Preparing Your Specimen

Silvering and bubbles are the two major faults one has to overcome in the resin casting. Silvering happens when the abdomen shrinks away from the plastic. This happens when the specimen is hardening in the plastic.

Some more examples of specimens to embed might include: a crayfish, clam, frog, perch, starfish, or a worm.

The main problem with embedding your specimen is the water content inside of the specimen. Most water is found in the abdominal cavity as part of it's abdominal juices. This water problem has to be dealt with before you embed your specimen. This water content is what is behind silvering. The water in the abdomen of the specimen will shift or change thus taking away it's partial support of the specimen's outer skin or covering. When this happens the skin or outer covering will shrink away from the plastic that is around it causing silvering to take place.

For a small bug specimen- make sure that it has been fully dried and that there is little water moisture inside of it. This is not difficult for rather small insects. However, this may prove difficult for rather large insects. These insects do not dry easily, especially if you have a large spider, a large moth, or a large grasshopper. If you try to dry these kinds then they will wind up looking shriveled and deformed. This is not a good senario.

There are two ways to solve this problem on large species of insects, for fish, reptiles and amphibians, as well.

The first method to get rid of water content is for you to be part taxidermist. A taxidermist stuffs animals. Turn your specimen upside down and cut open it's abdominal cavity and pull out it's guts with a pair of tweezers. Once the guts are removed you can replace the abdominal cavity parts with dry packing material such as small round pieces of toilet paper, napkins, or cotton balls. Superglue or stitch the incision back together after you have finished your operation. These dry items inside of your specimen should hold the outer wall of the abdomen in place against the plastic when it is poured against it.

The second method to get rid of water content is to soak your specimen in alcohol. Why? Because you don't want silvering. Also because you need to preserve your specimen against decay as long as you can. This is especially true once your specimen is encased in hard plastic resin.

Basically, you should not use liquid alcohol on small insects or other small specimens that you intend on immediately embedding as small insects can dry well. Hard shelled specimens usually embed well with little or no use of alcohol. This would include a small crab, scorpion, or horned beetle. Give it the trial and error method if you have any doubts.

This is not rubbing alcohol (isopropryl alcohol). Rather, it is called denatured ethanol. Because of it's dehydration and other properties it is considered poisonous to one's body.

If you place your specimen in alcohol then it will start to dehydrate the cells of your specimen. In other words tissue water is replaced by the alcohol. This is good for long term preservation.

Soaking in alcohol is optional for small specimens but is recommended for large specimens. A large specimen is any that is over 1/2 inch in thickness. It should be soaked for a couple of days. Make sure that your specimen is completely submerged under the level of the alcohol. For instance, the lizard that I caught in the back yard was considered a large specimen.

Here is another tip: if your specimen is 1/2 inch or more in thickness then take a hyperdermic needle and syringe and inject alcohol into it's abdomen, shoulders and hips. You have to do this because sometimes the alcohol does not soak that far down into the deeper tissue without your help. When finished, take your specimen out of the alcohol and then let it drain real good overnight in the open on a paper towel.

Kraig J. Rice. 2005. Plastic Embedding As A Hobby.