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Me and GsP

13 posts in this topic

GsP and ME.


When I retired in 1993 I decided to upgrade my fly tackle and started looking at high class rods, reels and backing lines. I found that it was that time of the "Spectra" introduction into Australian SWF. I was hit with the commercial "hard sell" about the product, and enormous prices, which when compared to those advertised in the USA seemed a little like highway robbery.

One American product was priced at 3.9 cents US per yard, while it was 35 cents per yard here. At 35 cents per yard a 100 metre spool costs $38. The price was increased by 466% which is not funny.

I was told that "Spectra" was the "ant's pants, the genuine article, the best ever, absolutely gorgeous, magnifique", while "Dyneema", only one obvious brand available, was "Japanese rubbish", again, "Absolutely, totally and definitely Japanese junk". Mind you this was in 1993, and things have changed, just a wee bit.

Trying to get to the nitty gritty of the material, Gel Spun Polyethylene, came up with a bundle of total fabrications about the manufacture. It all became too much to bear, torn apart by tackle dealers, all trying to lift my retirement cheque off me for one small spool of GsP braid.

I talked to Don McPherson from Australian Monofil Pty Ltd, who used "Gel Spun Polyethylene" in Platypus "Power Braid" and he told me who made it etc. He also said, "bear in mind this is a stiff fibre". My brain went, "click", stiff means high modulus, which means, you got it. Don also said "The trade name of the stuff, well, what the inventors call it is "Dyneema"... "Spectra" is the name given to it by AlliedSignal Inc. in the USA who make it under license. We get ours from Toyobo Co. in Japan, it is Dyneema" More cranial "clicks" like "Ah so, velly bright light shines. Truth are that velly much bulldust out there in tackle shops".

(Since then Toyobo Co has become Nippon-Dyneema and Allied Signal has been taken over by Honeywell)

I rang DSM High Performance Fibres in Holland. They sent me a brochure and told me a lot about the performance of GsP fibres.They said, "not good in knots, best about 80%, some as low as 45%". They were not kidding, a "Spider Hitch", good in monofilament, tests at 48%, in a good well tied knot.

Basically Gel Spun Polyethylene fibres are used in boat sails, body armour and ropes. Fishing lines were intended to be a sort of offshoot of the GsP production.


What is Polyethylene


Gel Spun Polyethylene fibre, or yarn, is made from Ultra High Density, or Ultra High Molecular Weight Polyethylene, which is a Hydrocarbon product. The short description is UHMWP.

The very simple explanation is that Hydrocarbons are compounds containing carbon and hydrogen. Saturated hydrocarbons are classified as "alkanes" and are different from unsaturated hydrocarbons which are called "alkenes". Ethylene is a colourless flammable gaseous "alkene" or unsaturated hydrocarbon. It is made from cracking petroleum.

Polymerisation is the chemical combination of simpler molecules, (monomers) to form long chain molecules of repeating units. In "addition Polymerisation" monomers simply add together and no other compound is formed. Polythene, or polyethylene, is a white translucent thermoplastic material made by the polymerisation of ethylene. Low density polyethylene is made at high pressure and is a soft material used for flexible pipes, sheets and bags.

High density polyethylene is made at lower pressures, is more rigid and softens at higher temperatures.


Gel-spun Polyethylene Yarns


DSM High Performance Fibres, Heerlen, Holland are the inventors of, and patent holders for, Gel-Spun Polyethylene fibres, or yarns, used in "Super Braid" fishing lines.

"Dyneema" is the registered trade mark of DSM HPF and of Nippon-Dyneema. Japan who are Far East producers of "Dyneema". "Spectra" is a registered trademark of Honeywell who are license holders for production in America.

Believe it or not, every millimetre of "Spectra" fibre braided into fishing lines in the USA comes out of the Honeywell production vats. Which means that there isn't a great deal of difference in those lines. Much the same can be said for the other producers, DSM HPF and Nippon-Dyneema. For the record any improved "Spectra" characteristics, are firstly improved "Dyneema" characteristics, since whatever the improvements are, they will have been "developed" if that is the correct word, by DSM HPF. Gel-Spun Polyethylene gets abbreviated to GsP or Gel-Spun depending on the writers, or publisher's preferences, but it all means the same braided line.

The process of manufacturing a super-strong fibre from a polymer such as polyethylene is, according to DSM HPF, easy to understand. (Maybe) Quote


"In the gel spinning process the Ultra High Molecular Weight Polyethylene, UHMWP, is dissolved in a solvent, to a gel state, and spun, (extruded), through a spinneret. (Which is, simplistically, a piece of metal with a large number of micro diameter holes drilled into it, probably with a laser). In the solvent solution or gel, the molecules that form clusters in the solid state become disentangled and remain in that state. As the fibre is drawn, extruded through the spinneret micro apertures, a very high level of macromolecular orientation is attained.

The filaments, the fibres, are heated to remove the solvent and cooled by fluid immersion. The end result is a fibre or yarn with a high tenacity and modulus. It is characterised by a parallel macromolecular orientation greater than 95% and a high level of crystalinity, up to 85%.


"Dyneema" has a density of slightly less than one, so that it floats on water. The tenacity can be up to 15 times that of good quality steel. The modulus is very high and is second only to special carbon fibre grades." Unquote. The text in brackets is my clarification of the detail.


Using DSM HPF numbers, "E" Glass, used for fishing rods, has a modulus of 28. And "High Modulus" carbon fibre 210; but Dyneema has a modulus between 91 and 120 depending on type. And that means that the fibre is stiff. So stiff in fact, that it cannot be extruded into a single filament, monofilament, fishing line. It would have a memory like an elephant and a minimum loop diameter about the radius of a bicycle wheel.


Elongation at break, stretch, is low but due to the high tenacity: the energy required to break is very high with the end result a fibre, or yarn, with very high strength to diameter ratio.


