To patina brass, clean the object, and oxidize the surface with a combination of salt, water and ammonia. For small objects, speed the process by applying heat from a hair dryer.Continue Reading
Soak solid brass in a lacquer thinner to get rid of any coating protecting the brass from aging. Do not use plated brass pieces, as this process also removes the brass finish. The next day, dry the brass with a clean rag.
Since you are working with chemicals, wear a respirator and gloves, and protect your clothes. For small items, mix 2 tablespoons of salt in 1 cup of water. In a 1-pound coffee can, add a 1/2 inch of ammonia. For larger objects, combine 3 cups of water, 1 1/4 cup of ammonia and 1/8 cup of salt in a sealed glass jar. Add cat litter to an airtight plastic container, and moisten it with the solution.
Attach a small brass object to a metal hook, and dip it in the salt water. Hook the brass object to a hole in the coffee can lid. Place the object inside of the coffee can, and secure the lid. With a hair dryer, heat the coffee can for 2 minutes. Remove the brass object, and repeat the process several times or until the desired patina is achieved. For large objects, bury the brass in the cat liter for several days.
Protect the patina by spraying the object with an acrylic sealer.