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Historic Preservation - Technical Procedures

Spectitle:

Preserving And Restoring The Aluminum Finish Of Decorative Architectural Features

Procedure code:

0501010R

Source:

Developed For Hspg (Nps - Sero)

Division:

Metals

Section:

Metal Materials

Last Modified:

02/24/2012

Details:

Preserving And Restoring The Aluminum Finish Of Decorative Architectural Features



PRESERVING AND RESTORING THE BARE ALUMINUM FINISH OF DECORATIVE
ARCHITECTURAL FEATURES


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure provides general guidelines for preserving
         and restoring the bare aluminum surface finish of
         decorative aluminum architectural features.

    B.   Decorative aluminum architectural features (bare,
         anodized, and conversion coatings) are frequently found
         with a variety of tooled finishes.  Some types of
         aluminum finish textures found in historic buildings
         include the following:  Embossed, sandblasted, wire-
         brushed or satin, or buffed/polished.

    C.   The best method of preserving the finish involves the
         application of a protective coating of lacquer or wax to
         prevent dirt and grime from accumulating.

    D.   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).

    E.   For general information on the characteristics, uses and
         problems associated with aluminum, see 05010-08-S.

1.02 REFERENCES

    A.   Technical Report #C-6:  "Aluminum and its Alloys," The
         Aluminum Association, September 1978, fourth printing,
         February 1984.

    B.   Technical Report #92:  "Care of Aluminum," The Aluminum
         Association, February 1983.

    C.   "Metal's in America's Historic Buildings:  Uses and
         Preservation Treatments", U.S. Department of Interior -
         National Park Service - Preservation Assistance Division,
         Chapters 8 and 18, Revised 1993.

    D.   Aluminum Association, 900 19th Street NW, Ste. 310,
         Washington, DC  20006

1.03 MAINTENANCE

    A.   To clean a waxed surface simply wash with clean, clear
         water and wipe with clean cloth.

    B.   To remove yellowed wax, apply appropriate solvent with a
         clean cloth.  If necessary, wash surface with mild soap
         and water and reapply wax after surface has dried.

    C.   Aluminum architectural elements should be protected by a
         non-absorptive, insulative coating to prevent direct
         contact with corrosive agents.

    D.   Aluminum architectural elements should be protected from
         rainwater run-off from wood and copper roofs and copper
         gutters.


PART 2---PRODUCTS

2.01 MANUFACTURERS

    A.   S.C. Johnson & Son, Inc.
         Carnu Street
         Racine, Wisconsin  53405
         414/631-2000

    B.   E.I. duPont de Nemours & Co., Inc.
         1007 Market St.
         Wilmington, Delaware  19898
         302/774-1000

2.02 MATERIALS

    A.   Methacrylate type lacquer such as "DuPont 1234 or DuPont
         RK 935" (E.I. duPont de Nemours & Co.), or approved
         equal.

    B.   Ground pumice

    C.   Soft bristle brushes

    D.   00 to 0000 stainless steel wool

    E.   Wax, most types including automotive and floor waxes
         without cleaners or abrasives such as "Beautiflor Liquid
         Wax No. 5951" and "Wax Emulsion" (S.C. Johnson & Son,
         Inc.), or "Dupont 7 New Car Wax" (E.I. duPont de Nemours
         & Co.), or approved equal.


PART 3---EXECUTION

3.01 EXAMINATION

    A.   Examine the surface to determine the extent of damage.

         1.   If the damage is not severe, the aluminum elements
              can be protected from abrasion or erosion by
              coatings of lacquer, wax or suitable paint.

         2.   If the damage is extensive, the deteriorated
              section(s) must be replaced with new metal of a
              heavier gauge, but which matches the existing in
              color, appearance, etc.

3.02 PREPARATION

    A.   Verify the finish prior to making repairs.  

    B.   Remove all oil, dirt, and other debris from the surface.

3.03 ERECTION, INSTALLATION, APPLICATION

    A.   Restoring the surfaces of decorative aluminum
         architectural elements:

         CAUTION:  DO NOT RESTORE ANODIZED OR CONVERSION COATINGS
         USING THESE METHODS - THEY WILL BE DAMAGED.

         1.   Apply wax or lacquer according to the surface
              texture desired (see 1a-1d below).  DO NOT allow
              coating to build up and discolor surface texture.

              a.   For an embossed texture:  Using a soft bristle
                   brush, apply finish compound of ground pumice
                   and water.

              b.   For a sandblasted texture:  Use light
                   sandblasting (only under factory conditions).

              c.   For a wirebrush or satin texture:  Using a
                   soft bristle brush, apply a finish compound of
                   ground pumice and water.

              d.   For a buffed or polished finish:  Using fine
                   stainless steel wool (0000 to 00), hand rub
                   the surface with ground pumice.  

         2.   Follow manufacturer's recommendations and
              procedures.  Buff accordingly to achieve
              appropriate finish.

                         END OF SECTION