Chapter 4B Flashcards
The process of drying wood by mechanical or physical methods.
Wood Seasoning
What are the methods of wood seasoning?
Natural Drying
Artificial Drying
What are the objectives of wood seasoning?
a) Reduce the occurrence of wood defects.
b) Minimize swelling/shrinkage of wood
c) Increase strength properties of woods
d) Facilitates preservative (easier penetration of varnish)
e) Improving machine and finishing qualities
f) Increase thermal and electrical resistance
g) Improve nail holding capacities of wood
h) Reduce weight for easy transportation
i) Enhance resonance quality
j) Reduce bond failure in wood products
Types of natural drying
Air seasoning
Water Seasoning
Solar Seasoning
Process of ageing the wood by exposing it to the nature, such as air or water.
Natural Drying
It is the oldest, simplest and traditional method. The timber is stacked in a way to allow plenty of air to circulate around each piece of timber.
Air Seasoning
It is a process of placing logs in a river with thicker ends pointing upstream side of the river for 3-4 weeks for the sap to be washed over by the river waters.
Water Seasoning
It is a solution provided for the low energy requirement of air drying and the speedy operation of kiln drying. It is slower and gentler.
Solar seasoning
Types of artificial drying
Seasoning by boiling
Chemical Seasoning
Electrical/ Rapid Seasoning
In this process wood is immersed in water and then boiled for 3-4 hrs.
Seasoning by boiling
In this process the timber is stored in suitable salt solution for some time. The salt solution used has the tendency to absorb moisture.
Chemical seasoning
Timber is subjected to high frequency alternating currents.
Electrical/ Rapid Seasoning
It is seasoning of wood in a chamber using artificially controlled temperature and humidity. The hot air circulates in between the timber logs and reduces the moisture content.
Kiln Seasoning
Types of Kiln seasoning
Progressive kiln seasoning
Compartmental kiln seasoning
A type of kiln where the timber enters and moves progressively through the kiln.
Progressive kiln
Types of progressive kiln
Draft Kiln
Forced draft kiln
A kiln where heater air is allowed to rise through the material by natural convection
Draft Kiln
A kiln where fans are employed to force the air through the wood.
Forced Draft Kiln
A single enclosed container/ building where timber is loaded into the kiln and remains in place throughout the drying process.
Compartmental Kiln
Kiln drying ________ _______ is to prevent drying defects during kiln drying
Quality control
Treatment where a steam is introduced to relieve stresses prior to end of kiln drying.
Conditional Treatment
A treatment where temperature is lowered with steam to have a more uniform moisture content of stocks.
Equalization Treatment
What is the standard MC for exported timber?
6-8 %
What is the standard MC for locally made timber?
13-15 %
The quality test performed to determined drying stresses in wood.
Prong test
It occurs when the core is in tension while the surface is in compression.
Case hardening
It occurs when the surface is in tension while the core is in compression.
Reverse Case hardening
A work-out sets of progressively increasing kiln temperature and decreasing relative humidity.
Kiln drying schedule
It is a guide to dry specific products at a satisfactory without causing objectionable drying defects and used by Kiln Drying Operator.
Kiln Drying Schedule
Types of Kiln Drying Schedule
General KD Schedule
Special KD Schedule
Easy dry wood species
Almaciga
Lanutan
Katmon
Banaba
Balakat
Moderate to dry wood species
Gatasan
Urong
Sangilo
Raintree
Batinog
Difficult to dry wood species
Agoho
Tuai
Palosapis
Bolong-eta
Kamuning
Very Difficult to dry wood species
Dao
Ipil
