Particle boards are very stable with little dimensional change (shrinking, warping, etc.), and even the absence of long fibres can be turned to advantage, for. as there is no end grain, boards can be glued and butt joined together at any angle without supporting constructional j oints. Working properties are as for other prefabricated woods and present no problems; they can be cut, planed, shaped, routed and bored with all normal tools, provided the cutting edges are kept sharp and feed speeds a little slower than for solid timber. For quantity production, tungsten-carbide cutting edges are recommended, as the high glue content dulls normal steels. Planing to thickness is not advised, as cross planing is inevitable and bound to create rough patches, but the boards are obtainable in a variety of thicknesses to close tolerances, and where surfaces have to be reduced it is better to sand them down. They are not intended for exterior use as the edges are susceptible to moisture penetration, although some manufacturers now incorporate a proportion of wax emulsion in the glue which gives a certain measure of protection. Screw- and nail-holding properties are not as good as long-grain materials, but sufficient for all but the heaviest loadings.
Uses for particle boards are the same as for blockboards and laminboards, viz. carcasses, flush doors, shelving, panelling, partition-work, etc. A point in their favour is that they have no hidden defects (see Defects in plywoods, etc., below) and are thus eminently suitable for large veneered table-tops polished to a high gloss, and as a substrate for plastic laminates. They can be satisfactorily veneered and the best-quality boards no longer require counter-veneering to hold back any tendency for the wood chips to show through the face veneers. Thicknesses of standard boards range from 3/8 in (9 mm) to l3/8 in (36 mm), and furniture-boards from 1/2 in (12.5 mm) to 7/8 in (21 mm), and boards can be obtained already veneered with a wide range of woods.
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