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The Statue of Liberty, showing advanced patination; verdigris is responsible for the statue's iconic green colour.. Verdigris (/ ˈ v ɜːr d ɪ ɡ r iː (s)/) [1] is a common name for any of a variety of somewhat toxic [2] [3] [4] copper salts of acetic acid, which range in colour from green to a bluish-green depending on their chemical composition.
The patches of bronze disease can be scraped off the surface using a fingernail or a wooden pick. These properties are all in comparison with verdigris, which is normally a duller shade, uniform across the whole of the affected object, and cannot be scratched off with wood or fingernails. Unlike bronze disease, verdigris serves to protect the ...
Patina (/ p ə ˈ t iː n ə / pə-TEE-nə or / ˈ p æ t ɪ n ə / PAT-ih-nə) is a thin layer that variously forms on the surface of copper, brass, bronze, and similar metals and metal alloys (tarnish produced by oxidation or other chemical processes), or certain stones [1] and wooden furniture (sheen produced by age, wear, and polishing), or ...
These electrochemical treatments resulted usually in the complete removal of any patina or surface material, returning the bronze to its original metal surface. Unfortunately this approach often had too severe of results, making the metal porous or leaving the surface with an unattractive appearance. [ 3 ]
Verdigris or Vert-de-Gris, is a blue-green, copper-based pigment. Its name comes from the natural pigments that form a patina on copper, bronze, and brass as it ages. [5] Oneexample is the green patina that formed on the Statue of Liberty in New York Harbor.
A mild solution consists of 3% to 5% of EDTA; 15% to 20% solution in water on ceramics to remove the stains. Iron oxides can be removed from the objects by the use of water in a 10% to 25% solution of hydrogen peroxide. The time required to remove the stains can vary from a few seconds to several hours. [8]
Brasso has also been used to polish out scratches in plastics: It has been used to polish CDs, DVDs, screens, and pools to repair scratches. It is a mild solvent and an extremely fine abrasive, so when applied to the reflective surface of the disc and rubbed radially (in straight lines between the edge and centre), it can smooth scratches and reduce their effect.
Electropolishing, also known as electrochemical polishing, anodic polishing, or electrolytic polishing (especially in the metallography field), is an electrochemical process that removes material from a metallic workpiece, reducing the surface roughness by levelling micro-peaks and valleys, improving the surface finish.