Treatments and Finishes for Wooden Furniture

There is an infinite range of treatments and finishes you can apply to furniture. Older items can be given a new lease of life; but it is important as in most things, to prepare the surface correctly, so that the finished result is worthwhile. Damage to furniture can often be repaired to be indistinguishable from new, using simple restoration techniques.

The main two areas of furniture-finishing are painting new whitewood and the restoration of older pieces, already finished, but looking the worse for wear.

Whenever finishing furniture, make sure that the working conditions are clean. Never work in a dusty garage; protect the floor with newspapers or dust sheets.

It is important, with nursery furniture, to see that any paint materials you use do not contain lead.

Whitewood

Furniture that has not been finished by the manufacturer, generally known as whitewood, varies considerably in quality – from well-made products to those that are rather roughly knocked together.

Because the new wood may not have been adequately seasoned – the ideal moisture content is 12 to 15 per cent – there is risk of warping and twisting. Shrinking may also take place, and this is twice as great across the grain than along it.

So, before applying any type of finish, stand the piece where it will eventually be housed, for several weeks if possible, to allow its humidity to adapt to that of the room. This is important where the home is centrally heated.

Do not buy whitewood furniture showing blue streaks. This indicates the use of sapwood, and the blue will often ‘bleed’ through the subsequent finishing coats.

Preparation

Before applying any type of finish, smooth the entire surface with flour-grade abrasive paper, preferably garnet as it has a fine cutting action, wrapped around a wood block of a size you can conveniently hold in the hand.

Quirks and enrichments will have to be tackled by wrapping the abrasive paper round your index finger or by using a blunt, pointed piece of wood. You could also use a fine nail file.

Gaps may have to be filled with wood filler, or with a cellulose powder filler. Knife this well in and finish slightly proud, so that it can be rubbed down level when hard. As shrinkage of the stopping material will occur, several applications are better than one, leaving time for each to harden, before applying the next.

In addition to stopping up obvious gaps, the surface may need filling – that is, making good the cellular construction of softwoods and the pores of some hardwoods.

Do this with a cellulose filler as for gaps but, instead of knifing it on in a thick consistency, mix to a cream and brush on in the direction of the grain. Leave for a few minutes and wipe off across the grain. When hard, smooth in the direction of the grain.

Whenever you are rubbing down timber, follow the direction of the grain. If you rub across, the hard portions will show scratch marks.

Some cheap plywoods are so furry that, however much smoothing is done, it is difficult to get rid of ‘hairy’ bits. Give the surface a coat of wood primer, thinned with the same quantity of white spirit and leave for several days to harden; then rub down and the hairs will snap off.

Touch over the exact area of exposed knots with patent knotting. Leave to dry for a few minutes and touch in again, this time extending the area slightly. Do not go too far, as paint does not adhere all that well to the shellac content of the knotting. This ‘staggered’ application will help to ‘feather off’ the edges of the knotting, so that a bulge is not obvious.

Leave for some hours before painting or the paint film will entrap solvents and cause blistering.

If a knot looks particularly resinous or is loose, cut it out. Stop up the hole with wood slightly thinner than the thickness of the piece you are treating. Glue it in position, fill proud with filler and sand level when dry.

Knots that are only moderately bad can often be made less virulent by warming them with a blow lamp and wiping off exuding resin with acetone or white spirit.

Where paint fails to adhere over patent knotting, touch in with a thin finishing coat. This will have far better inherent stickiness than either primer or undercoat. When dry, prime and undercoat all over.

Undercoats fill minor imperfections and give ‘body’ to the finish. Since these are highly pigmented, they tend to look ‘ribby’ – and this will appear through the finishing coat. To obviate this, apply the undercoat with a foam roller, leaving the brush for twists, twirls and corners.

10. November 2011 by admin
Categories: Handyman Tips | Tags: , , , , , , , , , | Comments Off on Treatments and Finishes for Wooden Furniture

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