not all that bad and in fact much better than it was a few years ago. Here are a few important tips for all those who want to get the very best out of their fishing lines: In order to be able to use the higher braking strains available, take extreme care when tying knots. When connecting the final trace use rig-rings or clip swivels wherever possible (depending on the kind of fishing). They achieve much better results than knotted connections such as knotted loop, blood knot, double grinner, or similar knots. If one goes to the trouble of using a needle to make a spliced-loop with the UHMWPE (provided there is a very close and compact special-braid, and not a multi-filament that is twisted, wound, glued, taped or coated), then one is rewarded with a connection that maintains 100% of the original breaking strain. Only then one can fully utilise all the advantages of a UHMWPE fishing line. A detailed description of how to produce such a spliced ​​loop can be found in the STROFT catalogue.

The table shows a summary of the braking strains of lines of 0.18mm diameter:

The breaking strains given here are the best possible at this time. That is, they are only feasible when
using state-of-art production technology and materials.
The values given for UHMWPE relate to an exceedingly compact, round braid.
The diameters quoted are actual (calculated) diameters including a tolerance of +0,02 mm.

Line diameter 0,18 mm
breaking strain (Kg) dry 50% humidity, 20°C, un-knotted
7,4 (100%)
3,6 (100%)
3,1 (100%)
breaking strain (Kg)

dry 50% humidity, 20°C, with knotted loop
2 x doubled and lubricated

4,2 (57%)
3,5 (97%)
2,4 (77%)
breaking strain (Kg) wet, immersed 5 hrs., 20°C, un-knotted
7,4 (100%)
3,4 (94%)
3,1 (100%)
breaking strain (Kg) wet, immersed 5 hrs., 20°C, with knotted loop
2 x doubled and lubricated
4,2 (57%)
3,0 (83%)
2,4 (77%)


Breaking strain
The relatively high percentage of elongation at breaking point of Nylon and Fluorocarbon (20% - 45%) has its advantages as well as disadvantages for the angler. At short range, a larger amount of elasticity is just what the angler needs; it cushions the strike, secures the hook hold and can help avoid the line or the rod breaking in a hard close quarter fight. Conversely, if angling at a great distance, one is better off using a line that possesses less stretch, such as UHMWPE that enables one to feel a bite and set the hook much more directly. UHMWPE has a maximum elongation at breaking point of 4% - 10%, depending on the kind of braid. However, it’s worth noting, as stated here, that there are monofilaments available that have an elongation at breaking point of only 20% and slightly above. This is very low. High quality Fluorocarbon stretches 26% - 30% at breaking point, and particularly “hard” Fluorocarbon lines attain 20% -26% at breaking point. Such lines also have the advantage that the line works as a shock absorber when the fish is close prior to landing, which is not the case with UHMWPE lines. Of course, one has to consider the action of the rod and its rate of recovery; so that the rod fits the line. Ultimately, whichever line an angler uses, whether he prefers a modern monofilament or multifilament line (in regard to line elasticity) is a very personal decision that every angler decides for himself.

Limit of elasticity
The limit of elasticity is different for different line materials. Whereas Nylon in the low to medium load range is still within the range of linear elasticity, Fluorocarbon reaches its limit of elasticity much sooner. As a result; Fluorocarbon does not readily return to its original length after loading. This also explains why Fluorocarbon tends to curl up on itself rather than Nylon. In this respect UHMWPE behaves similarly to Nylon, meaning it stays within its range of linear elasticity.

The differing limits of elasticity of Fluorocarbon and Nylon affect the minimal-load-elongation and consequently the sensibility of the respective lines. The stress-strain-diagram shows that the strain-curve of Fluorocarbon raises steeper at first, but then approaches the Nylon strain-curve. Correctly interpreted, this means that Fluorocarbon is less elastic than Nylon at the beginning of the load range. See: Sensibility. In the case of UHMWPE the minimal-load-elongation is irrelevant as the limit of elasticity is very low.

Strike-elongation, fighting-elongation
As the minimal-load-elongation of Fluorocarbon is slightly less than that of Nylon so is also the elongation upon striking. However slight, this can prove an advantage for Fluorocarbon. On the other hand, through elastically tuning the line during production one can reduce the strike-elongation whilst increasing the fighting-elongation. With lines such as STROFT GTM und STROFT ABR it is then still possible to set a “mid-distance” strike effectively. The fighting elongation of both lines is very similar. In the case of UHMWPE, the very low elasticity makes it easy to set the hook effectively at the greatest distances; however this low elasticity can prove disadvantageous during the fight as is already discussed.



