It's been alluded to, but I don't know if anyone really pointed out this aspect. On a laminated (plywood) bodied guitar, there are multiple layers of wood. The outer layer of wood under the finish is often not much thicker than the finish. Even if you strip the finish by means other than sanding, you still need to prep sand the body prior to refinishing. Even during a light prep sanding, those with no finishing experience will find it very very easy to sand through the outer veneer into the core laminate. Looks pretty ugly.
Even those with great experience are not immune. I recently refinished a 1970's S Yairi laminated body guitar that had been re-topped and then prepped for finish by a very experienced luthier. He sanded through the outer veneer in two places next to the binding. (Due to a dispute with him the customer took the guitar back before it was re-finished, and later gave the guitar to me)
Using blocks to sand rather than fingers is standard good procedure for leveling the wood surface and sealer or intermediate finish coats. It is no guarantee of success on an older guitar because it is unlikely the surface will be level to begin with due to 50 years of string tension.
__________________
Larry Nair
|