MANUFACTURED BOARDS A REPLACEMENT FOR SOLID TIMBER Manufacture

MANUFACTURED BOARDS A REPLACEMENT FOR SOLID TIMBER

Manufacture boards n Man made woods or manufacture boards have become important as a substitute for solid wood over the past number of years. n The main advantages are ¨ Help conserve tropical forests ¨ They are economic alternative ¨ They come in large sizes with uniform thickness ¨ They are stable

Manufacture boards Types n n n Plywood Strip Core boards Oriented Strand Board Medium Density Fibreboard Chipboard Hardboard

Plywood n n Thin strips of wood glued together like a sandwich Glue is positioned between each layer In plywood each layer is positioned at 90º There always an uneven number of sheets used

Plywood n n Advantages ¨ Very strong ¨ Stable does not warp or shrink ¨ Does not split easily when nailed ¨ Smooth uniform finish Disadvantages ¨ Unattractive edge must be covered with a veneer, moulding or a slip of wood

Strip core boards n Types: ¨ Blockoard ¨ Laminboard ¨ Batten boards n Solid centre or core with veneer on the outsides

Strip core boards n n Advantage ¨ Very strong due to different directions of veneer ¨ Resistance to attack from water, heat, chemical, fungi and insect attack ¨ Comes in large sizes ¨ Blockboard comes in large thickness Disadvantages ¨ Edges need to be covered ¨ Surface can be easily damaged

Oriented Strand board - OSB n n n Looks similar to chipboard but has similar characteristics to plywood Wooden strands or flakes from tree log are bonded together under heat and pressure by glue Strands are aligned in 2 outer layers and an inner core is position at 90º to outer layers giving board strength

Chipboard n n Made by mixing wood chips and glue This mixture is then pressed and pressed to form a sheet Plastic or veneer is then placed over it Used in furniture construction

Chipboard + OSB n n Advantages ¨ Can be veneered ¨ Cheap ¨ Uniform thickness ¨ Makes use of waste wood Disadvantages ¨ Rough surface if not finished with a veneer ¨ Chipboard is weak ¨ Water and moisture make the sheets swell

Hardboard n n n Hardboard is made up from wood pulp Water is added to the pulp The mixture is then pressed under high temperatures and the water is removed Sheets are smooth on one side and textured on the other 3 -9 mm thick

Medium Density Fibreboard - MDF n n Similar colour to hardboard but it is much stronger Manufactured from fibres mixed with synthetic resin binder No water is used so pressing temperatures are lower than for hardboard Both sides have a smooth finish, or boards can have a veneer

MDF Manufacture