69952
Description
Flashcards by Alec Stevens, updated more than 1 year ago
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Created by Alec Stevens
almost 11 years ago
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| Question | Answer |
| Plywood | Layers of veneers bonded using glue. Very strong and stable because each sheet has it's grain at 90° to previous sheet. Always an odd number of layers. Does not warp and distort because of this structure. However if it gets wet it can delaminate and layers will separate. Waterproof glues are thus used for outside plywood. |
| Blockboard | Strips of softwood about 25x25mm positioned edge to edge and covered by a veneer either side (normally beech). This is glued together under high pressure. Normally water based glues and so only suitable for indoor work. Good resistance to warping because of structure. If cut the edges will have to be covered with veneer strip to cover up internal structure. |
| Carbon Fibre | Composite of carbon fibre + resin. Can now be injection moulded and extruded. Very strong, light and versatile in terms of the shapes which can be made. Expensive but good for high performance equipment. |
| GFRP | Composite of thermosetting resin reinforced with glass fibres. Matting or strips or spray on. Glass provides tensile strength for resin's compressive strength. Can be as strong as steel. Good weight to strength ratio, but can shatter under high impact. Can be degraded by water if not gel coated. |
| MDF | Composite. Medium Density Fibreboard. Cheap, common/widespread. Made from wood waste mostly. Wood chips subjected to heat/pressure to soften fibres and produce a pulp. Pulp mixed with resin and pressured. Can be laminated. No grain so can't split or warp. Careful when drilling, cutting or sanding because dust can cause irritation + breathing problems. Often veneered with nice wood or Fomica. VERY HEAVY/DENSE. |
| Chipboard | Composite similar to MDF but with small chunks/chips of wood. Comes in High, Medium and Low Density forms. Fairly soft in normal density. Only suitable for inside work, veneered. If it gets wet, will absorb then swell then break down. |
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