The VMNH paleontology lab has been busy making many different casts for several upcoming exhibit and outreach projects. Paleo labs often make copies of important fossils so they can be shared with other museums and researchers, used in displays, and brought around for people to see and touch.
Right now our fossil preparator, Ray Vodden, is busy mounting the casted bones of a giant beaver skeleton for an upcoming display at Radford University. Why not use the real bones for this? For one, the technician has to insert metal bars throughout the skeleton to hold it together. If they were real bones, that would mean a lot of damage to the fossil, which would lose some of its potential for future research. Also, fossil skeletons are usually missing pieces, and casts help fill in the gaps.
Each of these casts starts as a mold first. The fossil bone is mounted in clay, then silicone is poured over to make the mold, like in the image below. Then you just flip it over to do the other side for a simple 2-part mold. This creates a near perfect negative impression of the fossil in the rubbery silicone. To make the cast we pour resin into the mold that hardens into a solid copy of the original bone.
Thanks to a cast trade deal with Dinosaur Brokers, we just got in a cast from an Ice Age wolf! Check this out as a special sneak preview for Ice Age Festival 2018!