Sanding, Filling and Painting Woodwork

Before you can paint or polish the things you have made, the final treatment of the wood and joints must be completed.

Sanding

This is the basic and essential job. Sandpaper is sold in varying degrees of coarseness. The sheets are numbered; the higher the number, the coarser the paper.

Curved surfaces are smoothed by rubbing with sandpaper held in the fingers, but flat surfaces will become slightly rounded if done like this. Wrap the piece of paper round a short block of flat-sided wood and rub the article with this. In doing so there is a risk of rounding off edges. This is acceptable if it is deliberate and fairly pronounced, but if an edge is supposed to be sharp, let it remain sharp. The edges of a table top, for example, should be either a perfect, sharp-edged square or a definite round or bevel.

  • Work along the grain of the wood when sanding. This seems slower than working across the grain, because it is hard to see where you have been. But cross-sanding will show through polish and sometimes through paint.
  • You can get a silky smooth finish by careful sanding, but it does take time and patience. In advanced work, scrapers may be used for getting a final silky finish.

Filling

Besides the smoothing, there will probably be a few little errors to correct. One of the woodworker’s most useful aids is ‘plastic wood’. This is a soft material sold ready to apply in tubes or tins. Press it into any odd cracks or poorly fitted joints and it will set hard to make the error invisible. Try to get the stuff down as far as possible, not just over the top of a crack. Then it will not shift later.

  • Any knots in the wood can be concealed by painting them over with ‘knotting’, a decorator’s material which prevents paint applied later being absorbed by the knot. Before polishing with some materials, such as French polish, you can fill the grain with plaster of Paris. Such work, though, is rather skilled so it is our advice to stick to plastic wood and sandpaper at first.
  • Finishing in paint, polish or stains
  • You can finish your furniture with paint, stains, varnishes or polish. Finishing is a very extensive subject and an entire book could easily be written on the subject. The notes below are just intended to help you get started.

Paint

At first it is probably best to make articles which can be painted. Paint applied over softwoods not only gives a gay colour scheme, it also conceals those small errors in fitting which everyone makes in their first pieces.

painting-wood

  • Remember that in working with raw wood, you will have to give a first coat of primer. This is a kind of sealer for the wood surface and makes a good foundation for the later, decorative layers of paint.
  • Do not omit this primer. It really does make an important difference to the appearance of your work.
  • The real secret of perfect painting is to sandpaper well between every coat of paint.
  • When you apply paint to wood, it has the effect of ‘raising the grain’. The surface becomes rough to the touch. This is especially so with the primer and undercoats.
  • Apply your primer first and let it dry thoroughly. Then go over all the surfaces with sandpaper until the work feels smooth again. Add the undercoat, which has no gloss. Let this dry and then sand it down too. Add another undercoat if you can, sanding after it. Then the whole article will be smooth for the final gloss finish. You can even give two coats of finish, sanding lightly between them, if you aim at a superb gloss.
  • As you see, painting is not a job you can do in an hour, or even in a day. Many beginners spoil their work by rushing to get it painted. It will take four days at least to put a good painted finish on raw wood, but the final result is well worth the trouble and will wear for a long time.
  • For maximum wear and strength, use a Polyurethane-based paint.

Polish

  • Polish is used direct onto the wood to give a beautiful sheen with long lasting qualities The simplest method is to apply ordinary furniture cream to the wood, continuing this until a film of polish is built up. This looks well but does not withstand much wear.
  • French polishing produces very good results but is rather a specialised technique which takes practice and care. You can buy French polish sets with full instructions. Practice on a few waste pieces of wood first.
  • Polishes can be applied to the original wood, or you can first alter the wood colour with colouring stains. If you do this, the effect is very pleasing when carefully applied, but the stain chosen should ‘match’ the type of polishing you intend. Some polishes affect underlying water-based stains, but work well with spirit-based stains. Buy stain and polish together and check at the time that they are compatible.

Varnishes

When you want your work to have a pleasing ‘wooden’ appearance but have used cheap wood with unattractive grain it is probably simplest to apply a varnish stain, in several coats. They are produced in many shades, from nearly clear and pale, through mahogany red to darkest, almost black oak. You should always sand down between the coats, as for painting, or the finished result will have a rough, irritating surface feel and will collect dust at an alarming rate.

  • If the wood you have used is pleasing in colour and grain, you can use a perfectly clear varnish.
  • Some modern varnishes need special preparation, so discuss the requirements for undercoating and priming with your paint supplier.
  • As a final coating over paint, varnish or many layers of polish, apply perfectly transparent hard-wearing lacquers to give a brilliant gloss. These tend to be expensive but certainly add life to the original finish.
  • Always pay great attention to the final sandpapering and filling of cracks with plastic wood, etc. Paint will not cover major defects. Then, between coats of paint one should always use sandpaper again to get rid of the minute particles of dust and wood that invariably appear. By repeated painting and sanding the surface can be improved out of all recognition, and the wear resistance made much greater.
  • Besides paint, one may cover some parts with self-adhesive sheet of various thicknesses and even after painting, on shelves subject to wear, one may apply a self-adhesive transparent sheeting to good effect.

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