How to Care For Your Bronze Sculpture

Overall Info

- Its important to know that bronze is about 95% copper (depending on the alloy). Copper turns green because of an oxidation reaction; that is, it loses electrons when exposed to water and air. The resulting copper oxide is a dull green. You've probably seen a copper penny turn green when left in water over time, or a public statue fade with a green tint. One of the most famous examples is the Statue of Liberty. Originally it had a shiny orange-red copper color, but because of the moisture in the air, it quickly oxidized into its famous green color. The important thing to remember is that all bronze darkens as it ages, but by with proper care of the surface of your sculpture, you may be able to slow this oxidation process for a time.

-Depending on preference, some people really like the look of an aged bronze, while others prefer a fresh, new patina look. The surface of your bronze can be cared for using the following steps below, but unfortunately over time there is a natural oxidation process that must occur. 

-There is always the option to put on a new patina to any bronze sculpture. The surface is "sandblasted" using high- pressured sand and air to remove the patina finish, allowing for a new patina to be applied. If you would like a piece "re-patinaed", feel free to contact us!

Caring for an indoor bronze sculpture

Cleaning and waxing an indoor bronze sculpture at least once a year is recommended, possibly twice a year in humid or corrosive environments. Never use spray or liquid furniture polishes to dust or clean a bronze sculpture as many of these products contain oils that can soften initial wax coatings, thus darkening lighter patinas and/or removing the protective finish. 

Cleaning your bronze sculpture:

1. Using a soft, clean cotton cloth, gently wipe the surface free of any dust and fingerprints. We recommend cleaning deeper crevices with a 2-inch paint brush (the cheap "chip" brushes work great for this). Wrap the metal ferrules of the brush with some masking tape to avoid scratching the patina while dusting. 

2. Using a new 2-inch Chip Brush and a can of Johnson Paste Wax (you can buy this at Home Depot or Lowes), lay the bristles of the brush across the wax surface back and forth in a sweeping motion. One or two strokes should do it, you really don't want to overload the brush with wax (especially with Johnson Paste Wax), that will result in a longer drying period and possible wax buildup. There is a possibility that too much wax can harm or even destroy a patina. Therefore, carefully put a super-thin coat of wax on the surface of the bronze in a gentle sweeping motion. Gently work the brush down into the crevices as you apply the wax. Over-waxing a bronze patina can shift and remove pigments suspended in waxes originally placed on the surface as part of the patina.

3. You will be able to tell where you have waxed as the surface will be matte and not shiny. Continue waxing until the entire surface has been covered. Wait about 30 mins until the wax has completely dried.

4. Using a clean, dry cotton cloth, begin gently rubbing the surface of the bronze until the desired shine appears. Work the cloth in a circular motion on the large smooth ares of the surface. If you would like to keep the matte look, you can forgo this final buffing step. 

The following is a list of commercial household products that should never come in contact with the patinaed bronze surface:

  • Bleaches

  • Oven cleaners

  • Glass and porcelain cleaners

  • Any other strong or weak cleaning solvents

  • Steel wool and scouring pads

  • Vinegars

  • Plant fertilizers

  • Furniture polishes

Other liquids in the form of beverages found in the household which are damaging when they come in contact with patinaed bronze are:

  • Alcoholic beverages

  • Soft drinks

  • Citrus fruit juices

 

For more information or tips on caring for your bronze sculpture, we recommend the book "The Care of Bronze Sculpture: Recommended Maintenance Programs" by Patrick V. Kipper

 

Caring for an outdoor bronze sculpture

For any outdoor bronze sculpture, we highly recommend contacting the artist, gallery, or even foundry that cast the piece to determine the best maintenance program for your specific piece. The following are general cleaning instructions and should not be used without further consultation.

The best time to clean and wax bronze sculpture depends on whether it has a light, dark, or multi-colored patina. It is recommended to choose a clear warm day in spring and again in fall. For a dark or light patina, we recommend cleaning in the heat of the day, allowing time for the bronze to dry. Multi-patinas, or those patinaed surfaces that contain more than one patina or color, should always be waxed carefully in the cool of the late afternoon.

Since maintenance programs for outdoor sculpture deal with larger surfaces than those normally associated with indoor care, waxing a cool bronze surface may take more time as it is advisable to apply, let dry, and buff these large surfaces in small sections. 

Cleaning your bronze sculpture:

1. Rinse the surface of the bronze sculpture with clean running water. Pay particular attention to places in textured surfaces that collect and hold water.

2. Use a mixture of non-ionic or neutral detergent and water to clean the surface of the bronze. Most janitorial supply stores carry a line of neutral detergents. It is always best to follow directions for recommended concentration mixtures which are usually found on the detergent bottle's label. It is never recommended to place concentrated detergent directly on the surface of the bronze, but rather, to mix the appropriate amount of detergent and water in a non-metallic bucket first.

Begin washing the surface down using a soft non-metallic scrub brush, gently working in a circular pattern. Rinse the surface of the bronze regularly to ensure that no loosened particles have been washed into lower lying areas of the bronze. Start washing and rinsing the surface from the top or upper-most part of the sculpted surface and work downward.

3. Allow the surface of the bronze sculpture to dry in the sun. Towels may be used to help soak up water remaining in low lying areas of texture. It is most important that the surface of bronze be very dry prior to waxing.

4. The waxing stage is where we highly recommend that you consult with the artist or casting foundry before proceeding. Many outdoor sculptures may require a more specific up-keep program than just waxing. If waxing is recommended in a consultation, as a general rule, you can follow the same waxing instructions listed above for an indoor sculpture. 

5. After the wax has dried, use a clean, soft cotton cloth and wipe the surface in a circular pattern to compress and shine the dried wax. Be sure that recessed ares of textured surfaces are waxed and buffed as well. 

 

Again we highly recommend consulting with an artist, gallery, or casting foundry before cleaning an outdoor bronze sculpture. For more information or tips on caring for your bronze sculpture, we recommend the book "The Care of Bronze Sculpture: Recommended Maintenance Programs" by Patrick V. Kipper