3.3 Testing and Finishing Woods Flashcards
What can woods be tested for?
- tensile strength
- toughness
- hardness
- corrosion
- malleability
How can tensile strength be tested?
By applying weight to a test piece and monitoring how much the material bends or deflects
How can hardness be tested?
By hitting a centre punch into a material and measuring the size of the dent created
How can toughness be tested?
By using the the Charpy and Izod tests
How can corrosion be tested?
by leaving the wood outside for a period of time and then inspecting the damage
What is the Janka test?
It measures the ability of wood to resist scratches or dents
What do the Charpy and Izod tests consist of?
- The test pieces are prepared to a set size
with a notch in the centre - The test piece is positioned
before a pendulum is dropped
to strike the test piece - The distance the pendulum
travels after breaking the test
piece is a measure of the
toughness of the material
What does ultrasonic testing do?
It detects internal defects using sound waves
What are non-destructive tests?
They help identify imperfections below the surface of a material invisible to the naked eye
What is X-ray testing?
X-ray beams are passed through a material and project an image onto a film or screen
Is wood a thermal conductor or insulator?
Wood is an excellent natural thermal insulator due to the air pockets in its cell structure
What is the Guarded Hotplate testing method?
This test sandwiches a material test piece between two temperature-controlled plates (one hot one cold), the test measures the time taken for the material to reach a constant temperature
How can the working properties and aesthetics of wood can be enhanced?
- by combining it with resin to create composite materials
- by adding a preservative, finish or coating to increase resistance to decay
- by adding a laminate to improve the properties of the surface