The tenacity of Dyneema, its tensile strength, is high enough that if one were to suspend a single fibre in a length long enough that it fractured by its own weight: it would be around 400km long.


Dyneema fibres are produced in three commercial grades.


Dyneema SK25/SK60/SK62/SK65 Used for ropes, fishing nets, cordage, protective clothing and for reinforcement of impact-resistant composites.


Dyneema SK75/SK78 has a higher tenacity than DK60 etc. It is specially designed for ropes, cordage, fishery and textile applications where high performance and quality is needed. (Most fishing lines are braided from SK75)


Dyneema SK76 Specifically designed for ballistic protection


It is resistant to chemicals, UV light and micro-organisms. It is hydrophobic, it does not absorb water and has a stretch, elongation, of around 3.5%. Being hydrophobic means that it is resistant to dyes and although it can be coloured it does not fix and eventually wears off exposing the natural white colour of the polyethylene.


Although the fibre is of micro diameter and flexible enough for fishing lines it is stiff and does have a critical radius. The critical radius is that amount of bend the fibre will accept without fracture. Beyond that level the fibre will break.While the critical radius is another micro measurement it does determine the performance in knots. Knots, after all, require that the line and the fibres will be bent or looped and that the line will cross over itself in a number of places which will, under high stress loads, cause individual fibres to fracture.

Remember that the critical words here are"under high stress loads" that is where the line is stressed to near its tensile strength, where the maximum load appears on the knot which, because of the thin, and slippery line, causes turns to slip and tighten up and fibres to fracture.

Some Gel-spun lines are braided from teflon coated fibre. The coating is applied by running the yarn, fibre, through a water based teflon solution.


Braiding Gel-spun Fibre



Gel Spun Polyethylene fibre is actually measured in "denier", or weight. It is a measurement of the fineness of silk or man made fibres and is equal to 1 gram per 9000 metres. That is 1 denier equals 1 gram per 9kms of a single fibre. The fibre extruded for high quality fishing lines needs to be within a specific range of denier, to keep product stiffness to a minimum. If the fibre is too heavy, it is very stiff and the knot performance, while normally bad, would be much worse. Generally, however, most lines of similar or equal breaking strains have similar denier and similar numbers of fibres in similar numbers of plaits.

Braiding GsP fibres into fishing lines is not a unique or special process but is quite normal to a world wide industry. There are thousands on companies around the world which can, and do, braid GsP fibre for many different applications. To suggest that there is some magical thing about braiding GsP fibre, or that it costs more to braid than say, nylon for stockings or polyester for Dacron, is gilding the lily a wee bit.

Braiding micro fibres is a slow process, each machine produces about 500 metres per day, but the manufacturers have large numbers of machines, often in excess of 4,000, to produce the required output which can exceed 2,000,000 metres per day.The braid consists of a number of bundles of fibre braided, or plaited into a cord. The bundles are called carriers and the line may have a lot of carriers or a few carriers.

Elongation or stretch of the GsP fibre is set by the chemical composition, the "parallel orientation greater than 95% and a high level of crystalinity, up to 85%." whereas the tightness of the weave determines the amount of weave displacement under stress. One is set during the Gel Spinning process while the other is a function of the braiding process. They are different and high levels of weave displacement occur at high stress loads before the elongation is exceeded and the fibre fractures.

Where loading stress is low level, in a normal fly fishing system, both the stretch and braid displacement are minimal and, in practical terms, have little effect. Where stress loads are high, big fish on critical systems, 30lb system and 20lb tippet with the fish a few hundred yards away, these factors may come into play. But with 50lb GsP braid as backing line both elongation and weave displacement, with a 20lb tippet system, are not really important since the loading stress on the 50lb braid never gets high enough to cause problems. The tippet will fracture long before these things come into serious contention.

But when you get right down to the reality of GsP braided fishing lines, in most cases, only the colour, spools and the brand names are different. So it really doesn't matter who braids the lines, or whether it is "Spectra" or "Dyneema".


Knot Strength


Regardless of protestation or denial most knots tied in GsP braided lines fail between 60% and 80% of the line breaking strain. Some knots, Spider Hitches for example, fail at around 48% of the line breaking strain. This is also a function of the Gel Spinning process, that high modulus and critical radius, and cannot be altered by tying knots of any kind.

There will be disclaimers about this, but remember I said "MOST" knots, and while there may be exceptions there are no perfect knots out there, that is knots which break at the line breaking strain, like 100%.

Bimini Twist knots, commonly regarded as a "Twenty times around" knot are not successful in GsP line because the fibre is very thin and very slippery. With a 20 twist Bimini the body of the knot can be slipped up and down the main line quite easily. This is because in the Bimini Twist the main line goes through the knot although it is twisted and wrapped with the loop section of the line. In general terms that twisting of the two lines, and the roll down, depends on tightness of the twist, friction, to hold the knot stable. The braided line is so thin and slippery that 20 line twists and the two half hitches and clench knot lock does not hold the knot and allows the body of the knot to slip.

The failure to effectively lock the knot means that the extra security of the doubled line is not there and the normal Bimini knot is really just a bundle of line wraps serving no useful purpose. This is easily demonstrated by tying a 20 twist Bimini in GsP braid and terminating the loop in a swivel or hook. If you apply some pressure on the line you can then grasp the Bimini knot and slide it up and down the main line until it is stopped by the termination .

Tying Bimini Twists with varying numbers of twists indicates that this condition will continue, with increasing tightness, until you get to greater than 45 twists. But the knot can be shifted under stress, i.e. more pressure on the knot. Which tells us that Bimini Twist knots are not ideal for GsP applications . As the pressure on the Bimini loop increases the load can shift to one leg of the double. This can also happen if the legs of the double are not EXACTLY equal, again because of the low stretch factor.

It is my opinion, and there is a lot of argument about this, that one should not use Bimini Twist knots in Gel-spun braided lines because it was designed for mono-filament, which is thicker and has greater friction in the twists. The lack of stretch in Gel-spun braids means that the end termination has to be carefully made to ensure that each leg of the double has equal load.

