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.
Projects involving paint removal or use of hazardous chemicals are subject to employee safety and environmental laws governing lead paint abatement, hazardous materials disposal and use of volatile organic compounds (VOCs). Specified products may not be permitted or appropriate for all locations. Products containing chemicals known to present health or environmental hazards should be used only as a last resort, where permissible, in accordance with manufacturer's directions and government requirements. Test milder formulations for effectiveness before proceeding to stronger alternatives.
A. This procedure includes guidance on removing deteriorated lacquer from bronze doors and hardware and applying a new clear coating.
B. 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). The guidelines cover the following sections
1. Safety Precautions
2. Historic Structures Precautions
4. Quality Assurance
5. Delivery, Storage and Handling
6. Project/Site Conditions
7. Sequencing and Scheduling
8. General Protection (Surface and Surrounding)
A. The George Basch Company, Inc.
B. StanChem Inc.
C. Weiman Products, LLC
E. Axalta Coating Systems
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 (*).
A. Metal cleaner such as "Nevr-Dull" (The George Basch Company, Inc.) or approved equal.
B. Standard solvent, such as:
1. Mineral Spirits:
a. A petroleum distillate frequently used as a paint or varnish thinner.
b. Other chemical or common names include Benzine* (not Benzene); Naphtha*; Petroleum spirits*; Solvent naphtha*.
c. Potential Hazards: TOXIC AND FLAMMABLE.
d. Safety Precautions:
1) AVOID REPEATED OR PROLONGED SKIN CONTACT.
2) ALWAYS wear rubber gloves when handling mineral spirits.
3) If any chemical is splashed onto the skin, wash immediately with soap and water.
e. Available from construction specialties distributor, hardware store, paint store.
a. Typically used as a solvent and thinner.
b. Potential Hazards: TOXIC AND FLAMMABLE.
c. Safety Precautions:
1) Work in a well ventilated area.
2) Observe safety rules as turpentine is flammable, and the fumes can trip an ionization smoke detection system.
3) Store soiled cloths in a metal safety container to guard against spontaneous combustion.
d. Available from hardware store or paint store.
e. Turpentine is several times more expensive than Mineral Spirits.
3. Denatured Alcohol:
a. Other chemical or common names include methylated spirits and ethanol.
b. Potential hazards: TOXIC AND FLAMMABLE.
c. Available from hardware store, paint store or printer's supply distributor.
d. Denatured alcohol should be a satisfactory substitute for ethyl alcohol for stain removing purposes.
4. Alternative Solvents:
a. A pre-manufactured solvent that is a mixture of mixture of 75% toluene, 24% acetone, and 1% butyl acetate. (Casual users should NOT mix this in the field; this information is for professional and instructional reference only)
b. As an alternate, solvents can be utilized that are normally used for thinning nitro-cellulose lacquers, such as "DuPont Thinner Mid Temp 3661" (Axalta Coating Systems), which is intended for use in temperatures between 50 and 80 degrees F.
C. Inhibitor/Cleaner: 1% Benzotriazole solution in warm water (40 grams Benzotriazole per gallon of water).
D. Paint/Lacquer Remover: Methylene chloride-free paint removers such as "10101 Safest Stripper Paint and Varnish Remover" (3M), "Citristrip" (W.M. Barr) or approved equal
1. NOTE: methylene chloride-free products will require longer dwell times on surfaces than that required for products that contain methylene chloride as their main active ingredient.
2. If methylene chloride-free products are unable to remove paint or lacquer, "Jasco Premium Paint and Epoxy Remover" (Jasco/W. M. Barr) is suitable for use on metal. NOTE: Contains methylene chloride, a known carcinogen. Methylene chloride is banned in some states such as California. Regulatory information as well as alternative or equivalent chemicals may be requested from the Environmental Protection Agency (EPA) Regional Office and/or the State Office of Environmental Quality.
E. Mild soap with pH of approximately 8.0, such as Ivory soap.
F. Clear Coating: Acrylic lacquer containing acrylic ester resins dissolved in toluene with benzotriazole as corrosion inhibitor, such as "Incralac" (StanChem, Inc.) or approved equal.
1. Silicon carbide abrasive pads, such as "Scotch-Brite" (3M) or approved equal
2. Standard commercially available pumice stone
3. Stainless steel wool
4. DO NOT USE STEEL WOOL, AS IT MAY PROMOTE DISCOLORATION OF THE BRONZE.
H. Oxidizing Agent: Aluminum chloride or liquid sulfur.
I. Diatomaceous earth abrasive such as "Wright's Silver Cream" (Weimer Products, LLC) or approved equal.
J. Clean cotton cloth.
K. Clean, potable water.
A. For large areas of coating deterioration, bulk application with power spray equipment is more effective.
B. The following equipment is recommended:
1. Spray gun, such as a bleeder-type gun and/or a gun with an external mix cap.
2. Small, portable air compressor rated for this type of use.
a. air hoses adequate for reaching all parts of the metal.
c. repair kit for spray gun.
d. small moisture traps.
4. Organic vapor masks to protect operator from breathing vapors or organic solvents during spray application.
5. Goggles, to protect operator's eyes from chemicals.
6. Gloves, neoprene rubber or polyethylene disposable gloves.
3.01 ERECTION, INSTALLATION, APPLICATION
A. Clean with mild soap and soft cloth, using fine abrasives, such as "Wright's Silver Cream" (a diatomaceous earth abrasive) and solvents, such as ordinary mineral spirits, only as necessary and lacquer light statuary bronze finishes on entrance door frames, transoms and sash, bronze grilles and light fixtures with acrylic lacquer.
B. Remove old lacquer, only if necessary, using lacquer remover applied with a cotton cloth wiped along the grain of the metal.
C. Allow the remover to stand on the lacquer for several minutes
D. Wipe away remover with a cotton cloth or by flushing with water. Several applications of the stripper may be necessary in order to remove all traces of the lacquer from the metal.
E. Follow the stripping operation with an application of metal cleaner on a soft cloth, rubbing along the grain of the metal.
F. Persistent stains or badly corroded areas may be cleaned using an abrasive and standard solvent, such as a pad of fine bronze wool and plain mineral spirits.
G. Remove all cleaning product residue from surface prior to the application of the clear protective coating by washing the metal surface at least twice with a standard solvent. This should be followed by a final wipe with the inhibitor/cleaner.
H. Clear coating is to be applied within 4 hours of cleaning. It is not to be applied in inclement weather or when the relative humidity exceeds 60%. The clear coating should be sprayed on using conventional spray equipment.
1. Apply first coat in a thin mist. Allow to dry a minimum of 30 minutes.
2. Apply four additional wet coats, allowing a minimum of 30 minutes of drying time between each coat.
3. Minimum thickness of coating shall be 1 millimeter.
I. Final drying time will be 48 hours before the doors can be touched or used.