you can actually use just about anything to turn a duck call. But, when it comes to turning the insert you had best stay with an acrylic or resin acrylic (Methyl methacrylate), unless you have some nice hard wood to use. You can use Delrin, a product made by dupont, which is a near teflon type material, with a rubber compound added for resilience against temp changes, I have used a resin plastic for both but you have to be careful about gouging into the material as it will chip out bad, you need sharp chisels, and light passes for all acrylic. Using unusual materials like bone or antler or ivory is a blast, they create super eye candy....there is a material called faux ivory which is a soft resin acrylic, you can also pour your own resin in a two part mix. Just jump in and experiment, you'll soon find that the choices are endless and the possibilities are only limited to your imagination..... pappy