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Historic Preservation - Technical Procedures

Spectitle:

Stripping Deteriorated Varnish Rom Wood Handrails & Refinishing

Procedure code:

0643004R

Source:

National Capitol Region Specifications

Division:

Wood And Plastics

Section:

Stairwork & Handrails

Last Modified:

02/24/2012

Details:

Stripping Deteriorated Varnish Rom Wood Handrails & Refinishing



STRIPPING DETERIORATED VARNISH FROM WOOD HANDRAILS AND REFINISHING


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on stripping and
         refinishing wood handrails where the varnish is
         deteriorated or has been damaged.

    B.   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).

1.02 PROJECT/SITE CONDITIONS

    A.   Existing Conditions: Determine that surfaces to which
         finishes are to be applied are even, smooth, sound,
         clean, dry and free from defects affecting proper
         application. Correct or report defective surfaces to
         Contracting Officer.

    B.   Field Measurements: Take all required field measurements
         and verify profiles and installation conditions for work
         of this section.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   The Sherwin Williams Co.
         101 Prospect Ave. N.W.
         Cleveland, OH  44101
         216/566-2000

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.   Varnish: Linseed-tung modified phenolic spar varnish such
         as "Rexpar" (Sherwin Williams), or approved equal.

    B.   Solvent: Mineral spirits, turpentine or denatured
         alcohol.

         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.

         Turpentine:

         1.   Typically used as a solvent and thinner.

         2.   Potential Hazards:  TOXIC AND FLAMMABLE.

         3.   Safety Precautions:

              a.   Work in a well ventilated area.  

              b.   Observe safety rules as turpentine is
                   flammable, and the fumes can trip an
                   ionization smoke detection system.  

              c.   Store soiled cloths in a metal safety
                   container to guard against spontaneous
                   combustion.

              d.   Available from hardware store or paint store.

         Denatured Alcohol:

         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.

    C.   Alternative Solvent: a mixture of 75% toluene, 24%
         acetone and 1% butyl acetate.

         Toluene (C7H8):

         1.   A liquid, aromatic hydrocarbon that resembles
              benzene but is less volatile, flammable and toxic;
              Is produced commercially from light oils from coke-
              oven gas and coal tar and from petroleum, and is
              used as a solvent, in organic synthesis and an
              antiknock agent for gasoline.

         2.   Other chemical or common names include Toluol.

         3.    Potential Hazards:  TOXIC AND FLAMMABLE.

         4.   Available from chemical supply house, hardware
              store, paint store or printer's supply distributor.

         Acetone (C3H6O):

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

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

         3.   Potential Hazards:  VOLATILE AND FLAMMABLE SOLVENT

         4.   Available from chemical supply house or hardware
              store.


    D.   Steel Wool: Grade 000 steel wool.

    E.   Clean, soft cloths

    F.   Sandpaper: 3 grades, finest grade 00.

    G.   Shellac burn-in sticks


PART 3---EXECUTION

3.01 ERECTION, INSTALLATION, APPLICATION

    A.   Stripping Deteriorated Varnish:

         1.   Make sure work area is well ventilated and wear
              protective clothing and rubber gloves. Do not allow
              smoking in the work area. Place a fire extinguisher
              for Class B fires at entrances for emergency use.

         2.   Always rub along the grain of the wood.

         3.   Change cloths as often as necessary to be effective
              in cleaning.

         4.   Cleaning:

              a.   Wet steel wool with solvent and rub over the
                   wood to remove varnish buildup and smooth out
                   checked surface. Replace soiled steel wool
                   frequently and continue the wiping process
                   until a smooth evenly colored surface is
                   achieved. Use no water on wood surface under
                   any circumstances.

              b.   Work only one 4' square area at a time. Work
                   area should be within a comfortable arms
                   reach. Protect areas of wood and adjacent
                   surfaces not to be refinished from solvent and
                   other stripping operations.

              c.   This process is to remove the varnish buildup
                   only. If solvent affects the stained color of
                   the wood, discontinue use and use Alternative
                   Solvent mixture listed under 2.02 Materials.

              d.   Allow surface to dry thoroughly, no less than
                   24 hours.


         5.   Fill scratches and gouges with shellac burn-in
              sticks matching the color to the wood stain.

    B.   Refinishing:

         1.   Apply full wet coat of varnish. Allow to dry
              thoroughly.

         2.   Sand out roughness with 6/0 open coat abrasive
              paper. Dust off thoroughly  with air jet or vacuum
              and wipe with a tack cloth to remove all dust.

         3.   Apply final full wet coat of varnish. Follow
              manufacturer's instructions for obtaining final
              satin finish.

    C.   For guidance on cleaning and maintaining woodwork, see
         06400-02-P, 06400-01-R, and 06400-01-P.

                         END OF SECTION