Finishing processes: Painting and powder coating
see p.84
What you need to know •
The tools, equipment, steps and safety measures used in painting and powder coating.
Finishing processes apply a coating to give the final colour to a product and to provide protection against corrosion.
Painting
FT
Conventional wet paint contains coloured pigments and binders carried in a water or oilbased solvent. The solvent evaporates into the atmosphere as the paint dries and so must be used in a well-ventilated area.
Painting is widely used on a diverse range of materials (for example, metals, polymers, wood, concrete, and so on).
Application
Powder coating
Paint spraying can achieve a high-quality surface finish.
A
Paint can be brushed on but a much better surface finish is achieved by spraying.
R
Powder coating applies a highly durable and protective layer of polymer onto metal components.
Application
D
The metal component and dry powder are given opposite electrostatic charges. This causes the fine power particles to be attracted to the metal and form an even coat. The coated components move through an oven where the powder particles melt, fuse together and then cure to form a continuous coating.
Fine polymer powders are applied electrostatically before being cured in a baking oven.
Practise it!
Remember it!
State one environmental advantage of using powder coating instead of wet paint spraying.
Finishing processes are used to:
44
(1 mark)
•
apply colour
•
provide protection against corrosion.
Revision Guide
Original material © Cambridge University Press 2022. This material is not final and is subject to further changes prior to publication.
