I’ve lately had a bit of trouble with fishing line snapping unexpectedly. This particular line, Rio Powerflex, is one of the latest examples of the manufacturers’ quest to innovate, sell more stuff and to satisfy fishermen’s unsatisfiable desire to catch more fish. These are the copolymer lines.
For many years I have used long-serving nylon lines like Maxima and Bayer Perlon because I’ve found, like many others, that they are reliable and consistent. I still use them, especially the green Maxima for fly fishing, which most of the time is perfectly satisfactory. But there are times in this world of diminishing fly populations when the trout have nothing to eat except midges and other minute insects. They often eat these and ignore anything larger. That is the time I go for the tiny flies, size 20 and down, sometimes a lot down. Then 3lb Maxima is in comparison rather heavy duty. You can’t even thread it through the eye of a 24.
The relative fineness of copolymer lines meets a need. For the same breaking strain you get a line that is a better match to small flies and hopefully doesn’t stand out to the trout like a hawser. Unlike ‘normal’ nylon, however, they are prone to break easily and I have left flies in a few fish, something I do not want to do. Compared to 3lb Maxima, I snap off more flies in the bushes with 3.4lb Rio; it doesn’t stand up to impacts.
So I consulted the sages on the internet, or at least I searched to see if anyone else has the same problems. They do. I also found the usual problem of a lot of poorly informed opinions by online experts who love the sound of their own keyboard. In the results, up came some discussion threads on that forum for reactionary old geezers, flyfishing.co.uk, including one I’d participated in.
If you want to know the technical details of nylon fishing line, there is remarkably little information on the internet. There is plenty of misinformation though, just as there is with all things fishing, and all things in general come to that. The introduction of AI (artificial stupidity) by Google to summarise search findings is a hindrance. It draws on the many error-filled websites to produce a lot of misleading nonsense. Unfortunately there are no authoritative sites that specifically inform on the composition of the different lines available today; this, the companies will tell you, is ‘proprietary’ information.
I have no specialism in chemistry so I’ve had to gather a range of snippets on nylon used in fishing line to get some understanding. The detail is one for chemists and those happy to read through a book on polyamides and other synthetics. But what can the ‘wise ones’ on the above forum tell us? Not much about line but something about themselves. Clearly monofilaments like Maxima are different to the new copolymers, most obviously the relative thinness of the latter and their tendency to snap suddenly, the reason for this post. Yet to read some of the online posts referred to above, there is no difference: the word ‘copolymer’ is purely a marketing exercise according to the resident know-all, Cap’n Fishy. This somewhat narcissistic individual bristles at anyone who challenges this unjustified view. If he and the rest of the self-regarding types had any genuine qualifications, they would be very quick to say so. Instead they brush the matter away and regurgitate what they’ve trawled from the net, pretending they’ve always known. Ohanzee, one of the good guys on that forum, sums it up thus:
The real elephant in the ‘understanding’ room is the motivations of men, why they need to declare themselves experts on understanding things, when it becomes patiently clear after 749’000 posts repeating the same thing without actually listening . . .
There is no discussing anything with them. You can poke fun at them and that’s about it. No one gets anywhere with people who pretend to expertise they don’t have and no interest in acquiring. They only want to close down debate.
So what of the technical stuff? A copolymer is a chain of molecules (called monomers) of two different kinds; the standard lines are, as far as I know, polymers of one type of monomer — homopolymers. It’s easier to understand what these are by reference to jewellery chains:
A wiser head than Fishy’s, moniker kingf000, noted that standard lines have the same density as the homopolymer Nylon-6 (6 carbon atoms), one of the first thermoplastic polymers synthesised. Therefore, he deduced, these lines must be homopolymers, distinct from copolymers. Cap’n Fishy responded with vacuous remarks about the lines not being labelled as homopolymers. He is right to the extent that ‘copolymer’ appears on spools to market the product as something new, but that doesn’t mean all lines are copolymer.
The density argument is not wholly conclusive because Nylon-6,6 (two monomers and therefore a copolymer) is only a little denser. However, if you trawl through plastics manufacturers websites, there are numerous references to Nylon-6 being the most used material for monofilament lines. Since Maxima lines date back to the 1950s, it’s a reasonable bet they are Nylon-6, hence not a copolymer. Moreover, another name for Nylon-6 is Perlon, a name that will be familiar to most anglers: Bayer Perlon is almost certainly Nylon-6 homopolymer.
Then there are ‘double strength’ lines, which appeared before the latest copolymer lines. Most anglers refer to these as ‘pre-stretched’, but all nylon lines are stretched after extrusion to line up the filaments, which increases the tensile strength as well as give usable diameters. So whether these are stretched that bit more to reduce diameter while maintaining strength I don’t know. The upshot is these lines are even worse for snapping under high impact, especially if you get a knot in them. I’ve used them once.
Lines are complicated things now. Some probably add other molecules to those above, and there is the possibility of polymers blended into ‘co-filament’ lines with other additives too. Most have dye added. The exact nature of the molecular structure is beyond the divinity of most anglers unless you have a spectrometer handy, and you can’t get those in the Middle of Lidl.
My attempts at getting information direct from the manufacturers has yielded little other than some marketing phrases. Despite my reservations about Google’s AI overviews, I decided to consult a couple of LLMs, ChatGPT and Filo’s AI facility.
ChatGPT:
For Maxima specifically:
Maxima’s fishing lines are mostly homopolymer nylon, especially the classic lines like Ultragreen or Chameleon. These are praised for their consistent strength and performance due to the uniform polymer structure of homopolymers.
However, without access to their proprietary formulation, it’s possible that some lines use modified nylons or small amounts of copolymers/additives — but the base is still primarily a homopolymer.
If you’re asking for a chemistry project or material science reason, you’d be safe saying Maxima lines are homopolymer nylon-based unless otherwise specified.
Filo:
Clear enough? Well, we know that these models ‘hallucinate’, in other words, come up with the wrong answer — remember, the web is littered with bad stuff as well as good. The way you word the question can affect the answer you get back.
The upshot of all this pondering and searching is that the old standard monofilament lines are probably homopolymers, whereas the newer, snapping copolymer lines are just what they say on the spool, exact structure top secret. I shall be sticking with good old Maxima, though on those difficult days I intend to try another copolymer line that others say is good. I might even ask the trout what they think.
The Secret Angler 