For metallic finishes, most of the section on spraying solid colours applies but with added technicalities to consider. Some older production cars were painted in metallic colours applied in one process, called single-layer. Most recent metallics are of the clear-over-base type, which involves a coloured metallic basecoat protected by a finishing coat of clear lacquer. Metallics can show a wide variation in colour dependent on application techniques. Please see the Colour Matching section.
All metallic paints gain their appearance by using aluminium particles as one of the pigments. Various grades and sizes are used to produce different effects, e.g., coarse, fine, lenticular.
Available as cellulose and acrylic air-dry, 2-pack and synthetic enamel. All must be thinned and/or activated as directed by the paint manufacturer.
Most metallic colours and quite a lot of normal solid colours are now applied in a two layer system, where the basecoat is applied first followed by a clear lacquer.
The basecoat must be thinned as directed by the supplier. Due to the multitude of products available it is almost impossible to give general guidance on thinning ratios - ask the supplier for a data sheet.
Now becoming common on even budget range cars. Some or all of the aluminium flakes in the paint pigment are replaced with mica particles. These particles are transparent and also produced in different shapes, giving the mica particles a prismatic effect.
Essential for any basecoat to provide protection and the final gloss. Available as air-drying acrylic lacquer, or 2-pack clear (lacquer plus activator) Cellulose clear lacquer or blending clear must not be used on its own as a finishing coat due to poor weathering properties, turning white very quickly.