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 because 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.
- This specification provides guidance on cleaning and polishing brass-plate. This includes both lacquered and unfinished brass.
- "Cleaning and Polishing Solid Brass"
- "Removing Old Lacquer or Paint from Solid Brass or Brass-Plate"
- "Removing Patina or Tarnish from Solid Brass"
- "Applying a Protective Coating to Brass-Plate and Solid Brass"
- Brass is an alloy of copper and zinc, plus sometimes metals such as lead.
- Brass-plate is a thin layer of brass bonded to steel. Solid brass is more durable than brass-plate and, therefore, can withstand more rigorous methods of cleaning.
Brass may be unfinished or lacquered. Architectural brass hardware and trim is generally maintained in a highly polished, "bright" finish.
- Unfinished brass MUST be polished frequently in order to maintain its luster. All polishing, however, removes some brass.
- Lacquered brass will usually last about 10 years and does NOT require frequent polishing.
- Lacquer protects the brass finish from deterioration, though some brilliance of its surface characteristics is sacrificed. Removal and reapplication of the lacquer, however, will not harm the brass surface.
Read "General Project Guidelines" along with this specification. These guidelines should be reviewed prior to performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO). These guidelines cover the following sections:
- Safety Precautions
- Historic Structures Precautions
- Quality Assurance
- Delivery, Storage and Handling
- Project/Site Conditions
- Sequencing and Scheduling
- General Protection (Surface and Surrounding)
- Flitz International, Ltd.
- Happich Simichrome
- Enviro Cool (U.S. distributor of Wenol, which is manufactured in Germany)
NOTE: Chemical products are sometimes sold under a common name. This usually means that the substance is not as pure as the same chemical sold under its chemical name. The grade of purity of common name substances, however, is usually adequate for stain removal work, and these products should be purchased when available, as they tend to be less expensive. Common names are indicated below by an asterisk (*).
- Mild detergent
- CAUTION: DO NOT MIX AMMONIA WITH CHLORINE BLEACHES, A POISONOUS GAS WILL RESULT! DO NOT USE BLEACH ON BIRD DROPPINGS.
- Other chemical or common names include Ammonium Hydroxide; Ammonia water*; Aqua ammonia*.
- Potential hazards: TOXIC; MAY IRRITATE THE EYES.
- Available from chemical supply house, grocery store or pharmaceutical supply distributor, or hardware store.
- Mild Commercial Brass Cleaner
- Such as "Simichrome Polish", "Wenol Metal-Polish", "Flitz Polish" or approved equal.
- Most brass cleaners will both clean and polish.
- NOTE: "Simichrome", "Wenol", and "Flitz" are German manufactured cleaners that come in tubes. They are generally more expensive and harder to find than liquid cleaners. They have a finer feel than the liquids, and are best used as an intermediary or finishing polish.
- Clean, soft wiping cloths.
- Eye and skin protection.
- Heavy gloves and protective gear.
- Soft, natural bristle brushes.
Before proceeding with steps to clean brass, examine the surface(s) to determine the extent of the work required. Look for:
- Broken, cracked, missing, distorted or loose parts.
- Coating failures such as chips, losses, peeling, cracks, bubbling and wear.
- Corrosion - caused by moisture, sea water and sea air, deicing salts, acids, soils, gypsum plasters, magnesium oxychloride cements, ashes, clinkers and sulfur components.
- General: Comply with recommendations of manufacturers of cleaners, polishes and coatings for protecting building surfaces against damage from exposure to their products.
- Protect adjacent surfaces from contact with chemical cleaners by covering them with liquid strippable masking agent or polyethylene film and waterproof masking tape. Apply masking agent to comply with manufacturer's recommendations. Do not apply liquid masking agent to porous surfaces.
Protect persons and surrounding surfaces of building where metal surfaces are being restored, from damage resulting from metal cleaning and refinishing work.
- Prevent cleaning solutions and coatings from coming into contact with persons and other surfaces which could be damaged by such contact.
- Erect temporary protection covers over walkways for persons who must be in area of operations during course of metal cleaning and refinishing work.
- Provide ventilation to eliminate the spread of fumes to unaffected spaces.
- Surface Preparation:
Before cleaning, determine if your brass surface is solid or plated:
- A magnet will stick to the steel beneath brass plating; it will not stick to solid brass.
- Solid brass can withstand much harsher treatment than brass plating can.
3.03 ERECTION, INSTALLATION, APPLICATION
NOTE: WHEN CLEANING, TRY TO RETAIN THE BRASS PATINA, AS THIS PROTECTS THE BRASS FROM FURTHER CORROSION. NOTE: BRASS-PLATE IS ALMOST ALWAYS PROTECTED WITH A CLEAR COATING.
CAUTION: DO NOT USE STEEL WOOL OR METAL SCRAPERS ON BRASS- PLATE.
For unlacquered brass-plate:
- Clean with mild detergent or ammonia and a soft cloth. DO NOT USE ABRASIVES.
- Wear plastic gloves to prevent getting fingerprints on the surface.
- Rinse thoroughly and dry with a clean, soft cloth. DO NOT BUFF BRASS-PLATE; THE PLATING WILL COME OFF.
For lacquered brass-plate:
- Clean using ONLY a mild detergent and water.
- CAUTION: DO NOT USE AMMONIA-BASED CLEANERS ON LACQUERED BRASS. THEY WILL DETERIORATE THE COATING.
- Rinse thoroughly and dry with a clean, soft cloth.
For brass-plate that is heavily tarnished:
- Use a mild commercial polish such as "Simichrome", "Wenol", "Flitz" or approved equal.
- NOTE: TEST POLISH FIRST IN A SMALL, INCONSPICUOUS AREA.
- Wipe down cleaned and polished piece with lacquer thinner to remove all traces of cleaning solutions and polish.
- During the work, remove from the site discarded cleaning and coating materials, rubbish, cans and rags at end of each work day.
- Upon completion of coating work, remove all protective coverings and coatings, and clean window glass and other coating-spattered surfaces. Remove spattered coatings by proper methods as recommended by coating manufacturer, using care not to damage adjacent surfaces.