Lesson 2, Topic 1
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# Wood Seasoning

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Timber, which has just been converted, is called fresh or green timber. Green timber contains a lot of water and is not suitable for engineering, or furniture work.

The process of reducing the moisture or water content of wood is called wood seasoning.

Since sawn timber contains some amount of water, it must be seasoned before use.

There are two methods of seasoning; Natural or Air Seasoning & Artificial or Kiln Drying.

### 1. Natural Seasoning or Air Seasoning:

This method of seasoning involves stacking the converted timber planks in the open air, for a period of time, and allowing them to dry naturally. They are usually done in a roofed building to keep off the rain. This method requires little attention and is relatively cheap. A disadvantage, though, is that it takes a long time to dry.

### 2. Artificial Seasoning or Kiln Seasoning:

A kiln is a specially prepared oven or furnace for drying materials. In this method, the planks are stacked in the kiln, similar to natural seasoning, and left to dry. This method is very fast, taking only a few weeks at most to dry up wood, but it is relatively expensive to operate when compared to the natural method.

### Reasons for Wood Seasoning:

1. Seasoning makes the wood stronger.

2. It makes the wood lighter in weight.

3. It makes wood take in (absorb) preservatives easily.

4. Seasoning makes the wood more stable when being used for furniture work.

5. It makes the wood more durable.

6. Wood is able to be polished easily when seasoned.

7. It reduces the moisture content of the wood.

### Calculating Moisture Content:

The formula for calculating moisture content is given as;

Moisture content (MC) = Wet weight – Dry weight

Moisture content is also calculated as a percentage, respective to the wetness or dryness of any wood.

The general formula used in calculating percentage moisture content is given as;

⇒ $$\frac{wet\:weight \: – \: dry\:weight}{wet\:weight}\: \times \: \frac{100}{1}$$

Example:

1. Calculate the moisture content of timber which weighs 960 grams before drying and 876 grams after drying.

Moisture content (MC) = Wet weight – Dry weight

MC = 960g – 876g = 84 grams

2. If a sample of wood weighs 80gm before and 60gm after drying, what is the percentage moisture content?

Solution:

Given that,

$$\frac{wet \: weight \: – \: dry \: weight}{wet \: weight} \: \times \: \frac{100}{1}$$

$$\frac{80gm \: – \: 60gm}{80gm} \: \times \: \frac{100}{1}$$

= $$\frac{20}{80} \: \times \: \frac{100}{1}$$

= $$\frac{1}{4} \: \times \: \frac{100}{1}$$

= $$\scriptsize 25 \%$$

Nowadays, the moisture content of timber is determined electronically by using an electric meter.