Question 3
Question 3a
required candidates to list two defects each from the classes of timber defects
Question 3b
required candidates to state two qualities of waterborne preservatives.
.
Question 3c
required candidates to list two methods of seasoning timber.
Observation
The expected responses are:
(3A) Types of Natural defect:
- Growth defects
- brittle heart
- heart rot
- burr
- gum veins and pocket
- resin canals and pockets
- insect holes
- knots
- shakes
- Grain defects
- cross grain
- diagonal grain
- interlock grain
- spiral grain
- wane or weney edge
- case hardening
- sap stain
- end split
- warp (cup, twist, bow or camber, spring)
- check (end, heart, internal, ray, through, surface)
- collapse
(3B)
Types of seasoning defects:
(3C)
Methods of seasoning timber:
- air / natural seasoning
- kiln / accelerated /artificial/ seasoning
- chemical seasoning
- water seasoning.