Remember that the maximum elongation is 3.5% and if the double legs are not of equal length all of the load can be on one leg and that is not an ideal situation. The use of Bimini Twists in GsP braids involves precision, more so than with monofilament applications. Then here is that added factor that the knot cutting also applies to loop to loop connections in GsP braids.

The point about Bimini knots in GsP braid is that increasing the number of twists, or adding dental floss to the body of the knot, to compensate for a problem which is a function of the manufacturing process and the chemical composition of the line; doesn't solve the problem. It is a case that "Man cannot change what the Lord, and DSM HPF provide". Man can compensate for it, but alter it, not likely.

This may ruffle some feathers but the manufacturers, DSM HPF say, or at least they told me, that no knot, regardless of how simple or complex it is or who ties it, or invents it, has a 100% performance in GsP braided lines. And after a lot of testing I believe them absolutely.

Looking at the variation in fly system breaking strains, if a knot has a strength of 90% in a 30lb system the breaking strain is reduced to 27lb. If it is 80% it is reduced to 24lb. What this means is that the difference between the 10kg tippet, 22.2lb, and the system breaking strain is reduced until one almost equals the other. Even a 100% system with 30lb the amount of safety factor, 7.8lbs is getting into dangerous territory with a 22.2lb tippet. Using 35lb or 40lb breaking strain increases that safety factor. This does not only apply to GsP backing systems but can also apply to 30lb Dacron and Micron, which are braided from Polyester fibre.

But generally with GsP braids a 30lb line, the number on the spool, will break around 42lb and 50lb GsP braid will break around 70lb.

I can hear the comments now. "Here hold on. I use a double Uni Knot, or a 70 twist Bimini and it is great". Well I know you do, so do hundreds of others but I really don't care who says what, or writes what, about knots in these braids, I have stopped listening to the experts, because I haven't found one knot that is 100% and I have broken hundreds of knots of all types.

Let me reiterate this point, I'm not particularly interested in other people's opinions on this subject: these things I did for me, others get it as a by product of 3 years of testing knots etc. If they believe it, OK, if they don't, again Ok.

If knots tied, and tested, under good conditions, in my backyard fail, what is going to happen when a recreational angler starts to tie these knots on a beach at night with very little light and the southerly wind belting in like a tropical cyclone.

Authors who give us very involved and complex GsP knots to use in fishing lines seem to be trying to prove that man can overcome the inbuilt limitations, from the chemical composition, of the fibre, and they also seem to forget the practical side of things.

That in the reality of angling conditions, doing their thing on a beach or rock, or in a tinny on a river, or even on a rocking charter boat, are anglers and where they are isn't a place conducive to tying complex and critical connections. Some of these knots require one to be a double jointed Olympic class acrobat, with some pretty nimble fingers. Under those circumstances the most simple connection, like a single Uni Knot and one drop of Super Glue, beats anything else.


The reality is that if you put a drop of Loctite 406 superglue on your pet knot it will be 100%. If you catch one fish on it, just one fish, it has done it's job and you can tie up another knot in a few seconds. Nothing is forever so one uses the principle of "one fish one knot".


Super Glues and Fishing


This is not a plug for any brand of Super Glue but I mention Loctite products because they are the best available for this purpose. Loctite have not given me any cheapies, nor have they solicited any favours. The subject matter is my own opinion and results from testing carried out by myself at my home address.

Super Glue, cyanoacrylate ester adhesive, such as Stren Lok-Knot, Loctite 406 or any other Super Glue does not glue Teflon or Polyethylene, unless you are using an oxidising primer like Loctite 770, although it is effective when used on knots in Gel-spun Polyethylene braided line.

There is some variance in the thickness, or viscosity, of Super Glues and all of the tests indicate that to be really effective, to saturate the GsP braid, monofilament knots and braided monofilament lines the glue must be thin and runny.

The ideal is for the viscosity to be less than 50 C.P.S. so that a single drop of glue will flow along and into the line for at least 5mm. The tighter the braid in the line, GsP, or monofilament braid the thinner the glue should be.

A suitable Super Glue is Loctite 406, which is particularly designed for wicking fibre bundles and is industrial strength and available in 25mil bottles. Loctite 406 is a very thin, low viscosity fluid and a single drop of Loctite 406 glue will saturate around 5mm of braided monofilament and Gel Spun braided line. The thin glue saturates the air space in the knot and between the braids, physically locking the turns. Because of the high sheer strength, this prevents movement of the turns in the knot. Generally speaking general purpose CA glues are "gap filling" and are not really adequate for use with GsP braids.


While the CA glue does not actually "Glue" the GsP to the braided monofilament, it penetrates the GsP braid completly and locks it to the braided monofilament. It immobilises the turns in the knot, preventing slippage which prevents that "knot cutting" problem.

Cyanoacrylate ester adhesives are said to be water resistant in both fresh and salt water but it is known that water immersion does break down the glue "eventually". And that "eventually" is not something on which Loctite representatives want to speculate. It could be weeks, months years, but really they don't know and I suspect that it is a variable depending on the usage rate, the amount of water immersion, that is the time in the water. But from my testing it will not degrade in minutes, hours or even days of continuous high stress effort. But you can get a water proofing agent, Loctite 741 which you can apply to the connections.

The US tackle market has "Zap-a-Gap" super glue and "Fishin' Glue" which is stated to be able to "instantly strengthen knots in all types of line, repair cracked rods, hold plastic baits on hooks and fix damaged lures".

These glues are similar and do the same job and they do fix plastic baits to hooks very effectively. Like sticking Mr. Twister tails to the jig head. There is nothing worse than a plastic tail that absolutely refuses to stay put on the jig head.

Super Glues, cyanoacrylate ester adhesives, are necessary items in todays fishing systems. Quite a few of the recommended knots for GsP braid include the words "Secure with a dab of glue". And, for what it is worth, quite a few anglers are dabbing with glue to secure knots in fresh and salt water.

