I just finished sanding the Pro Zinger 15x4 with 400 grit and 600 grit sandpaper. It is smooth as glass now. I sharpened the leading and trailing edges a lot - it is like a knife. I think doing this also changed the airfoil shape, in the sense it is closer to a thick, semi-symmetrical airfoil now rather than a blunt plank of wood.

To finish the prop I took some NHP 30 minute epoxy and took my heat gun to it to thin it. Once that was done I soaked the entire prop in it, then I wiped the excess off with a paper towel. I then heated the prop, to keep the epoxy thin, and wiped it again. I put on a second coat and did the same thing. This allows the epoxy to soak into the wood without adding significantly to the weight or changing the shape of the blades. It also fuelproofs and strengthens the prop a bit. If nothing else it is pretty. I'll post pictures as soon as I can find my camera.

I'll let you know how this works. I'm hoping it will pull about as hard as the APC 15x4w (it's got almost the same shape, especially now that I've sharpened and thinned it out) with a much better spool up and hopefully higher RPMs (to get a bit more velocity). I'll test it on the stand to make sure it doesn't rip apart before I fly it.