What causes string life deterioration?

Discussion in 'Fred's Barcalounge' started by Jelly Roll Horton, Jun 15, 2021.

  1. montereyjack66

    montereyjack66 Country Gent

    Feb 29, 2012
    LA-ish
    Heavy drinking, loss of employment, spouse leaves the relationship, 3mm picks...
     
  2. Ricochet

    Ricochet Senior Gretsch-Talker

    Nov 13, 2009
    Monkey Island
    Beach property or Saline sea breeze. ;)

    Seriously, the main culprit is acid content in sweat. Hard to put numbers on it.
    Sweat composition of a person varies as a function of physical, pharmacological and
    environmental conditions, gender, age, sweat rate, etc.
     
  3. Henry

    Henry I Bleed Orange

    Apr 9, 2014
    Petaluma
    It does. If you pluck your guitar string harder than normal while tuning, you will see that the initial attack is slightly sharper.
     
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  4. Synchro

    Synchro The artist formerly known as: Synchro Staff Member

    Jun 2, 2008
    Tucson
    Admin Post
    I get years out of the lower three strings, on all of my guitars. I was playing my older Tele, just yesterday, and the Thomastik Jazz Swings on it are at least five years old, and they sound great. I live in the desert, which may impede the progress of corrosion, but my guitars are all on wall hangers, directly above my humidifier, so they are not entirely isolated from atmospheric humidity.

    Double Basses can have string lives measured in decades. An acquaintance recently replaced one string on a double bass that he had owned for 35 years. That was the first string he had ever replaced in his years of ownership. BTW, the bass sounded wonderful.

    Materials are apart of the equation. Pure nickel wound stings, as opposed to nickel-plated wound strings, make a huge difference. I use Thomastiks, almost exclusively, and these are made with pure nickel. I replace the plain steel top three strings much more often than the lower three.

    Every guitar case I own has a polish cloth, a spare set of strings and a string winder/cutter, and I am religious about wiping down the strings every time I play my guitar. IMHO, that is the most effective way of increasing string life.

    BTW, I use a fairly solid RH technique, but in the last 45 years, I have broken but two strings.

    I would agree. There is a yield point and the strings on a guitar do not approach that yield point when tuned to pitch. The yield point can be calculated converting the diameter of the string’s steel core, in circular mils, and comparing theaters information with readily available information regarding the yield point of mild steel.

    However, there is another effect, which explains string failure, and that is work-hardening. I remember this well, because of missing a question regarding this phenomenon on a quiz while taking an aviation sheet-metal class. Missing that question bored it into my mind, pretty much forever.

    Simply stated, if you bend a piece of metal, it hardens the metal. Bend an aluminum can, repeatedly, and it will harden and shear, after a few cycles.

    Now, think about string breakage. In most cases, strings break at the machine heads, the tailpiece, or the bridge, all of which are places where a string is bent.

    None of this is to suggest that there is no effect from string tension. If you were to leave a guitar strung and tuned to pitch for long enough, chances are that a string would break, sooner or later, and in most cases it would break at the machine head, or at the tailpiece.

    The one set of Thomastik Jazz Swings that I had to replace was on a guitar I had worked on a lot, and had detensioned and retensioned the string numerous times. In this case, I eventually detected some problems with intonation. Apparently, all of the changes in tension eventually harmed the cores of the strings and there were some problems in the string’s core. I’m no metallurgist, but I suspect that this could have been work-hardening causing the string to bend unevenly, when fretted.
     
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  5. MotorCentaur

    MotorCentaur Synchromatic

    557
    May 11, 2016
    Seattle
    Real answers are always in the comments :)
     
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  6. hcsterg

    hcsterg Friend of Fred

    Feb 13, 2012
    France
    No @MotorCentaur - I do not have such studies about guitar strings, but I do have to study this aspect of fatigue when I designed metal constructions at ALSTOM : fatigue of rods, profiles and cables by tensile strenght, repetitive or steady, etc...

    The string is under tension, so it has to widthsand a tensile strenght, and then necessarily fatigue of the material due to the effort (in N/mm2). By the way, this is the same on a piano, but since the strings are much heavier gauge, they are more resistant, and as wrote @pmac11, the piano strings are certainly less "mistreated" than on a guitar...

    A+!
     
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  7. stevo

    stevo Friend of Fred

    May 1, 2012
    Atlanta
    Ha - I just replaced the CV axles on my wife's Outback. Didn't need any Liquid Wrench, no rust, no need to torch it. That is one of the only good things about this ridiculous weather we have down here.
     
