| The term paint is used to describe a wide variety of | | | | They will slick firmly to the surface, seal, and provide |
| coatings which are applied as a liquid and | | | | a key for subsequent coats of paint. They should |
| subsequently dry to form a durable, decorative and | | | | also be used when you want to paint over sound old |
| apparently solid film. Paint is a very versatile coaling | | | | paintwork with a new. completely different, type of |
| medium - it can be used on almost any surface no | | | | paint. In this situation, primers and sealers prevent |
| matter how intricate, and can be applied in a number | | | | chemical attack between the different paints, reduce |
| of different ways. | | | | the likelihood of the new paint not sticking to the old |
| Most paints are mixtures of three main ingredients - | | | | one and should stop the colour of the old paint |
| a pigment, a binder and a liquid. The colour and | | | | bleeding through. |
| opacity of paint are due to the presence of a | | | | A primer by itself is not permanent protection for |
| pigment. This can also impart considerable protection | | | | the surface below - it should be painted over with an |
| to the other ingredients by harmlessly absorbing | | | | undercoat or topcoat as quickly as possible. |
| otherwise destructive ultra-violet light. The simplest | | | | Undercoats. |
| paint is whitewash which once applied is merely a | | | | Normally, you use one of these immediately after a |
| coating of pigment in this case chalk. Whitewash | | | | primer when building up a paint system, or on old |
| does not offer much protection to the surface | | | | paintwork when you are changing the colour |
| beneath it because it does not generally contain a | | | | significantly. Undercoats are designed to have: good |
| binder (sometimes called a film former or resin). A | | | | opacity or hiding power so that you can cover a dark |
| binder holds the pigment together and sticks it to the | | | | colour with a lighter one without having to apply |
| surface. Binders are normally solids, so to produce a | | | | many coats of paint; a high build capability so that |
| paint which can be spread over an uneven surface | | | | you can put on a thick coat of paint around corners |
| the binder is usually broken up into small pieces and | | | | and over sharp edges where paints tend to be |
| suspended in a liquid. | | | | spread too thinly; and a soft finish which can be |
| Paints by use. | | | | rubbed smooth easily with abrasive paper (ready to |
| An ideal 'all purpose' paint should satisfy a number of | | | | lake the next coat). |
| criteria - it should stick strongly to the surface it is | | | | Topcoats. |
| applied to, it should cover well, it should leave a | | | | These are dual-purpose paints providing both a |
| decorative and desirable finish, and should last, | | | | decorative and protective final coat. They are often |
| particularly when used outside. No one paint performs | | | | available in a choice of finishes matte, eggshell, satin |
| all these functions well; as a result, paints are | | | | and full gloss. The choice of the topcoat affects the |
| formulated for specific uses. For example, when | | | | overall appearance of the paint system, its durability |
| painting woodwork, a three-coat system is usually | | | | and its ability to withstand knocks. |
| needed consisting of a primer (to stick to the surface | | | | One-coat paints |
| beneath), an undercoat to cover well) and a top-coat | | | | Some modern paints, including microporous paints and |
| (to give a pleasing, durable finish). | | | | preservative wood-stains. are designed to act as |
| Primers and sealers. | | | | their own primer on bare woodwork and, often, only |
| These should be used on new or exposed | | | | one, or at the most two coats are needed. |
| woodwork, brickwork, metalwork, plaster and so on. | | | | |