LEADER TESTING & EVALUATION

     The several brands shown above were tested to determine the absolute and relative performance characteristics. The 5X diameter was chosen because it is in the rangeof 4X to 6X most commonly used for tippets in trout fishing and where, due to the fragile nature of fine tippets, knot strength, elasticity and abrasion resistance are most important.

IINTRODUCTON

What should we look for when selecting leader material? There is no simple answer, because the need changes with the application. To start with there are three general types of leaders: Tapered, linear and big game. Where the desirable characteristics of the various parts of each vary considerably. However, there is one thing for certain: it is impossible to obtain enough information from the labels on the dispensing spools (or distributor advertising claims) to select the best material.

All that can be determined from the labels is the advertised dry break strength (usually overstated) and the specified diameter that often isn't matched by the material on the spool. Knowing the "Break Strength" doesn't help select the best material because we won't know how much energy will be required to reach the breaking strain. As an example: if there were two frames, one holding a sheet of glass and the other a sheet of rubber, each with the same "breaking strength", dropping a weight sufficient to break the glass, on both sheets, would not break the rubber sheet because the energy required to stretch the rubber to the breaking point is much greater than for the glass. So, Choosing from the sport shop rack, based upon the labels, is something like playing Russian Roulette.

To make a valid selection, we need to know the energy per foot required to break the material, the effect on strength caused by a wind knot ("knot strength") and the relative effect of abrasion. Further, these must be the characteristics exhibited after the material has been soaked in water.

Few of us have the lab equipment to make these measurements. So we end up depending upon the advice and recommendations from sport shops, guides and fishing partners. Unfortunately, most of them don't know either and base their advice on experience and/or hearsay, which, although helpful, probably won't produce the most desirable assembly.

Methods were devised to make the required measurements using materials and devices commonly found at home or easily obtained at a hardware store - nothing fancy.

THE MEASUREMENTS

Prior to the measurements the leader material is soaked in water for one hour and then kept in zip bags with a wet sponge until used. The characteristics that must be measured and/or calculated are:

1. a) Break Strength: ................................................... (B) = (Strain required to break the material).

   b) Cross Sectional Area: ......................................... (A) = (pD²/4)   (Where D is the leader diameter).

   c) Tensile Strength: ................................................. (T) = (B/A)   (Calculated as: pounds per square inch).

2. Elongation (prior to breaking): .............................. (E) = (L2 - L1)x(12/L1) (inches per foot).

3. Knot Strength: ........................................................ (K) = (strain required to break material with a wind knot).

4. Abrasion Resistance: ............................................. (R) = (Inches of 600 grit with (B/2) as a load and (B/16) as a deflection force).

5. Energy to break: .................................................... (W) @ (B/2)x(E)   (Calculated as: inch pounds per foot).

BREAK STRENGTH (B)

The method for measuring the break strength requires a piece of 1/2", or larger, dowel, a one or two gallon bucket and a spring or digital weight scale. To make the measurement, wrap one end of the tippet around the bucket handle and wrap the other end of the tippet around the piece of dowel. Five over overlapping wraps is usually enough to secure the tippet (put a layer of masking tape around the handle and dowel as a cushion). With the dowel clamped to a table or counter top and the bucket hanging below, pour water into the bucket, to increase the strain, until the tippet breaks. Be prepared to stop pouring the water when the line breaks (place a stand under the bucket to catch it). The break strength (B) is determined by weighing the bucket of water (It's a good idea to start with enough water in the bucket to bring the weight to at least 75% of the expected break strain).

CROSS SECTIONAL AREA (A)

Since tippet material has a circular cross section the diameter is measured, using micrometer calipers, and the area (A) is calculated from (A) = (pD²/4).

TENSILE STRENGTH (T)

This is determined from the cross sectional area (A) and break strength (B) of the material and is given by ( T = B/A ).

ELONGATION (E)

This is the amount the tippet stretches before breaking. This can be measured using the same apparatus as that for Break Strength (B). After the tippet breaks, for the Break Strength measurement, attach another piece of tippet between the dowel and Bucket. Any length is OK but 10" will give elongation directly as a percentage (each inch of Elongation becomes 10% ). Remove 10% of the weight from the bucket, by removing some water (use the weight scale to determine the reduction) and release the weight slowly to avoid snapping the tippet from the added force of kinetic energy. If plastic flow occurs replace the tippet, reduce the weight a bit more and try again. Measuring the change in length gives the Elongation (the change in length divided by the initial length times 100 will give the % Elongation ).

KNOT STRENGTH (K)

This is measured by tying a knot in the tippet material (an overhand knot - wind knot - is used when the "knot strength" of the material is to be defined) and then determining the strain to break the line. Use the same procedure as for break strength (B). The Knot Strength is given as a percentage of the break strength without the knot, as determined from the measurement of (B) - knot break strength divided by no knot break strength times 100 = Knot Strength %.

ABRASION RESISTANCE (R)

This is a somewhat arbitrary measurement because the conditions "in stream" vary so widely but any technique that provides a relative break point will be a useful indicator of this characteristic. The tippet should be under tension and the abrading surface should apply a representative force to the surface of the tippet. All line materials must be the same diameter for valid comparisons.

