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Historic Preservation - Technical Procedures

Spectitle:

Chemically Removing Paint From Wood Features

Procedure code:

0640007R

Source:

Hspg Prepared For Nps - Sero

Division:

Wood And Plastics

Section:

Architectural Woodwork

Last Modified:

02/24/2012

Details:

Chemically Removing Paint From Wood Features



CHEMICALLY REMOVING PAINT FROM WOOD FEATURES


BEFORE UNDERTAKING ANY PROJECT INVOLVING PAINT REMOVAL, APPLICABLE
STATE AND FEDERAL LAWS ON LEAD PAINT ABATEMENT AND DISPOSAL MUST
BE
TAKEN INTO ACCOUNT AND CAREFULLY FOLLOWED.  STATE AND FEDERAL
REQUIREMENTS MAY AFFECT OPTIONS AVAILABLE TO OWNERS ON BOTH PAINT
REMOVAL AND REPAINTING.  THESE LAWS, AS WELL AS ANY REQUIREMENTS
PROHIBITING VOLATILE ORGANIC COMPOUNDS (VOCs), SHOULD BE REQUESTED
FROM THE STATE HISTORIC PRESERVATION OFFICER IN EACH STATE.  (From
Preservation Brief 28, "Painting Historic Interiors".)  REGULATORY
INFORMATION MAY ALSO BE REQUESTED FROM THE ENVIRONMENTAL
PROTECTION
AGENCY (EPA) REGIONAL OFFICE AND/OR THE STATE OFFICE OF
ENVIRONMENTAL QUALITY.


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on removing paint from
         interior and exterior wood features using chemical
         methods.

    B.   Chemical strippers should be used on extremely intricate
         details that might be scorched by too long of an exposure
         to the blast from a heat gun.  They are also useful as
         final cleanup after paint removal using one of the
         thermal methods.  Follow manufacturer's instructions.

    C.   Safety Precautions:

         1.   Workers shall wear appropriate clothing to protect
              themselves against the harmful effects of paint
              stripping activity.  Old paint layers will likely
              contain lead.  Avoid breathing paint dust during
              removal.

         2.   No food or drink shall be allowed near any work
              station so as to prevent contamination from paint
              chips, dust or chemical removers which contain lead
              and other toxic substances.

         3.   Protective clothing shall be removed at the end of
              each day and kept at the site to prevent workers
              from tracking dust and paint chips to other parts
              of the site or to their homes.

         4.   Wash hands and face often, especially before eating
              and at the end of the day.

    D.   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).

    E.   See also 06400-02-S for supplemental information on
         removing paint from wood features.

    F.   For additional information on the history and properties
         of paint along with general procedures for paint removal,
         see 09900-01-S, "Preservation Brief 28, Painting Historic
         Interiors", and 09910-01-S, "Preservation Brief 10,
         Exterior Paint Problems on Historic Woodwork".

1.02 REFERENCES

    A.   AWI Quality Standard:  Comply with applicable
         requirements of "Architectural Woodwork Quality
         Standards" published by the Architectural Woodwork
         Institute (AWI), except as otherwise indicated.

1.03 DEFINITIONS

    A.   Chemical Methods:  as used herein shall apply to the use
         of commercial chemical paint strippers.

         1.   "Do-it-yourself" chemicals available through local
              paint stores, hardware stores, building supply
              centers.

         2.   Professional, heavy-duty type used by paint removal
              contractors, generally only available through the
              manufacturer and/or qualified contractors.  May
              also be available by special order from local paint
              stores.

    B.   Chemical paint strippers are divided into solvent-based,
         caustic-based, and alternative-based strippers.

         1.   Solvent-based:  Most use methylene chloride to
              dissolve and swell varnish and/or paint film for
              removal.  Some are water-rinsable.

              a.   Liquid:  fast working; best used on horizontal
                   surfaces, or for clean-up when using thermal
                   methods.

              b.   Semi-paste:  good for vertical and overhead
                   surfaces, rounded features, intricate details.

              c.   Will soften oil-based paints, lacquers,
                   varnishes and synthetic baked finishes.  

              d.   Can be used on both hardwoods and softwoods
                   without changing the color of the wood so that
                   the feature can be refinished with a clear
                   finish if desired.

              e.   Non-water rinsable products are safe for use
                   on most water-based wood glues.

              f.   Before refinishing, surface must be completely
                   cleaned of stripper residue but neutralization
                   of the surface is not required.

              g.   Benzol is another solvent often used in the
                   past in formulating solvent-based paint and
                   varnish removers.  IT IS HIGHLY FLAMMABLE AND
                   HIGHLY TOXIC AND ITS USE IS NO LONGER
                   RECOMMENDED.

