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Historic Preservation - Technical Procedures

Spectitle:

Classifications Of Aluminum Cleaners

Procedure code:

0501012S

Source:

Care Of Aluminum - Aluminum Association, 1992

Division:

Metals

Section:

Metal Materials

Last Modified:

02/24/2012

Details:

Classifications Of Aluminum Cleaners



CLASSIFICATIONS OF ALUMINUM CLEANERS


The following standard was developed from information produced by
The Aluminum Association in their publication "Care of Aluminum".


ALUMINUM CLEANERS MAY BE CLASSIFIED INTO FIVE GROUPS:  (Listed from
gentle to severe)

1.   Mild soaps and detergents and non-etching cleaners

2.   Solvent and emulsion cleaners

3.   Abrasive cleaners

4.   Etching cleaners

5.   Special duty cleaners

NOTE:  THE GENTLEST METHODS OF CLEANING SHOULD BE USED FIRST.  IF
THESE ARE NOT EFFECTIVE, MORE SEVERE METHODS MAY BE USED WITH
CAUTION ALONG WITH THE NECESSARY EXPERTISE.


MILD SOAPS AND DETERGENTS AND NON-ETCHING CLEANERS

-    May be applied with bare hands.

-    Spot test strong detergents.

-    Non-etching cleaners are alkaline or acid-based formulations
    mixed with inhibitors, which permit the cleaners to remove
    soil without attacking the metal or its finish.  

-    Nature and strength of chemical and length of application will
    vary from cleaner to cleaner.

-    Use with a long-handled fiber brush and rubber gloves.

-    After cleaning, thoroughly wash aluminum with clean, clear
    water and dry.


SOLVENT AND EMULSION CLEANERS

-    Mild in action, but more effective in removing dirt and stains
    than milder cleaners.

-    Effective in removing surface dirt and some stains, but NOT
    very effective in removing heavy dirt encrustations.

-    May be used on bare, anodized, conversion-coated and
    porcelainized aluminum.

-    The surface must be thoroughly rinsed and wiped dry to prevent
    water-spot staining.

-    Spot test these cleaners on painted and lacquered finishes.
    An inappropriate solvent of solvent-containing emulsion can
    remove many paints and clear organic coatings (lacquers) used
    with aluminum.


ABRASIVE CLEANERS

-    USE WITH CAUTION

-    Range from moderate to heavy-duty depending on how coarse of
    an abrasive is used.

-    Can remove most dirt, staining and corrosion from aluminum.

-    Some generic descriptions of these cleaners include polish,
    cleaner, cleaner-polish, wax-cleaner, wax-polish, metal
    brightener and scouring powder.

-    Abrasive cleaners contain abrasives to which water, oil, wax,
    silicones, soap and an acid or alkali may be added, either
    singly or in combination.  The abrasives cut away the dirt and
    surface oxidation while the soaps, acids and/or alkalies
    clean, leaving traces of the wax, oil or silicones behind to
    provide luster and a small measure of surface protection.

-    Abrasive cleaners containing fine grit or polishing agents may
    be used with care on all aluminum finishes.  Cleaners
    containing moderately coarse grit may be used ONLY on
    porcelain finishes.  

-    Avoid prolonged rubbing with abrasive cleaners.  This may dull
    a bright, specular finish.  

-    Apply abrasive cleaner-polish to a clean cloth and rub over
    the soiled area.  Follow by polishing with a clean, dry cloth.

-    DO NOT use a cleaner-polish on aluminum surfaces to receive an
    organic coating.  Cleaner-polishes protect the aluminum
    surface by leaving a thin wax, or wax-like coating on the
    surface.  This coating will prevent subsequent layers of paint
    or lacquer from adhering to the aluminum surface.

-    These types of cleaners are often used to remove heavy soils
    and oxides prior to final cleaning and polishing with a fine-grit cleaner.

-    Thoroughly remove abrasive cleaner before applying polish to
    avoid scratching the surface.

-    On bare aluminum, moderate abrasives produce a finely
    scratched, light grey surface.  The scratches are easily
    blended into a matte or satin finish by working the abrasive
    with the grain of the metal.

-    Abrasive cleaners may be supplemented with a fine abrasive
    such as pumice or fine stainless steel wool (0000 to 00) or an
    abrasive nylon pad.  DO NOT USE REGULAR STEEL WOOL.  IT MAY
    LEAVE BEHIND RUST STAINS.

-    Coarse abrasive cleaners are sometimes used to prepare
    anodized surfaces for painting.  Apply light pressure ONLY to
    avoid deep scratches, which may be visible through the paint.

-    DO NOT allow chemical-based cleaners to remain on bare or
    anodized aluminum too long.  They may etch the surface finish
    of bare aluminum; white blemishes may develop on anodized
    aluminum.


ETCHING CLEANERS:  

-    USE WITH CAUTION AND ONLY ON BARE ALUMINUM THAT IS HEAVILY
    CORRODED OR STAINED.

-    APPLY WITH CAUTION; these cleaners remove small quantities of
    metal each time they are used; they MUST be rinsed thoroughly
    and neutralized.

-    Not normally used on painted, plated, anodized or conversion
    coatings.

-    For proprietary etching cleaner formulations, follow
    manufacturer's directions.  A general procedure is as follows:

    1.   Prepare the mixture and apply it carefully with a sponge
         or brush to an area no larger than can be kept wet.

    2.   Allow cleaner to remain in place for the recommended
         time; rinse the surface thoroughly with clean, clear
         water.

-    In general, cleaning should be performed from the bottom up.
    Etchant drips on uncleaned aluminum are more difficult to
    remove than drips on already cleaned aluminum.  

-    Etching cleaners may be supplemented by using a fine abrasive
    such as pumice or fine stainless steel wool (0000 to 00) or an
    abrasive nylon pad.  DO NOT USE REGULAR STEEL WOOL WITH THESE
    CLEANERS.  IT MAY LEAVE BEHIND RUST STAINS.

-    Before applying a water-based etchant cleaner, the metal
    should be grease-free.  When cleaning, rub all areas equally
    and/or soak areas for similar lengths of time.

-    Hot water may be used for final rinsing to increase the drying
    speed of smaller aluminum products.  Small parts may be rinsed
    in methyl alcohol and water.


SPECIAL DUTY CLEANERS

-    USE WITH CAUTION AND ONLY BY AN EXPERIENCED PROFESSIONAL.

-    These types of cleaners may require the use of steam, rotary
    wire-brushes and/or abrasive blasting.

-    Pure steam is most suitable for use on bare, plated and
    porcelain aluminum finishes.

-    DO NOT hold steam jets too close or too long against painted,
    anodized or conversion-coated aluminum.  Paint may soften and
    lose adhesion; anodized or conversion-coated finishes may
    blush or craze.

                         END OF SECTION