Tuesday 8 September 2009

notes write up from - friday 4th september 09 and 2nd october 09


1) We learnt about steels and woods and the many types of both.
There are alot of different types of steels and in a-level tests simply saying "steel" rather than a particular type of steel isn't good enough.
The most commonly used steel is mild steel as it is easier to use and weld and etc.
Timber is a natural sustainable resource.
2) Soft woods are trees like Firs and Pines, more commonly known as "evergreens" as they do not shed their pines. they grow faster than hardwoods and because of that they are cheaper.
3) hard woods are woods such as Mahogany and Oak which take longer to grow and the hardwood trees have leaves. they cost more as more of the woods are rarer like mahogany and ebony trees.

Timber is fiberous which means it is pretty much made up of fibres, 55% of the tree is made up of Cellulose, 28% resin. therefore there is alot of moisture in timber.

Trees that have been cut down usually go through this cycle:
1) Harvest the tree
2) Chop up into boards ( converting )
3) Seasoning it (dry it)
4) Board preperation

I also found out that Quarter sawn wood is stronger than plain sawn wood, it leaves more wastage But it is alot stronger and bows alot less when dried out as the annual rings are shorter which means when it bows along the annual rings it bows alot less as the rings are shorter. Unlike when the wood is plain sawn where the annual rings are usually quite long which get shrunk along thus creating bowing.

Things to think about when buying wood:
1) Physical strength - Timber alot stronger along the grain rather than across it.
2) Asthetic properties - Knotts in wood , colour , complex or simple grain structure.
3) Moisture content - Shrinkage/timber movement , where the wood will be used ie ; outside, central heated house.
4) Protection - Dry/Wet rot , Insects.
5) Cost - Harwoods more expensive, Softwoods Cheaper, Rare woods usually very expensive.
6) Sustainability/Environmental issues- Using timber.
7) Size- Size of board available, may have to glue different boards together if wood size wanted not available.
Some examples of Softwoods are : Scots Pine, Douglas Fir , Paranah Pine, Larch and Spruce
Some examples of Hardwoods are: Ash, Oak , Beech , Mahogany , Teak , Walnut and Mahogany

F.S.C stands for the Forestry Stewardship Council



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