Cleaning And Polishing Bronze
- CSI Division:
- Division 5 - Metals
- Metal Materials
- Last Modified:
Technical Procedures Disclaimer
Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.
We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.
ALL CLEANING REMOVES SOME SURFACE METAL AND PATINA. THEREFORE, USE CAUTION, AS EXCESSIVE CLEANING CAN REMOVE THE TEXTURE AND FINISH OF THE METAL.
THE CLEANING OR STRIPPING OF METALS MAY INVOLVE THE USE OF ABRASIVES, LIQUIDS OR SOLVENTS WHICH MAY SPLASH OR RUN OFF ONTO ADJACENT MATERIALS. TAKE SPECIAL CARE TO PROTECT ALL ADJACENT MATERIALS, AND DO NOT USE THIS PROCEDURE ON METALS OTHER THAN THOSE SPECIFIED IN THE SUMMARY.
A. This procedure includes guidance on the general cleaning of dirt and oil on bronze.
B. For general information on the characteristics, uses and problems associated with bronze, see 05010-03-S.
A. The Procter & Gamble Co.
P.O. Box 599
Cincinnati, OH 45202
B. Leo Silfen, Inc.,
Industrial Chemical Division
525 Fourth Avenue
Mt. Vernon, New York
NOTE: When the common name of a chemical is used on the label, it is usually a sign that the substance is not as pure as the same chemical sold under its chemical name. However, the grade of purity of the common-name substance is almost certain to be adequate for stain removal work, and because it is likely to be less expensive, the common-name product should be purchased when available. Common names are indicated by an asterisk (*).
A. Mineral spirits:
- Other chemical or common names include Benzine* (not Benzene); Naphtha*; Petroleum spirits*; Solvent naphtha*.
- Potential Hazards: TOXIC AND FLAMMABLE.
- Safety Precautions:
- AVOID REPEATED OR PROLONGED SKIN CONTACT.
- ALWAYS wear rubber gloves when handling mineral spirits.
- If any chemical is splashed onto the skin, wash immediately with soap and water.
- Available from construction specialties distributor, hardware store, paint store, or printer's supply distributor.
B. Neutral detergent such a "Orvis" (Procter & Gamble), or approved equal.
C. Marine Type Metal Polish Formula 90 (Leo Silfen, Inc., Industrial Chemical Division), or approved equal.
D. Clean, potable water
E. Lint-free wiping cloths
A. Soft natural bristle brushes (non-metallic)
B. Wooden scrapers
C. Fine bronze wool -or- Silicon carbide abrasive pads such as "Scotch-Brite" (3M Company), or standard commercially available pumice stone or stainless steel wool. DO NOT USE STEEL WOOL, AS IT MAY PROMOTE DISCOLORATION OF THE BRONZE.
D. Rubber gloves
3.01 ERECTION, INSTALLATION, APPLICATION
NOTE: WHEN CLEANING, TRY TO RETAIN THE BRASS PATINA, AS THIS PROTECTS THE BRASS FROM FURTHER CORROSION.
A. Remove loosely adhered soiling, such as bird droppings, with wood scrapers before washing.
B. Remove more tenacious deposits with fine bronze wool.
C. Mix warm water (ONLY) with neutral detergent, or use proprietary metal cleaner.
NOTE: AVOID CLEANING BRONZE WITH ALKALINE SOAPS THAT DO NOT CONTAIN SODIUM HYDROXIDE, DETERGENTS CONTAINING PYROPHOSPHATES SUCH AS "TIDE" OR AMMONIA SOLUTIONS (ESPECIALLY ON LACQUERED SURFACES). THESE WILL DETERIORATE THE COATING ON BRONZE.
D. Brush solution on bronze with soft natural bristle brush (no metallic bristles) or a lint-free cloth. Rub along the grain of the metal.
E. If dirt is greasy, dilute cleaning solution 1:1 with mineral spirits.
F. Rinse thoroughly and dry with another lint free cloth.
G. Wash bronze periodically (twice a year) with a non-ionic detergent such as "Orvis" (Procter & Gamble). Rinse with distilled water and wipe dry with a clean soft cloth, to prevent water spots and streaks.
H. For guidance on removing corrosion, removing lacquer and reapplying a protective coating, see 05010-31-R and 05010-12-P.