Super glues such as Loctite 406 will work on monofilament lines and knots. When applied to splices in braided monofilament lines, cyanoacrylate ester adhesives effectively weld the spliced lines together. Glued joints should very small in area and should not be in areas of flexion because the joint is not flexible, but is rigid and can fatigue under flexion. The shear strength of glued joints is 3190psi so any glued joint in a splice between braided monofilament and GsP braid will be very strong.

It should be understood that nothing is forever. Cyanoacrylate ester adhesives are not a new magic formula and glued knots, connections or splices should be renewed after heavy use. There is no real proof that super glues weaken monofilament, GsP, or Dacron braided lines but there is no real proof that it doesn't either.

My own tests indicate that the life of glued joints using Cyanoacrylate ester adhesives could be many months but that is not some kind of standard.


A word of warning. Because thin Super Glues, with C.P.S numbers under 50 can squirt out of tube nozzles, can bond skin instantly and are eye irritants one should always have a tube of Super Glue Remover in your tackle box. It might be handy one day.


The Gel Spun Reality


Basically, Gel Spun Polyethylene is a stiff fibre. It has a very high modulus, about halfway between "S" glass and carbon fibre, and they make fishing rods out of those fibres. As a result GsP has a critical radius, which means it fractures if bent over that limit. It also floats, has a specific gravity less than 1, has bad knot strength, low abrasion resistance which is critically related to breaking strain, or line thickness, and absolutely hates sharp edges.

It is super slippery which causes the line to slip between layers on reel spools unless loaded at high tension and cross hatched on the spool every few layers. It will not hold dyes, cuts like a scalpel, cannot be glued, when tangled is very hard to untangle, and, (mind you this is just my opinion which doesn't amount to much), just about the worst fishing line ever invented and sold at very high, and ridiculous, prices, and that is looking in from the bright side.

On the other hand it has low stretch, elongation 3.6%, and a very high strength to diameter ratio, in other words it is very thin: and very strong, all of which is the bright side. Regardless of this I love it.

To verify the abrasion resistance I carried out a few tests. The testing method was rubbing the line sample across the edge of a textured brick. All lines were rubbed across the same spot on the brick and as far as was possible the same tension was used.. Mind you this testing was done a few years ago and other brands have been produced and developments have been made over the years, but the reality is that the fibres have not changed in critical areas.

Trying to find a spot on the edge of the brick that was blunt enough that it did not fracture 20lb GsP instantly, was a problem, but once a point was established ALL lines were tested across that spot. But it pointed out that these lines were not the thing to use amongst oysters, barnacles or ocean rocks or for that matter wrap tightly on "holy" fly reel spools. Particularly those with sharp edges on the holes. The lighter braids seemed to fracture even before they hit the brick, like they died of shock. It was like, "Not the brick, please God, no, not the brick. Anything but the brick." Or, it could be said "Not the spool, please God, not the spool".

While this methodology would not be regarded as being very scientific, or even close to being a "proper" way to do it, it does actually show what happens when these lines are rubbed on abrasive surfaces, like rocks.


Abrasion Testing



Line Material Break Strain Rubs

Spiderwire SpectrGsP 20lb(26)7

TritonDyneema GsP 20lb (27)) 6

Spiderwire 2000 Spectra GsP 30lb(40)11

Cortland Spectron Spectra GsP 35lb(45)19

Berkley U-MaxSpectra GsP 40lb 48

Blue Wave DyneemaGsP 44lb(50)38

Gudebrod SST SpectraGsP 45lb(52)25

Cortland Micron Dacron 30lb 2

Spiderwire Fusion Spectra GsP 24lb(35)5

Platypus Pre Test Mono10kg 7

Stren Powerbraid Kevlar 15lb (30.5lb) 55

Stren PowerbraidKevlar 25lb (50.2lb) 71


It is not a definitive test but provides some information on the abrasion resistance of GsP and Kevlar lines particularly in relation to breaking strain, ie. line diameter. It certainly is not an absolutely accurate test because of the many variables. It might have been nice to test a lot more GsP lines.

With the lighter braids it was rather revealing that the line, in some spots, fractured instantly and in others survived a number of rubs. What this means is simply that the sharper the lesser and in relation to high tension backing loads on reel spools with holes the possibility of fibre fracture is there. The result of this is reduced breaking strain. I have a feeling that so long as the pressure remains the effects could be cumulative.

This supports the, "use a heavy GsP braid for backing, it will survive the sharp edges, and general pitfalls, better than lower breaking strain lines" theory. Just maybe, it also points to the "We need better fly reel technology" theory.

While I gather in a large amount of criticism for my comments on holes in modern fly reel spools, one has only to look at some reels to have a GsP nightmare, there are huge slots in arbors, holes running around edges and altogether the things look like they are constructed from aluminium chicken wire.

But people and reel manufacturers seem to forget or ignore that GsP has a very high modulus, much higher than fibreglass, and that if one fibre in the line is fractured by being bent around the sharp edge of just one hole in a spool, or by a bulky knot being crashed into a runner at high speed, the breaking strain of the backing line is reduced.

In Saltwater Flyfishing, one has to have an optimum system, anything that may, for any reason, reduce the breaking strain of the GsP backing, bad knots, bulky loop connections or holy spools, are not really desirable. One should not have to use a heavy GsP braid as backing because it will accept fibre fracture from bad knots or bad spools better than lighter lines.

You can make GsP work, and work very well, if you forget knots, and use Super Glue. It will do a job if you are not terribly particular about the in-built problems, there are many, and use it in those areas where it excels.

That low stretch is a definite advantage in bottom bouncing, and fly fishing but not much help elsewhere. That low stretch means instant reaction which means you need a soft rod for lure fishing, otherwise you can pull lures out of the fish's mouth before it can get a grip. It also transmits sudden high force loads onto graphite rods instantly. And the higher the rod modulus the greater the problem.

