Maxg
24-03-2006, 03:37 AM
Braiding Gel-spun Fibre
Gel Spun Polyethylene fibre is 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. The manufacturers have large numbers of machines, generally around 400 machines. some companies claim to have in excess of 4,000 machines. But that number is usually the sum of many small companies who are contracted to the bigger company. They descriptive words should be “control 4000 machines” rather than “have 4000 machines”. The output of these operations can exceed 2,000,000 metres per day. The machines run 24 hours per day 7 days per week, non stop.
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. Normally, to produce a round product eight carriers are used, and the weave is tight. In some cases lower numbers of carriers are used and the line tends to be flat and with an open weave. But the number of carriers can vary depending on the end user product.
What all of this means is that the GsP fibres are extruded in long continuous runs of many thousands of metres. There are no joints of individual fibres in GsP fishing lines. Well; there are not supposed to be so one assumes that because of the tenacity, the very high breaking strain in relation to diameter there is no breakage of individual fibres during the braiding processes. But I have good information that “You know, that happens” so, if “that” does happen the machine is stopped and started on a new run.
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 line fractures.
In a normal low stress 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 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". There may be some variations in the braiding and finishing process but the yarn is Gel Spun Polyethylene.
Knot Strength
Regardless of protestation or denial most knots tied in GsP braided lines fail between 60% and 90% 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 or in excess of, the line breaking strain
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 knot the body of the knot can be slipped up and down the main line quite easily. This is because in the Bimini Twist knot 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 to hold the knot stable. The braided line is so thin and slippery that even under extreme pressure or twist tightness, the two half hitches and clench knot lock does not hold the knot and allows the body of the knot to slip. And wetting the knot, in the fishing exercise simply adds lubrication to the slip function.
The failure to effectively lock the knot positively means that the extra security of the doubled line is not there and the normal Bimini Twist knot is really just a bundle of line wraps serving no useful purpose. This is easily demonstrated by tying a 20 twist Bimini knot in GsP braid and terminating the end of the double. 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 Twist knots 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, and various methods of increasing twist tension or tightness, that one should not use Bimini Twist knots in Gel-spun braided lines because the knot was designed for mono-filament which is thicker and has greater friction in the twists. The lack of stretch, and the high level of “tension slip” or knot compression under load, 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.
The problem with the Bimini Twist is that the main line goes directly through the knot, although it is twisted with the tag end of the double. It is the tag end of the double that is used in the roll down and the half hitches and clench which provides the ultimate security of the knot.
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 mono-filament applications. Knot cutting, that critical radius problem 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.
One of the main reasons for the bad knot strength of GsP braided lines is described as fibre fracture caused by knot compression and slip under load. A perfect example of this is a “Spider Hitch”which has a disasterus knot strength due to compression and “critical radius” fibre fracture as the random twist system of the knot compresses under load.
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.
I can hear the comments now. “Here hold on. I use a double Uni Knot, or a 70 twist Bimini with dental floss, 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, and there are many. These things I did for myself others get it as a by product of 3 years of testing knots. If they believe it, OK, if they don’t, again Ok.
Gel Spun Polyethylene fibre is 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. The manufacturers have large numbers of machines, generally around 400 machines. some companies claim to have in excess of 4,000 machines. But that number is usually the sum of many small companies who are contracted to the bigger company. They descriptive words should be “control 4000 machines” rather than “have 4000 machines”. The output of these operations can exceed 2,000,000 metres per day. The machines run 24 hours per day 7 days per week, non stop.
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. Normally, to produce a round product eight carriers are used, and the weave is tight. In some cases lower numbers of carriers are used and the line tends to be flat and with an open weave. But the number of carriers can vary depending on the end user product.
What all of this means is that the GsP fibres are extruded in long continuous runs of many thousands of metres. There are no joints of individual fibres in GsP fishing lines. Well; there are not supposed to be so one assumes that because of the tenacity, the very high breaking strain in relation to diameter there is no breakage of individual fibres during the braiding processes. But I have good information that “You know, that happens” so, if “that” does happen the machine is stopped and started on a new run.
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 line fractures.
In a normal low stress 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 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". There may be some variations in the braiding and finishing process but the yarn is Gel Spun Polyethylene.
Knot Strength
Regardless of protestation or denial most knots tied in GsP braided lines fail between 60% and 90% 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 or in excess of, the line breaking strain
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 knot the body of the knot can be slipped up and down the main line quite easily. This is because in the Bimini Twist knot 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 to hold the knot stable. The braided line is so thin and slippery that even under extreme pressure or twist tightness, the two half hitches and clench knot lock does not hold the knot and allows the body of the knot to slip. And wetting the knot, in the fishing exercise simply adds lubrication to the slip function.
The failure to effectively lock the knot positively means that the extra security of the doubled line is not there and the normal Bimini Twist knot is really just a bundle of line wraps serving no useful purpose. This is easily demonstrated by tying a 20 twist Bimini knot in GsP braid and terminating the end of the double. 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 Twist knots 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, and various methods of increasing twist tension or tightness, that one should not use Bimini Twist knots in Gel-spun braided lines because the knot was designed for mono-filament which is thicker and has greater friction in the twists. The lack of stretch, and the high level of “tension slip” or knot compression under load, 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.
The problem with the Bimini Twist is that the main line goes directly through the knot, although it is twisted with the tag end of the double. It is the tag end of the double that is used in the roll down and the half hitches and clench which provides the ultimate security of the knot.
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 mono-filament applications. Knot cutting, that critical radius problem 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.
One of the main reasons for the bad knot strength of GsP braided lines is described as fibre fracture caused by knot compression and slip under load. A perfect example of this is a “Spider Hitch”which has a disasterus knot strength due to compression and “critical radius” fibre fracture as the random twist system of the knot compresses under load.
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.
I can hear the comments now. “Here hold on. I use a double Uni Knot, or a 70 twist Bimini with dental floss, 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, and there are many. These things I did for myself others get it as a by product of 3 years of testing knots. If they believe it, OK, if they don’t, again Ok.