What Is Seasoning Of Timber |link| -

Report on the Seasoning of Timber 1. Executive Summary Timber, in its freshly felled state (known as "green timber"), contains a high percentage of moisture. This moisture leads to dimensional instability, susceptibility to decay, and reduced strength. Seasoning is the controlled process of reducing this moisture content to a level appropriate for its intended use. This report outlines the purpose, methods, advantages, and disadvantages of timber seasoning. 2. Definition Seasoning of Timber is the process of removing excess moisture from green timber to achieve a moisture content (MC) in equilibrium with the surrounding atmospheric conditions (typically 10–20% for most applications, or 6–8% for indoor furniture). 3. Objectives of Seasoning The primary goals of seasoning are:

To reduce shrinkage and swelling: Prevents warping, cracking (checks), and distortion after the timber is used in construction or furniture. To increase strength and stiffness: Dry timber is significantly stronger than green timber, especially in bearing and bending. To improve workability: Seasoned wood saws, planes, nails, and glues more easily and holds a better finish. To prevent decay and fungal attack: Fungi require moisture (above 20%) to grow. Seasoning below this threshold protects the timber. To reduce weight: Lower weight reduces transportation costs and handling effort. To facilitate chemical treatment: Preservatives penetrate more easily into seasoned timber.

4. Methods of Seasoning Seasoning methods are broadly classified into Natural (Air) Seasoning and Artificial (Kiln) Seasoning . 4.1 Natural or Air Seasoning Timber is stacked in open air, allowing atmospheric air to circulate and carry away moisture. Process:

Logs are sawn into planks. Planks are stacked with stickers (small wooden strips) between each layer to allow airflow. The stack is placed on a raised foundation, protected from rain and ground moisture, with a roof covering. Air circulates naturally or via low-speed fans. what is seasoning of timber

Characteristics:

Slow process: Takes several weeks to months (e.g., 1 inch thick oak may take 2-6 months). Final MC: Typically reaches 12–18% (depending on climate). Low energy cost.

4.2 Artificial or Kiln Seasoning Timber is placed inside a sealed chamber (kiln) where temperature, humidity, and air circulation are precisely controlled. Process: Report on the Seasoning of Timber 1

Timber is stacked in kiln trucks. Heated air (40–80°C initially, up to 110°C for hardwoods) is circulated. Humidity is gradually reduced to prevent surface cracking. Moisture is expelled via vents.

Common Kiln Types:

Compartment Kilns: Batch processing – entire chamber loaded and unloaded together. Progressive Kilns: Continuous process – timber moves through zones of increasing temperature. Vacuum Kilns: Uses reduced pressure to boil water at lower temperatures (faster, but expensive). Seasoning is the controlled process of reducing this

Characteristics:

Fast process: Days to a few weeks. Final MC: Can be as low as 6–8% (ideal for indoor furniture). High energy cost (fuel/electricity).