From DIYinfo.org
Before you buy paint, make sure that it fits into your colour scheme by holding a colour card against curtain or carpet samples. If possible, take home a small tin of paint and try it out on a wall. Paint tends to look darker once it is covering a wall so, if you are doubtful about which shade of a colour to buy, choose the paler one. The colour of paint can vary from batch to batch so when you buy paint make sure that all the tins have the same batch number.
There are two main types of paint. Conventional paints are liquid in consistency. They are sometimes referred to as oil based (gloss) for wood and metalwork, and water based (emulsion) for walls and ceilings. Oil based paint must be used with an undercoat. Emulsion paints do not need an undercoat but two or more coats may be needed to obliterate the colour of the surface, The first coat of emulsion acts as an undercoat.
The second type (specially formulated for beginners) is non drip paint, which is also called thixotropic, jelly or one coat paint. The paint looks like jelly in the tin and becomes liquid when it is brushed onto a surface. Then it gels again, making it less prone to drips and runs. Non drip paint has good covering power, because it is thicker than conventional paints and incorporates the undercoat. For this reason, non drip paint is no more expensive than other paints in the long run, even though it often costs more per litre. Non drip emulsion paints are supplied in both jelly and solid form. The application of a roller to the solid paint which is sold in a tray, liquefies the paint so that the roller picks up just enough. The non drip quality makes it ideal for painting ceilings. Never stir non drip paint before use, even if it looks lumpy in the tin. If the paint becomes liquid because it has been accidentally stirred or shaken, leave it to set again before using it.
The final coat of paint (the topcoat) can have a gloss, semi gloss or matt finish. Alternative names for semi gloss include egg shell, silk, satin and sheen, depending on the paint manufacturer. The glossier the paint, the tougher and more durable the surface will be. Paints also tend to be stronger and more weather resistant if they include a synthetic resin, such as polyurethane.
Some paints contain additives which make them more fire resistant than ordinary paint. They help to reduce the spread of flames, which makes them suitable for painting expanded polystyrene tiles, wood and any combustible surface.
| Choosing Paints For Every Purpose | |||
| Follow the manufacturer’s advice on the paint tin. This will usually state what surface can be coated with the paint, the length of drying time and the expected covering power. | |||
| Coating | Where To Use | Description | Advice |
| Undercoat |
Interior and exterior primed surfaces, before applying topcoat. Dark surfaces which are to be painted a paler colour. |
A full bodied paint with more pigment than topcoat. Has good covering power. |
Apply a second coat if under colour shows through the first. Wash tools with turps after applying undercoat. |
|
Oil-based, or synthetic, gloss paint (topcoat) |
Interior and exterior woodwork and metalwork. Can also be applied to walls and ceilings, if desired. |
For both decorative and protective purpose. A relatively thin coating with little covering power. |
On wood always use with an undercoat. This is not necessary on metal. Apply two thin coats of gloss, rather than one thick one. Do not allow paint to harden on brushes after use. Clean them immediately with turps. |
| Non drip (thixotropic) paint |
Gloss for interior and exterior woodwork. Emulsion for interior walls and ceilings. |
Gloss is brushed on, emulsion is applied with a roller. Combines undercoat and finish coat. |
Two coats might be needed when gloss paint covers a dark colour. Clean tools for gloss paint with turps; emulsion with water. |
| Interior emulsion paint | Walls and ceilings |
Water based, which makes tools easy to clean. Dries quickly and does not leave brush marks. Acrylic resins are sometimes assed to make the paint more hard-wearing. |
Does not need an undercoat. Can be diluted with water to form its own primer. Use a roller for fast coverage. Two or three coats may be needed. Clean tools with water and soap or detergent. |
| Exterior emulsion paint | Outside walls |
Water-based paint but extremely hard wearing. Keeps the surface looking clean for longer because a very small part of the coating washes away with rain, taking dirt with it. |
Fill any fine cracks before painting; the paint is not thick enough to fill them. Apply with a brush at least (125mm) wide, or a shaggy roller. Clean tools with soap and water. |
| Microporous (acrylic) paint |
Exterior, new, untreated timber. Can also be applied to most interior surfaces. |
A water based paint. Some types are one coat, combining primer, undercoat and topcoat. Others are two coat; prime: primer in the first and undercoat And topcoat in the second. Allows surface to breathe. Keeps out damp. Reduces blistering and flaking. |
Drying time is much faster than with oil based paint, so microporous is useful for a quick repaint. Gloss microporous is not as shiny as oil based glosses. Clean tools with water and detergent, as for emulsion paints |
| Masonry paint | All types of exterior rendering |
Most are strengthened with materials like silica, nylon, sand, which help to form a more durable finish. |
Stabilise the surface with surface binder and use fungicide as necessary, before applying paint. Will fill any very fine cracks. Clean tools with water. |
| Bituminous paint |
Exterior metal pipes and guttering, and over concrete |
A special paint for waterproofing surfaces. |
Other paints will not take over it, so once you have applied it to a surface, continue to used bituminous paint. Clean brushes with kerosene, but even when clean keep only for bituminous paint. |
| Textured (plastic) coating |
Interior walls and ceilings with uneven or unattractive surfaces. |
A compound much thicker than paint. Forms a permanent coating which is extremely difficult to remove. |
Apply with a shaggy roller, unless the manufacturer specifies, otherwise. Coat with emulsion once dry. Will not take a wall covering. Clean tools with turps. |
| Anti-condensation or anti-mould paint |
Surfaces in bathrooms, kitchens and any room likely to have a steamy atmosphere |
Semi porous emulsion which absorbs moisture in the air and allows it to evaporate as the air dries. Prevents droplets forming on the surface. Often contains a fungicide to deter mould. |
Apply as interior emulsion. Will not cure condensation, only reduce its effect on the painted surface. Clean tools with water and detergent. |
| Enamel paint |
Metal and wood. Children’s toys and furniture. |
Non toxic. Contains very finely grounded pigment. Tends to be expensive. Some enamel’s are available with a rust inhibitor |
No primer or undercoat needed. Enamels are best for small jobs. Clean brushes with turps. |