The low abrasion resistance is bad news in rock fishing, in among mangrove areas and around jetties. And that is just some of the story. This is difficult because all testing machines ar

Testing GsP lines is difficult because most machines are set at the IGFA standard load rate of 400mm per minute. Which is designed for stretchy monofilament and Dacron. Use that on GsP braid with a elongation of 3.6% and it is a snap load which causes erratic results. The ideal load rate, so I'm told by John Devitt, is about 100mm per minute. A rather slow creep. I used a gradual sand load in a bucket and a set of good scales, which is not perfect but adequate for this job.

It proved that most GsP braids actually tested well in excess of the manufacturers label numbers. Approximately 30% higher.

While testing Bimini Twists I found that anything less than 45 twists was ridiculous since the knot slipped under load. By this I mean that you could slip the knot, the actual Bimini knot, up and down the main line. To do this I hooked the loop over a nail, applied some tension and slid the knot up and down the line. It does this because the main line is twisted with the other leg of the loop, it goes straight through the knot. If you secure the double, by putting a knot in it, the tension is ALL on the main leg rather than the double, since the knot really serves no useful purpose. You might just as well tie the main line to whatever the double is connected to. Fact is there is not enough tension on the twist to hold the knot. You really need about 70 twists for the knot to be secure. And the twists have to be really tight.

There can be large amounts of damage to the knots in the backing line due to runner abrasion. Basically the knots go through the runners a large number of times over a period of fishing, particularly those knots close to the fly line. As they hit the runners the shock causes fibre fracture which reduces knot breaking strain and reduces the backing line safety factor.

I started looking at splicing the braid and but, since it is not tubular, you couldn't splice it. So I started splicing it co-axially with braided monofilament and got 100% results every time. I found that you could dispense with knots in GsP braids and you would get what a fishing line should be, a 100% breaking strain product.

There are arguments about this "fishing lines should be a 100% product" it seems not everyone wants a knot that is 100% because "it might break the line first" .I want a 100% system every single time and, after all, I did this for me. Everyone else gets it as a sort of bonus. Which they might not like anyway.

This series of tests produced the co-axial spliced loop, in which the GsP braid is inserted right through a short section of braided monofilament. The breaking strain of the braided monofilament isn't important since the system breaking strain is set by the GsP. The co-axial line is then spliced back into itself, so that the GsP braid goes right around the loop. It is trimmed, and glued with Loctite 406.

I have used this system on bait casting tackle, to fit quick connect clips. It works fine, not a problem and you can change lures instantly which is something of a bonus. In other words, CA, Super glues do have a very serious application in connecting fishing lines if the angler is prepared to accept it.

After some long and involved discussion about the failure rate of glued joints in water, and how this system was doomed to failure because of immersion is salt water I decided to find out how these glued splices stand up to the dreaded immersion.

I set up a few splices and dumped them in my chlorinated swimming pool for 72 hours. Then I took them out and hung each one up, in the summer sun, with a 15lb load, bricks, for 72 hours. I then testing the breaking strain and got a 100% result. Which says that a glued splice isn't going to be effected by immersion while I am fishing with my fly rod. Even if I am attached to a whale for a couple of days.

I did these tests a number of times and the conclusion was that I could have a 30lb(42lb) GsP backing system and hang it on good fish using a 20lb/10kg tippet and it would not fall apart. The disadvantage was that the 30lb GsP braid system had a lower abrasion resistance than 50lb(72lb) GsP. Which basically says, "Be careful if you use this system around rocks, reefs and barnacle encrusted jetties". Subsequent experience indicates thatgetting reefed can be a serious problem.

For the record 30lb Bionic Braid fractures at 42lb, so that a SWF backing system using 30lb Bionic Braid will provide a full 42lb breaking strain system. Even if you use knots.. The spool is still marked 30lb. The 50lb Bionic Braid now breaks at 72lb.

But most GsP braids will test over the spool figure anyway.

When it comes to using GsP braid as fly reel backing, you have to remember that most reel spools have a number of holes drilled into the spool for various reasons. These holes are drilled from the outside in, which means that drill scarf is on the inside. Getting this off and smoothing the hole edges, from inside the spool is not easy, and generally is left until the finishing and polishing cycle of manufacture. If this is a bit on the minimum side those holes will have sharp edges.

Before you attempt to put GsP on the spool, check the inside of the spool for rough edges on the holes, in fact do it before you buy the reel. Also check the holes in the arbor of LA type reels and if you are really serious thread a short section of GsP braid through the holes and pull it backwards and forwards a few times under tension. This is not designed to thrill the guy selling the reel, in fact he will probably be downright offended. He might even try to stop you doing it.

Some reel spools are pretty rough, it depends on the reel value. The expensive reels have better finishes, generally, which means less sharp edges to the holes. It is something like a lottery, but check first and remember that the thinner the braid the lower the abrasion resistance and, consequently, the lower the resistance to sharp edges.

It has been suggested that I have a thing about fly reels, and am continually attacking reels that are very good quality and work very well. Perhaps this is so: my point is about holes in fly reel spools on which anglers wrap GsP braids under high tension. If we look at the abrasion test results it indicates that GsP braid does not tolerate sharp edges, and moreso in the lighter breaking strains, which are very thin. And holes in fly reel spools provide places for the braid to be bent at critical angles

On the technical side one does not have to drill numerous holes in fly reels to lighten them. One can remove material without breaking into the inner surfaces of the spool, and you can simply forego the hole drilling sequence of the manufacturing process.

The simple facts are that, among other unalterable technical attributes, or idiosyncracies, high modulus GsP Braid is prone to fibre fracture on sharp edges and when it is loaded on the spool under high tension the lines are bent across the hole edges under high pressure and because of this, holes, sharp edged or otherwise, should not be drilled into spools under any circumstance. Well that's my view anyway.

