Is the instrument properly humidified?
It may be super dry, Ron. Are you placing the humidifier (washrag) inside the body of the guitar? If not, it really can't do much good. It may also take longer for it to humidify after all those years of neglect.
I think for others to be able to suggest anything beyond routine humidification, you'll need to post a few clear pictures so we can see what you're describing.
I'm sure you'll get more suggestions from other forum members.
Best of luck :)
Just make sure it's well humidified, and in a tight hardshell case. Also check inside for loose bracing.
Removing the top or back is not going to help, just create more problems and unnecessary work.
Thanks for sharing about your Problem Guitar.
Without the benefit of pictures, for me there's a little guesswork and leaning on experience, which I am just hoping is accurately related to the issue you have.
Reading your interesting post, it appears that despite your long patience, in attempting to Add Humidity to your Guitar, it genuinely isn't responding at all, and looks as if it never, ever will during your lifetime.
Provided I have read you correctly, and what I described, is in fact the case. My hunch would be that the Conditions the Guitar has experienced at some point in its life, were so extreme, that as a result, the Cell Structure of the Top's Wood, have been Significantly Changed, Forever.
So I would described such a fault as a Warped Top, as opposed to a Sunken Top. A Marginally Sunken Top can often be corrected by Humidifying. A Dramatically and Permanently Warped Top however, is a very different kettle of fish, and simply won't be corrected in any such easy way, as placing Wet Sponges inside etc.
Severely Dried Out Spruce Shrinks, but across the grain, rather than along its length. Once at Cell Level, such a badly Warped Top Caves In, in my opinion it is extremely unlikely they will ever be able to Return to their Proper Dimensions, as Specified when they were Manufactured. Any resulting cracks, probably will also not close, utilising Normal Approaches to such a Problem.
Wood gains or loses moisture from the Air, It is Hygroscopic. However in addition to that fact, Wood is Anisotropic. In other words, the Wood has Quite Different Properties depending on the Orientation or Direction of its Grain. It simply does not Behave The Same, in all Directions. And this Anisotropic Effect, where the Properties of the Wood React Differently, Depending on the Direction of the Grain, is most easy to observe in a Shrinkage from its Original Dimensions. So I would be wondering whether this is the Root of the Problem, if Humidifying doesn't Solve It, though it is the First Thing to Do.
It is the Cell Change and the Alterations to its Structure.
That is the Dividing Line for me to Define between what I regard as a Sunken Top or a Warped Top.
What it probably means, (without viewing the problem) is Deconstructing the Relevant Parts of the Instrument and Re-Fabricating the Guitar Anew. So plenty of work there.
I can well understand you might not wish to go down that path, therefore, if it's still Playable, my recommendation would be to Simply Enjoy Playing it, until the Point it Finally Becomes Completely Unplayable, then Fix It, As Necessary.
Only a thorough inspection can determine the best next move forward, but it probably won't be too hard to determine.
I do hope this is of assistance to you.
It's very late here and I have been working hard.
So I hope you will kindly forgive, this extremely short post.
If it were my guitar I would remove the bridge and put a hot wet cloth on the inside over the bridge plate with the the guitar upside down as well as one over the place you removed the bridge from ,and leave it fore a day.And see what it look's like. If it look's like it is getting a little spunge,Then I would heat two pieces of hardwood in the MIC-wave one fore each side and clamp it up tite leave it fore two days and see what it looks like. Unless there is a broken brace or some other thing wrong inside that should fix the problem. Good luck .Bill.......
Does it still have the sink behind the bridge when fully strung up?
How much depression is there over the X in front of the bridge?
If Humidification does not achieve anything, you may have loose or cracked braces.
The X intersection under the cloth patch is particularly vulnerable
Peter - I agree, the top has sunk because of irreversible changes to the wood as a result of catastrophic drying. And, I'd most likely not go to the extreme of rebuilding, but deal with neck angle and bridge to accommodate things the way they are.
No need to apologize for "extremely short post." My experience is that anything over a dozen lines or so will tend to be skipped over by readers of Internet forum threads, so detailed explanations are often missed altogether.
Thank you for your information.
I have pictures but have not been able to attach them.
It is very playable as is and I would not change the neck angle with out fixing the top.
Ron , the picture that you have up is the Martin you are concerned about?
Man , those autographs alone warrant leaving the top as is!
If it's very playable as is .............?