Guitar Finish

I've looked everywhere and couldn't find a answer to this question.

What would happen if you left a guitar totally unfinished.

What are the pros (aging and appearance with wear) and the cons (tuning issues etc) overtime.

Thank you for any help with this.

Tom,

The first thing is that the instrument would turn grey from the goop in your hands. You can see this grey on maple fingerboards where the finish has worn off. I made a mahogany guitar neck with lots of pearl and carving. The body of the guitar was lost in the Mossman fire, in 1975, so I've just used the neck as a demonstrator since then. It was never sprayed with finish, and it is nasty!

I think that where this line of questioning starts is the fact that too thick a finish dulls an instrument's resonance. So, if a thinner finish is better, why not no finish at all? The question is further confused by the fact that the vibrating plates of an instrument are thicknessed to account for finish. You can't remove the finish without making the plate thinner than the maker intended. If the plate is, through bad design or incompetent manufacture, too thick, making the tone too bright, removing the finish will make it bassier. You can lower the resonating pitch of a plate by thinning it. The stripped guitars that I have played tend to sound mushy; too much bass, no clear treble. If the guitar was designed and built to be played without finish it would sound fine.

The primary function of a finish is cosmetic. Wood is porous and will absorb whatever crap it comes in contact with. Having it absorb a clear, glassy finish, that can lens the beauty of the wood, is a good option. Finish could slow the swelling and shrinking effects of humidity, except that the insides of guitars are not usually finished. The finish will protect the wood from a spilled Coke, unless you spill it inside the guitar. Guitars have pickguards to protect the finish, they have finish to protect the wood. The "pick scratches" are generally made by your fingernails dragging on the top as you play. A top consists of alternating stripes of very hard summer growth and very soft spring growth. Rubbing the bare wood quickly removes the soft wood and leaves ridges of hard. A bare wood guitar would look old quickly but it should last as long as a finished guitar. And, except for the feel of bare wood on the back of the neck, it should play the same. There would be no effect on action, tuning, etc.

The next step in this discussion is oil. Oil finish can leave the wood looking bare while it soaks and protects the wood fibers. A fast drying lacquer that sits on top of the wood allows the wood to vibrate. Oil takes forever to dry and increases the weight of the plate. Violin makers, who prefer oil varnish, tend to seal the wood to keep the oil on top, out of the wood fibers. Some people strip and oil the back of their guitar neck. If they like that feel, fine. You should not do that to the body of an acoustic guitar.

Steve Mason