I am in the process of making some duck calls for Christmas presents. I have never done this before so I am curious about what type of finish works best. I was leaning toward Spar varnish or wipe on poly on the outside and Varathane natural oil on the inside. I have never used a friction finish applied on the lathe for anything. Would this be a good application for this type of finish? Can the type of finisih effect the tone?

Thanks in advance.

Quinn