Deciding the amount of GsP braid you need to fill the fly reel spool is not easy but 600 yards of 35lb Cortland "Spectron" GsP braid, which breaks slightly above 35lb, has approximately the same volume as 250 yards of 30lb Cortland Micron. The 30lb Cortland Micron is approximately 2.4 times greater in volume than 35lb "Spectron" GsP braid. If Dacron rates as 1.0 for water drag then 35lb GsP should rate as 0.42 or 58% less than dacron.

Taking this a little further, 30lb Micron is about 1.8 times greater in volume than 50lb(72lb) "Bionic Braid" and you can use that 2.4 times figure for 30lb(42lb) "Bionic braid" although the Bionic Braid is slightly thinner than the Cortland "Spectron"

Using a spliced backing system, such as 42lb Bionic Braid removes the need to use 25kg (50lb) backing line. It is less costly, in Australia anyway, and gives adequate security for 10kg tippet systems. But it is extremely thin and could be prone to turn slippage under high loads so it has to be spooled under high tension and cross hatched. It also provides lower water drag, and a higher spool capacity.

Securing GsP braid to a spool arbor can be a problem because the braid is thin and slippery. After securing the line to the arbor, using a knot, a few drops of super glue to secure the knot and backing line to the spool will prevent slippage and if you ever need to remove it the glue can be softened and easily removed by the application of boiling water to the join.


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Max from my perspective, you have written a brilliant important article. I only wish you had written it earlier as you will see below. I want to say at the start that my own tests fully support your tests and science--as you would already know. I did not have the benefit of Loctite 406 which I now have on order. I want a 100% system where I pick what is most likely to break first. (Spinning Reel application)


One question for you, if you splice Jerry Brown hollow core for a foot or so it seems to have 100% breaking strength. Do you have any idea what breaking strength a loop-to-loop will have if you test two Jerry Brown loops back to back?


My story


This summer, I decided to take up bluefin tuna fishing and the fish in this area are 100 pounds or so. I got a good rod and reel with 50# braid. Here's what I "discovered".


I've used PowerPro (20#, 30# and 50#) for the past 6 years or so and love it. Sure, I've had a couple break-offs and Uni knot failures, but who hasn't? (I did realize that pulling too tightly on the tag of a uni seemed to weaken it.) Knowing how hard a big fish can hit and wanting to tie a strong leader/braid connection (50# braid, 50# leader), I decide to test my first uni-uni by pulling and breaking it with a fish scale. The result, the braid broke, above the knot at 18#! I was shocked.


I have since tied and broken dozens of combinations of unis, surgeons, albrights, palomars, yucatans/reverse albrights, biminis, australian plaits, SFs, SIGs and a couple slim beautys, using a scale, dead weight, and bounced weight. After cutting and bruising my hands from whiplash, here is some of what I learned:


--Spectra braid ratings can be anywhere from 100% of spool marking to over 150%. Some 50# is 50# and some is over 75#.


--Most simple knots (Uni, Overhand, Figure 8, Surgeons, Clinch, etc.) break between 40% and 50% of ACTUAL (not labeled) line strength. Tie an overhand knot in 50# line, and you've got 20# test. Overhand knots break quickly, often below 20#.


--Taking the first two points into account, I reliably recorded breaks using Calcutta and PowerPro 50# braid between 18# and 30# in my various 50# line/50# leader tests. (The higher breaking strengths weren't due to the knots as much as one of the 50# braids actually tested higher.)


--Braided lines are very slippery. Once the knot starts to slip under high pressure it breaks, almost always somewhere above the knot. This can lead to the same type of knot breaking higher or lower in the range I measured.


--The Bimini twist (BT) is the best knot I measured. It breaks at over 40# (I used 40 twists. I haven't actually broken the BT knot, something else, such as the leader/terminal tackle knot breaks first at over 40#)(UPDATE: I HAVE LEARNED THAT 70-100 TWISTS ARE NEEDED). I always thought the BT was a trick knot and hard to tie. It was well worth my time to learn.


--A Spider hitch doubles the line like a BT, but broke above the knot at about 25# or less.


--The Austrailian Plait doubles the line but in braided line, is very hard to make so that it doesn't slip and fail.


--Yucatan/Reverse Albright type knots (made with doubled braid) broke above 40# but casting them through my rods guides weakened them quickly due to the stiff leader tag end hitting the guides on the way out.


--After tying the BT in the braided line, it can be attached to the leader with surgeons, uni-uni, etc. This connection reliably broke between 30-40# if well tied. The Japanese friction knots (FG, SF, SIG, MID, etc.) never broke and cast well, the leader to swivel knot in the fluoro always broke first at a little over 40#. (Slim Beauty is another friction-type knot.)


--When I bounced the weights I used to test the lines, even a couple inches, the lines broke at a much lower weight. Something like half or two-thirds. Made me realize that rod flex and leader stretch are important.


--I've read a lot of articles suggesting that a longer leader (15-20') adds a couple feet of stretch to the system and takes pressure off the knots.


In Conclusion: I've put a Bimini Twist on all my rods/reels that are loaded with braid. On my tuna setups I'm attaching the Bimini Twist-ed braid to a 15' leader with a friction knot (SIG knot which you can find at This knot makes it easy to equalize the bimini leg length) and leader to tackle with a Palomar-type knot (if somethings going to break, an 80% of line strength knot at the lure seems best). If I were in a hurry in the heat of battle I think I would tie a Bimini in the braid, a Surgeons to the leader, and a Palomar to the tackle.


Having read your article, I'm now looking at the coaxial splice versus spliced Jerry Brown loop to loop with a 20' fluoro leader.

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All of the article was good but some points here:


1) No one has ever proven that in a good quality reel that the holes cause the GSP to exceed the critical radius and break. Not one single instance can be found by anyone either by you or on the internet. Therefore you have neither proven that nor has there been any empirical evidence to prove it. Basically the science is faulty and reality is it's a non issue.


