What is the lifespan of a hardwood acoustic guitar?

[adorshki]

If re-frets, repairs, realignments, part replacements, are all taken into account - is there a point when the instrument has gradually evolved into a (relatively) new instrument? It reminds me of the story of the ship "Queen Mary". The ship sits docked permanently. Meanwhile, every week, another part is replaced. Eventually, while it is still the "Queen Mary", all parts original to the ship will have been replaced. So the question is mostly a philosophical one. Everyone will have their own opinion.

This is directly analogous to a debate common in the whole vintage/collector car market. Originality does always seem to command a higher value, but one of my personal standards for evaluating a car OR an instrument is: "Will it be worth rebuilding?". I don't care if a car has OEM replacement parts. BUT on a guitar if your have to replace the top, I think you just started all over again having to develop tone. At that point in my opinion it is in fact a different instrument than the one originally built.

 

[12 string]

I would like to know the 'life-cycle' of a typical hardwood acoustic guitar and how Guild acoustics compare with other brands in this regard. ....does there come a time when a fine hardwood guitar begins to decline?

Another way to look at this is "how do you define life cycle". In my opinion that would really mean "how many times can it be re-fretted/re-finished/repaired before the sound quality is unaceptable or it simply is no longer playable, regardless of cost" since cost is an owner decision independant of the actual usability issue. The one point you raised I can't answer is "compared to other brands". But as far as Guilds specifically I've seen any number of threads here about re-built Guilds and can only re-call seeing one about a guitar that probably wasn't worth recovering, and a few about GAD's with build quality issues which weren't handled through warranty repair, including one that was warranty replaced. Aagin, the critical issue being "original build quality".

If re-frets, repairs, realignments, part replacements, are all taken into account - is there a point when the instrument has gradually evolved into a (relatively) new instrument? It reminds me of the story of the ship "Queen Mary". The ship sits docked permanently. Meanwhile, every week, another part is replaced. Eventually, while it is still the "Queen Mary", all parts original to the ship will have been replaced. So the question is mostly a philosophical one. Everyone will have their own opinion.

This is a very interesting point. The Stradivarius violins currently in use have newer necks, longer fingerboards, stiffer bass bars inside, are now strung under higher tension with metal wire, tuned about a semitone higher than what was considered standard when they were made, and are now played with a completely different bow than what was in use at the time. These instruments have changed dramatically over the years and yet thy still endure.

' Strang

 

[kostask]

I think you guys are leaving the neck block out of the equation... :wink:

In my case you're correct, hadn't thought of that, can you expand, is there a potential source of wear internally where the truss is braced? Thanks!

It isn't wear from the truss rod, it is the neck block moving/deforming, and the support structures around the neck block gradually succumbing to the effects of string tension. A neck reset requirement is caused by the tension of the guitar strings basically trying to fold the guitar up, and also trying to make the bridge and nut move closer together. The first causes the neck angle to gradually change, so that after 20-25 years, the neck angle will become sufficiently shallow that the neck needs to be reset to a better angle (one that essentially restores the break angle of the strings over the saddle to the point where the guitars sounds its best). The second results in the neck being driven closer to the bridge, and often can be seen as the crack running beside the neck on the soundboard (on treble side, bass side, or both), leaving jagged edges in the sound hole and sometimese breaking the rosette. What has happened is that the neck has moved slightly down (not rotated as in the first case), and the neck block has been driven down towards the tail block, and the sides near the neck block have bent inwards, along with the possible failure of the transverse brace glue joint. In many cases, you will see the two conditions at the same time, if the neck angle has gotten so bad that the fingerboard is pressing down on the top and impacting onto the transverse brace under the end of the fingerboard.

The truss rod isn't being constantly used, and most truss rods are sufficiently strong to be able to withstand the forces of the strings quite easily. Wear on truss rods is minimal, thought sometimes you can have rusted truss rods, and trying to adjust a rusted one (if it is sufficiently rusted) can break a truss rod. This is caused more by negligence and forcing a rusted part than any wear out mechanism.

Kostas

 

[GuildFS4612CE]

Thanks so much.

I knew somebody smart would be along to explain it clearly.

 

[adorshki]

This is a very interesting point. The Stradivarius violins currently in use have newer necks, longer fingerboards, stiffer bass bars inside, are now strung under higher tension with metal wire, tuned about a semitone higher than what was considered standard when they were made, and are now played with a completely different bow than what was in use at the time. These instruments have changed dramatically over the years and yet thy still endure.

