Painting Skills

Paint is used both for decoration and protection. Paints intended for outside work are designed to stand up to bad weather. They can be used inside, but there are some inside paints that are unsuitable outdoors. Modern paints have synthetic ingredients and some require different techniques from traditional paints. Read and follow the directions on the can. Varnish may be regarded as colourless paint and treated in the same way.

Tools Good paint brushes produce better work. The widest brush that can be used on a surface would be preferable, but to economize use narrower brushes — 75 mm (3 in) for general use and down to 20 mm (¾ in) for narrow parts.

For broad surfaces and many paints a roller and its tray is quicker to use and produces an even finish. When your brush or roller are out of use overnight, immerse them in solvent for an oil paint or water for emulsion paint. White spirit will clean out oil paint, or you can use a paint cleaner fluid, then wash with detergent and clean water.

Paint can be stripped with a chemical stripper or burned off with a blowlamp (gas or paraffin) and a scraper. A filling or putty knife is needed for pressing stopping into holes or cracks. Glasspaper wrapped around a block of wood can be used for sanding. A wire brush will remove rust from iron. Masking tape is useful for defining areas and divisions between areas of different colours.

STRIPPING

If an old paint surface is sound, there is no need to remove it before repainting. However, it shouldbe cleaned. Wash with warm water and detergent, then wipe over with clean water and allow to dry. If any gloss remains, rub with glasspaper wrapped around a block of wood or scour with water and cleaning powder, followed by clean water. If there are bare patches, paint them and sand the whole surface level before adding an all-over coat.

A chemical stripper.

If paint is flaking or is in bad condition, it should be removed. If a chemical stripper is used, read the directions — the chemical can damage clothing and skin. The stripper will cause the paint to bubble and it can then be scraped away. For a broad surface use a straight-edged stripping knife with a pushing action. For mouldings and shaped parts it is easier to pull a shave hook. Neutralize the surface as directed by the manufacturers, then leave to dry.

To strip with a blowlamp, experiment first to get the correct distance for the flame. Swing the lamp so as to blister the paint without charring the wood. As the blisters form on the paint, scrape them off. Do not use a blow lamp on plaster, asbestos or around glass. Ousters.

SURFACE PREPARATION

The quality of the final painted surface depends as much on adequate preparation as on the application of the paint.

Nails should be punched below the surface. Knots, which tend to stand up because of their hardness, should be sanded level. Nail holes and cracks should be stopped. Buy stopping in a tube or a powder which is mixed and pressed in with a filling or putty knife, although an old table knife will do. Leave it slightly raised to allow for sanding. Plastic wood makes a harder stopping and it could be used if wood has broken away and has to be built up to trim to shape. Sand the surface all over after stopping.

Some porous wood also needs filling, using a paste which is rubbed into the wood and sanded to prevent absorption. Some hard-board is also very absorbent.

PAINT CHOICE

The traditional paint for most purposes was oil-based, with pigments and natural resins. The modern equivalent is synthetic and has improved drying qualities and durability. A good gloss oil paint is best for outside work on wood or metal. Normally it is applied with a brush. A non-drip version is like a thick jelly, which can also be brushed.

Polyurethane paint in a one-can form has similar qualities to oil paint, with increased waterproofness. A two-can version, mixing the parts before use, is one of the toughest paints made.

Acrylic paint can be thinned with water and is suitable for inside surfaces. Finishes are semi-gloss and matt. It will make steel rust if a primer is not used first.

Emulsion paints can be used on interior walls and ceilings. They are not satisfactory on woodwork. Washable distempers are similar in effect to emulsion paints and are now mostly used for walls and ceilings. Both can be used with a brush or roller. Emulsion comes in matt, silk and gloss finishes; distemper is matt.

Varnishes are made in several qualities. The best for exterior work is boat varnish and this is also toughest for interior use. Normally, varnish has a slightly orange colour. Varnish stain has a colour added, but a better result is obtained by staining the wood and then using clear varnish.

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