  8. stevo

    stevo Friend of Fred

    May 1, 2012
    Atlanta
    Do you have peer reviewed studies refuting it? How many things in life do you accept from common sense rather than demanding to see peer reviews?

    Why is fatigue hard to believe? We're putting relatively low quality steel under tension by winding it around a tuner, bending it over nuts and bridges, pressing it down over hard frets, plucking it with picks, and often bending it. And take into account that we're further weakening it with sweat and oils...that sounds like a perfect environment for fatigue to me.

    Compared to piano - the use case is very different. They're treated rather gently compared to guitar strings. And apparently they do wear out, it just takes longer.
     
    Last edited: Jun 16, 2021
    pmac11 likes this.
  9. pmac11

    pmac11 Country Gent

    Mar 4, 2018
    Toronto, Ontario
    You're a structural engineer?
     
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  10. pmac11

    pmac11 Country Gent

    Mar 4, 2018
    Toronto, Ontario
    Accelerated corrosion in metals under stress is a known metallurgical phenomenon. Combined with external factors like the salt in sweat, it's almost a no brainer that the tension in the strings contributes.
     
    Ricochet likes this.
  11. Electrosynthesis

    Electrosynthesis Gretschie

    136
    May 11, 2011
    São Paulo
    Well put. And +1 to thomastiks
     
  12. pmac11

    pmac11 Country Gent

    Mar 4, 2018
    Toronto, Ontario
    Agreed re work hardening at a culprit. I'd point out however that guitar strings are not made of mild steel, but very high strength steel with a yield point around 1700 MPa... nearly 5x higher than common structural steel used in buildings and bridges. When properly tensioned, a guitar string is subject to a tensile stress anywhere from 50 to 80% of it's yield stress. This is still within the linear elastic range of the material, so all good. But where the string crosses the nut, the bridge, the tuner pegs there are much higher local stresses in the string. I suspect that this, as well as bending the string, pushes the material close to or past it's yield point, into a the zone of non-linear/plastic response. Unlike elastic deformation below the yield point, the string will not recover from any plastic deformation. With high strength steels, the plastic region is rather small, and the characteristic failure mode past the yield point is not ductile, but somewhat sudden and brittle.
     
  13. wabash slim

    wabash slim Gretschified

    Age:
    71
    Feb 10, 2010
    lafayette in
    I live where they build Subarus. They're great in snow. Go figure.
     
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  14. Synchro

    Synchro The artist formerly known as: Synchro Staff Member

    Jun 2, 2008
    Tucson
    Admin Post
    That makes sense. It’s been some number of years, but I remember calculating the yield point of guitar strings and came to the conclusion that guitar strings were not near the limit, when properly tuned.

    Based strictly on personal experience, I have found that if I lock-back the strings, there is little tendency for strings to stretch, once they’ve been tune to pitch. The first tuning to pitch might be a little bit dodgy, but one else everything is up to pitch it seems pretty stable.

    I credit some of this to the fact that I lock-back the strings and try to have less than one turn of string on each post, which prevents binding. My impression is that a lot of what is perceived as elasticity is actually binding and slippage of wound strings at the machine-head post.

    I bought a 2004 50th Anniversary Strat with locking machine heads and noticed that the OEM strings had far less than one turn of string wound on the post. I duplicated this on non-locking machine heads and found that it really helped with tuning stability. I’m a big fan of locking-back strings.
     
  15. stevo

    stevo Friend of Fred

    May 1, 2012
    Atlanta
    Which makes me think about tuning phenomena - when you tune a string to correct pitch and then play/bend it, the pitch comes down a bit as it stretches some. (Binding in nut slots and at bridge slots not withstanding.) In a few seconds or minutes, it typically returns to pitch or close to it. If you retune it before it recovers, pitch will be higher than correct pitch. This drives me crazy. I need to try the NYXL strings - they supposedly recover faster.
     
  16. hcsterg

    hcsterg Friend of Fred

    Feb 13, 2012
    France
    That's it, exactly. You have explained it for me with the correct technical vocabulary in English, @pmac11 - thanks :cool: ! I'll complement it with the matching diagram... In French :oops: :

    upload_2021-6-16_17-29-28.png

    No, I wasn't specialized in structures, but I was a project / R&D tech engineer and my job was to work on "unusual" projects - or intervine on parts of greater projects also (think CERN) - in very various domains : locks, dams, tunnels, bridges, plants and production process of all kinds, facilities, laboratories, nuclear energy, etc...

    So I had to work with technical experts engineers and scientists in my team - from ALSTOM, from joint ventures, from the end user/customer, and and be able to understand what they did in their field.

