TIMBER (WOOD) Types, Properties, Joints and Finishes

Families of Wood Softwood Coniferous / Evergreen Needles Cone Producing Fast Growing Widely Spaced Grain Easier to cut and work Pine Cedar Douglas Fir

Families of Wood Hardwood Deciduous Large leaves, lost in winter Slow Growing Denser Grain Harder to work but stronger and more even Oak Beech Mahogany Teak Maple

Families of Wood Manufactured Boards Made out of softwoods or hardwoods that have been industrially reconstituted Only available in large flat boards Made to be inexpensive (eg Chipboard) or to improve the properties of the material (eg strength – plywood) No Grain Direction Can be manufactured out of recycled wood Chipboard MDF / HDF Plywood Blockboard

Types of Wood Available Timber is available in a variety of market forms: Planks Boards (1.8 m+ in length, mm wide) Strips (1 m+ in length 22x22, 35x35, 47x47 mm PAR (Planed All Round)) Dowel ( m in length, diam. 4,6,9,12,15,18,21,25,28,34,38 mm) Mouldings (timber preformed into different cross-sectional shapes such as skirting board). Woods types commonly used in school: Pine – Softwood which is inexpensive, easy to work and acquire with attractive grain patterns Oak – Hardwood which is easily available and hardwearing but relatively expensive Teak – Hardwood which is more expensive and has to be imported but has a pleasing colour and very dense grain MDF – Manufactured board which is very inexpensive and easy to work/machine but looks dull Plywood – Manufactured board which is strong in any direction and fairly inexpensive. Looks good on the sides but can be scruffy on the edges

Methods of Joining wood Joints: Methods of cutting wood to increase the strength of the structure Butt Lap Mitre Finger Dovetail Adhesives: For nearly Everything PVA (Poly Vinyl Acetate) is excellent as it is very strong and inexpensive but it is water based Cascamite is a very strong waterproof adhesive for wood Screws: Woodscrews provide a strong and simple method of joining wood Round Head Countersunk Head Slot HeadPozidrive Head

Methods of Joining wood Knock Down Fittings: Plastic or metal fixings that allow wooden products to be easily assembled and disassembled Enables “Flat-packed” products Inexpensive and easy but not strong, durable or attractive

Methods of Joining wood Hinges: Brass or Steel fixings that enable doors to be added to wooden products BUTT HINGE: Comes in a range of sizes from 13mm to 150mm and is normally used for cabinet doors. They are very strong but cannot be adjusted once they are fitted. BUTTERFLY HINGE: This is often used on light-weight doors and different shapes and patterns are available. They are generally easy to fit. FLUSH HINGE: This type of hinge does not require a recess to be cut. They are not as strong as butt hinges but can be used for light-weight doors and small box construction. BARREL HINGE: This comes in two parts. The threaded part of the hinge is screwed into a pre-drilled hole. They are easy to fit and the hinge can be dismantled. CONCEALED HINGE: These normally come in two sizes (25mm and 36mm. The hinge is adjustable once fitted and is designed with chipboard and MDF in mind. CONTINUOUS or PIANO HINGE: This is a hinge that comes in different lengths and can be bought in brass or steel. It is ideal where a long hinge is required such as a desk top or a cupboard door. Small countersink screws are normally used to fix it in position.

Finishes for wood Finishes are always applied to wood to prevent it drying out and warping Paint: is used for wood which is to be exposed to high wear eg. Outdoors, skirting boards. Oil based / Water based Varnishes: Are used to protect the surface of the wood to enhance the natural grain of the wood e.g. Polyurethane Beeswax or Linseed oil are used to bring out the natural grain and seal the wood Vegetable oils are used for food preparation surfaces