U.S. General Services Administration
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.
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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.
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.
PART 1–GENERAL
1.01 SUMMARY
A. This procedure includes guidance on removing ink or paint based graffiti from “Incralac” coated bronze using a solvent. If this protective coating is removed in the process, it may be reapplied (see 05010-= 11-R “Repairing a Scratched or Worn Incralac Coating on Bronze”).
B. Safety Precautions:
- DO NOT save unused portions of stain-removal materials.
- DO NOT store any chemicals in unmarked containers.
- EXCELLENT VENTILATION MUST BE PROVIDED WHEREVER ANY SOLVENT IS USED. USE RESPIRATORS WITH SOLVENT FILTERS.
- No use of organic solvents indoors should be allowed without substantial air movement. Use only spark-proof fans near operations involving flammable liquids.
- Provide adequate clothing and protective gear where the chemicals are indicated to be dangerous.
- Have available antidote and accident treatment chemicals where noted.
C. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:
- Safety Precautions
- Historic Structures Precautions
- Submittals
- Quality Assurance
- Delivery, Storage and Handling
- Project/Site Conditions
- Sequencing and Scheduling
- General Protection (Surface and Surrounding)
- 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).
D. For general information on the characteristics, uses and problems associated with bronze, see 05010-03-S.
PART 2–PRODUCTS
2.01 MATERIALS
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. Acetone (C3H6O):
- A volatile fragrant flammable liquid ketone used chiefly as a solvent and in organic synthesis and found abnormally in urine.
- Other chemical or common names include Dimethyl ketone; Propanone
- Potential Hazards: VOLATILE AND FLAMMABLE SOLVENT
- Available from chemical supply house, hardware store, or from manufacturing company such as Fisher Scientific Co., or approved equal
IMPORTANT: NOTE FIRE AND SAFETY PRECAUTIONS IN HANDLING THIS SOLVENT.
B. Absorbent cotton
C. Incralac, spray can or solution for application with a spray gun
D. Rags, clean soft, lint free, unsized, (such as old T-shirts or toweling)
E. Paper towels, lint free, such as Kimwipes (Fisher Scientific)
F. Wax and pigment under “Waxing” (see 05010-05-P “Applying Paste Wax Over Incralac Coated Bronze)
2.02 EQUIPMENT
A. Tweezers
B. Spray bottles
C. Goggles or glasses
D. Stencil brushes, 1/2 inch diameter brush end, unpainted wood handle, white tampico fiber, metal ferrule. These are available at most art supply stores.
E. Polygloves, disposable polyethylene gloves or neoprene rubber gloves, both of which will not be dissolved by organic solvents.
PART 3–EXECUTION
3.01 PREPARATION
A. Protection: Provide adequate wash solutions (i.e. water, soap and towels) before starting the job.
3.02 ERECTION, INSTALLATION, APPLICATION
NOTE: DO NOT TRY MORE THAN ONE TREATMENT ON A GIVEN AREA UNLESS THE CHEMICALS USED FROM PRIOR TREATMENT HAVE BEEN WASHED AWAY.
A. Apply acetone with the small stencil brushes or cotton held with tweezers. Limit application of solvent only to substance to be removed. Contain all drips with the clean rags or paper towels to avoid the unnecessary spreading of the ink or paint.
CAUTION: AVOID INHALATION OF SOLVE= NT VAPOR. KEEP TOPS ON SOLVENT BOTTLES AS MUCH AS POSSIBLE. PROTECT HANDS WITH GLOVES, AND EYES WITH GOGGLES OR GLASSES.
B. Work in small areas at a time, completely removing the graffiti material in one area before moving on to the next.
C. When the graffiti has been removed, retouch the Incralac coating with one or two spray applications (see 05010-11-R).
D. When the coating is dry, wax, either pigmented or unpigmented, as required, may be applied to adjust surface color and degree or gloss (see 05010-05-P “Applying Paste Wax Over Incralac Coated Bronze).