The Plastination Process
There are five steps in the standard process of Plastination:
- Fixation (embalming)
- Dehydration (fluid removal)
- Forced Impregnation in a vacuum
Water and lipid tissues are replaced by curable polymers. Curable polymers used by Plastination include silicone, epoxy and polyester-copolymer.
The first step of plastination is fixation (embalming). Fixation, frequently utilizing a formaldehyde based solution, serves two functions. Dissecting the specimen to show specific anatomical elements can be time consuming. Formaldehyde or other preserving solutions help prevent decomposition of the tissues. They may also infer a degree of rigidity. This can be beneficial in maintaining the shape or arrangement of a specimen. A stomach might be inflated or a leg bent at the knee for example.
After any necessary dissections take place, the specimen is then placed in a bath of acetone. Under freezing conditions, the acetone draws out all the water and replaces it inside the cells.
In the third step, the specimen is then placed in a bath of liquid polymer, such as silicone rubber, polyester or epoxy resin. By creating a vacuum, the acetone is made to boil at a low temperature. As the acetone vaporizes and leaves the cells, it draws the liquid polymer in behind it, leaving a cell filled with liquid plastic.
In the next step the specimen is positioned into the final posture. With needles and clamps muscles are put back into the desired position.
In the final step the plastic then is being cured with gas, heat, or ultraviolet light, in order to harden it.