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 The soft brushed
finish of raw copper & brass will gain a rich natural patina
with time or they can be cleaned occasionally and coated with
paste wax or clear lacquers to preserve the original finish.
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 With weathering, the copper will
first turn a rich red bronze color and eventually progress to
a green or blue green/turquoise color.
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 This coloration is called 'patina'
which is actually a thin layer of oxidation on the surface
or the metal.
The
distinctive green color of aged copper is called 'verdigris'.
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 The most famous
example of this is the Statue of Liberty. Natural patinas acquired
over time are deeper, richer and more durable color. Copper roofs
may last many hundreds of years.
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- It is possible
to speed up the natural patina process somewhat by exposing the
item to a coastal salt air environment or placing the item near
a swimming pool where it will be exposed to the chlorine in the
air.
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- A faster method
of obtaining different colored patinas is to apply a commercial
patina solution. Bottled patina formulas are available in the
paint departments of most craft supply and hardware stores. Caution
should be used as these chemicals are corrosive and must be used
in a well ventilated area.
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- It is best to
patina an item after it has been crafted. Pre -patinaed metal
will show shiny areas every where the metal is bent, hammered,
or stretched. In addition soldering will discolor the patina.
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- Blue
green patina induced on our sailfish using commercially available
prepared patina solution
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- The first step
obtaining a successful patina or finish on copper and brass is
to thoroughly clean the item to be patinaed. The surface must
be free of any grease or oil (including that from fingerprints)
and in a bare metal state. Grease and oil can be removed with
dish washing detergent and a brush or rag. The metal should then
be cleaned with an abrasive pad, or a small brush (such as a
tooth brush) and an abrasive metal cleanser such as Bar Keeper's
Friend. Metal cleansers contain a mild powdered acid that is
activated by water and removes surface oxidation. Metal cleansers
can be found where other house hold cleaning supplied are sold.
Once the metal has been prepared, follow the directions that
come with the commercial patina solution.
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- Paste wax or Lacquer can be
applied to the cleaned bare metal once it has been thoroughly
dried. If moisture is trapped under the finish coating it will
tarnish. Coppersmiths in the 1800s used to pack the cleaned piece
in hot saw dust to remove the moisture. Today lighting fixture
and faucet manufacturers go to great lengths to prepare, clean
and dry their brass fixtures for the lacquer coating that keeps
them looking bright as long as possible. It is our experience
that a permanent clear coating for brass and copper is very difficult
if not impossible to obtain. Periodic cleaning and re-coating
is always necessary.
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