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  #31  
Old 02-19-2019, 06:37 PM
Pitar Pitar is offline
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All metals are elastic and, in the case of filaments like guitar strings, are wound by the tuning machines to a certain elastic tension where each will emit a frequency relative to their varying tensions.

Once the strings begin to stretch out they lose their initial tension (tuning) and must be re-tensioned with the tuning machines. They will continue to stretch throughout their usable life, requiring corrective tuning, until their elasticity is gone. This is fatigue. Once a string reaches its fatigue point it will break if tightened.

When a string will no longer stretch it will not lose tension anymore. This is when people claim their (old) strings hold tuning very well. They may hold their tuning but their sonic frequency response is only a fraction of their response when new. This is the point they are said to go flat. I've read many, many posts claiming a preference for stretched-out (flat) strings. That's not a bad thing. It just means that their guitars do not provide the sound they like with new strings on. I buy guitars that sound their best with new strings and change them often.

That all said, new strings are not at their highest (possible) tension when tuned to pitch. They are only at their tuned tension. They can be stretched beyond that to their breaking point, which exceeds their normal elasticity for their alloy characteristics and respective cross-sections (circular mils), or metallurgical specifications, but they are alloyed and sized to meet the demands of music wire requirements. This includes ensuring the total tension of all the concert-pitched strings combined to be of a value that does not place undue compression loads grain-wise across the guitar top, or excessive shearing loads on the bridge, and still manage to have the flexibility needed to easily pluck them (place them in motion). This means the strings are engineered to specifications that far exceed concert pitch playing demands if they are to offer reliability, longevity (ear dependent) and playability to the user. This means they are capable of stretching well beyond their concert pitch mean tension respective of the frequency responses they are design to emit.

All strings of a certain alloy will stretch after being brought to concert pitch. We all know this because we usually have to retune them frequently after replacing them until they settle down and become somewhat stable. This is the normal stretching out. Coatings cannot impart anything to the metal to prevent this characteristic. They can only slow down the entrance of corrosive skin acids by virtue of their coatings (wound strings only) but the unwound strings typically reach their flat states of fatigue well before any corrosive damage occurs to the wound strings.

The rate of stretch over the life of a particular alloy/size string lessens with age until it can't stretch anymore. The rate is increased and the life is decreased with playing (player induced fatigue) so the maximum life of a string varies with age and play. But, remember that it's metal elasticity that makes strings resonate at frequencies dependent upon their tensions higher, lower or at concert pitch stretch .
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  #32  
Old 02-19-2019, 06:43 PM
rick-slo rick-slo is offline
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Quote:
Originally Posted by zmf View Post
Yes, that's really all I was attempting to get at. If there is any effect on the elastic property over time, so that there is not complete rebound, there will be some increase in length that requires compensation.

If a string used in normal guitar function doesn't lose any elasticity, it's a moot point.
There are places on a string where it does get deformed (permanent change in shape) such as where it wraps around the tuning peg and where it bends over the saddle. Metal fatigue can occur there (why strings usually break at those locations). As far as continuing to stretch over all, not. Not good for things like suspension bridges and car engine tolerances if otherwise.
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  #33  
Old 02-19-2019, 06:52 PM
Mycroft Mycroft is offline
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It's on the Internet. It must be true.
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  #34  
Old 02-19-2019, 08:13 PM
zmf zmf is offline
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Quote:
Originally Posted by Pitar View Post
But, remember that it's metal elasticity that makes strings resonate at frequencies dependent upon their tensions higher, lower or at concert pitch stretch .
My head is feeling some elastic stretch.

If a guitar were strung with strings of a non-elastic material, and tensioned below it's breaking point, it could not produce a given pitch -- i.e., oscillate appropriately -- when plucked?

It would not return to its original length, and be good for one note? Or maintain integrity through "strength"?
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  #35  
Old 02-20-2019, 06:55 AM
JimH JimH is offline
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If you want a real deep dive into tension and torque--
http://siminoff.net/cms/wp-content/u...whitepaper.pdf

