Working with man-made boards

You only have to make some simple furniture or a few shelves from natural timber to realise just how expensive wood is. Man-made boards are the cheap alternatives. But they’re not just substitutes for the real thing. In many situations, they have much more to offer than a low price. Most resist shrinking, swelling and warping better than natural woods. And because all are carefully manufactured for consistency in use, it’s worth knowing exactly what each board can and can’t do.

Fibreboards

Standard hardboard is the cheapest of all man-made boards and is produced by compressing wood fibre into hard, brown sheets. It is smooth on one side with a rough, mesh pattern on the other. Because it contains no adhesive, it’s relatively weak, and if it gets wet it’ll break up. But it’s worth considering as a cladding, especially if you want something you can easily bend round curves.

• Thicknesses 2mm (5/64in) to 13mm (>/2in); 3, 5 and 6mm (Vs, 3/i6 and 1Ain) are by far the most common.

Tempered hardboard is standard hardboard which has been treated to improve its strength and resistance to moisture, and is therefore suitable for use outdoors. It shouldn’t be confused with oil-treated hardboard, which has only a short-lived and superficial moisture-resistance. Decorative hardboards may be covered with PVC or melamine. They may also be factory-painted in a process known as ‘enamelling’. Both types are easy to clean, but only their surfaces resist water. You can also get standard hardboard ready-primed for painting.

Moulded hardboards are often used as wall claddings. Some

S even have a paint or plastic finish. You can buy them with embossed and textured designs -woodgrain, tile and brick being among the most popular. But you’ll probably have to order the less common types. Perforated hardboard has holds or slots in it. It comes in a range of designs, including plain ‘pegboard’ (with regular rows of small holes).

Duo-faced hardboard is smooth on both sides.

Medium board is softer and weaker than the others, and this is the main reason why it’s used in thicker sheets – 6-13mm (’/j-V^in). The denser type HM, also called ‘panelboard’, is used for cladding partitions in much the same way as plasterboard. The velvety grey/ brown type LM is used for pinboards, etc. Both are available in versions made to withstand high humidity, and may also be flame-retardant, oil-treated, duo-faced or lacquered. Softboard (‘insulating board’), also made from fibres, is not compressed and is therefore even lighter and less dense than medium board. Apart from insulation, it too is used for pinboards.

MDF (medium-density fibreboard), although expensive and hard to obtain, is an extremely versatile material and can often be used instead of solid timber. It’s far stronger than other fibreboards because it includes adhesive (like chipboard), and is highly compressed so that it’s far denser than medium board. This means it not only does everything other man-made boards do, but also overcomes their two main problems – it doesn’t flake or splinter, and when sawn it gives a smooth, hard edge which doesn’t need disguising (it can even be stained to match a face veneer).

• Thicknesses 16mm (%in) to 35mm(13/ain).

Chipboard

Chipboard is made by bonding wood chips with plastic resin. It’s quite strong, and one grade is tough enough to be used for flooring. However, it’s difficult to work it neatly or to screw into it effectively: the thread breaks up the chips so the screw pulls out under load. Few chipboards can withstand moisture, though grades for external use are available.

– In the simplest type of chipboard, all the chips are approximately the same size – but usually those nearer the surface are finer. The surfaces mostly come filled and sanded, ready for decoration, and some are even primed for painting. Much chipboard is sold with a wood or

PVC veneer, or a melamine laminate. Plastic-faced boards come in a limited range of colours and wood effects.

– Thicknesses range from 4mm (3/i6in)to40mm(1 1/2in);12,18, 22 and 25mm (V2, ¾, % and 1 in) are commonest.

Plywood

Plywood is made by glueing wood veneers in layers. The grain of each veneer is laid at right angles to the ones on either side, the aim being to stop the sheet warping (though this isn’t always completely successful). The sheet has an odd number of layers -hence the names, ‘three-ply’, ‘five-ply’ and so on. This ensures that the grains of the outside veneers always run in the same direction.

– Birch and gaboon are two of the main woods used for plywood.

Ideally, the veneers should be of the same wood and the same thickness. In fact, the outermost ones are always thin, and you’ll often find thick veneers made of less dense timber in the centre.

– ’Stouthearf plywood is the name given to a sheet where there is only one central thick veneer. This makes the edges of the sheet harder to work.

– Some plywoods have a decorative finish, which can range from a factory-applied paint or a plastic laminate to a particularly attractive wood veneer. Others are grooved to resemble matchboard cladding.

– Two grading systems are used for plywood. The first indicates the number of knots, joins and other blemishes in the surface veneers. Its three grades are A (perfect), B, and BB for rough work. Where a board appears to have two grades (eg, B/BB), the first refers to one veneer the second to the other. The other system grades the adhesive between the veneers. WBP (weather-and-boil-proof) will withstand severe weathering for at least 25 years; then, in order of durability, come BR, MR and INT, the last of which is only for dry internal use. The adhesive may outlast the veneers; but especially durable types of plywood (eg, marine plywood, used in boatbuilding) are also available.

• Thicknesses range from 3 to 6, 12 and 19mm (Va, ‘A, V2 and %in), but thinner and thicker types are made.

Biockboard

Biockboard is a bit like stout heart plywood. It has a thick core of softwood slats glued side by side, and two outer hardwood veneers, one of which may be decorative. The veneer grain runs at right angles to the core grain. In more expensive (double-faced or five-ply) boards, two outer veneers are used on each face, which makes the core joins less likely to show through.

– Biockboard is very useful where you need a relatively light, inexpensive slab, eg, for a tabletop or door. However, it’s hard to get the edges neat, especially those where the core endgrain shows: there are often unsightly gaps between the slats, too. Fixing into these edges can be a problem for the same reasons.

– Surface veneers and adhesives are graded as for plywood, but no biockboard is really suitable for external use. There’s no WBP grade , and anyway the board contains too much softwood to be truly durable. Laminboard is a superior biockboard. Its core is made from thinner, more uniform slats with no gaps between them. But it’s hard to get.

– Thicknesses range from 12mm (1/2in)to32mm(1’/iin); occasionally up to 50mm (2in).

Buying boards

Say exactly what you want -name, grade, finish, thickness. A good timber merchant’s catalogue helps a lot. Remember you can get a number of different veneers – from rosewood to oak – on chipboard, plywood and biockboard.

Think carefully how much you want. There are several ‘standard’ sheet sizes -commonest is 2440 x 1220mm (8 x 4ft). Buying a whole sheet is cheapest. If that’s too much, or you have no power saw. Sma sheets may be available. Failing that, get it cut specially – but allow a little extra for trimming at home; shop sawing may not be very neat or accurate. -K

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