I have a Gibson F5 from 1974, which I bought used a couple of years ago. From the start the A and E strings are corroding, i.e. becoming very rough within half a day. The corrosion only appears around the picking area or rather around the fretboard extension. The frets in that area is also corroded, so I'm thinking that it might be connected. A contact pick-up was installed when I bought the mandolin and at some point I thought that the electrical circuit could have something to do with it, but the corrosion progressess even when I don't plug in. Anybody have had any experience with something similar and more important anybody who has a clue to how to fix this?
I played a 74' F5 Master Model for several years and had no similar problems. Clean all the rust off your frets with 0000 steel wool. Rust / corrosion travels. Take all the strings off your mandolin and clean the fingerboard and everything else then lightly oil the wood the fingerboard. Music stores usually have products for cleaning and treating the fingerboard and the rest of the body. Restring it and set the bridge in the correct place so your intonation is accurate. When the bridge is in the "right" place the open string , the same string noted at the twelfth fret and the harmonic at the twelfth fret will be the same tone. Save time by marking where the bridge is set with masking tape before removing your strings. Bridges do shift over time anyway so this needs to be done annually or so. Some people also just rust strings because of the ph of their skin and thr E and A strings are the first to show corrosion. If that is the problem you need to try a string with a polymer coating like Elixirs or D'Addarrio coated strings. Wash your hands before you play and wipe down your instrument when you finish playing with a clean dry cloth. Lastly visit The Mandolin Cafe site and search out Rob Meldrum's free mandolin setup book. There is a wealth of information there. R/