key words Flashcards
what does conversion do
turn trees into timber
what are the two methods of conversion
slab / plain sawing
quarter sawing
what slab / plain sawing
produces timber which is less stable and more prone to warping
what is quarter sawing
produces more stable timber, often with more attractive grain patterns but is more expensive
what is seasoning
newly cut timber is left to dry
what is the percentage seasoning is aiming to reduce the moisture of timber
reduce the moisture by 20 percent
what are the benefits of seasoning
- increases strength and stability of timber
- reduce moisture = reduce risk of timber casuing corrosion to the surrounding metal work
defects of timber
if not seasoned correctly its shape can change which makes it more difficult to use
what are knots and what can they do to wood
where branches of the tree grew
can weaken the structure of wood as well as produce irregular grain which makes it more difficult to work iwth
what are veneers
thin layers of wood that have been peeled off the truck of a tree
what are veneers made from
hardwood
- more decorative than soft woods
what is laminates
process of gluing layers of material together
veneers = plywood
what does lamination do
improve strength
improve aesthetic
what is plywood
kayers of hardwood laminated together
arranging layers so that the grain is 90 degrees to the prevuious layer, a very strong material is made
what is forest stewardship council
non-gov
promote responsible management of worlds forest
where does hardwood come from
trees with broad leafs
where does softwood come from
trees with needle - like leafs
where does man amde wood come from
factories
what are the benefits of using man-made over natural timbers
more strength in timber pieces
cheaper
more bigger pieces
grain eliminated
more stable
lighter
ways you couold fabricate a joint so that it can be flat-packed
provide holes for screws / dowels
provide know/down fittings
what is a dowel joint
connect two pieces of wood by drilling dowel holes in each piece and using a wooden peg (the dowel) to attach them
advantages of dowel joint
much stronger than butt joints but look the same
disadvantages of dowel joint
difficult to line holes up without a dowelling jig
when are halving joints used
in framework, where one piece of timber crosses over another
