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