It's not just a newer Martin issue, though there seems to be a resurgence. Until the last decade or so, most of the loose bindings I saw on Martins were from the 1970's. I attribute that to the Boltaron (PVC) binding, which is hard to glue to wood.
IMHO, it is not a low humidity issue, since that causes the wood to shrink. If the wood shrank instead of the binding, then the binding would not pull loose at the waist, which indicates that the binding has shortened. If the binding is loosened for more than a couple of inches, it leaves a gap when reattached because it is now shorter.
This shrinkage occurs with all plastics, including celluloid. The difference is that celluloid is glued on by melting it, which is a stronger bond than that achieved by gluing PVC with whatever glue Martin uses.
Super glue is a much stronger bond for attaching PVC, but it is very difficult to use for repairing loose binding a finished guitar.
The new D-28 has 'antique white' binding, not ivoroid. I have not seen that specified before. I am curious if it is PVC or some other kind of plastic.
|