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Historic Preservation - Technical Procedures

Spectitle:

Applying Hot Wax To Outdoor Bronze

Procedure code:

0501004P

Source:

Outdoor Sculpture Manual - Center For Public Buildings

Division:

Metals

Section:

Metal Materials

Last Modified:

08/20/2013

Details:

Applying Hot Wax To Outdoor Bronze



APPLYING HOT WAX TO OUTDOOR BRONZE


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on applying a hot wax
         sacrificial coating to outdoor bronze.  This barrier
         helps prevent harmful atmospheric pollutants from
         contacting and reacting with the surface.  The
         application of hot wax to a heated surface, followed by
         sacrificial coatings of cold paste wax should provide the
         maximum bonding and protection.

    B.   Apply as needed to restore maximum protection following
         the removal of older wax coatings.

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


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   www.Chemindustry.com (search engine for the chemical industry)


    B.  Museum Services Corporation (MSC)
         www.museumservicescorporation.com
         

    C.  Conservation Support Systems (CSS)
         www.conservationsupportsystems.com
         

2.02 MATERIALS

    OTE:  The wax product selected should be a synthetic 
    microcrystalline wax including natural carnauba wax forming a blend.

    A.   Outdoor Sculpture Wax (MSC), or approved equal

    B.   Sculpture Wax (CSS), or approved equal.

    C.   Cosmolloid 80 H (if needed per manufacturer's product guidance)

    D.   Benzotriazole (BTA) corrosion inhibitor (MSC or CSS),
          or approved equal (if needed per manufacturer's product guidance)

         NOTE: BTA has been identified as a chemical with health hazards; following manufacturer's Material Data Safety Sheet for guidance for safe            use.

    E.   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.

    F.   Rags, clean soft, lint free, unsized, (such as old T-shirts or toweling)

    G.   Paper towels, lint free, such as Kimwipes (Fisher
         Scientific Company), or approved equal.

2.02 EQUIPMENT

    A.   Portable, hand-held propane torches

    B.   Hogshair brushes


PART 3---EXECUTION

3.01 PREPARATION

    A.   Protection:

         1.   General:  Comply with recommendations of
              manufacturers of waxes and coatings for protecting
              building surfaces against damage from exposure to
              their products.

         2.   Protect adjacent surfaces from contact with run-off
              from hot oily waxes 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.

         3.   Rags should be used to intercept any oily wax run-
              off, so it does not come in contact with adjacent
              materials.

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   For the wax product chosen, follow the manufacturer's product guidance in its use.

    B.   Heat the wax until dissolved into a liquid.

    C.   Add BTA, if needed according to the manufacturer's guidance, to make 3% solution (97% wax to 3% BTA).

    D.   Add mineral spirits to wax solution as it cools to make
         a creamy, paste wax mixture.

    E.   Heat the surface of the bronze evenly with the portable
         propane torches.

    F.   Brush the wax onto the heated surface, thoroughly coating
         the surface.  Take necessary precautions to contain all
         drips with clean rags or paper towels to prevent the hot
         oily wax from coming in contact with adjacent materials.

    G.   Allow to cool and dry thoroughly.

    H.   Apply two coats of paste wax (see 05010-06-P "Applying
         Cold Microcrystalline Wax to Bronze Sculpture").

                         END OF SECTION
 


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