Resource Library

clear search

Can patination of copper be prevented?

For smaller articles, a properly applied lacquer can be used, but this may need reapplying after a number of years. A specialist company must be consulted.

For architectural objects such as statues, natural waxes can used. These will need to be reapplied every few months.

For thorough prevention, it is possible to use both lacquer and wax.

For very large areas, such as copper roofing, patination prevention is generally not practical.

How can bronze works of art be protected from corrosion if they are situated outdoors?

Either by the use of lacquers, wax polishing, or both.

What range of colours can be achieved with a finished bronze casting?

Using chemical treatment, any desired colour can be obtained. Specialist companies should be consulted to identify the correct product for a particular project.

I am a jewellery designer interested in using brass wire which has a white colour and good corrosion resistance, what should I use?

Use nickel silver wire CuNi10Zn27 (CW401J). This is used in dental applications, model making and for jewellery.

What surface treatments can be used to protect outdoor copper, brass and bronze objects?

Brasses will slowly tarnish in the atmosphere; outdoors the process is more rapid due to the effect of moisture, salt (in marine environments) and pollutants such as sulphur dioxide (acid rain) in industrial areas. The tarnishing can be greatly delayed and the range of colours, which give copper alloys their aesthetic appeal, maintained by either lacquering or waxing (or both).

Lacquering: one of the most effective lacquers is Incralac. Lacquers must be applied in dry, factory conditions and are not suitable for protecting components which are handled by the public, such as handrails, since acid levels of moisture in the skin (pH 5.5) damage the lacquer.

Waxes: copper alloys may be more cheaply protected by waxing. It is important to use natural non-reactive waxes such as Carnauba or Beeswax, not synthetic waxes which will eventually granulate and absorb water. Natural waxes are not affected by UV light.

What type of bronze is used for modern works of art?

Bronze has been used for centuries to create statues, and is still the first choice for modern, striking works of art. The most widely-used alloys for such objects are leaded gunmetals, such as CC492K and CC491K.

I have a brass table top which has been scratched. How can I restore the surface?

By hand polishing (buffing) using a soft abrasive such as T-Cut or Brasso. Follow this by waxing with a natural wax.

What finishes are available for copper?

Bright copper, pre-oxidised copper, pre-patinated copper or post-patinated copper.