Skip to main content

Historic Preservation - Technical Procedures

Spectitle:

Repairing Small Holes, Nicks, And Minor Imperfections In Cast Iron

Procedure code:

0501012R

Source:

Hspg Prepared For Nps - Sero

Division:

Metals

Section:

Metal Materials

Last Modified:

02/24/2012

Details:

Repairing Small Holes, Nicks, And Minor Imperfections In Cast Iron



REPAIRING SMALL HOLES, NICKS AND MINOR IMPERFECTIONS IN CAST IRON


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure includes guidance on using epoxy to repair
         minor surface imperfections in cast iron such as small
         holes, nicks and minor cracks.

    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).

    C.   For general information on the characteristics, uses and
         problems associated with cast iron, see 05010-04-S.



PART 2---PRODUCTS

2.01 MATERIALS

    A.   Epoxy patching compound.  Some different types of epoxy
         include the following:

         NOTE:  THE EPOXY PRODUCT SELECTED MUST BE COMPATIBLE WITH
         THE PAINT CHOSEN.

         1.   Auto body putty, such as "Bondo" (available from
              auto body stores or hardware stores).

         2.   Resin-impregnated fiberglass (available in mesh or
              strands from marine supply stores).

         3.   Polyester or epoxy resin (available in cans from
              marine supply stores).

    B.   Emery paper

    C.   600 grit aluminum oxide paper

2.03 EQUIPMENT

    A.   Wiping cloths

    B.   Eye and skin protection

    C.   Putty knife


PART 3---EXECUTION

3.01 PREPARATION

    A.   Surface Preparation:

         1.   Surface preparation shall be done under the
              supervision of the RHPO.

         2.   The RHPO will designate sample areas for testing of
              surface preparation on the various different
              components that require repair.  No other surface
              preparation is to be done until sample areas have
              been approved.  Approved areas shall become the
              standard of comparison for all surface preparation
              work.  Protect from weathering, but do not alter or
              opaquely cover sample areas until all preparation
              work has been completed and approved.

         3.   The time interval between final cleaning and
              application of primer shall not exceed two hours.
              Prime coat shall be applied prior to application of
              plastic metal materials.  Allow 48 hours between
              application of prime coat and application of
              plastic metal material.

         4.   See 05010-17-R for cleaning and rust removal of
              metal surfaces prior to making metal repairs.

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   Abrasively clean with sandpaper the pit and surrounding
         materials until all evidence of paint and corrosion is
         gone and a "white metal" condition is achieved.  If the
         RHPO judges that the area cannot be adequately cleaned it
         shall be ground out.

    B.   Prime paint the area immediately (see 05010-13-S and
         09900-07-S for guidance).

    C.   Carefully and completely fill hole, nick or imperfection
         with epoxy no sooner than 48 hours after prime painting
         and allow to dry.

    D.   When dry, apply second primer coat of paint over the
         patch and finish with paint to match existing.

                         END OF SECTION