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Historic Preservation - Technical Procedures

Spectitle:

Paint Removal And Repainting Sheet Iron, Steel And Tin-Plate Ceilings

Procedure code:

0501004R

Source:

Developed For Hspg (Nps - Sero)

Division:

Metals

Section:

Metal Materials

Last Modified:

11/21/2013

Details:

Paint Removal And Repainting Sheet Iron, Steel And Tin-Plate Ceilings



PAINT REMOVAL AND REPAINTING SHEET IRON, STEEL AND TIN-PLATED
CEILINGS


THE CLEANING OR STRIPPING OF METALS MAY INVOLVE THE USE OF
ABRASIVES, LIQUIDS OR SOLVENTS WHICH MAY SPLASH OR RUN OFF INTO
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 chemically removing
         paint from and painting sheet iron, steel and tin-plated
         ceilings.

    B.   Metal ceilings can be made from either sheet iron or
         steel, or tinned steel.  Older ceilings are most likely
         sheet iron or steel, while modern ceilings are made from
         tin-plated steel.

    C.   Copper is, and was, also used to make metal ceilings but
         they are usually left unpainted and as a result will not
         be discussed here.  

    D.   Many of the white metals popular in the 1920s and 30s
         were also sometimes used to create highly decorative
         ceilings.  Like copper, these were left unpainted and so
         shall not be included here such as nickel silver and monel.

    E.   One of the main reasons for the paint failure is
         moisture.  Before work is begun on removing the existing
         paint film or otherwise preparing the surface all sources
         of excess moisture shall be determined and repairs
         completed as required.  

    F.   An archives of the paint history of the building is to be
         maintained.  This is to include any paint samples taken
         during research, samples of the new paint colors and the
         manufacturer's technical information.

    G.   Safety Precautions:

         1.   Paint being removed most likely will contain lead.
              All workers must wear protective clothing
              (including hair), goggles and respirators with
              proper filters.

         2.   No food or drink shall be allowed near any work
              station so as to prevent contamination from paint,
              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.

         5.   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.

    H.   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 SYSTEM DESCRIPTION

    A.   The primary purpose of paint is to protect the metal from
         deterioration.  To do so, paint manufacturers have
         developed paint systems which are made to work together
         to protect the metal substrate.  These systems include
         primers and appropriate, compatible top coats which can
         vary depending on the substrate and can vary between
         manufacturers.  As a result appropriate primers and
         compatible top coats, both from the same manufacturer
         should be used.  

    B.   A paint film is in good condition when it is clean and
         free of any peeling, cracking or rusted areas.  It also
         retains its color and gloss.  


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   For Chemical Paint Removers:

         1.   Savogran Company
              www.savogran.com
              

         2.   Zip-Strip Products
              www.lastnlast.com/zip-strip_products.php
              

    B.   For Fumed Silica:

         1.   Evonik (Aerosil)
              www.evonik.com              

         2.   Cabot,Corporation (Cab-o-sil)
              Cabotcorp.com

         3.  Wacker Chemie-Dow Corning
              www.dowcorning.com              

         4.  OCI (Konasil)
             www.ociunid.en.ec21.com

         
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.   Semi-paste, water rinsing, nonbenzol chemical paint
         remover such as "Strypeeze Semi-paste" (Savogran Co.), or
         approved equal.

         1.   Available from hardware store and paint store.

         2.   Characteristic orange color.

         3.   Will work on both latex and oil-based paints,
              lacquers and varnishes.  

         4.   Cling well to round or vertical surfaces.  

         5.   Form an anti-evaporative film as they dry.  

         6.   Clean-up by either washing or scraping off.  

         7.   All traces must be removed and a neutral pH
              achieved before repainting.

    -OR-

         Non-flammable, heavy bodied, methylene-chloride based
         paint removers such as  "Zip-Strip" (LastnLast), or methylene chloride-free
         product such as "Zip-Strip Premium Green", or approved equal:

         1.   Available from hardware store or paint store.

         2.   Good for interior use because they are non-flammable.  

         3.   Will soften oil-based paints, lacquers, varnish and
              synthetic baked finishes.  

         4.   Will cling well to vertical and irregular surfaces.

    B.   Cornstarch or fumed silica to thicken chemicals so they
         will adhere to ceilings.  
         
         1.   Fumed silica such as "Cab-o-sil" (Cabot Corp. or from other
              manufacturers noted above) is also used as a filler in epoxy repairs.

         2.   Available from grocery store.

    C.   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.

    D.   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.

    E.   Phenolphthalein:  

         1.   Used to test pH of a surface after stripping with
              chemicals or any alkaline product.  

         2.   Available from chemical supply house or drug store.

    F.   Chemical rust remover such as "Naval Jelly", or approved
         equal.

         CAUTION:  DO NOT USE HYDROCHLORIC ACID BASED PRODUCTS.

    G.   Zinc-rich oil-based primer such as zinc chromate or red
         iron oxide-linseed oil paint:

         1.   Good for use on partially deteriorated surfaces
              such as old ceilings.

         2.   Provides protection where moderately corrosive
              conditions exist.

         -OR-

         Modern alkyd paint:

         1.   Should only be applied to clean, non-corroded
              surfaces.  

         2.   Provides protection where there are only mildly
              corrosive conditions, and where normal humidity and
              condensation ranges exist, i.e. a residential or
              office environment.

         NOTE:  Consult the paint manufacturer for appropriate
         choice for use on metal.  

    H.   Oil-based Top Coats:

         1.   Any oil-based top coat, made to be used with the
              primer, may be applied as the top coats.  

         2.   Use paint from the same manufacturer for both prime
              and top coats, and make sure they are made to work
              together.

    I.   Latex caulk

    J.   Plastic sheeting

    K.   Clean, potable water

2.02 EQUIPMENT

    A.   Wire brushes (various sizes and shapes)

    B.   Duct tape

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

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

    E.   Natural bristle paint brushes

         NOTE:  Condition new brushes by soaking in raw linseed
         oil for 24 hours before using.


PART 3---EXECUTION

3.01 PREPARATION

    A.   Protection:

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

         2.   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.

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

3.02 ERECTION, INSTALLATION AND APPLICATION

    A.   Remove all loose paint and rust with wire brushes.  

    B.   Remove remaining paint using the thickest chemical paint
         remover available.  Add cornstarch to thicken it further
         so that it will cling to the ceiling surface.  Work in
         small areas at a time to provide maximum control over
         dwell time and removal.

    C.   Cover with plastic and allow to remain on the ceiling as
         per manufacturer's instructions.  Remove sludge with
         scrapers.  

    D.   Rinse thoroughly with mineral spirits and fine steel
         wool.

    E.   If areas of rust still remain, use a chemical rust
         remover to remove the last traces, or as much of the rust
         as is possible.

    F.   After removal has been completed, rub all surfaces down
         with mineral spirits to remove all traces of dust and
         chemical residue.  

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

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

         3.   Treat the surface with additional mineral spirits
              and continue testing until there is no color change
              in the phenolphthalein solution.  

    G.   Prime immediately to prevent rust and paint.  Use a brush
         for complete, even coverage.

    H.   Fill any open joints with a paintable latex caulk.

    I.   Brush apply two top coats of the selected paints to
         insure adequate protection of the metal.  

         NOTE:  DO NOT USE LATEX-BASED PAINTS AS THE WATER VEHICLE
         WILL CAUSE THE METAL TO RUST.

                         END OF SECTION
 


sheet iron, steel, tin-plate, metal ceiling, painting metal ceilings, paint removal