Natural and artificial seasoning of timber

SEASONING OFTIMBER

1. Natural and artificial seasoning of timber PRESENTED BY : ADONICA BYNOE-BARNON

2. Types of seasoning Natural / Air Seasoning Artificial/ Kiln seasoning

3. Natural/ air seasoning With this process the timber is roughly sawn to size and stacked using spacers called stickers, with the timber stacked in the open air. Vertical spacing achieved by using timber battens (25mm) of the same species. The piling sticks should be spaced close enough to prevent bowing (600 to 9 00 mm centres ) This allows the free movement of air. The ends of the beams must be painted to prevent splitting.

4. natural/ air seasoning

5. Natural/ air seasoning The stack should be protected from the direct influence of the elements

6. Video on air seasoning

7. Advantages and disadvantages of air seasoning ADVANTAGES- No expensive equipment needed Small labour cost once stack is made Environmentally friendly- uses little energy DISADVANTAGES Slow drying rate Large area of space required for a lot of timber Only dries the timber to approximately 20% M.C. so leaving it open to some insect and fungal attacks while it is only suitable for outdoor joinery

8. ARTIFICIAL/ KILN SEASONING There are two main types of kiln used in artificial seasoning: COMPARTMENT KILN AND PROGRESSIVE KILN. Both methods rely on the controlled environment to dry out the timber and require the following factors: 1. Forced air circulation by using large fans, blowers, etc. 2. Heat of some form provided by piped steam. 3. Humidity control provided by steam jets.

9. ARTIFICIAL/ KILN SEASONING The amount and duration of air, heat and humidity again depends on species, size, quantity, etc. In general, the atmosphere in the kiln at first will be cool and moist The temperature is gradually increased and the humidity reduced until the required moisture content is achieved.

10. COMPARTMENTAL KILN

11. COMPARTMENT KILN ANIMATION

12. PROGRESSIVE KILN

13. VIDEO ON PROGRESSIVE KILN.

14. ADVANTAGES AND DISADVANTAGES OF ARTIFICIAL SEASONING ADVANTAGES: Quicker due to higher temperatures, ventilation and air circulation Achieve a lower moisture content Defects associated with drying can be controlled Allows more precise rates of drying for various timber species and thickness of boards

15. ADVANTAGES AND DISADVANTAGES OF ARTIFICIAL SEASONING. DISADVANTAGES: Is expensive Requires supervision by a skilled operator Uses a lot of energy

16. NOW ITS YOUR TURN DESCRIBE THE PROCESS OF AIR DRYING TIMBER WHAT ARE THE TWO TYPES OF KILN USED FOR SEASONING TIMBER? GIVE TWO ADVANTAGES AND TWO DISADVANTAGES OF EACH METHOD OF SEASONING. STAY IN THE GROUPS AROUND EACH TABLE AND STACK THE PIECES OF TIMBER AS FOR AIR DRYING.

17. THE END!