Surface Protection

Q What is ‘INCRALAC’?

A A clear acrylic resin finish containing tarnish inhibitor. It is an air drying ester lacquer containing Benzotriazole, a corrosion inhibitor. It can be relied upon to provide protection for 3-8 years outdoors and for much longer indoors .

Q I wish to restore the brass cladding on a shop front. Over a long period of time the brass has tarnished.

A The first job is to clean the surface. Use a detergent with a kitchen scouring sponge (usually green). For a badly stained surface it may be necessary to incorporate pumice powder with the detergent .For large areas it may even be necessary to shot blast the surface. After cleaning dry the surface with hot air and as soon as possible wax the surface using natural wax. Natural wax is essential since it will enhance the true colour and form a protective coating, repelling water. Artificial wax should not be used since it will crack in time and draw water in.

Q I am in charge of a large renovation project and I have to recommend surface treatments to protect a number of outdoor copper, brass and bronze objects including hand rails, wall plaques, door handles and statues?

A 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.