' Strang

I think what we're boiling down to here is "What is the real heart of the instrument" and it looks like at least you and I agree it's the sound box. As I mentioned above, I think once you replace a top or really any element of the body you've actually just made a "new" instrument. From your post it appears the critical surviving elements of these viollins is the sound box, and after all that's the primary functional element to create the "tone" so sought after and which defines the instrument. All the other "parts" are pretty much "wear" items like tires and brakes. Kostas has me worried with his observations about neck blocks though. But now I think what's really going on is the whole body of the guitar is actually warping around the neck joint, not the other way around, since the sound box is the more flexible and less "braced" structure. And while string tension is obviously the culprit, I still wonder if there is a "ideal design tension" that is intended to prevent this from occurring?

 

[adorshki]

It isn't wear from the truss rod, it is the neck block moving/deforming, and the support structures around the neck block gradually succumbing to the effects of string tension. A neck reset requirement is caused by the tension of the guitar strings basically trying to fold the guitar up, and also trying to make the bridge and nut move closer together. The first causes the neck angle to gradually change, so that after 20-25 years, the neck angle will become sufficiently shallow that the neck needs to be reset.

This is a whole new can of worms. Your explanation of the process is quite understandable/ accurate I'm sure, but wouldn't this bring us to the old debate about whether or not it's better to store a guitar with tension on the strings? The rule I've gone by is if you're going to play it at least an hour a week, as an arbitrary figure, it's better to leave 'em tuned, but for "long term storage" (which I've never seen precisely or even loosely defined), it's better to leave them loose....your turn!

 

[GuildFS4612CE]

And while string tension is obviously the culprit, I still wonder if there is a "ideal design tension" that is intended to prevent this from occurring?

How can that be if tension is not a static quality?

Humidity, temperature variations, expansion and contraction, string gauge tolerance variations, string changes or lack of same, actual playing styles...

Dreaming is always nice. :wink:

 

[kostask]

If a 6 string guitar is not going to be used regularly (my definition is at least one hour a month, this isn't everybody's definition), then it should be stored without being strung up to tension. The strings can be left on without tension, I suppose, but there really is no advantage to that, and you'll just end up having to take them off before you start to play the guitar again, as they will probably corrode pretty badly over time. I can see no reason to have a guitar in long term storage strung up to tension. I don't think anybody does that. There is the possibility of doing that with a solid body electric, and getting away with it, but any acoustic flat top/acoustic arch top (and some semi-hollow bodies) will suffer greatly.

The term regularly for 12 strings is appreciably shorter (my definition is used at least 1 hour every 2-3 weeks) due to the extra tension involved. Again, this is my personal rule of thumb, everybody elses may be different. And yes, I do realize that 12 string necks (especially our dual truss rod Guild 12 string necks) and soundboards are designed to take the extra tension, but if you look at most 12 strings, the accommodation is in the size/strength of the neck, and the thickness/bracing of the top. The neck blocks and dovetails are certainly NOT almost twice the size of those on the 6 strings (they are somewhat larger), and the sides/backs of the guitars are generally the same as they are for 6 strings, even though 12 string tension (.010 12 strng light set) has 260-270 lbs. or so of tension (will vary some with materials, core wire vs. wrap wire ratio, actual individual string gauges in the other strings of a set) vs. about 160-170 lbs. or so (.012 light gauge 6 string set, variations in tension as per the 12 string set above) for 6 strings.

Kostas

 

[adorshki]

And while string tension is obviously the culprit, I still wonder if there is a "ideal design tension" that is intended to prevent this from occurring?

How can that be if tension is not a static quality?

Humidity, temperature variations, expansion and contraction, string gauge tolerance variations, string changes or lack of same, actual playing styles...

Dreaming is always nice. :wink:

I'm thinking that perhaps the known strength of the woods are calculated to withstand the known stresses calculated for the "specified" strings"? The factors you mention I think have minimal effect on total tension of a given gauge set. From another perspective, if the designers are in fact taking string tension into account they must also be well aware of those variables and take them into account. My real question is, "When Guild published those strings specs, could it be because they have calulated the guitar's ability to withstand the tension range of that set?"