The tension is provided using the Break Strength apparatus with the weight of the bucket and water set to 50% of the average break strength for the class of the tippet material (weight should be the same for all materials of the same diameter). For the abrading surface, glue a 6" by 3/4" strip of 600 grit wet or dry sand paper along a 1/2" dia. dowel, 12" in length. Mark a measuring scale along the length of the dowel. The dowel is positioned so that it can slide, at a right angle to the tippet, on a track made by fastening a strip of 1"X 1/4" slat 1/4" below the edge of the work bench, positioned such that the sand paper comes in contact with the tippet about 6" below the tippet support and offset from the support enough to form an angle of 7 degrees between the tippet and the horizontal plane at the point of contact with the dowel. The 7 degree angle was chosen to provide a force of about 1/8 of the applied tension between the tippet and the sand paper. Directly below the track and in line with the tippet material a guide pin is installed just touching the tippet to prevent it from being horizontally displaced by the friction of the abrading surface as it is moved along the track, also, the bucket must be restrained from rotating. The dowel is put into place after the load has been applied to the tippet by pulling the tippet away from the track, inserting the sand-papered dowel and carefully releasing the tippet to contact the sandpaper without any initial abrasion. The dowel is then moved along the track, at a right angle to the tippet, until the tippet breaks. The distance that the dowel moves is recorded and used as a relative indicator of abrasion resistance. The abrasion resistance (R) is given in inches of 600 grit sandpaper at a force of 1/8 the tension.

ENERGY TO BREAK (W)

This can be approximated from Break Strength (B) and Elongation (E). Since the force of Elongation was not integrated as a function of stretch (stretch is a nonlinear function of strain) the mid point force (B/2) is used to obtain a relative measure of (W). Giving: (Wrel) = (B/2)x(E). This value is then converted into energy per foot of tippet (inch pounds/ft ) by multiplying by 12/L1, where L1 is the initial length of the test piece when (E) was measured.

Energy to break along with abrasion resistance are the best indicators of the relative worth of these tippet materials.

These tests and calculations were applied to five samples each of the several brands of tippet material shown on the cover page and the results averaged. The various brands were ranked by Tensile Strength, Energy to Break, and Abrasion Resistance. Knot Strength was included to determine the effect of wind knots and whether or not the standard knots will be as strong as expected [(K) must be at least 65% for knots to perform to specifications].

It will be instructive to compare the data with the claims on the labels.  

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* The scales used in making the measurement of strength were calibrated against Super Market digital scales by measuring the weights of several containers of water on both systems. While I make no claim as to the absolute accuracy of the measurements, the actual values should be within ± 5% of those recorded.

Regardless of the accuracy of the measurements the relative standings of the various brands would not change, since all were measured in the same manner, the same time frame and using the same equipment.

# Maxima material, sampled from several 5X spools, measured 0.0074" or more, so, all tests, except tensile strength, were made on 0.006" material obtained from a spool marked 0.005" (6X). This is usually the case for Maxima material, it is typically 0.001" to 0.002" over the size printed on the label.

When selecting material for the tests, the diameters were found to be from one size under, that marked on the label, to two sizes over, so, if  the specified size is desired, take Micrometer Calipers to the shop and check before you buy.

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LEADER TESTING, EVALUATION & CONCLUSIONS

The test data should be examined with the following principles in mind.

The line and rod system must absorb the energy of the runs, jumps and thrashing of a fish such that the break strength of the tippet and knots isn't reached. To do this the shocks must be absorbed by the spring action of the rod and the stretch action of the various line segments. Each line segment and the rod are somewhat decoupled from each other by the relative masses and the amount of drag caused by the water in which they may be immersed. Thus, there is a delay in the transfer of shock from one to the other such that the leader must be able to absorb the initial energy of any quick motion (thrashing, jumping, head shaking) by the fish. The fly line mass and water drag on it prevents the rod from buffering these actions, particularly when there is a lot of line in the water. So, for very fine tippets, the amount of ENERGY required to break it is very important (tippet should be quite elastic).

As the break strength of the leader and tippet increases there will be more time, before the break point is reached, for the fly line and rod to take part in the energy absorption and then tensile strength begins to play a more important role. The cross over between these requirements (for trout leaders) occurs at about 4X diameter (0.007") or 6# to 7# test.

Other factors to consider are knot strength and abrasion resistance, since sensitivity to wind knots and abrasion are both undesirable.

Looking at the test data on the basis of Energy to Break places Umpqua, Climax, Fenwick and RIO in the top half of the ratings. When the knot strength factor (Energy Knot Strength Product) is included Umpqua, Climax, RIO and Orvis occupy the top half. When abrasion resistance is considered Climax (#5) should be eliminated from the top ratings and when knot strength is considered Fenwick (@ only 69%) should be eliminated. Leaving Umpqua, RIO and Orvis as the top three with Umpqua and RIO clearly the best.

Among the eight materials tested, Umpqua, with the highest energy to break and energy knot strength product is THE material to use for the 5X to 8X tippets.

RIO with the highest tensile strength, knot strength and abrasion resistance is the clear winner for 4X and larger diameters.

Considering Maxima's reputation, as a great leader material, it is surprising to find it at or near the bottom in all the important characteristics.

By using this data base as a reference, it makes evaluating the performance of other materials easier. Whenever there is a change in the label appearance of a product it should be tested again and compared against the available data base to establish its ranking.

A factor, not included in this test data, is the strength of the knots used to interconnect the line segments. Testing shows that there are knots that are best (100%) for each application and, if the knots are properly chosen, the entire system, from arbor to fly can be 100%. Without the best material AND the best knots there will be too many of those sickening break offs.

The knot testing data along with system assembly recommendations and line selection information have been compiled into a manual titled "Fly Casting Systems".  For more information and pricing:  Content

There are, also, Videos available with 2 1/2 Hrs of demonstrations on the tying and assembly techniques for the most often needed knots, leader, and line systems to help those of us having spatial perception and/or manual dexterity problems.

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© 1999, Bill Nash