Bronze is a lusterless metal alloy composed primarily of copper and tin that is generally more corrosion-resistant than brass (a more reflective alloy of copper and zinc). As the Mesopotamians discovered around 5,000 years ago, it is also a very versatile metal for casting objects of art. Although bronze sculptures are among the most durable forms of art, there are still a few recommended guidelines and tips to observe to keep the works pristine and damage-free. With proper care and handling, they can survive the sands of time.
Foremost, sculptures and other artifacts made from bronze (as well as from other semi-precious metals) should not be handled with bare hands because salts and oils excreted from skin can etch into uncoated metals and may even cause permanent damage. (Fingerprints are often discernible as darkened disfiguring marks on the uncoated metal.) Soft cotton gloves should be worn whenever the work is touched or moved.
Bronze pieces need to be kept as clean as possible. Accumulations of dust and dirt can gradually eat into the metal surface. A gentle dusting using a soft cloth should be performed regularly; however, it is advised not to rub too vigorously especially on any protruding parts. If a bronze piece has been neglected for a long time and is covered with grime, it can be thoroughly cleaned with a soft brush. If de-greasing or heavier cleaning is required, test a small area first, using a mild soap and distilled water, rinse thoroughly and allow it to dry. Never use abrasive polishes or chemicals, which could scratch the metal surface. Remember, bronze is intended to have a dull finish and usually doesn't look as attractive if buffed to a high sheen.
As with all other collectibles, bronze sculptures are best displayed in a location free from environmental fluctuations—in ventilated areas away from excessive heat and humidity.
What makes bronze sculptures particularly endearing is the green patina that forms on the surface due to the natural reaction of atmospheric conditions. (Sculptors often accelerate the formation of patina artificially through chemical processes and then coat the surface of the sculpture with wax or a lacquer to protect it from the negative effects of oxidation). This is most delicate part of a bronze sculpture and can be protected by occasionally being re-waxed. Rather than using waxes or polishes that may contain cleaning agents though, many foundries recommend Johnson’s Traffic Wax, Mohawk Blue Label Paste Wax or Renaissance Wax, which is inert and will not yellow over time. A very thin, even coat of wax should be applied with a soft brush and buffed with a rag or soft bristle brush. Highly humid areas may call for more frequent applications. Allow the wax to sit and dry for six to twelve hours before polishing; a second coat of wax will add additional gloss if desired. Never use spray or liquid furniture polishes to dust or clean a bronze sculpture—these polishes may contain oils, which could damage the original patina finish. Some prefer to let the wax coating wear thin and enjoy the natural reaction and aging process of the patina.
“Bronze disease”, a chemical reaction resulting when chlorides and oxygen combine in a damp environment, is one of the most serious hazards of bronze. It takes the form of a sudden outbreak of small patches of corrosion and is distinguished by rough, light green spots. Applying a thin layer of coconut oil over the entire surface can usually alleviate this rapidly spreading form of corrosion.
If, in the cleaning process, special coatings or unusual varied patinas are discovered, take care to not alter the surface or remove coloring that could damage the future value of the bronze sculpture. Very heavily corroded bronze objects, like those unearthed or found in water, artifacts with painted surfaces, or those damaged by salts or other chemicals may require the assistance of a trained conservator. Trying to remove thick corrosion with steel wool or other scrapers may result in scratching the metal surface. With proper maintenance and care, a work of art in bronze can endure for centuries.
The recommendations contained here are intended as guidance only. TamarindArt does not assume responsibility or liability
