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International Creative Metal, Inc.

Architectural Custom Metal Fabricator since 1973

37-28 61st Str. Woodside, NY 11377 Tel (718) 899-7306, Fax (718) 565-0854
Natural Oxidation of Bronze Stage 1 Clean Bronze
Natural Oxidation of Bronze Stage 2 Sometimes this is desired color for refinishing
Natural Oxidation of Bronze Stage 4 Heavy oxidation and greenish color is visible. This item requires cleaning and refinishing. After cleaning it will look like a brand new!

What is metal oxidation and oxidizing?

Oxidation is the natural coloring of metal which occurs when the oxygen in the air makes contact with various metals. Natural oxidation (tarnishing) will occur with bronze, brass, and copper just by weathering and aging alone. Oxidation may also be achieved chemically. Bronze and many other metals may be oxidized chemically. The oxidizing of metal surfaces is a finishing process that uses certain chemicals to speed up the natural reaction of the metal to the atmosphere and thus quickly achieve the desired color. Oxidizing is commonly used for coloring natural metal surfaces. It is used on historical buildings, museums, and for various architectural surfaces to achieve a specific statuary color.

The most commonly oxidized metals are:

  1. Bronze
  2. Brass
  3. Copper

Other metals that may be oxidized include:

  1. Steel
  2. Iron
  3. Aluminum
  4. Nickel

Commonly oxidized surfaces include:

  1. Doors
  2. Revolving doors
  3. Elevators (interior and exterior)
  4. Elevator doors
  5. Window frames
  6. Fascia panels
  7. Building facades
  8. Building marquees
  9. Handrails
  10. Ornamental structures

Oxidation may be achieved in different ways. Natural oxidation is common on buildings where the exterior elements play a major role in changing the bronze surface color. Natural oxidation occurs in four stages. The metal turns a light brown during the first stage. It turns brown and then dark brown during the second and third stages. Finally, it turns light green to dark green during the fourth stage. This natural process requires very little attention from the modern metal polisher. Basic cleaning and proper protective coatings may be applied to this naturally occurring oxidation. Different types of oils or waxes along with specific cleaning techniques can be applied to these oxidized bronze surfaces to protect or enhance nature‘s process.

Chemicals and chemical treatments can be applied to speed up the oxidation process. With the use of chemicals on bronze metal surfaces, there is control in obtaining desired colors. The basic idea is to speed up nature‘s process and stop it at a desired decorative finish. Different colors will develop by chemically treating the natural bronze metal surface. These include statuary finish, black, brown, light brown, or gold. Protective clear coatings are usually applied to protect the bronze from continued oxidation. The chemical changing of the bronze metal surface to a desired architectural finish is an exciting challenge and an interesting skill to learn.