Woodwork Paper 3, May/June 2013  
Questions: 1 2 3 4 Main
General Comments

question 2

  1. State one cause of each of the following timber defects:
  1. interlocked grain;
  2. cupping;
  3. waney edge;
  4. thunder shake.


  1. State three advantages of kiln seasoning over air seasoning.
  2. The table below shows incomplete information about two West African timbers.  Copy and complete the table.






Best Use


  1. Iroko




  1. Obeche



  1. State one use of an escutcheon.

Most candidates were able to:

-           state the cause of the given timber defects;
-           state the advantages of kiln seasoning over air seasoning;
-           differentiate between Iroko and Obeche trees.

However, few of them could not state the cause of some of given timber defects.

The expected response to question 2 is as given below:

(a)       (i)         Interlocked grain:      Occurs when the fibres of adjacent layers in
the growing rings are inclined at different angles to the axis of the timber.

                        (ii)        Cupping:        Caused by shrinkage, poor or bad stacking while drying.

                        (iii)       Waney edge: Caused by inadequate edging of boards during conversion.

                        (iv)       Thunder shake:        Caused by strong wind, storm and thunder strike
resulting in a distress or separation of wood layers in a living tree.



            (b)       Advantages of Kiln Seasoning Over Air Seasoning

                        -           Permits exact/accurate moisture content to be obtained.
                        -           Minimises degrade (seasoning defects).
                        -           Kills/destroys insect lavea.
                        -           Leads to greater turnover.
                        -           Faster in drying timber.
                        -           Requires less timber yard storage space.
                        -           Temperature, humidity and air circulation can be more easily controlled.
                        -           Allows for larger quantities of timber to be seasoned at a time.

(c)        (i)         Iroko:  Yellowish-brown to dark chocolate.  Used for good
quality interior and exterior joinery, doors, windows, laboratory furniture, roofing, boat/canoe building, chairs, frames, tables, chairs, tennis rackets.

                        (ii)        Obeche:         Near-white to pale yellow.  Used for fittings, interior
decoration, carving, veneers, plywood, corestock, boxes, handicraft work, temporary structure.

            (d)       The escutcheon is used mainly to protect/prevent the wearing of keyholes;
 it may also serve as a decoration.

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