How to Passivate Copper

How to Re-Round Copper Tubing
Published: Jun 13, 2011
Updated: Nov 20, 2021
1 minute read

Things You Will Need

  • Ammonium sulfate
  • Copper sulfate
  • Ammonia

However, through both natural and chemical means, copper can be made resistant to corrosion.

  1. Expose copper to the elements. Although it is a gradual process that varies in speed depending upon the humidity and heat in the environment, baring copper to the outdoors is the simplest way to passivate it. Within four to eight weeks, a dull blue-green patina will form on the copper. This patina is a corrosion inhibitor.

  2. Accelerate the growth of the patina with a chemical bath of ammonium sulfate, 6 pounds; copper sulfate, 3 ounces; ammonia, 1.34 fluid ounces, and water, 6.5 gallons.

  3. Apply the mixture as a spray. Allow it to dry between six applications. Wait six hours to see the patina deepen in color. Growth of the patina film will now spread faster.

Photo Credits

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