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Historic Preservation - Technical Procedures

Spectitle:
Applying A Protective Coating To Brass-Plate And Solid Brass

Procedure code:
0501012P

Source:
Hspg Prepared For Nps - Sero

Division:
Metals

Section:
Metal Materials

Last Modified:
02/24/2012

Details:
Applying A Protective Coating To Brass-Plate And Solid Brass



APPLYING A PROTECTIVE COATING TO BRASS-PLATE AND SOLID BRASS


ALL CLEANING REMOVES SOME SURFACE METAL AND PATINA.  THEREFORE, USE
CAUTION, AS EXCESSIVE CLEANING CAN REMOVE THE TEXTURE AND FINISH OF
THE METAL.

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 protecting brass-
         plate and solid brass by applying a clear protective
         coating such as tung oil, lacquer, or a commercial wax.
         This procedure should follow thorough cleaning of the
         brass.

    B.   For additional guidance relating to cleaning and
         maintaining brass, see the following procedures:

         1.   For cleaning and polishing brass-plate, see 05010-03-P.

         2.   For cleaning and polishing solid brass, see 05010-10-P.

         3.   For removing old lacquer or paint from solid brass
              or brass-plate, see 05010-31-R.

         4.   For removing patina or tarnish from solid brass,
              see 05010-32-P.

    C.   Brass is an alloy of copper and zinc.  Brass-plate is a
         thin layer of brass bonded to steel.  Solid brass is more
         durable than brass-plate and, therefore, can withstand
         more rigorous methods of cleaning.  

    D.   Brass may be unfinished or lacquered.  Architectural
         brass hardware and trim is generally maintained in a
         highly polished, "bright" finish.  

         1.   Unfinished brass MUST be polished frequently in
              order to maintain its luster.  All polishing,
              however, removes some brass.

         2.   Lacquered brass will usually last about 10 years
              and does NOT require frequent polishing.

         3.   Lacquer protects the brass finish from
              deterioration, though some brilliance of its
              surface characteristics is sacrificed.  Removal and
              reapplication of the lacquer, however, will not
              harm the brass surface.

    E.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precautions

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   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).


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   Stanley Chemical Co.
         401 Berlin Street
         East Berlin, CT  06023
         203/828-0571

2.02 MATERIALS

    A.   Commercial wax or resin such as "Brasswax", or approved
         equal.

         -OR-

         Tung oil

         -OR-

         "Slipit" silicone coating, or approved equal:  

         1.   A lubricant containing silicone sold in hardware
              stores for easing sticky windows, drawers, etc.  

         2.   It is long-lasting, brass will darken only slightly
              over many years.

         -OR-

         Air-drying clear acrylic lacquer such as  "Incralac"
         (Stan Chemical Co), or approved equal.

    B.   Clean, potable water

    C.   Clean, soft cloths

2.03 EQUIPMENT

    A.   Eye and skin protection

    B.   Heavy gloves and protective gear

    C.   Soft natural bristle brushes


PART 3---EXECUTION

3.01 EXAMINATION

    A.   Before proceeding with steps to clean brass, examine the
         surface(s) to determine the extent of the work required.
         Look for:

         1.   Broken, cracked, missing, distorted or loose parts.

         2.   Coating failures such as chips, losses, peeling,
              cracks, bubbling and wear.

         3.   Corrosion - caused by moisture, sea water and sea
              air, deicing salts, acids, soils, gypsum plasters,
              magnesium oxychloride cements, ashes, clinkers and
              sulphur components.

3.02 PREPARATION

    A.   Protection:  

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

         2.   Protect adjacent surfaces from contact with
              chemical cleaners 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.   Protect persons and surrounding surfaces of
              building where metal surfaces are being restored,
              from damage resulting from metal cleaning and
              refinishing work.

              a.   Prevent cleaning solutions and coatings from
                   coming into contact with persons and other
                   surfaces which could be damaged by such
                   contact.

              b.   Erect temporary protection covers over
                   walkways for persons who must be in area of
                   operations during course of metal cleaning and
                   refinishing work.

              c.   Provide ventilation to eliminate the spread of
                   fumes to unaffected spaces.

    B.   Surface Preparation:  

         1.   Before cleaning, determine if your brass surface is
              solid or plated:  

              a.   A magnet will stick to the steel beneath brass
                   plating; it will not stick to solid brass.  

              b.   Solid brass can withstand much harsher
                   treatment than brass plating can.  

3.03 ERECTION, INSTALLATION, APPLICATION

    NOTE:  WHEN CLEANING, TRY TO RETAIN THE BRASS PATINA, AS THIS
    PROTECTS THE BRASS FROM FURTHER CORROSION.  

    A.   Protecting Brass with Tung Oil:

         1.   If possible to remove piece, preheat oven to 150
              degrees F and heat piece for 20 minutes.

         2.   Using a soft cloth apply tung oil, rubbing back and
              forth and in a figure 8 pattern until only a thin
              but even coat remains.  

         3.   Dry for at least 4 hours before reinstalling.

    B.   Protecting Brass with Lacquer:  Brass may either be
         dipped or sprayed.  DO NOT BRUSH ON COATING.

         1.   Apply coating within 4 hours of cleaning.

         2.   Apply coatings evenly to cleaned and polished brass
              according to the coating manufacturer's written
              instructions.

         3.   For brass to be dipped:  Dilute lacquer to a 50/50
              solution with an appropriate lacquer thinner; dip
              or spray brass with dilute lacquer; hang it up to
              dry.

         4.   For brass to be sprayed:  Use an automotive spray
              lacquer and apply in 2 to 3 thin coats, from a
              distance of about 8".

         5.   See also 05010-11-R for additional guidance on
              applying a lacquer coating.

    C.   Protecting Brass with Commercial Wax:  If pieces cannot
         be removed, try using a commercial wax, such as
         "Brasswax", or approved equal.  Follow manufacturer's
         instructions.

3.04 ADJUSTING/CLEANING

    A.   During the work, remove from the site discarded cleaning
         and coating materials, rubbish, cans and rags at end of
         each work day.

    B.   Upon completion of coating work, remove all protective
         coverings and coatings, and clean window glass and other
         coating-spattered surfaces.  Remove spattered coatings by
         proper methods as recommended by coating manufacturer,
         using care not to damage adjacent surfaces.

                         END OF SECTION