 

[kostask]

This is a very interesting point. The Stradivarius violins currently in use have newer necks, longer fingerboards, stiffer bass bars inside, are now strung under higher tension with metal wire, tuned about a semitone higher than what was considered standard when they were made, and are now played with a completely different bow than what was in use at the time. These instruments have changed dramatically over the years and yet thy still endure.

' Strang

I think what we're boiling down to here is "What is the real heart of the instrument" and it looks like at least you and I agree it's the sound box. As I mentioned above, I think once you replace a top or really any element of the body you've actually just made a "new" instrument. From your post it appears the critical surviving elements of these viollins is the sound box, and after all that's the primary functional element to create the "tone" so sought after and which defines the instrument. All the other "parts" are pretty much "wear" items like tires and brakes. Kostas has me worried with his observations about neck blocks though. But now I think what's really going on is the whole body of the guitar is actually warping around the neck joint, not the other way around, since the sound box is the more flexible and less "braced" structure. And while string tension is obviously the culprit, I still wonder if there is a "ideal design tension" that is intended to prevent this from occurring?

Violins and guitars are NOT the same. Violins have sound posts, are considerably smaller in size, and are heavily arched both on the top and the bottom plates. High end violins are also re-built every 50-100 years or so. The guitar (as a generic instrument) has only been in existence for about 150-170 years, and has only had metal strings since the 1920s (at least in general use), is a much larger instrument (even a parlor is bigger than a violin), doesn't use a sound post, and doesn't have the arching of the violin. While Stradivarious and Guarnini (?) violins "endure", they have probably been rebuilt 6-8 times. It is hard to say where the Stradivarius ends and the rebuilder begins.

The "heart" of a flat top acoustic is the soundboard with its associated bracing and bridge. Everything else is a minor contributor to the sound (like the back and sides), or is support structure (neck blocks, back braces, side braces). Depending on who you ask, the soundboard is responsible for 80% or more of the sound of a guitar. When you re-top a guitar, you get a NEW guitar, it isn't the old guitar with a new top, it literally IS a new guitar, and will age and "break in" just like a new factory guitar.

You don't design string tension around the guitar, you design the guitar around the string tension. The string tension is something the guitar maker uses as a baseline to design his guitar around. In other words, the design starts off with (for a 6 string) a standard tension (150-170 lbs for light gauge strings, 180-200 lbs for mediums), and the structure of the guitar is made to work with that tension without collapsing yet still maximizing resonance. As some luthiers put it, the best guitar will be one with the absolute least amount of weight that doesn't explode under string tension.

Structurally, the guitar neck does rotate around the neck joint. Sonically, the center of the guitar is the soundboard (specifically the area below the sound hole). If you want to really see what string tension will do to a guitar over time, just find a really cheap nylon string guitar, and string it up with some medium steel strings (try to find one with a dovetail neck joint). Wait a few weeks to a few months, and if the bridge hasn't pulled up, you will see signs of the neck starting to bend, possibly th neck joint failing, and all the other tension related issues that take much longer for a steel string guitar to exhibit, but will eventually.

 

[Russell Letson]

If a 6 string guitar is not going to be used regularly (my definition is at least one hour a month, this isn't everybody's definition), then it should be stored without being strung up to tension.

My D-40 has been strung up and kept at concert pitch for more than forty years, and completely unstrung only when being repaired. How is that different from being kept unplayed in its case for long periods? And I have several seldom-played guitars that are stored strung to pitch and not touched for months at a time. I've owned most of them for ten or twenty years and seen no problems that would not have emerged in any case (for example, a split in a bridge slot).

 

[kostask]

Like I said, those are MY definitions, and I have no doubt that others have different definitions.

None of this is cast in stone, it is all probabilities and reductions of risk. The difference in s played guitar being tuned to pitch for 40 years is that you do not really want to be tuning and detuning the guitar constantly, if you are using it regularly. The costs of replacing strings due to metal fatigue in that example would be prohibitive, even compared to a neck reset. Sitting unplayed in a case means having it detuned/unstrung once, and not retuning it constantly, so the costs of a potential neck reset outweigh the costs of string replacement. With the guitar detuned/unstrung, there is none of the string tension to cause the neck angle to change or other string tension related structural problems.
Another way to think if it is this way: Take 2 brand new guitars. Put them in their cases, one strung to standard pitch, and the other with no strings at all. Wait 25-30 years without touching either guitar. Which do you think will need a neck reset after the 25-30 years are up? Now, think if why the strung to tension guitar needs a neck reset.

