STABILIZING VERTEBRATE FOSSILS FOR REMOVAL AND TRANSPORT USING POLYURETHANE FOAM

For the past 150 years vertebrate paleontologists have been using the plaster cast method. Wrapping vertebrate fossils in a jacket of burlap and plaster has been the least expensive and most effective method of ensuring that they are not damaged during removal and transport. However, today's technology offers various materials that may offer a better solution to the field preparation of vertebrate fossils. In this study experiments using cardboard and spray polyurethane foam suggest a method that may be more effective than, and cost competitive with, the plaster cast method. The following procedure is herein recommended as an alternate to plastering: 1) pedestal the fossil as normal for the plaster cast method; 2) wrap the fossil in dampened newspaper to ensure that the foam does not come in contact with the fossil; 3) create a form around the fossil using cardboard to ensure a full two-inch clearance between the fossil and the framing material; 4) spray a liberal amount of the foam to completely fill the form and seal with duct tape; 5) allow a curing time of 8 hours; 6) break the pedestal and flip the fossil, then repeat the procedure for the bottom of the fossil. The spray polyurethane foam method provides several advantages over the plaster cast method and some of these are the following: 1) no mixing of materials or messy residue to clean up; 2) the foam acts as a padding agent and provides a strong rigid package; 3) the foam adds very little weight to the fossil, provides water resistant protection, and is much easier to remove than a plaster cast; 4) curing time is predictable at 16 hours, as opposed to 24 to 48 hours for plaster; and 5) the regular shape of the packaging provides stackable surfaces.