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Historic Preservation - Technical Procedures

Spectitle:

Repairing A Scratched Or Worn Incralac Coating On Bronze

Procedure code:

0501011R

Source:

Outdoor Sculpture Manual - Center For Public Buildings

Division:

Metals

Section:

Metal Materials

Last Modified:

02/24/2012

Details:

Repairing A Scratched Or Worn Incralac Coating On Bronze



REPAIRING A SCRATCHED OR WORN INCRALAC COATING ON BRONZE


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on selectively repairing
         damaged or worn areas of the protective acrylic resin
         coating (Incralac) on bronze.

    B.   Incralac is designed to be applied by spray.  Brush
         applied coatings are not recommended, as they tend to be
         thicker and contain flaws created by the movement of the
         brush hairs through the resin during application.  Both
         factors reduce the durability of the coating.  When a
         brush-applied coating begins to deteriorate, it will
         deteriorate first along the brush-hair excursions and
         thereby produce numerous crevices in the coating where
         corrosion can occur, visible as a fine network of green
         hairline striations.

    C.   Perform repair work as needed when the Incralac coating
         is damaged or missing.

    D.   For general information on the characteristics, uses and
         problems associated with bronze, see 05010-03-S.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   Stanley Chemical Co.
         401 Berlin Street
         East Berlin, CT  06023
         203/828-0571
   
    B.   Conservation Materials
         P.O. Box 2884
         Sparks, NV  89431
         702/331-0582

    C.   Maas & Waldstein Co.
         Division of Seagroves Coatings Corp.
         P.O. Box 187
         320 Paterson Plank Road
         Carlstadt, NY  07072
         800/426-0496

    D.   Custom Aerosal Packaging
         128 East Water Street
         Piqua, OH  45356
         800/237-6765

    E.   Fisher Scientific Company
         711 Forbes Avenue
         Pittsburgh, PA  15219
         800/388-8355 or 412/562-8300

    F.   Procter & Gamble Co.
         P.O. Box 599
         Cincinnati, OH  45202
         513/983-1100

2.02 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.   Acrylic lacquer such as "Incralac" (Stanley Chemical
         Co.), (Conservation Materials), (Maas & Waldstein Co.),
         (Custom Aerosal Packaging), or approved equal.  Available
         in spray cans or 5-gallon drums.

    B.   Polyethylene dispersion, added to final Incralac coating
         to produce desired degree of matt/glossy appearance,
         (71X-202 polyethylene dispersion) (Stanley Chemical Co.),
         or approve equal.

    C.   Mineral Spirits:

         1.   A petroleum distillate that is used especially as a
              paint or varnish thinner.

         2.   Other chemical or common names include Benzine*
              (not Benzene); Naphtha*; Petroleum spirits*;
              Solvent naphtha*.

         3.   Potential Hazards:  TOXIC AND FLAMMABLE.

         4.   Safety Precautions:

              a.   AVOID REPEATED OR PROLONGED SKIN CONTACT.

              b.   ALWAYS wear rubber gloves when handling
                   mineral spirits.

              c.   If any chemical is splashed onto the skin,
                   wash immediately with soap and water.

         5.   Available from construction specialties
              distributor, hardware store, paint store, or
              printer's supply distributor.

    D.   Mild detergent such as "Ivory", "Joy" or "Thrill"
         (Procter & Gamble Co.), or approved equal.  Available in
         supermarket or drugstore.

    E.   Clean, potable water

    F.   Sponges and soft towels or rags

2.03 EQUIPMENT

    A.   For large areas of coating deterioration, bulk
         application with power spray equipment is more effective.
         The following equipment is recommended:

         1.   Spray gun, Binks or DeVilbiss with accessories; for
              example, DeVilbiss bleeder, external mix gun with
              cup, or approved equal.

         2.   Air compressor, small, portable, either gas (for
              exterior use) or electric (if electricity is
              accessible), or electric compressor powered by a
              portable generator.

         3.   Accessories:  air hoses adequate for reaching all
              parts of the metal, couplers, repair kit for spray
              gun, small moisture traps.

    B.   Organic vapor masks, basic safety equipment to protect
         operator from breathing vapors or organic solvents during
         spray application.

    C.   Goggles, to protect operator's eyes from organic solvent
         and Incralac.

    D.   Gloves, neoprene rubber or polyethylene disposable
         gloves.  Skin contact with solvent or Incralac should be
         avoided.


PART 3---EXECUTION

3.01 ERECTION, INSTALLATION, APPLICATION

    A.   If bronze has a protective wax coating over the Incralac,
         use mineral spirits or other appropriate solvent to
         remove wax from affected area.

    B.   Wash area to be recoated to remove all surface dirt,
         grease and foreign matter including flaking Incralac
         coating.  

         1.   Wipe the surface with a clean cloth saturated in
              clean, clear water and mild detergent.  DO NOT
              FLOOD ENTIRE SURFACE, SIMPLY WIPE AFFECTED AREA.

         2.   Thoroughly rinse the surface with clean, clear
              water and allow to dry.

    C.   Apply clear protective coating within 4 hours of cleaning
         operations.  For small areas use Incralac in a spray can.
         Large areas will require the use of power spray
         application equipment.

         NOTE:  BRUSH-APPLIED COATINGS DO NOT PROVIDE UNIFORM
         COVERAGE.

         1.   Apply first coat in a thin mist.  Allow to dry.

         2.   Apply two additional wet coats, allowing minimum
              thirty minutes drying time between each coat.

         3.   Minimum thickness of Incralac coating shall be 1
              mil.

    D.   If Incralac coating has a protective wax finish, apply
         wax as directed in procedure 05010-06-P, "Applying Cold
         Microcrystalline Wax to Bronze".

                         END OF SECTION