Fishing line tensile test with Instron Machine

Discussion in 'Fishing Line Review' started by paidin, Nov 2, 2006.

  1. paidin

    paidin New Member

    Clarksville, TN

    I started testing some fishing line with our Instron Machine. It measures and graphs the stretch and tensile strength of whatever is unfortunate enough to be placed in it.

    Test methodology:
    Sample line has two loops tied on each end. Length from end of loop to loop is roughly 12". Loop length is roughly 1". Line is new off spool. Graph is generated and data is recorded.

    Yo-zuri 12lbs Flourocarbon
    Average Diameter: ? oops forgot to look
    Max Displacement: 2.392"
    Max Load: 13.170lbs
    Note: Broke at knot

    Mustad Ultra Line Pro Plus 10lbs Mono
    Average Diameter: 0.012"
    Max Displacement: 2.175"
    Max Load: 11.710lbs
    Note: Broke at knot

    Berkley Trilene XL 10lbs Mono
    Average Diameter: 0.011"
    Max Displacement: 2.267"
    Max Load: 9.136lbs
    Note: Did not break at knot

    Some surprises here for me. Flourocarbon stretched as much as the Mustad line. Additionally, my favorite (Berkley XL) broke at a smaller stress than expected.

    I understand I need more samples in order to be statistically confident. I will do more samples later when I have time. If you guys want me to test your favorite lines for you, please feel free to send me some. All I ask is you guys prepare the line for testing and send me the details of the line including the diameter. It would be nice to get a database of all lines to see what is the best bang for the buck is concerned. Unfortunately, I dont have a good way to test abrasion or shock at the moment. Would be neat if we can get that information as well.

    Thanks for lookin.
  2. dademoss

    dademoss Member

    Interesting testing :big_smile:

    A couple of other things you may want to vary are the crosshead speed, wet vs dry line, and what knot is used and how it's tied.

    It's not really surprising most of the samples failed at the knot, the standard test uses a set of capstan grips so samples are tested without knots.

    Since we use knots to rig, the biggest factor there would be making the knots as uniformly as possible.

    The crosshead speed I have seen used most is 300 mm/min, it would be interesting to see the results of a higher crosshead speed to simulate the stress seen when you set the hook.

    Here is some data from Johnson tackle of some testing they performed.

    Have fun and keep us up to date :)


  3. Mark J

    Mark J New Member

    Four Oaks, NC
    Another thing to consider is multiple tests along the length of the spool of line.
    Fishing line varies even from the same spool. The first 5 feet may break at 2 pounds under the specified weight and the next 20 feet may break at 3 pounds higher then the specified weight. Some lines will have closer proximity to a breaking point then others.
    This is one reason a line sample has to be submitted for an IGFA record. They will test it.
    I only know of one line designed just for the IGFA criteria and that is tournament grade ANDE. Supposedly it will never break over the specified weight.
  4. Ol Whiskers

    Ol Whiskers New Member

    Fairfield Township, Ohio

    Thanks for a most relevant post, and for taking the time to think this out. As you have seen, there are so many factors in "line quality" that might not be revealed in some test regimens. The objective, from a fisherman's standpoint, is to determine which line will perform up to expectations in the environment to which he/she subjects it. So the exercise is to separate those factors that matter from those that might no matter so much. You are on a good start. What you need is a DOE (Design Of Experiment) that will segregate the characteristics and allow you to identify variables that contribute to "line quality."

    Environment starts with the fisherman, in how the line is tied (kind of knot -clinch, double clinch, palomar, uni, trilene - tied wet or dry, lubed or unlubed, pulled fast or slow...) and to what the line is tied (surface finish and diameter of the swivel, hook, split ring, lure...) all affect whether the line will break at the knot or in the body), ambient temperature, speed of hookset, and maybe water resistance.

    If you just want to know about the body strength of the line, use the capstan test as dademoss describes. This is a starting point, and basically what the line companies use to tell you the average tensile strength of their product. If you want to know how the fishreman-induced environment affects the outcome on the water, you need a more robust test. This will be very involved, in terms of sample constructions, number of samples, repeat runs, and data collection. To reduce the variables introduced by the testing itself, you'll need to standardize the test process.

    To get a good idea of the performance differences in dry versus wet test, create a sample batch size, and soak half for some specified time (30 minutes?) in distilled water, and perform the test on the wet specimen in the same manner as the dry.

    Capstan testing is pretty easy, with a little bit of fixturing. Moving on to testing knot conditions takes a liitle bit more preparation. Since most of us use swivels and hooks, maybe construct the specimens with a hook on one end and swivel on the other. This is not meant to add complexity, rather to demonstrate whether the knot strength is affected by some finish characteristic. Stress in the knot is probably affected by the diameter of the article to which it's tied, all other things being equal. So, you might want to have a selection of matched diameters of swivels and hooks (say, .020, .030, .040, .050, .060 - or some reduced set of sizes) to simulate the variations in rigging. You would want to reduce variability in each knot by having all knots in a discrete sample group tied by one person. Since it's likely that knots are applied wet or dry (do you spit on the knot when you tie?), split the sample groups further.

    The Instron test adadpter for this can be a simple pin-in-block arrangement, to simplify the insertion of the sample.

    If you've done wet/dry tensile on the body (capstan) test, it might be advisable to only perform wet testing on the knot specimens to reduce the time and number of samples. Of course, always at 20°C.

    I would be able to set up the data recording spreadsheets, and have access to Minitab to run statistical analyses. It's a lot of work on your end testing and recording. I just put a simple spreadsheet together with just the basics. If you're intersted, send me a PM and your e-mail and we can exchange ideas.

    Someone on BOC may have done this to some extent already, If not, I'm sure some of the brother and sisters would supply short spool ends of lines, myabe some sample hooks, and may be willing to tie samples per some sketch and intsructions. We could end up with a lot more useful data and anecdotes than the line companies are putting on the box.