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Historic Preservation - Technical Procedures

Spectitle:

Removing Old Lacquer Or Paint From Solid Brass Or Brass-Plate

Procedure code:

0501031R

Source:

Hspg Prepared For Nps - Sero

Division:

Metals

Section:

Metal Materials

Last Modified:

02/24/2012

Details:

Removing Old Lacquer Or Paint From Solid Brass Or Brass-Plate



REMOVING OLD LACQUER OR PAINT FROM SOLID BRASS OR BRASS-PLATE


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 removing deteriorated
         lacquer or paint from brass-plate or solid brass.

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

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

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

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

         4.   For applying a protective coating to brass-plate or
              solid brass, see 05010-12-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.   Diedrich Technologies, Inc.
         7373 South 6th Street
         Oak Creek (Milwaukee), WI  53154
         800/323-3565 or 414/764-0058

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.   Household items such as ammonia, vinegar, baking soda and
         table salt:

         1.   Household ammonia:

              CAUTION:  DO NOT MIX AMMONIA WITH CHLORINE
              BLEACHES, A POISONOUS GAS WILL RESULT!  DO NOT USE
              BLEACH ON BIRD DROPPINGS.

              a.   Other chemical or common names include
                   Ammonium Hydroxide; Ammonia water*; Aqua
                   ammonia*.

              b.   Potential hazards:  TOXIC; MAY IRRITATE THE
                   EYES.

              c.   Available from chemical supply house, grocery
                   store or pharmaceutical supply distributor, or
                   hardware store.

         2.   Vinegar:

              a.   Potential Hazards:  CORROSIVE TO CONCRETE,
                   STEEL, WOOD OR GLASS.

              b.   Available from grocery store or supermarket.

              c.   Vinegar itself, which contains about 4% acetic
                   acid, may be suitable for some purposes
                   requiring acetic acid.

         3.   Baking soda:

              a.   Other chemical or common names include Sodium
                   bicarbonate; baking powder*.

              b.   Available from grocery store or supermarket,
                   or drugstore or pharmaceutical supply
                   distributor.

         -OR-

         Mild cleaner such as "Mr. Clean"

         -OR-

         Commercial paint and lacquer remover, such as "Diedrich
         400 - Enviro-Safe Strip" (Diedrich Technologies, Inc.),
         or approved equal.

         -OR-

         Lacquer thinner

         -OR-

         Acetone (C3H6O):

         1.   A volatile fragrant flammable liquid ketone used
              chiefly as a solvent and in organic synthesis and
              found abnormally in urine.

         2.   Other chemical or common names include Dimethyl
              ketone; Propanone

         3.   Potential Hazards:  VOLATILE AND FLAMMABLE SOLVENT

         4.   Available from chemical supply house such as Fisher
              Scientific Co. or hardware store.

    B.   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.

    C.   Mild soap

    D.   Clean, potable water

    E.   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.   Remove coating using a chemical stripper, such as lacquer
         thinner, paint stripper or acetone.

         1.   Apply stripper to the brass surface with a stiff
              bristle brush or roller.  Stroke the brush or
              roller along the grain of the metal.  

              NOTE:  DO NOT USE STEEL WOOL TO APPLY LACQUER
              REMOVER.  STEEL WOOL IS OFTEN TREATED WITH
              CORROSION INHIBITORS WHICH CAN STAIN COPPER BASE
              ALLOYS.

              CAUTION:  ALWAYS WEAR GLOVES AND WORK IN A WELL
              VENTILATED AREA WHEN USING CHEMICAL STRIPPERS.
                   
         2.   Allow the stripper to dwell for a length of time as
              recommended by the manufacturer.

         3.   Carefully remove loosened coating and stripper from
              the surface using a trowel, broad-knife or scraper.

         4.   Remove the residue left by the stripper with
              mineral spirits and/or mild soap and water.

         -OR-

         Completely submerge brass item in one of the following
         mixtures:

         1.   One part ammonia and two parts hot water, or

         2.   Four tablespoons baking soda and one quart water
              (bring this mixture to a boil), or

         3.   Solution of Mr. Clean.

         -OR-

         Place the brass to be cleaned in a stainless steel or
         enameled pot.

         1.   Cover the brass with white vinegar, then pour on a
              coating of regular table salt (sprinkle so that all
              areas are touched).

         2.   Simmer on low heat for 10 to 15 minutes.

         3.   Remove brass item with tongs; Buff with a clean,
              soft cloth; Rinse well, dry, and rebuff to a satiny
              luster.

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