Seasoning of timber


Seasoning is the name given to the methods of drying timber

There are two methods by which timber can be dried:
(i) natural drying or air drying, and
(ii) artificial drying.

Air drying

finish_timber02.jpgAir-drying is the drying of timber by exposing it to the air. The technique of air-drying consists mainly of making a stack of sawn timber (with the layers of boards separated by stickers) on raised foundations, in a clean, cool, dry and shady place. Rate of drying largely depends on climatic conditions, and on the air movement (exposure to the wind). For successful air-drying, a continuous and uniform flow of air throughout the pile of the timber needs to be arranged. Coating the planks with any substance that is relatively impermeable to moisture can control the rate of loss of moisture; ordinary mineral oil is usually quite effective. Coating the ends of logs with oil or thick paint, improves their quality upon drying. Wrapping planks or logs in materials, which will allow some movement of moisture, generally works very well provided the wood is first treated against fungal infection by coating in petrol/gasoline or oil. Mineral oil will generally not soak in more than 1-2 mm below the surface and is easily removed by planning when the timber is suitably dry.

Natural seasoning of timber

Kiln drying

large-kiln.jpgThe process of kiln drying consists basically of introducing heat. This may be directly, using natural gas and/or electricity or indirectly, through steam-heated heat exchangers, although solar energy is also possible. In the process, deliberate control of temperature, relative humidity and air circulation is provided to give conditions at various stages (moisture contents or times) of drying the timber to achieve effective drying. For this purpose, the timber is stacked in chambers, called wood drying kilns, which are fitted with equipment for manipulation and control of the temperature and the relative humidity of the drying air and its circulation rate through the timber stack

Kiln drying provides a means of overcoming the limitations imposed by erratic weather conditions. In kiln drying as in air drying, unsaturated air is used as the drying medium. Almost all commercial timbers of the world are dried in industrial kilns. A comparison of air drying, conventional kiln and solar drying is given below:

1. Timber can be dried to any desired low moisture content by conventional or solar kiln drying, but in air drying, moisture contents of less than 18% are difficult to attain for most locations.
2. The drying times are considerably less in conventional kiln drying than in solar kiln drying, followed by air-drying.
1. This means that if capital outlay is involved, this capital is just sitting there for a longer time when air-drying is used. On the other hand, installing an industrial kiln, to say nothing of maintenance and operation, is expensive.
2. In addition, wood that is being air-dried takes up space, which could also cost money.
3. In air-drying, there is little control over the drying elements, so drying degrade cannot be controlled.

The sawmill

Kiln seasoning

Treatment and Preservation of Timber

Strength Grading of Timber

Timber Products

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43 Responses

  1. This page is very useful

  2. this was really useful and the animation was reli useful!:D

  3. there is nothing on natural drying!!

  4. Its called ai drying. CTD

  5. Do we just need to know wat both of the seasoning timber do for exams???

  6. Yes you covered both types during the year.

  7. thankz this ws really useful and the pics are kwl hehe =D

  8. The kiln seasoning animation was really usfull :)

  9. *Useful

  10. gr8 info n uzeful 4 examz!!! thenkx alot..

  11. It’s quite hard to understand!!!!!

  12. this is ok
    maybe links to other websites for more info?

  13. it shuold say wat temp the kiln drys the wood at

  14. is this all about seasoning ?… so there’s nothing else?… well i guess all this is enough information especially when studying for exams

  15. thanks alot !!!!!!!!!!!!!!!!!!

  16. thanx alot for this usefull subject

    i have assignment in this subject and i want help

    could someone help me

  17. THAMKS ALOT FOR THIS PAGE IT HELPED ME ALOT THANK U

  18. THANK U FOR THIS PAGE OK

  19. hi thats me agian thank alot for the home work

  20. thannnxxx for the information

  21. thnks thi was realy helpful

  22. its very useful

  23. this is realy helpful

  24. How do you post homework online ?????????????????????

  25. this is really useful 4 hm :) thnxxx :D

  26. this helps with revision !!!!!!!!!!!!:)

  27. this page very use full

  28. It was good

  29. thanks a lot 4 helping me u rock

  30. brill really helped me

  31. Thanks this realy helps with homeworks

  32. this sight rocks :)

  33. Air-drying is the drying of timber by exposing it to the air. The technique of air-drying consists mainly of making a stack of sawn timber (with the layers of boards separated by stickers) on raised foundations, in a clean, cool, dry and shady place. Rate of drying largely depends on climatic conditions, and on the air movement (exposure to the wind). For successful air-drying, a continuous and uniform flow of air throughout the pile of the timber needs to be arranged. Coating the planks with any substance that is relatively impermeable to moisture can control the rate of loss of moisture; ordinary mineral oil is usually quite effective.

  34. THIS WEBSITE IS CLASS FOR REVISION!!!!! :D

  35. THIS WEBSITE IS REALLY HELPING ME WITH MY REVISION THANKS!!!!

  36. 1. Timber can be dried to any desired low moisture content by conventional or solar kiln drying, but in air drying, moisture contents of less than 18% are difficult to attain for most locations.
    2. The drying times are considerably less in conventional kiln drying than in solar kiln drying, followed by air-drying.
    1. This means that if capital outlay is involved, this capital is just sitting there for a longer time when air-drying is used. On the other hand, installing an industrial kiln, to say nothing of maintenance and operation, is expensive.
    2. In addition, wood that is being air-dried takes up space, which could also cost money.
    3. In air-drying, there is little control over the drying elements, so drying degrade cannot be controlled – You’ve done 2 1′s and 2 2′s. Just updating you.

  37. tanks 4 the help,it really help

  38. this website really helps with assignments thanks sooo much :-D

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