Insects are encased in resin using a process called casting. During this process, a synthetic resin is mixed with a catalyst, or polymer, which causes the resin to harden. The mixture is then poured into a silicone mold and an insect is placed inside the mold. Once the resin dries, it will be a hard, clear substance that preserves the features of the insect inside.
The resin used for casting insects is in fact a plastic synthetic that is mixed with a hardening agent to create a clear, preserved insect cast. Synthetic resins were developed to mimic natural tree resins, which are sticky, clear substances commonly produced by coniferous trees that harden when dry. Synthetic resins are also made of polyester or acrylics, though plastic resin is most frequently used for casting insects. Insects encased in synthetic resins can be made at home using materials purchased from hobby stores and are also commercially manufactured and sold at collectible stores.
The process of embedding insects in resin is called casting. Resin is mixed with a liquid hardener, or catalyst then poured into a plastic mold that can be many different shapes and sizes. The insect specimen is then placed into the mold and the resin is allowed to dry for at least 48 hours. Once the resin is dry, the edges are sanded using 200- to 600-grit sandpaper. The insect can also be encased in resin using layering. A primary layer fills the mold halfway and then the insect is placed in the resin. Air bubbles are removed from the resin, and then once the primary layer dries, a secondary layer is poured over it to fully encapsulate the insect.
Specimens and Specimen Treatment
Any insect can be encased in resin using the casting process, however, certain insects require preparation before they are encased to guarantee a good-looking resin cast. Silvering is what happens to an insect when it is cast before it is dried. The bodily water content of the insect begins to evaporate and the abdomen begins to shrivel away from the mold that has been cast. This is especially common in larger insect casts, such as grasshoppers, moths and large spiders. To prevent this, most large insects are soaked for several days in denatured ethanol, which dries the water out of the insect before casting.
Once the insect has been cast in resin, it can be used for many different things. Sometimes resin casting is simply used to preserve interesting insect specimens. Additionally, insects cast in resin have been used as paperweights and collectible toys. The resin-cast insect can also be attached to jewelry fixtures and made into necklaces, bracelets and earrings.