Hi! I have got an excellent condition second-hand Yamaha APX 500 and 3 days ago I decided to oil the frets with lemon oil. I was told by the salesperson in guitar shop that I should oil the frets until they stop absorbing, so I put that oil really generously. Now the frets look and feel excellent, but I have noticed that 12 fret action changed visually (now it is nearly 5/32 inches, I dont know the exact previous number), playing right to 12 fret became little uncomfortable. I guess that oil humidified the rosewood too much, it shank a bit and the fretboard have arched a little.
The second thing I have noticed is that when I pulled the strings back after oiling, 3 thinest strings became 1 tone lower in say 2 minutes after tuning and playing and I had to pull them up 4-5 times. Can it be that wood became too soft after oiling and arched on with strings tension?
So the question is: is that really oil that caused the problem or is it just my imagination? What should I do now: wait until the fretboard dries in some reasonable time and become as it was before OR change saddle height right now? The guitar has System55T piezosensor right under the saddle and I don't even know if it is detachable.
Many thanks to all of you that will give me some advice!
I oil my fretboard with orange oil every time I replace the strings and have never had this problem. Just make sure you don't over-do it.

Put three drops of oil for each fret and your good.

In terms of the arching, that sounds more like a humidity problem that is in unison with the oil.

What kind of temperatures are you subjecting this guitar too? Your most likely putting way too much oil + probably being in a hot area.
Quote by rockhard90s
you probally need to readjust trust rod and actions too.

Good Point, But I don't see how oil could do this on it's own.

Hey, did you by any chance change your strings to something that you don't normally use? Maybe a thicker gauge?
Quote by Funk Monk

What kind of temperatures are you subjecting this guitar too? Your most likely putting way too much oil + probably being in a hot area.

That sounds like a good idea: the guitar stands in an unconditioned room and yesterday we had 85F/80% humidity outside in the street, while all the previous month there was 60-70F.
Speaking about the stings: I have Rotosound JK11 strings installed, but the same day I had to put a string from another, thiner set (actially, B, but still 0.011) in the first (higher E) position.
Quote by patticake
too much oil can soften the fretboard so that the frets start coming out.

Fortunately, no sign of it
I have disassembled the saddle unit and saw an amazing engineering idea: the previous owner, who has, to my knowledge, really large fingers, decided to make the saddle a bit higher, precisely 1/5 inch higher 'cause I found there A NAIL with the head and spike accurately cut off So I removed it and the action is now as it should be. Many thanks to all of you, folks!