Generally one can say that the sensibility (feed-back) increases in direct proportion as the elasticity decreases. In this respect UHMWPE has a clear advantage. Both Fluorocarbon and Nylon behave similarly in this respect apart from the minimal–load-elongation of Fluorocarbon, which as discussed above is slightly more positive. If using Fluorocarbon the angler will receive slightly more feed-back from lure or bait than if he was using Nylon and bites will be more readily registered. Of course one should also consider a factor that is often forgotten. Just how often does a fishing line run in a straight line? Generally, in practice, the line sags somewhat and of course even more so if it is windy and especially so, if the line is light. A line that is heavier such as Fluorocarbon could be of advantage in this situation, certainly so over UHMWPE which is very light. As long as the UHMWPE line is not running straight then there is not much chance of the line giving much feed-back. The greater the weight of the baited trace or lure and the thinner the line the quicker the line will straighten. This is certainly a theme that is open to a lot of discussion.



UHMWPE lines have a very low memory, compacter and tighter UHMWPE braids even less so, this fact becomes clear when examining STROFT GTP. When a braid is coated or are welded or glued it has the effect of increasing the line-memory. Nylon possesses a much greater line-memory, however this can be reduced by accordingly tuning the line during production. STROFT monofilaments are a good example. Fluorocarbon has a slightly higher memory effect than Nylon; this is probably as a direct result of the lower limit-of-elasticity.



Lines that have a low abrasion-resistance will quickly become rough when used on a stony bottom or mussel bed. The abrasion-resistance of all three materials is basically similar, although different circumstances can effect the lines in different ways which makes evaluation difficult. Nylon’s water absorption decreases the line’s resistance to abrasion. So does exposure to ultra-violet light. On the other hand the abrasion-resistance can be greatly improved during production. Firstly by ensuring the correct mix of copolymers and secondly by production-tuning the line during the manufacturing process. STROFT ABR is a good example of this, although after the lines has been immersed in water for a longer period, Fluorocarbon does have advantages over Nylon. This is one of Fluorocarbon´s great strengths.The abrasion-resistance of UHMWPE lines is quite different. The more compact, round and dense the line the greater is the abrasion-resistance, such as by STROFT GTP. Coated lines, which are mostly loosely woven and are usually not round, or lines that are twisted, woven, glued or welded and sometimes additionally sheathed, have a far lower resistance to abrasion. Under no circumstances can the coating achieve the toughness of a UHMWPE fibre. Subsequently such lines have a much shorter useful life.



Nylon´s specific weight (1.14 g/cm³) always was a lucky coincidence for anglers, it’s just about perfect for a fishing line. Greasing Nylon makes it into a floating line, de-greasing it results in it sinking. UHMWPE is lighter (0,97 g/cm³) than water (1g /cm³) so it tends to float, Fluorocarbon is heavier(1.78 g/cm³) so it tends to sink. That makes it ideal, if one requires a strong line that sinks quickly, more so than either Nylon or UHMWPE. Some manufacturers try and influence the rate at which the line sinks by mixing heavier or lighter fibres, which works to some extent; unfortunately this reduces the tensile strength.


Flexibility, suppleness, softness, stiffness

The softest line is made of pure UHMWPE, provided it has not been coated and is not welded or glued. If sheathed (welded or glued) it becomes a rather stiff with wire-like characteristics. Fluorocarbon is somewhat stiffer than Nylon. This can be influenced during production, but generally more elasticity results in less tensile strength, less sensibility as well as less abrasion-resistance and vice versa.