         2.   Caustic-based:  Use sodium hydroxide, and to a
              lesser extent potassium hydroxide, to decompose the
              binder in the coating.  Proprietary products are
              mostly for commercial rather than "do-it-yourself"
              use.  

              a.   Liquid:  used for dip-stripping of shutters,
                   doors, furniture, etc.

              b.   Semi-paste:  basis for most professional
                   proprietary products; good or horizontal,
                   vertical and overhead surfaces, also intricate
                   details.

              c.   Will work on most types of coatings from oil-
                    based and latex paints to sophisticated epoxy-
                    ester finishes.  Check with manufacturer for
                   appropriate usage.

              d.   Will darken hardwoods so should not be used on
                   features made from oak, walnut, mahogany, and
                   other hardwoods if a clear finish is to be
                   used.

              e.   Because they are water-rinsable, caustic
                   strippers will likely raise the grain on many
                   woods so extra finish steps, such as sanding,
                   may be required regardless of whether the
                   surface is to be painted or given a clear
                   finish.

              f.   Caustic strippers will dissolve many types of
                   wood glues--a problem when stripping shutters,
                   wood veneers, plywood, etc.

              g.   Surface must be neutralized with mild acid
                   wash before refinishing.

         3.   Alternative-based:  Water-based products which use
              nonflammable, biodegradable active ingredients to
              soften the paint.  Most are water-rinsable, or
              removed with common household cleaners.  Active
              ingredients include dibasic acid esters.  Semi-paste form.

              a.   Separate formulas for clear finish removal
                   versus paint removal.

              b.   Require considerably more time to soften the
                   old finish than either methylene-chloride-
                   based or caustic-based strippers.

              c.   Can be used on both hardwoods and softwoods
                   without discoloring the wood.

1.04 DELIVERY, STORAGE AND HANDLING

    A.   Storage and Protection:  All chemicals shall be stored in
         metal cabinets.  No cans shall be left open or out of the
         cabinet overnight.

PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   For Chemical Paint Removers:

         1.   AFM Enterprises, Inc.
              1140 Stacy Ct.
              Riverside, California  92507
              714/781-6860

         2.   Bix Manufacturing Co.
              P.O. Box 69
              Ashland City, TN  37015
              615/792-3260

         3.   Diedrich Technologies, Inc.
              7373 South 6th Street
              Oak Creek (Milwaukee), WI  53154
              800/323-3565 or 414/764-0058

              Availability:  Through contractors licensed by
              manufacturer, and authorized paint supply centers.

         4.   Dumond Chemicals, Inc.
              501 Broadway
              New York, NY  10036
              212/840-2666

              Availability:  Through contractors licensed by
              manufacturer, and authorized paint supply centers.

         5.   Klean-Strip
              P.O. Box 13146
              Memphis, TN  38113
              901/775-0100

         6.   Master Products, Inc.
              P.O. Box 274
              Orange City, IA
              800/747-3436 or 712/737-3436

              Distributors:  Martin Paint or Herb Saltzman,
              Flushing, NY.

         7.   3M D-I-Y Division Wood Refinishing Products
              P.O. Box 33053
              St. Paul, MN  55133-3053
              800/364-3577 or 612/737-6501

         8.   ProSoCo, Inc.
              755 Minnesota Avenue
              P.O. Box 1578
              Kansas City,  KS  66117
              800/255-4255 or 913/281-2700

              Availability:  Through contractors licensed by
              manufacturer.

         9.   Red Devil, Inc.
              2400 Vauxhall Road
              Union, NJ  07083
              800/423-3845 or 201/688-6900

         10.  Reliable Remover & Lacquer Corporation
              62 Woolsey Street
              Irvington, NJ  07111
              201/399-2121

              Distributor:  Pacoa, 133-36 36 Road, Flushing, NY.