As for your guitars that have sat unplayed, they may have not been damaged. It is also possible that they may have. You won't know until such time as a repair is required that a glue joint failed inside the guitar. Your guitars may never have such a failure, or they may already have failures like this. Keeping the tension on the guitars that are not being played constantly just increases the stress on the entire instrument, but does not automatically mean the problems will occur. I prefer to err on the side of caution, and remove the strings on any guitars that I don't use regularly. You are free to do as you wish. As I said repeatedly in my post, these are my guidelines, and I am sure that others have theirs. Feel free to check with your trusted luthier regarding this, or any other matter.

In human terms, think if it this way: When you are working as a bricklayer, you may need to haul 150-170 lbs of bricks from the brick pile to the brick wall that is being built (analogous to a regularly played guitar). I don't know of anybody who would just walk around with an extra 150-170 lbs strapped to his back (analogous to an unplayed guitar). In both cases, there is no reason to carry the weight (in the case of the bricklayer) or tension (in the case of unplayed guitars) if it doesn't serve a purpose. In the case of unplayed guitars, detuning a guitar involves a couple of revolutions of a tuning knob. For me, that is something that I am fine doing. You are free to do as you wish. You can put heavy strings on, tune the guitars to higher than concert pitch, and leave them on the rear deck of a car in the middle of a hot summer day. Your money, your choices, not for me to make decisions for you.

Kostas

 

[Russell Letson]

I'm trying to make sense of the difference between a played and an unplayed guitar kept at pitch. My observation is that there are no more maintenance issues between the instruments that I play regularly and those I do not. I currently own more than a dozen, ranging in age from 8 to 110 years, and I keep all of them tuned to pitch--and have done so with all my guitars for more than fifty years.

The sentence I'm having trouble with is this one: "Keeping the tension on the guitars that are not being played constantly just increases the stress on the entire instrument." (Emphasis added.) Does playing really change the amount of stress? None of the builders I know or have interviewed ever mentioned this phenomenon. Nor do any of the ones I know personally store their instruments unstrung. Instead, they worry about humidity and temperature, since those can affect finish and glue joints, and a compromised joint is going to be trouble whether the guitar is being played or stored.

BTW, a guitar and a bricklayer are such dissimilar systems that comparing them generates more questions than it answers. And the heavy strings/overtuning/hot car situations all represent stresses the system was not designed to withstand. Guitars aren't designed to withstand gunshots, either, or hammer-blows.

 

[adorshki]

I still wonder if there is an "ideal design tension" that is intended to prevent this from occurring?
You don't design string tension around the guitar, you design the guitar around the string tension. The string tension is something the guitar maker uses as a baseline to design his guitar around. In other words, the design starts off with (for a 6 string) a standard tension (150-170 lbs for light gauge strings, 180-200 lbs for mediums), and the structure of the guitar is made to work with that tension without collapsing yet still maximizing resonance. As some luthiers put it, the best guitar will be one with the absolute least amount of weight that doesn't explode under string tension.

I posed the question backwards, but that's what I meant. Thanks. PS sorry I screwed up the quote but I think it's clear I asked the question, Kostas gave an answer.

 

[adorshki]

I'm trying to make sense of the difference between a played and an unplayed guitar kept at pitch. My observation is that there are no more maintenance issues between the instruments that I play regularly and those I do not. I currently own more than a dozen, ranging in age from 8 to 110 years, and I keep all of them tuned to pitch--and have done so with all my guitars for more than fifty years.

Yes, I'm still unclear on that specific point unless the issue is that constantly changing the tension is undesirable? One would think that the total playing time wouldn't be that much of a percentage of the total time kept at pitch, especially if you're only playing for an hour a week. I can see Kostas' point about slow degradation of glue joints etc, but how does playing it make storage at pitch more desirable? I guess I'm not satisfied that the costs of string replacement are really that significant, I still suspect there must be another reason for this philosophy, but I have respect for K and maybe this really is the simple reason nobody ever explains or knew in the first place. I guess I see it as kind of analogous to parking your car with the parking brake in a level place. (ie. Guitar is strung up to pitch) Will pumping the brakes ("playing") while you're not moving make any appreciable difference in your brake wear?
By the way, sincere thanks to all who are participating, I'm truly trying to expand my understanding of the instrument here, it's why I joined this place. My hypotheses are offered up for feedback, not as "truths", so I try to pose them as questions. The only FACTS I can vouch for are the ones about the history and condition of my own instruments.

