I originally posted this in the General Call Making Discussion board but it's relevant here:
Interesting stuff here... I too like a traditional, non-glossy finish on my calls. I too believe wholeheartedly in 100% pure Tung Oil. (I've never used Velvet Oil so I don't know anything about it.) I've not went to nearly the effort that gooseforsupper has but I very much like my finishing recipe. It's simple and effective and doesn't involve burning nearly as many rags!
I mix 100% pure Tung Oil, (not the diluted or misrepresented garbage sold at the big box stores) along with 100% pure Gum Spirits of Turpentine and McCloskey's Gloss Spar Varnish. 1/3 (equal parts) of each ingredient mixed together in a jar. Don't worry, the Gloss Spar doesn't produce a gloss finish with this mixture. I only use McCloskey's Gloss because I've found it to be the best. Why, I don't know, it just is. For some reason, again I don't why, Gloss works better than Satin.
I soak my calls in this for up to a week or so and then pull them out, wipe them off, and hang em for a couple more weeks. In about 30 days or so the turpentine odor fades away. The end result is a gorgeous traditional looking, water resistant finish that will last a very long time.
I use a jar a bit larger than my largest call. I take a piece of copper wire and bend it into a "V". The point of the V goes into the call opening and the tips of the V push up against the top of the closed jar lid, effectively keeping the call submerged in the mixture. The finish lasts a long time in the jar and is used over and over until it needs to be replenished. Incidentally, it stays mixed and does not separate or settle out like varnish or stain does.
I wish I could take credit for coming up with this recipe but I can't. I picked it up from someone much more knowledgeable than I am. It was explained to me that with this recipe the turpentine becomes part of the finish so should not be substituted for Mineral Spirits. Since Turpentine is made from tree resin, this tends to make sense, at least to me. That is why using only 100% pure Gum Spirits of Turpentine is necessary.
Very simple and very effective.