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15 manufactured boards
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- 2. Chapter 15 Manufactured boards: Areplacement for solid timber.
- 3. Manufacture boards Man madewoods or manufactured boards have become important as a substitute for solid wood over the past number of years. The main advantages are – Help conserve tropical forests – They are economic alternative – They come in large sizes with uniform thickness – They are stable
- 4. Manufactured boards Makingboards and sheets from wood or wood products – Veneers – Sawdust – Wood fibres – Wood strips – Wood flakes
- 5. Plywood Thin strips ofwood glued together like a sandwich Glue is positioned between each layer In plywood each layer is positioned at 90º There are always an uneven number of sheets used
- 6. Plywood Rotary cuttingof the veneer Make-up of plywood – Veneers at 90° to each other – Odd number of layers (5/7)
- 7. Plywood 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
- 8. Types of plywood WBP – Water and Boil Proof – Exterior grade Marine plywood – Boat building – Exposed situations, roofs
- 9. Blockboard Strips ofsoftwood glued together and faced with veneers Does not split easily Can screw into the edge Wide sheets (8’ X 4’)
- 10. Blockboards Advantage – Very strongdue 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
- 11. Pineboard/lamwood Made fromthin softwood strips, glued together Makes a wide board in softwood Uniform thickness (12 – 25mm) Boards tend to cup Useful for projects Hardwood examples can be obtained
- 12. Oriented Strand board- OSB 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
- 13. OSB – orientedstrand board
- 14. Chipboard Made by mixing woodchips 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
- 15. Chipboard Wood chipsare glued Pressed into sheets Often faced with wood veneer or plastic laminate Edges of the board need to be covered
- 16. Edges • Edges ofchipboard should be covered
- 17. Chipboard + OSB 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
- 18. MDF (Medium densityfibreboard) Very popular board material Often faced with veneer or plastic laminate Made with fine wood fibres in three layers Need to drill into face before nails or screws are inserted Fine dust is harmful
- 19. Medium Density FibreboardMDF 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
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- 22. Hardboard Hardboard is madeup 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 3-9mm thick
- 23. Hardboard • Available inthin sheets • One face smooth, one textured • Often faced with plastic laminate • Back of cabinets, base of drawers • Only used indoors
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- 25. Name thefollowing manufactured boards − Pineboard − Chipboard
- 26. Three layersof wood are being glued to make plywood. Draw a sketch to show the direction in each layer.
- 27. The edgesof chipboard look poor. Draw a sketch to show how the edges are covered.
- 28. State someadvantages of manufactured boards − − − − − − − − Large sheet sizes Cover large areas easily Uniform thickness Stable – no shrinkage Do not warp Use woods efficiently Little waste Often veneered over – helps to save the rainforests
- 29. What dothe letters WBP stand for? Water Boil Proof