Remember when you were a kid, and you had to finish your ice cream cone before it melted down your arm? Or maybe you were the type that bit the end off the bottom of the cone and liked melted ice cream down your arm. Now that most 50's Gibson and Fender guitars are getting into their late 50's, melting plastic is on my mind. So far, it seems it is only Gibson's and not Fender's that are a real melting problem. Vintage Guitar Magazine just republished a piece about Kluson 'Keystone' and white oval-type tuner buttons on Gibsons that are deteriorating. The problem also extends to bindings and pickguards. In Dan Erlewine's book "Guitar Player Repair Guide" Mr Erlewine says "Some plastics used during (the 1950's) are ticking time bombs with 30-year fuses". He mentions that some guitars (like Fender from my research) used different types of plastics, so do not suffer from this "melting" problem. According to Mr Erlewine, the causes of this melting come from solvents and plasticizers used when the plastic was manufactured. If a guitar that is susceptible is left in it's case for many years and these gases cannot escape, these solvents and plasticizers can result in damaged finishes and wood, corroded metal parts and also a sticky smelly mess. Not that leaving your guitar out of it's case all those years would necessarily avoid the plastic pieces deteriorating... you might however avoid the secondary effects the gases can have on the rest of your guitar. The only real solution is to replace the parts before they melt.