2) Your biggest peeve is with the abrasion resistance of GSP, yet the only other material in common use, Dacron, seems to show even worse abrasion resistance (30 # Micron - 2 rubs versus anywhere from 5 to 19 pulls depending on brand for GSP). If we go by these numbers we simply should not use anything other than Kevlar or mono for backing which of course is not true. Neither dacron nor GSP has shown a history of breaking from abrasion from holes in reels nor will they ever.

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I send quite a few of my Coaxial loop details to American anglers, so anyone who wants it, just email me a address and you get it. No problem.


F1.....Let me say this, the internet is not the font of fishing knowledge and a few million anglers from quite a few countries use GsP braids on fly reels and some may not read these posts and may have had a backing line break. I once had a conversation with Rod Harrison about this and he said "The next time a backing line breaks will not be the first time its happened". And if anyone knows anything about GsP its Harro, he brought Bionic Braid into life here in Australia.

Technically, you know that funny stuff, any fly reel that has holes is loaded with GsP under high tension, has the opportunity for it to happen, and it probably doesn't happen with dacron because the load tension isn't the same. The load tension is the real problem, because it provides the force that bends the GsP into the holes. And the more of and bigger the holes the greater the opportunity.

Can you say absolutely, and promise to commit Hari Kari if you are wrong, that it's impossible. I wouldn't be that crazy, even at 78.

IHMO, current fly reel technology, holes and stuff is very bad technology because there is the opportunity for things to bend or shift under stress. Too many people worry too much about what reels look like and its only since Graphite arrived that its been "necessary" to drill holes in reels. For lightness. There are other ways of doing it and the weight difference in reels with holes and no holes is minimal.

Anyone who thinks current fly reels are the brass knuckles of technology is off his gourd. Definitely. If I was a reel manufacturer I'd be ashamed to admit it openly. I think I'd wear a ski mask in public. VBG


I don't discuss dacon, although I used it for years, before GsP arrived and it was all we had, wasn't it? But it wasn't a good backing line and still isn't. It soaked up water, had a terrible water drag and was all round bloody awful. The abrasion resistance of Dacron is a myth.


On Hollow Spectra, I've used it and found that it splices quite well, but Loctite 406 seems to be reluctant to get involved since its at least a 12 carrier braid, well the 60lb is and while I havent counted the carriers in the 80/120/150 braids I suspect its much the same or greater.

I have a trick way of getting 406 into the Hollow Spectra. I wet the piece of GsP sticking out of the back of the splice with glob of 406 and very quickly pull it back into the splice. If you get the message and then give it a quick squeeze.

I haven't tried pulling on a looped pair of splices in the stuff, but have given a spliced and glued loop a pretty serious pull to see what happens. If the CA glue isn't set right it just comes apart, which is why I'm a bit reluctant to get too involved.

I have made running lines out of it, used Jerry Brown Line-One in 60lb and 80lb. Stuffed them with 6lb mono. Worked quite well, zipped through the guides. But now I've got a monic running line. Its less time and less problems.. One just pulls out the credit card and Monic send it here. Like zip.

I'm looking for another glue.


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Pfisher. I use that coax loop on my light spin gear and I simply put a clip in it. The mono braid used for the loop actually protects the GsP from the funny things that can go wrong. In the SWF system it protects the GsP from runner hits.

But you can use loop to loop connections, like with mono leaders. I mostly use wire leaders on my "other" fishing gear, toothy critters abound, and I generally put a ring, or a clip on the coax loop to connect the wire.

The lures I use a 99% lead head jigs, white or fluorescent chartruse.

You have been busy. But its a worthwhile experience because after its over you can be sure you have the right terminations on your gear, and everything from the arbor to whatever hangs on the end is as good as it gets.

Congrats MaxG.

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Since I wrote last night I have built and tested a splice in 65# Jerry Brown. The loop is about 4" in diameter and the "tag" end is "overspliced" for 12 inches and then "inside spliced" for another 12", using no glue.


I took the loop, threaded a pail handle through it, and lifted 60# of dumbells off the floor, slowly. I then jiggled the line and it snapped, a foot above the end of the splice. The splice looks like new.


Because I use a SIG knot now, I can keep the lengths of the loop equal while I pull the knot tight on my 20' leader. I would like to use loop to loop with a JB end loop spliced onto the fluoro--JB running line connected to JB spliced leader--then I can buy the leaders and not have to build them.


Next test tomorrow will be 65# spliced loop to 65# spliced loop.


I have another idea for everyone who prefers to tie "regular" knots. Pull 4' of JB braid inside itself. Then the last four feet of the line is doubled. A regular 50% knot would then perform close to 100%. What do you think? Also, JB makes a two step glue, I guess you know that.



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Formula1, so help me, I don't want another post on whether MaxG's opinion on the damage done to line by holes in reel spools. Never again, as along as you live. OK? This particular flea has been done to death. Everybody here has gotten bored with the subject.


Pametriver, all new guys to this Forum must post a joke .... even when they've contributed as much to fly fishing in salt water as you have. Ante up.

..... I have a looseleaf binder full of stuff I printed from pametriver.

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Most of my Splices in JB GsP hollow have three in/outs to ensure it is very strong, and I glue the very last section. But because of the GsP fracture ability I still don't trust it enough to take it fishing seriously. Even though its 60 JB stuff. I think the BP glue is a CA type with an oxidiser. Might even be 406 with 477 oxidiser. Which is probably the way to go.

The quick snap result is due to that very fast stop at the bottom of the drop which causes the braid weave to destruct.

I was bottom jigging in around 80 feet and had a very serious hit, using my usual 45lb GsP line, and I gave the fish a hell of a jolt and the line broke down there. It actually came back up out of the water, like a big heap of GsP line exited the water right in front of me. Another time I was testing the stuff and it broke and the tail end of the line came back at me like a rocket. Make sure you wear protective glasses when you do those snappy things. The stuff stores a heap of energy. Could destroy an eye.

60lb GsP is pretty strong stuff, especially if used in SWF systems.

