Supply ~ paint is usually supplied in metal containers ranging from
250 millilitres to 5 litres capacity to the colour ranges
recommended in BS 381C (colours for specific purposes) and BS
4800 (paint colours for building purposes).
Application ~ paint can be applied to almost any surface providing
the surface preparation and sequence of paint coats are suitable.
The manufacturers specification and/or the recommendations of
BS 6150 (painting of buildings) should be followed. Preparation of
the surface to receive the paint is of the utmost importance since
poor preparation is one of the chief causes of paint failure. The
preperation consists basically of removing all dirt, grease, dust and
ensuring that the surface will provide an adequate key for the
paint which is to be applied. In new work the basic build-up of paint
coats consists of:-
- Priming Coats † these are used on unpainted surfaces to obtain
the necessary adhesion and to inhibit corrosion of ferrous
metals. New timber should have the knots treated with a
solution of shellac or other alcohol based resin called knotting
prior to the application of the primer. - Undercoats † these are used on top of the primer after any
defects have been made good with a suitable stopper or filler.
The primary function of an undercoat is to give the opacity and
build†up necessary for the application of the finishing coat(s). - Finish † applied directly over the undercoating in one or more
coats to impart the required colour and finish.
Paint can applied by:-
- Brush † the correct type, size and quality of brush such as
those recommended in BS 2992 (painters and decorators
brushes) needs to be selected and used. To achieve a first
class finish by means of brush application requires a high
degree of skill. - Spray † as with brush application a high degree of skill is
required to achieve a good finish. Generally compressed air
sprays or airless sprays are used for building works. - Roller † simple and inexpensive method of quickly and cleanly
applying a wide range of paints to flat and textured surfaces.
Roller heads vary in size from 50 to 450 mm wide with
various covers such as sheepskin, synthetic pile fibres, mohair
and foamed polystyrene. All paint applicators must be
thoroughly cleaned after use.
Paints and Painting