 

[kostask]

I'm trying to make sense of the difference between a played and an unplayed guitar kept at pitch. My observation is that there are no more maintenance issues between the instruments that I play regularly and those I do not. I currently own more than a dozen, ranging in age from 8 to 110 years, and I keep all of them tuned to pitch--and have done so with all my guitars for more than fifty years.

The sentence I'm having trouble with is this one: "Keeping the tension on the guitars that are not being played constantly just increases the stress on the entire instrument." (Emphasis added.) Does playing really change the amount of stress? None of the builders I know or have interviewed ever mentioned this phenomenon. Nor do any of the ones I know personally store their instruments unstrung. Instead, they worry about humidity and temperature, since those can affect finish and glue joints, and a compromised joint is going to be trouble whether the guitar is being played or stored.

BTW, a guitar and a bricklayer are such dissimilar systems that comparing them generates more questions than it answers. And the heavy strings/overtuning/hot car situations all represent stresses the system was not designed to withstand. Guitars aren't designed to withstand gunshots, either, or hammer-blows.

I don't seem to be expressing my thoughts clearly, so I will try one more time.

As I have repeatedly said, unplayed is a term that means different things to different people. I have also stated that neck resets are required due to string tension, and I hope there is no more clarification required.

A played guitar tuned to pitch, and an unplayed guitar tuned to pitch have the exact same string tension, and will therefore need a neck reset at approximately the same time (generally 20-25 years, but it does vary). An unplayed guitar, detuned, or completely unstrung will not have any tension applied, and will not need a neck reset. The played guitar is being used for something useful (ie. being played, and making music, or in my case, some form of noise). The unplayed, tuned to pitch, guitar, is not doing anything, but its neck joint (and all the other joints, for that matter) are under string tension. It will need a neck reset in 20-25 years, even though it has not done anything besides sit in its case. For the not taking time to detune a guitar, it will be necessary to pay for a neck reset after 20-25 years. All of the above assumes that the guitars are under ideal humidity and temperature.

I'm sorry the analogy between the bricklayer and the guitars didn't work for you. But the essential point is quite clear: do not put things under stress unless there is a purpose for them being under stress.

As for the heavy strings/hot car statement, I was simply trying to say that you can do anything you want with your guitars. They are your guitars, and you can use, abuse. or cherish them as you see fit. Whatever you do, it doesn't change the way guitars work, act, and react. Those mechanisms are known and have been established over years of repair and observation, and nobody will change them unless there is a fundamental change in guitar construction and/or materials (like carbon fiber, for example).

Kostas

 

[adorshki]

A played guitar tuned to pitch, and an unplayed guitar tuned to pitch have the exact same string tension, and will therefore need a neck reset at approximately the same time (generally 20-25 years, but it does vary). An unplayed guitar, detuned, or completely unstrung will not have any tension applied, and will not need a neck reset. The played guitar is being used for something useful (ie. being played, and making music, or in my case, some form of noise). The unplayed, tuned to pitch, guitar, is not doing anything, but its neck joint (and all the other joints, for that matter) are under string tension. It will need a neck reset in 20-25 years, even though it has not done anything besides sit in its case. For the not taking time to detune a guitar, it will be necessary to pay for a neck reset after 20-25 years. All of the above assumes that the guitars are under ideal humidity and temperature.
Kostas

Ok I was writing my question above while you were writing this. THIS makes perfect sense, thanks!

 

[12 string]

Don't know if this is true, but I have heard it said that leaving a neck without tension for a long time risks a permanent and incurable back bow.

Back to the OP, I guess we just don't know how long our guitars will last. My oldest guitar is a mid-forties Gibson Banner Headstock J-45. In its seventh decade it still performs beautifully, and as has been pointed out, many forum members have older instruments. I'm confident that all of my guitars will outlast me...

' Strang

 

[Jazzdog]

I think it all depends on if Pete Townshend gets his hands on it.

 

[fab467]

I think it all depends on if Pete Townshend gets his hands on it.

Who?