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  for Metal Finishing since 1989
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Protecting copper from sunlight

We are constructing a copper sculpture (a wall mounted piece of artwork). The finished product will be displayed in a reception area of our company which will be exposed to a lot of direct sunlight. We are thinking that we need to protect the copper with a sealant. What do you advise? Mickey Johnson

Mickey Johnson
Boeing - Huntsville, Alabama
2002

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To my knowledge pure copper is not affected by sunlight, but I stand to be corrected. However, it is affected by the atmosphere and will turn all sorts of different colours depending on the pollution in the air. Some of these colours are caused by oxides and/or sulfides that can be photosensitive and semiconductors in their own right. It is also known that glass will prevent the passage of UV light, so perhaps putting the sculpture in a controlled atmosphere glass box may do the trick. Alternatively, if the copper is affected by sunlight, move it out of the direct sunlight.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2002

I am also looking for ways to protect copper and have heard of clear electrocoating which ought to seal and prevent oxidation. Don't know if it is sales talk or if it works and for how long...

Vic Bee
- Hong Kong
2002