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REMOVING LINSEED OIL PAINTS FROM MARBLE


THE CLEANING OR REMOVAL OF STAINS FROM STONE MAY INVOLVE THE USE
OF LIQUIDS, DETERGENTS OR SOLVENTS WHICH MAY RUN OFF ON ADJACENT
MATERIAL, DISCOLOR THE STONE OR DRIVE THE STAINS DEEPER INTO POROUS
STONES.  USE THE PRODUCTS AND TECHNIQUES DESCRIBED HERE ONLY FOR
THE COMBINATIONS OF DIRT/STAIN AND STONE SPECIFIED.


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on poulticing marble
         stained with paints which have a linseed oil binder and
         "carbonaceous" or sooty soiling.

    B.   Historic Structures Precautions:

         1.   Efflorescence may appear after treatment.

         2.   There is a risk of brown ferric hydroxide stains
              being formed in the presence of iron compounds in
              the stone.

         3.   Protective clothing and eye protection should be
              worn to prevent burns, irritation and optic damage.

         4.   Adjacent paint work may be damaged, if not covered
              or protected.

    C.   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).

    D.   For additional information on poulticing, see 04455-02-R.

    E.   For general information on the characteristics, uses and
         problems associated with marble, see 04455-01-S.


PART 2---PRODUCTS

2.01 MANUFACTURERS

   A. Prosoco, Inc.

       www.prosoco.com

2.02  MATERIALS

    A.   Baking soda or some other alkaline cleaner to be used to
         form the poultice paste:  Available from hardware store.

    B.   Liquid laundry bleach for making the paste

    C.   Mineral water

    D.   Plastic sheeting

    E.   Clean dry towels for blotting the area after treatment

                        -OR-

   A commercial cleaner such as "Stand Off Oil & Grease Stain Remover" (Prosoco), or approved 

   equal.

2.02 EQUIPMENT

    A.   Glass or ceramic container for mixing the solution

    B.   Wooden utensil for stirring the ingredients

    C.   Wood or plastic spatula

    D.   Masking tape


PART 3---EXECUTION

3.01 EXAMINATION

    A.   Examine the marble CAREFULLY to determine the cause of
         staining before proceeding with any cleaning operation.

3.02 ERECTION, INSTALLATION, APPLICATION

    NOTE:  DO NOT USE BLEACH ON DARK COLORED STONES AS THIS WILL
    CAUSE THE STONE TO LIGHTEN.

    A.   Protect adjacent painted surfaces.

    B.   Rinse the area to be treated with mineral water.

    C.   Pour the liquid laundry bleach in a glass or ceramic
         bowl.

    D.   Thoroughly moisten the stained surface with this liquid.
         Be sure to dampen well beyond the stain.

    E.   Mix the remaining liquid with the white absorbent
         material to form a paste the consistency of oatmeal or
         cake icing.  (Approximately one pound of paste is needed
         for every square foot of surface area to be treated.)

    F.   Using a wooden or plastic spatula, apply the paste to the
         stained surface in layers no more than 1/4 inch thick.
         The poultice should extend well beyond the stain to
         prevent forcing the stain into previously clean stone.

    G.   Check the coating for air pockets or voids.

    H.   After the poultice has been applied, cover it with damp
         cloths to keep the poultice moist.

    I.   Leave the cloths in place overnight.

    J.   Remove the cloths and wet the poultice with mineral
         water.

    K.   Remove the poultice with a wooden or plastic spatula to
         avoid scratching the surface.

    L.   Thoroughly rinse the treated area with mineral water,
         blot, and allow to dry completely.

    M.   If there is residual staining, repeat the procedure.

                            -OR-

   If using a commericial cleaning product, follow manufacturer's instructions.

  

                         END OF SECTION