Hi Mr. Ford,
A few years back (I think 7 years ago) you re-glued and flattened the black pickguard on my Martin 00-18. It's been fine all these years. But just last week I noticed that it started to curl up again! Is this going to happen every few years? I have not had the guitar in any extreme temps -- although we don't leave our heating on when we are at work. The cat and guitars might have been a little nippy -- but not freezing.
(You also did the same job on my Martin 5-18 (1958) celluloid pickguard. It's fine. )
Thanks for your time.
Yep, those black guards shrink a good deal more than the tortoise celluloid ones, so it's predictable that they will curl again and again, eventually shrinking so much there's an unsightly bare edge all around them. The time between regluing is really variable and there's not much you can do about it except the obvious - don't store the instrument in a hot parked car.
Once it gets really bad, the only logical alternative is replacement.