How much to loosen strings for storage?

[Wade Hampton]

First, Steve wrote:

Originally Posted by steveyam

And on the subject of resets, in my opinion, there is a preoccupation on AGF with them. Maybe it's different in the US, but here in the UK, it's something we rarely see or need. And that includes old acoustic guitars from the 50s and 60s.

Most of the local climatic conditions in the United States are considerably more severe than in the United Kingdom. In most parts of the US we have much colder winters and considerably hotter summers than you folks in the Mother Country.

This has its impact on acoustic guitars, particularly on those left mostly unattended for decades at a time.

Then Steve wrote:

Originally Posted by steveyam

Ok, point taken. And Wade, I KNOW you know what you're talking about, but that doesn't mean to say that I sometimes disagree about things, and we get an interchange going, and points are examined and knowledge shared.

Hey, I enjoy your posts and enjoy responding to the issues you raise. You're among the most thought-provoking contributors we have on this forum.


Wade Hampton Miller

[charles Tauber]

Originally Posted by murrmac123

Guitar necks are never under tension, they are, for most of their working lives, under compression.

They are under compression, due to the fact that the strings are under tension.

The neck can be seen as either a cantilevered beam or a column subject to eccentric loading/bending. Due to the bending force, the back of the neck is in tension, the top/fingerboard surface is in compression. Somewhere in between is a neutral plane that is in neither tension or compression.

For example, when a head cracks/breaks, it usually does so in tension, not compression.

[FrankS]

Oops hit enter too soon.

[FrankS]

Originally Posted by charles Tauber

Why, exactly, is it not good for them? People repeatedly say this, but what is the basis for this assertion?

I am with Charles on this one. Time and tension are the two factors that give bellies and and need for neck resets. While I do not advocate complete loosening of the strings, tuning down two notes can take tens of pounds of force off of all structural components of the guitar. Taking all of the tension off and then on again will unnecessarily cycle glue joints and interface points of the guitar and this is not a good thing.

Also, for shipping or longer term storage, ALWAYS detune a note or two but no more for the same reasons as above and because in shipping or in seasonal changes, there are greater temperature and humidity variations. Have you even wondered why sometimes a guitar that stays in tune can one day be off by quite a few cents? It is because wood and steel (strings) change dimensions with changes in temperature. Their coefficient of linear expansion is different so with any given temperature difference the tune will change. Also with humidity changes the wood will change but the steel will not. Worse case would be to have a guitar tuned on a cool dry day and ship it that way. A 10 C increase in temperature and 15% more humidity can increase the tension by as much as half a note or more which can be an additional ten pounds of pressure. Not a good thing in itself but jostle it around in shipping too and it is a recipe for problems. Maybe not today or tomorrow but over stressing components can only lead in a direction that is not productive.

Frank Sanns

[murrmac123]

Originally Posted by charles Tauber

The neck can be seen as either a cantilevered beam or a column subject to eccentric loading/bending. Due to the bending force, the back of the neck is in tension, the top/fingerboard surface is in compression. Somewhere in between is a neutral plane that is in neither tension or compression.

For example, when a head cracks/breaks, it usually does so in tension, not compression.

You are , of course, perfectly correct Charles, and particularly so in regard to headstock breakage.

I don't have the mathematical chops to back it up, but intuitively, it would seem to me that when a neck is subjected to the compressive effect exerted by the strings,which is then counteracted by the truss rod, then the neck is under an overall compressive stress, and definitely not under an overall tensile stress.

But hey, what do I know , I am just a country boy ..

[Zigeuner]

Originally Posted by murrmac123

A lively thread.

Just as a matter of interest, Jean Larrivee advises that when shipping guitars back to his factory for any reason, the strings should be left at full tension.

I personally don't agree, but just thought I would mention it.

One more observation, which might be slightly on the pedantic side, but here goes anyway,( it would be invidious to identify specific posts ).

Guitar necks are never under tension, they are, for most of their working lives, under compression.

They are under compression, due to the fact that the strings are under tension.

Hope that makes sense ( © Wade Hampton Miller, used with permission. (I hope ...))

It's a matter of how you look at it. I say they are under tension. We must agree to disagree.

[FrankS]

Originally Posted by Zigeuner

It's a matter of how you look at it. I say they are under tension. We must agree to disagree.

Actually, the parts will fail due to torque since the forces are not exactly opposing. If they were then they would be plenty strong and never fail.

Frank Sanns