         11.  Savogran Company
              P.O. Box 130
              Norwood, MA  02062
              800/225-9872 or 617/762-5400

         12.  Specialty Environmental Technologies, Inc.
              4520 Glenmeade Lane
              Auburn Hills, MI  48326
              810/340-0400

         13.  Star Bronze Co.
              P.O. Box 2206
              Alliance, OH  44601
              216/823-1550

    B.   For Fumed Silica:

         1.   Miller-Stephenson
              P.O. Box 950
              Danbury, CT  06813
              203/743-4447
              (distributors of epoxy materials)

         2.   Samuel Cabot, Inc.
              100 Hale Street
              Newburyport, MA  01950
              508/465-1900
              "Cab-o-sil"

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.   Solvent-based chemical paint remover such as any of the
         following, or approved equal:

         1.   Strypeeze Semi-paste (Savogran Company)

         2.   Super Strip Non-flammable and Zip Strip (Star
              Bronze Co.)

         3.   All Purpose Kwik Paint and Varnish Remover, Non-
              Flammable Sprayable Paint Remover, KS-3 Semi-Paste
              Paint Remover, Heavy Bodied Paint Remover (Klean-Strip, Inc.)

         4.   Peel Away II and III (Dumond Chemicals, Inc.)

         5.   Rock Miracle

         6.   Old Master's TM-4 Paint Remover (Master Products,
              Inc.)

         7.   Reliable #78 Liquid No-wash Paint Remover    
              (Reliable Remover & Lacquer Corporation)

         8.   Semi-Paste #77, Liquid #99, Water-soluble #122 (Red
              Devil)

         9.   Spray-On Stripper (Bix)

         10.  509 Paint Stripper (ProSoCo, Inc.)

         11.  505 (Diedrich Chemicals)

    -OR-

         Caustic-based chemical paint strippers such as any of the
         following, or approved equal:

         1.   Peel Away I (Dumond Chemicals, Inc.)

         2.   404 Rip Strip, 606/606X (Diedrich Chemicals)

    -OR-

         Alternative-based such as any of the following, or
         approved equal:

         1.   Safest Stripper (3M)

         2.   MF, Stripper 66 (AFM Enterprises, Inc.)

    B.   Plastic sheeting

    C.   Cornstarch or fumed silica such as "Cab-o-sil" (Samuel
         Cabot, Inc.), or approved equal.

         1.   Used to thicken chemicals so they will adhere to
              vertical surfaces and ceilings.

         2.   Fumed silica is also used as a filler in epoxy
              repairs.  

         3.   Available from grocery store.

    D.   Denatured alcohol:  (to remove last traces of chemical
         residue)

         1.   Other chemical or common names include Methylated
              spirit*.

         2.   Potential hazards:  TOXIC AND FLAMMABLE.

         3.   Available from hardware store, paint store or
              printer's supply distributor.

         4.   Denatured alcohol should be a satisfactory
              substitute for ethyl alcohol for stain removing
              purposes.

    E.   For Caustic-based paint strippers, neutralizer as
         recommended by paint stripper manufacturer, to return
         surface to neutral pH prior to refinishing.

    F.   Steel wool, cheese cloth, or other cloths for final
         clean-up.

    G.   Phenolphthalein:  Used to test pH of a surface after
         stripping with alkaline chemicals.  Available at some
         drug stores or chemical supply houses

2.03 EQUIPMENT

    A.   Steel wool, scrapers and small picks to remove sludge

    B.   Metal containers such as old coffee cans to dispose of
         sludge

    C.   Putty knives and paint scrapers (of different shapes and
         flexibility)

    D.   Natural bristle brushes or plastic spatulas as
         recommended by paint stripper manufacturer to apply
         stripper.  

    E.   Duct tape

    F.   Spray equipment (only if recommended or provided by
         manufacturer)


PART 3---EXECUTION

3.01 EXAMINATION

    A.   One of the main reasons for paint failure is excess
         moisture, both from internal and external sources.
         Before work is begun on removing the existing paint film
         or otherwise preparing the surface, all flashing and
         gutters and downspouts shall be inspected and repaired or
         replaced as required.  Make provisions as required for
         removing excess moisture from areas of high humidity.  

    B.   All wood elements shall be carefully inspected for rot
         and, if deteriorated, marked for later replacement, after
         the paint has been removed.

3.02 PREPARATION

    A.   Protection:

         1.   General:  Comply with recommendations of
              manufacturers of paint strippers for protecting
              surrounding building surfaces against damage from
              exposure to their products.  

         2.   Protect adjacent surfaces, including grass, shrubs
              and trees with paper, drop cloths and other means.
              Items not painted which are in contact with or
              adjacent to painted surfaces shall be removed or
              protected prior to surface preparation and painting
              operations.

