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Trimmer string keeps breaking off in head!!!

Discussion in 'Lawn Mowing' started by baldbeefman, Jun 19, 2001.

  1. rlitman

    rlitman LawnSite Bronze Member
    Posts: 1,552

    You can believe what you want, but you will still be wrong.
    This has been VERY well studied in the field of tournament fishing, where nylon monofilament dominated the field until newer lines came out, and the effects of water absorption are pretty well understood.
    Here's a decent technical explanation of what's happening:

    "Nylon monofilament is a lot like spaghetti—it absorbs water in copious quantities. Trying to pull a piece of dry spaghetti apart end to end is tough, but as soon as it gets cooked (i.e., it has absorbed a bunch of water) it pulls apart with ease. That’s an extreme example, but you get the picture.

    In reality, nylon monofilament will absorb up to about 10% of its weight in water. Water absorption is a mixed blessing. On the upside, nylon monofilament that has absorbed water becomes more limp and supple, and makes knot tying easier. On the downside, water-logged nylon monofilament swells, increasing its diameter, reducing its break strength by about 20% (i.e., 10-pound test becomes 8-pound), and increasing its elongation (stretch) by 25% to 30%."

    Professional competitive fishers have been soaking their line in water (and sealing it in wet zip lock bags) for a long time now, as it gives an edge in competition.

    In the case of string trimmer line, the cheapest lines are simply pure nylon monofilament (just like plain old timey fishing line), while some more expensive lines include aramid for greater strength as well as shock resistance, plus resistance to welding.

    By soaking the string in water, it may have a lower tensile strength, but the weight increase gives it more momentum at the tip, which causes it to cut more while flexing less. This will make it last longer.
    Also, the additional stretchiness will help it flex at the eyelets without breaking.
  2. weve

    weve LawnSite Senior Member
    Male, from Central Illinois
    Posts: 381

    I talked to a man at the Desert Extrusion booth at GIE-EXPO several years ago. He said that in the manufacturing process there is a percentage of water used in the trimmer line. When the line dries out over time it get more brittle. He recommended soaking the line in water but not more than once.

    For years now I have cut line to the lengths that I need and keep it in an ice cream bucket with a little water in the bottom. The fresh line is always more pliable than the last of the line in the trimmer head. One place where I notice a difference in the water soaked line and the dried out line is in a cemetery that I mow. It works for me.
  3. dboyd351

    dboyd351 LawnSite Bronze Member
    Posts: 1,101

    Why not soak it more than once?
  4. cgaengineer

    cgaengineer LawnSite Fanatic
    Posts: 15,782

    I guess we use it fast enough that it never becomes brittle...Meanwhile I'll drink the water instead. ;)
    Posted via Mobile Device
  5. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 14,108

    Just make sure to remove the trimmer line first.:laugh:
  6. jsf343

    jsf343 LawnSite Bronze Member
    Posts: 1,767


    mine has done that after sitting in the warm shop and just gets brittle, I bought a new spool and it was fine. I then took the other spool and left it in a bucket of water over night and it was fine.

    Never tried WD-40 but seems like it would work.
  7. CapitalLawn

    CapitalLawn LawnSite Member
    Posts: 9

    try not to wind the string on the spool so tight I use stihls Just my theory works for me tho
  8. ashgrove landscaping

    ashgrove landscaping LawnSite Gold Member
    Posts: 3,460

    Soak your spool of string in a bucket of water over night. It will help. Most folks don't but it make the string more durable.. It dries out quite a bit after it's produced and you don;t know when it actually was made so give it a try. Works for me.
  9. lawnboy dan

    lawnboy dan LawnSite Gold Member
    Posts: 3,712

    use an edger instead.
  10. imow in NC

    imow in NC LawnSite Member
    Posts: 56

    I use Stihl FS94 SC trimmers with .095 gator wire string. This has been a great combination for us when using as an edger on ornamental beds. With new hires, adjust the power band down a 3rd, and it trims well, edges wonderfully and does a great job without breaking off.

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