Nylon’s perfectly round cross-section and smooth surface form the basis of its excellent castability with both multiplier and fixed spool reels.
The suppleness, together with the low memory and smooth finish, result in the quiet way in which the line leaves the reel and slips though the rings. The high linear tensile strength together with the good knot strength allows sudden acceleration at the beginning of the cast and enables the angler to cast great distances. To some extent this also applies to Fluorocarbon as well. When using Fluorocarbon as a main-line then one has to expect slightly shorter casts, not only does Fluorocarbon have a lower tensile strength, but the slightly higher specific weight (1.78 g/cm³) reduces the casting distance. The casting weight has to pull a heavier load behind itself. Also the stiffness and greater memory, particularly in the larger diameter lines, also have a negative effect on the casting distance, especially when using a fixed spool reel. The greatest casting distances are achieved using good quality UHMWPE lines. However, this is only the case when the higher linear tensile strength is fully utilised at the beginning of the cast. That can only be the case when the knot strength is approximately equivalent to the linear breaking strain of UHMWPE, this can be achieved by using spliced ​​loops. Also the ring-linings should have a relatively large diameter so that the line is not bent too acutely during the first phase of acceleration. Only then can UHMWPE’s high tensile strength of 450 kg/mm² be used to full advantage. Compared to Nylon lines the consequently thinner UHMWPE lines result in greater distance. The “dimples” on the surface of the braid also have a positive effect on the casting distance. See also: What are STROFT Dimples? Finally, the lower specific weight of UHMWPE (0.97 g/mm³) also has a positive effect on casting distance when compared to Nylon (1.14g/mm³). In practice the results are often quite different, UHMWPE’s poor knot-strength using ”normal knots” often results in a comparatively thick UHMWPE line being used so its advantages can not be fully utilised, in which case the casting distance is not much improved compared to Nylon. A round and compact braid is a further necessity when wishing to achieve optimal casting performance with UHMWPE braids. Otherwise, distance will again suffer, particularly when using a fixed spool reel.


Visibility and sensibility

Fluorocarbon’s refractive index is the most often used argument in its favour. Fluorocarbon’s refractive index (1.42) is much closer to that of water (1.33) than is Nylon (1.54). The refractive index of UHMWPE is 1.54, this relates in all cases to a single, un-coloured, transparent fibre of the material in question. As soon as one braids UHMWPE the refractive index becomes considerably higher which results in UHMWPE having high visibility when immersed. One can see the difference in the visibility for oneself by comparing a strand of each material in a glass of water, Fluorocarbon appears to be at an advantage; but there is no proof that fish also “see things our way”. However, there is clear proof that thinner line results in more bites. Consequently, using Nylon with a high knot-strength enables the angler to use thinner line and increase his bite ratio. So the knot-strength can be more important than the visibility in this case. Sensibility is extremely relevant; fish hear and locate objects with the aid of their side line. Several expert lure fishermen are of the opinion that fish “pick up” the existence of a UHMWPE line because of the vibrations caused by its strongly structured surface; one supposes that this produces more vibrations than a smooth monofilament when it passes through the water.



Fishing line is generally coloured for one of two reasons. Mostly it is coloured so that it has a similar colour to the surrounding water and is as unobtrusive as possible. Sometimes it is of advantage for the line to be highly visible, for example in poor light conditions. The extruder operator receives the raw material as graduals from the chemical company; they look much like coarse, milky salt. Either one can mix pigments in with the granulate and predetermine the final colour of the line. In this way one achieves a line that is coloured through and through. Or one can endeavour to die the line after it has been extruded by running it through a bath. Of course, only lines that have a predetermined colour won’t fade or bleach out. All STROFT lines contain pigments that predetermine the final colour.



Light, ultra violet light and abrasion all affect the useful life of a fishing line. Ultra violet light can reduce the tensile strength of a fishing line after only ten hours of exposure. Nevertheless, appropriate production processes can greatly decrease Nylon’s photo sensibility and so increase the length of time that the line remains useful. STROFT ABR and STROFT GTM are prime examples of this. See also: How long does STROFT fishing line keep?  Both Fluorocarbon and UHMWPE are very much in advantage here as neither shows any real signs of aging, even after decades. This is of course a disadvantage from an ecological point of view.



Nylon’s last, but certainly not the least important advantage is the cost. A Nylon line is very inexpensive compared to UHMWPE or Fluorocarbon.



All three materials have advantages and disadvantages. This said, anglers will find that Nylon still covers the largest spectrum of uses adequately. UHMWPE has experienced a great deal of acceptance in many areas of angling. Fluorocarbon on the other hand is useful for particular niches and has found its way into the tackle box of many specialists. That’s enough; now it’s up to you, the angler, to discuss the issues and decide which line is best for which purpose. If this article is helpful or encouraging then it has achieved its purpose.

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