         3.   All waste material shall be collected at the end of
              each work day and disposed of in a manner
              consistent with local environmental regulations.
              It is considered Hazardous Waste.

         4.   Work area shall be sealed to prevent the spread of
              paint dust and debris beyond the work site.

         5.   All rags shall be disposed of nightly and removed
              from the building.

         6.   Adequate ventilation should be provided in each
              area where solvents and strippers are used.

         7.   A fully charged fire extinguisher suitable for
              solvent fires shall be kept in each area where work
              is going on.

         8.   Contractor shall provide multiple fans with high
              CFM to move fumes out of the building and away from
              areas where work is being done.

         9.   Compressor motors, heat lamps, etc., must be of
              explosion proof type.

         10.  No spraying of solvents or strippers permitted
              unless specifically allowed by the manufacturer of
              the product being used.

         11.  Do not operate a building's central heating system
              while stripping interior wood features using
              chemicals, or for several days afterwards.
              Chloride compounds in the vapors of these removers
              can combine with the combustion air and move into
              the furnace-burner compartment of the heating
              system.  Chemical reactions occur with the flue
              gasses which create highly corrosive acids which
              can condense on the heat exchanger, vent piping,
              etc.  Once started, the corrosion created by this
              acid, cannot be stopped.

         12.  After paint removal is complete, all areas around
              the site shall be cleaned of all paint dust and
              debris, and such debris shall be properly disposed
              of in a manner consistent with local environmental
              regulations.  Vacuums used to clean up dust shall
              be equipped with High Efficiency Particulate Air
              (HEPA) filters.

    B.   Surface Preparation:  Use scrapers of a variety of sizes
         and shapes, whose edges have been rounded, to remove
         loose paint before removal using chemicals.  

3.03 ERECTION, INSTALLATION, APPLICATION

    NOTE:  WORK IN WELL-VENTILATED AREA TO AVOID INHALATION OF
    TOXIC FUMES.

    A.   Lay the chemicals onto the surface in the manner and
         amount recommended by the manufacturer.

    B.   Allow to sit or "dwell" according to the manufacturer's
         instructions.  If required, cover with plastic wrap.

    C.   Remove the sludge using scrappers and steel wool.  A
         second application may be required on those areas where
         paint is especially thick and/or the detail is intricate.

    D.   After removal has been completed, rub all surfaces down
         with denatured alcohol or water (for water rinsable
         strippers only) to remove all traces of chemical residue.
         
         1.   For solvent-based strippers:

              a.   Most solvent-based chemicals also contain wax
                   to help retard evaporation during the dwell
                   period.  Unless completely removed, this wax
                   will inhibit the performance of the new
                   finish.

              b.   Thoroughly rub all surfaces, and especially
                   deep crevices, with denatured alcohol to
                   remove all traces of remover.  Mineral spirits
                   will work as well, but it may also leave a
                   somewhat oily residue.

         2.   For caustic-based strippers:

              a.   Carefully and completely neutralize feature as
                   directed by manufacturer to return surfaces to
                   a neutral pH.  

              b.   To test whether all chemicals have been
                   removed dissolve a 2" piece of phenolphthalein
                   in denatured alcohol.  

              c.   Brush the solution onto the surface.  If it
                   turns a shade from pink to magenta there is
                   still chemical residue.  

              d.   Treat the surface with additional neutralizer
                   and continue testing until there is no color
                   change in the phenolphthalein solution.  This
                   test will work with any alkaline product.

              e.   Testing the damp surface with litmus paper
                   until a pH level of 7 is achieved will also
                   work if phenolphthalein is not available.

         3.   For alternative-based strippers:

              a.   These products contain neither waxes nor
                   strong alkalies so clean-up is simplified.
                   Follow manufacturers instructions for removal
                   or residue.

    F.   For guidance on repainting wood features, see 06300-01-S,
         06300-02-R and 09900-07-S.  For guidance on refinishing
         wood with a varnish or stain, see 06400-10-R.

3.04 ADJUSTING/CLEANING

    A.   Upon completion of this work, all floors, walls and other
         adjacent surfaces that are stained, marred, otherwise
         damaged by work shall be cleaned and repaired and all
         work and the adjacent areas shall be left in a clean and
         orderly condition.

    B.   All completed work shall be adequately protected from
         damage by subsequent building operations and effects of
         weather.  Protection shall be by methods recommended by
         the manufacturer of installed materials and as approved
         by the Architect.

                         END OF SECTION