Test 1 Hard goods

Why wood is used

excellent strength

retains shape under pressure

resists breaking by when subjected to bending & pulling forces

Disadvantages of Wood

easily burns, rots, decays, and attacked by insects

swells, shrinks, warps

looses moisture if not properly treated

2 classification of Trees

hardwood- angiosperm

softwood- gymnosperm

Common Hardwoods

oak, maple, mahogany, teak, walnut, ash, hickory

Common Softwoods

cedar, pine, redwood, spruce

Veneering

the method of gluing thin slices of wood

How is Plywood made

veneer process, layers criss cross technique, grain runs perpendicular

Advantages of Fiberboard

Strong, resistant to warping, durable

good for painting

Disadvantages of Fiberboard

Heavy

not as strong as plywood

creates lots of sawdust

Types of Glass

lime soda, lead, heat resistant

Lime soda characteristics

inexpensive

durable

brittle

dull toned when tapped

shaped and decorated by pressing it into a mold

Lead glass characteristics

resonating

heavier

softer surface

brighter & more lustrous

usually odorless

Types of Heat Resistant glass

Borosilicate, glass ceramic, laminated glass

Borosilicate characteristics

less clear than lime soda

withstands extreme temps

usually thicker than lime soda

3 types of Pottery

Stoneware

China

Earthenware

Differences between the types of pottery

The type of clay used

firing temp, higher the heat the stronger the pottery

Earthenware Characteristics

heavy

thick

poor durability/ chips easily

colorful with primitive designs

simply shaped

Stoneware Characteristics

opaque

dishwasher safe

dull finish if not glazed

heavy

stone like texture of unglazed

withstands extreme temps well

China/Porcelain Characteristics

completely non porous

expensive

durable

thin and delicate in appearance

produces a bell like sound

less likely to stain

Where Plastic came from

originated from nature 3,500 years ago

Olmec of Mexico used sap from gum trees to make rubber balls

Synthetic plastic

made from extract crude oil and natural gas

Thermoplastic

molecules do not chemically bond to each other- don’t develop cross linkages

can be reheated and reshaped

Thermoset

permanent chemical bonds

retain shape and strength

Metals characteristics

malleable

good conductors of heat and electricity

crystalline

Iron

plentiful in the earths crust

hard to work with

impurities are hammered out to become wrought iron

cast iron

not limited in shape & size

wasn’t strong enough under extreme conditions

aluminum

3x lighter than steel

alloy transformed itself

copper was strengthened with tin

Super Alloy

excellent mechanical strength

resistance to thermal creep deformation

good surface stability

resistance to corrosion or oxidation

Synthetic Rubber

takes 6 hours to produce

uniform/machine

chemicals and additives

Natural Rubber

tree-reuse

takes longer to produce

cut out imperfections

thin sheets

air dry or smokehouse

Natural Rubber characteristics

elastic

resistant to moisture and electricity

soften by oil

Synthetic rubber characteristic

complex chemical process

more uniform and higher quality

more adaptable to end uses

Benefits of Vulcanization

added strength

improved resistant to: wear, extreme temps, water

harder to be reformed & melted down into other products