PREPARING NATURAL WOOD SO THAT A FINISH CAN BE APPLIED

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PREPARING NATURAL WOOD SO THAT A FINISH CAN BE APPLIED

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WHY IS A FINISH APPLIED TO WOOD?

A finish is applied to wood and in particular natural wood, for a variety of reasons. A good quality finish such as varnish, offers a level protection to the surface of the wood. A finish will enhance the natural grain (only if the surface is prepared first), so that it offers a satisfying visual effect. A quality finish will lift the perceived value of the product. Preservation of the wood is another reason for applying a finish, lengthening the lifespan of the piece of furniture / product. This is especially important if the product is to be for external use, such as garden furniture. A dye applied as a finish, will change the ‘colour’ of the wood, giving the illusion that ‘cheap’ pine is actually more expensive mahogany. A finish will provide a gloss, matt of matt finish, depending on preference of the customer.

INITIAL PREPARATION

The preparation of a surface is crucial before a finish is applied. First select the material very carefully, avoiding cracks, holes and even knots, although often it is not always possible to obtain faultless material. Even small imperfections will be seen, once a finish applied, so it is best to avoid using difficult material. If recycled material is used, more preparation may be necessary.

Filling cracks can be achieved successfully in a number of ways. The traditional method is the mixing a small amount of PVA or cascamite with wood dust to produce a paste, which is then applied to cracks and gaps. This can be really effective.

A range of premixed wood fillers are available, as powders to be mixed with water or straight from a tube. Dye can also be added to fillers, so that they blend in with the natural wood colour. This is even an effective when using a general filler such as ‘Polyfilla’. Remember to apply wood filler sparingly, as it will be necessary to sand down / levelled the surface when the filler drys.

Shellac is supplied in stick form, in various shades. Shellac is actually resin secreted from tree loving bugs found in India and Thailand. It is melted into holes / cracks in the wood with a soldering iron and then levelled, usually with a chisel.

Wax sticks can also be purchased and again they are available in a variety of colours and shades. These are very useful when there is need to repair a scratch, nail hole or crack. The wax stick is warmed up (minimal heat required) until it becomes soft and then it is pressed into the hole / crack, with a suitable tool. The surface is then levelled with glass paper. If necessary, wax sticks can be mixed to produce the required shade.

SHELLAC STICKS AS A FILLER

STAGE ONE:
Heat the shellac with a heat source, such as a soldering iron and as it melts ensure that it fills the crack / hole.

STAGE TWO:
When the shellac cools, use a chisel to remove the excess, levelling the surface.

STAGE THREE
Use glass paper to smooth the surface so that it is ready for varnish or another finish.

WAX STICKS AS A FILLER

STAGE ONE
Wax stick is heated with a hair drier, until it becomes soft and pliable.

STAGE TWO
Cut away a small amount of wax from the stick and press into the crack.

STAGE THREE
Smooth the wax with a spreader, until it is almost level with the surface.

STAGE FOUR
When the wax is cool, use glass paper to smooth and level.

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