I had a dream of producing the ultimate SWF system, a backing line of 60 JB, and a stuffed running line of 80 JB and a shooting head made out of a competition T40 head, tungsten and thin but 20lb b/s. I dreamed of stuffing it inside a chunk of 150 JB. Then I would have the ultimate system, all no stretch, loop to koop connected and with a break strain of hell knows.

I though about it for a while and kind of woke up.

I think about it occasionally but mostly when I'm drinking port.

Very Big Grin


PS I have a 3 foot length of 60JB with loops at each end on the desk here, which I play with quite often. I just destroyed one loop, the glue gave up.

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Max, Impressive array of technical data! Far more than I ever wanted to know, for sure wink.gif


All my reels for the salt have some form of spectra type lines for backing but few have seen more than 50'-100' come off the spools, unfortunately! Bluewater fly fishing is way too rich for me to be active in and I may get out there once a year anymore so hooking pelagic frieght trains is not my idea of fun anymore and if I am going to work I want to get paid for it and not pay for it! $1000-$1500 for the opportunity to get a hernia, or a heat attack/stroke in not a deal in my eyes and I don't need any Hero Pics if I do survive.


So for me the Gsp issue is a non-issue for the fishing I do. Others may have great value in it. I will say if my Pate Bluefin ever get near spooled by a bluewater fish it can have it all cause I'm not reeling that many yards of line back on the spool again. Loading it the first time was once to many as it was.




I do think tip top loops and roll over guide loops that tear off guides during a fight happens more using Gsp than Dacron and IMO is a more serious condition

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After the first leader exploded on my hands and gave me a one inch long blood blister, I decided that gloves, safety glasses and lifting behind my back were in order. When 60# fluoro connected to 65# braid gives out after lifting 60 pounds or so, it's a bullwhip. Makes me wonder if I should be wearing one of those cups the hockey players where, eh?


With a bad wind forecast through the next few days, I'm thinking what kind of line system to break. I'm going to double-end loop-splice 6' of 65# JB and then single-end splice another 6' and loop to loop connect and see what gives. Then if any of the loops are still standing, I'll take another 6' of JB, thread some 50# fluoro (all I have at the moment) into the JB, test that, and then if that's survived, loop-to-loop it to one of the first JBs and see what I think of the loop-to-loop. I need to get a life.


Then I have to think about writing a joke for BrianBM.




Try to picture this--


Friday morning I wake up and want to go fishing. By noon, I've done enough chores that I can fish guilt free for the afternoon. I load up the boat, drive to the harbor. It's a grey day but both ramps are free, I'm salivating thinking about bluefin tuna, a dozen miles offshore. I back down the ramp, stop, go back to disconnect the trailer lights ... to find a little grey SUV, the exact color of the sky, with the lights off. There, with half their car in the water are three Germans guys (Pamet Harbor is out near Provincetown) launching their 10' beauty of a white dory, with a 25hp Merc.


I apologize, and feel like an idiot. The lead German tells me not to worry and says that it is their first time boating, it has taken them 40 minutes to get the boat into the water and don't know what to do. He adds that he didn't run up to stop me because he wasn't sure, "how it worked on ramps." (He's got a better imagination than me.) I pull off and back the other ramp, wondering if I'm going blind or am blinded by tuna fever--you know the answer.


So as I back toward the water in lane 2, the situation is: German #1 is driving his slate grey car to park it and the trailer (which I decide I don't want to watch). German #2 is in the dory two feet from the end of the launch ramp, asking me how to start the engine. German #3 is holding the boat from the bow while the wind tries to blow it toward my ramp... and while he tries to keep his feet dry by standing on the lane divider--oops, that divider is slippery, German #3 is down and wet. There's no way I'm backing further down the ramp yet.


Germans #2 and #3 get into the boat, get the oars out (I kid you not) and paddle to the end of the courtesy dock where they get the engine going and head off into the rock-filled harbor at low tide.


All of this to explain why I don't go through my usual preflight routine (excuses, excuses). I'm charged up though, the boat's in the water, wind's are light, out through the jetties, up to 38 mph, on plane, life's good. Twenty-five minutes later I'm at the Fishing Ledge, testing the drags once more and loading a RonZ onto one rod and a pencil popper onto another.


BEEEEP! "Low Fuel Alert!"


Can't be, I had 60 gallons two trips ago, saw 40 gallons on the gauge the trip before last and estimate from memory that I must have had 25-30 gallons. Now what to do, trust my memory 15 miles out in the bay at 3 p.m. or head back? Deck covers up, head into the hold, cloudy and dark outside, can't see a thing. So now, maybe I should just leave the engine off, fish for a while and head back as DARK approaches. Nope, can't do that.


By the time I reset and restart, I've seen 3 gallons on the fuel gauge, which doesn't seem right but I'm not going to fool with it. My fishing rush now replaced with a growing "oh f..." feeling, I point the boat right at the harbor and hope that the three gallons will last till I get back. It was a long 23 minutes. Anyway, I made it.


I'm here this morning: coffee, leather gloves, safety glasses and an athletic cup (Max put the idea in my head). Try and picture it.






I filled the tank on the boat. It took 62 gallons, I have a 90 gallon tank. Fish 1, Pametfisher 0

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You mate are even crazier than I am. I did a trip 30 miles up Shark Bay, got to the mob of tuna, discovered my tackle box was in the car., One fly rod and reel, fitted with fly and no other stuff available, 6lb tippet and I hooked a tunny. Lost it at the boat after 30 minutes.

Then another 30 milres back to the ramp. Gave up in disgust and went home and got into the good cheer fluids.

Fly guys are definitely nuts.


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Pametfisher, your joke dues are marked as paid. It IS windy out there, isn't it? I put aside the fly gear this a.m. and spent a pleasant morning tossing plastic shads on 2oz heads to little bass. 50lb GSP on a Penn 525, as far away from a flyrod experience as you can get and still be casting ... fun though.

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