Large leaves, lost in winter - Toot Hill School · • Large leaves, lost in winter • Slow...
Transcript of Large leaves, lost in winter - Toot Hill School · • Large leaves, lost in winter • Slow...
• Coniferous / Evergreen
• Needles
• Cone Producing
• Fast Growing
• Widely Spaced Grain
• Easier to cut and work
• Pine
• Cedar
• Douglas Fir
• Deciduous
• Large leaves, lost in winter
• Slow Growing
• Denser Grain
• Harder to work but stronger
and more even
• Oak
• Beech
• Mahogany
• Teak
• Maple
• 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
Timber is available in a variety of market forms:
• PlanksBoards (1.8 m+ in length, 50-200 mm wide)
• Strips (1 m+ in length 22x22, 35x35, 47x47 mm PAR (Planed All Round))
• Dowel (0.9 - 2.4 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 asskirting 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
Wood was cut from living trees
It is made up of long “straw-like” cells which carried the water to the leaves.
When the wood is cut, the wood begins to dry out.
However, some moisture remains and to properly “season” wood can take years
Commercial timer is kiln dried to speed up this process
Poorly seasoned timer has a tendency to warp and/or crack
The ideal moisture content for timber to be made into products is between 10-20% water.
Therefore it is important to apply a finish to seal the wood as well as protect and enhance the appearance.
Heart Wood
Because of the lengths of the endgrain, wood is less likely to warp when it is cut from the heartwood
Therefore it can be rift sawn (best) or quarter sawn (2nd best) to get better quality but it is more wasteful (£$£$£$£)
Thin VENEERS can be cut from the logs to create plywood or for use in laminating
Veneers can be LAMINATED together to form strong, often curved shapes. Because the layers are bonded strongly with adhesive, the cannot slide against each other and so are very strong
Formers are used to hold the veneers while the laminating takes place
(either one with clamps or 2 squeezed together)
Eames Lounge Chair
Ikea Poang
One of the most common ways we see and hear of Laminates is on flooring and worktops
Cheap manufactured boards like chipboard can be laminated to either make them look like real wood or to add a colour.
Themosetting Polymers like Melamine Formaldehyde can not only add colour but also provide a heatproof (non-melting) surface (so hot pans can be put down in a kitchen
Laminate flooring is a cheap and hardwearing alternative
Methods of cutting wood to
increase the strength of the
structure
Butt
Lap
Mitre
Finger / Comb
Dovetail
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
Contact Adhesive is excellent for
applying laminates across a large area.
Screws: Woodscrews provide a strong
and simple method of joining wood
Round Head Countersunk Head
Slot Head Pozidrive
Head
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
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 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