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

Procedure code:
501012S
Source:
Hspg Prepared For Nps - Sero
Division:
Metals
Section:
Metal Materials
Last Modified:
11/12/2014


REPAIRING SMALL HOLES, NICKS AND MINOR IMPERFECTIONS IN CAST IRON

REFERENCES:

Margot Gayle, David Look, John Waite. Metals in America's Historic Buildings. Washington,DC: National Park Service, 1995.

L. William Zahner. Architectural Metals. New York: John Wiley & Sons, 1995.


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"(www.bondo.com) 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.


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