Put on a pair of latex gloves and mix 1 teaspoon of ferric chloride, 1/2 teaspoon of ferric nitrate and 1 pint of distilled water in a large glass bowl. Stir the mixture with a wire whisk until it is thoroughly incorporated. Always work in a well ventilated area to prevent the inhalation of fumes.
Use a paint brush to apply the mixture over the entire surface area of the bronze statue. Allow the mixture to dry overnight. A light brown rust color will form once the mixture is dry.
Rinse the bronze statue with cool water and dry it with newspaper. Use a sponge to remove all of the ferric chloride mixture from the statue.
Rub the entire statue with steel wool, and allow the statue to sit for 24 hours. Repeat the entire process to achieve a darker finish.
Use a paint brush to apply sculpture wax over the entire surface of the sculpture. Sculpture wax will help the patina to darken as the sculpture ages. It will also help to create the beautiful dark color of bronze on the surface. Apply wax in thin layers. This will prevent the under layers of wax from being removed during the application procees.