Currently trying his strings for the first time and I do like them for low tension strings and half the price of the similar Santa Cruz strings.
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  #36  
Old 02-20-2019, 07:23 AM
Merak Merak is offline
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Sounds like a good experiment, put some accurate tensiometers on a composite frame and monitor tension and length in a climate controlled room. Need more time and money.......
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  #37  
Old 02-20-2019, 07:26 AM
Tony Burns Tony Burns is offline
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Dont believe everything you hear on the internet -
its like this forum -most is just a persons opinion -
were guitar players - that doesn't put a PHD after our names .
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  #38  
Old 02-20-2019, 08:20 AM
Golffishny Golffishny is offline
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Since I've learned to properly seat my strings when I put them on my guitars go weeks at a time without going out of tune. The only thing that changes that is when major weather fronts go by. I suspect that has more to do with the wood changing to humidity that string change. The top flexes and changes the bow of the neck ever so slightly. Just my opinion.
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  #39  
Old 02-20-2019, 08:38 AM
John Arnold John Arnold is offline
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Quote:
Guitar strings aren't tune up to or above their elastic limit.
That is simply not true. There is some plastic deformation when steel strings are tuned up to pitch. This deformation (which is an extension of the hard drawing process used to make music wire) actually makes the steel stronger. Music wire, which is plain carbon steel, gets its strength during the drawing process, which elongates the grains. Where a higher alloy may become brittle, the low alloy used in music wire is more ductile.
Old strings become harder to tune because they are no longer perfectly uniform along their length. Perfect intonation can only be achieved with a string that is uniform. But I don't believe the typical amount of reduction in cross section is enough to feel as lowering the tension.
I believe the main reason for this perceived effect of lowered tension is a reduction in the bending stiffness of the wound strings, due to loosening of the windings. This is one reason that strings go dead.
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  #40  
Old 02-20-2019, 09:03 AM
charles Tauber charles Tauber is offline
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Quote:
Originally Posted by John Arnold View Post
That is simply not true.
.......................

Last edited by charles Tauber; 02-21-2019 at 07:09 AM.
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  #41  
Old 02-20-2019, 10:25 AM
Glennwillow Glennwillow is offline
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Quote:
Originally Posted by John Arnold View Post
That is simply not true. There is some plastic deformation when steel strings are tuned up to pitch. This deformation (which is an extension of the hard drawing process used to make music wire) actually makes the steel stronger. Music wire, which is plain carbon steel, gets its strength during the drawing process, which elongates the grains. Where a higher alloy may become brittle, the low alloy used in music wire is more ductile.
Old strings become harder to tune because they are no longer perfectly uniform along their length. Perfect intonation can only be achieved with a string that is uniform. But I don't believe the typical amount of reduction in cross section is enough to feel as lowering the tension.
I believe the main reason for this perceived effect of lowered tension is a reduction in the bending stiffness of the wound strings, due to loosening of the windings. This is one reason that strings go dead.
This is helpful John. Thanks for your contributions here.

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  #42  
Old 02-20-2019, 10:41 AM
Manothemtns Manothemtns is offline
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Quote:
Originally Posted by Glennwillow View Post
This is helpful John. Thanks for your contributions here.

- Glenn
Yes, interesting topic from a materials engineering perspective. Thanks.
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  #43  
Old 02-20-2019, 10:52 AM
Glennwillow Glennwillow is offline
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Originally Posted by Manothemtns View Post
Yes, interesting topic from a materials engineering perspective. Thanks.
For me, the idea that a guitar string is actually being stretched up to and slightly beyond its elastic limit is new information. When I think of work hardening in metal, I think of forging, where work hardening is created by imposing compressive stresses in excess of the elastic limit of the metal. I have never heard of work hardening under tension.

But John Arnold is a known expert in the world of acoustic guitars and guitar related materials. If he says this is what happens, I tend to believe him.

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  #44  
Old 02-20-2019, 10:57 AM
AndrewG AndrewG is offline
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Quote:
Originally Posted by charles Tauber View Post
That'd be wrong. They do stretch and they do settle. Prove it to yourself with the experiment I suggested previously.

Tune up a nylon string guitar and watch the fun. The strings do "settle", but they also stretch like crazy and do so for several days. One of the ways of speeding the process of both settling and stretching is to pull on them. Common practice by classical guitarists.
Are they actually being stretched though, or simply taking more time than steel to tighten and settle at both the bridge and tuner?
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  #45  
Old 02-20-2019, 12:17 PM
charles Tauber charles Tauber is offline
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Quote:
Originally Posted by AndrewG View Post
Are they actually being stretched though, or simply taking more time than steel to tighten and settle at both the bridge and tuner?
Both.



.

Last edited by charles Tauber; 02-21-2019 at 07:09 AM.
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