"Crease" on back of guitar

[Petrainy]

I have an A201 (Gold Series with a serial number A0013, purchased about 4 years ago), and a 8 inch "crease" has appeared in the finish directly at the seam between the book-matched pieces of the back. It isn't so much of a crack, really, as it appears to be cosmetic (?), and does not extend to the edges of the guitar (it stops about 1-2 inches from both the guitars edges. There is no indication that the corresponding brace on the inside of the guitar is loose or damaged. I am the original owner and I baby the guitar, and keep it humidified and in the case at all times. No significant bumps, bruises or shocks have occured. My brother is a luthier and says this should be one of the strongest parts of the instrument, and it may be a glueing issue? Is there anything that can be done and would it be covered by warantee? I love the instrument and would hate to have the problem progress any further. Thanks!

[Petrainy]

Actually, the serial number is A00313.

[JB]

Your brother is correct, the back seam is a very strong part of the guitar and what you're seeing is more than likely the glue line and not a crack.

The most common reason for a glue line becoming noticably raised or sunk is when a guitar dries or takes on moisture so that points to a humidity issue.

In summer time when humidity levels are higher a solid wood acoustic can take on moisture very slowly over a few months if not kept in a reasonably controlled enviroment ... 45% - 60% is a good target for acceptable levels.

All solid wood acoustics will take on and loose moisture through the year to some degree but will normally settle down and return to normal providing it's keep in a suitable enviroment.

If you bought the guitar new there would have been a leaflet in the case explaining the importance of proper humidity controls for your guitar.

Best advice is not to do anything with it, but rather let the guitar settle slowly ... do not force dry it.

If the guitar has been in a dry enviroment then an opposite action is required ... get a humidity unit for your guitar like a "damp-it" to get the levels normalised.

I get this on my guitar from time to time if we've a very humid summer but my guitar will always return to normal.

Cheers
JB