    It was a exciting time, full of emulation and creativity ! :cool::cool::cool:

    A+!
     
  17. MotorCentaur

    MotorCentaur Synchromatic

    557
    May 11, 2016
    Seattle

    The burden of providing the proof is on the one making the claim, not the one questioning it.

    Common sense is a logical fallacy.

    "putting relatively low quality steel under tension by winding it around a tuner, bending it over nuts and bridges, pressing it down over hard frets, plucking it with picks, and often bending it. And take into account that we're further weakening it with sweat and oils..." - That is a conflation. I am talking about tension alone.

    hscterg said:

    "For me, there are 2 main causes :

    + corrosion, atmospheric and coming from your hands.
    + metal fatigue, due to tension and playing. "


    Guitar strings are specifically built to be at tension/pitch as are piano strings. Y 'all are making claims that the tension on the strings is causing them to wear out. But when it has not been demonstrated than the tuned tension exceeds the modulus of elasticity (in fact quite the opposite as pmac11 stated above, a tuned string is well within the limits).

    This is merely an inquiry into the cause of string wear. So if the supposed things that cause the wear are true, they should cause demonstrable wear both in isolation, and in other cases ie; piano.

    Sure bending an 0.09 string at 7th fret up to the top of the fretboard is going to cause some permanent damage (likely breakage), but I am not talking about that.

    As I had questioned earlier can wear be demonstrated by appropriate tension alone?

    To say "metal fatigue, due to tension and playing." would be akin to saying "I got old because the sun came up, and the years went by" ..and then trying to prove I got old BECAUSE the sun came up, by demonstrating that the years did in fact go by.
     
  18. Henry

    Henry I Bleed Orange

    Apr 9, 2014
    Petaluma
    Entropy. Things fall apart. I think a stretched string existing in a vacuum and protected from all elements and left unplucked would eventually break. Perhaps it would take thousands or millions of years, but I think it would eventually happen.
     
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  19. hcsterg

    hcsterg Friend of Fred

    Feb 13, 2012
    France
    OK.

    "For me, there are 2 main causes :

    + corrosion, atmospheric and coming from your hands.
    + metal fatigue, due to tension and playing. "


    So let's consider a simple experiment with a hi-E string :

    - We do not install it on a guitar, we let that string wound as is, out of its package, without any tension on it.
    - Everybody can touch it anytime, and it is exposed to variable atmospheric conditions.

    It will certainly corrode sooner or later, as would corrode the usually mounted and played strings.
    + So the first cause of wearing that I mentioned will be met.

    It will never break, as common sense tells us, since it is not mounted nor played, unlike usual guitar strings use.
    + So the second cause of wearing that I mentioned will never be met.

    The burden of providing the proof is on the one making the claim, not the one questioning it.

    Common sense is a logical fallacy.


    Now my question is :
    - why that unmounted, unplayed string will never break ?

    No, @MotorCentaur : I do not have stricto sensu proofs on hand that guitar string dies by fatigue.

    Certainly, the guitar strings manufacturers have probably done such studies, or commissioned them to specialized laboratories (like I did when I was at ALSTOM for structures), in order to improve the resistance to wear of their strings versus other parameters like comfort, tone, etc... - within certain limits, having in sight sales considerations.

    I think that the works about Material Resistance of precursors like Galilée (1638), Robert Hooke (1678), Leonhard Euler, Thomas young (circa 1750), Poisson, Lamé, Saint-Venant (circa 1820-1850) are serious enough and still valid to make a parallel between a rod, a cable and a guitar string under tensile strenght and the resultant material fatigue.

    Of course, today, the predictive FEM (Finite Elements Methods) done by computer allow to have more precise and complex models, particularly if there is a stresses concentration (combined bending, tension, shear).

    Sorry, I did not mentioned tangential efforts due to playing like bending, hitting the strings with a pick, which incerases momentarily but repetitively the tensile strenght, along with bending and shearing work, these variations increasing the fatigue stress on the string.

    Now that's the way I see the phenomenon, through the prism of my personal experience.
    But it's me, OK ? :D
    And I may be wrong, making a confusion, or missing something, as usual... :oops::confused:

    A+!
     
    Last edited: Jun 16, 2021
    Electrosynthesis likes this.
  20. stevo

    stevo Friend of Fred

    May 1, 2012
    Atlanta
    This is true - whenever I play a guitar at Guitar Center, they have the strings wrapped 5 times around the posts and I can never get enough tuning stability to actually play the guitar without wild fluctuations in pitch. Even with non locking tuners, I don't have more than a whole wrap required on wound strings.
     
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