Some types of wood contains sap inside. The sap wood is needed to be secreted from the wood at the first time of wood processing. The sap wood will disrupt the process of drying. It could make the drying take too long time or imperfectly done that may affect the wood quality. Some wood need that vacuum treatment to avoid the problem with of insect or fungi. The vacuum treatment is the secretion of the sap wood using the vacuum force. The vacuum process is ussually continued with the application of wood preservation solution; anti fungal and anti insect chemical. The vacuum process is also can be held to handle the oily wood such as teak wood.
Vacuum process can be described as follows:
The wood planks are inserted into a tube as a vacuum room. The process is started by flowing the hot water into the tube until it full the room. The water is then heated to boil the wood. The boiling time is varied according to the wood types and the wood plank sizes, usually is about 1 to 2 hours. Then the hot water is pumped and released from the room, then a vacuum force is used to suck the all the water from the room. The suction is continued to pull out and release the sap wood or oil out from the woodcell.
When the sap and oil are completerly released, then the process is continuing with infuse the wood preservation chemical. The anti insect or anti fungal (or both) chemical is flowed to the vacuum room to let the wood is saturated with the chemical. It takes few minutes to let the chemical solution to seep into the wood and fill the wood pores, grain and cells.
The timber out of the vacuum process is still has high moisture content, then the drying process is needed to meet the standard of moisture content in the woodworking. Some vacuum machines are equipped to do the drying process and the drying can be continuing done in the same tube. The wet wood planks can also be released from the machine and dried in the other kiln dry.
The advantages of vacuum treatment.
The vacuum process is process that need time, effort and cost, then there should be some benefit are offered by this process. For some types of wood, for example the rubber wood and mango wood the vacuum treatment is absolutely needed. While for some types wood this process could be option to increase the quality of the wood. The vacuum will help the drying to be faster and more perfectly done, especially for the wood that containing sap or oil. The vacuum process also help the anti fungal and anti insect chemical to penetrate better into the wood. Wood has a structure like a sponge, when there is oil or sap in the wood, the wood would not be able to receive the other chemical solution. The vacuum process releases the sap and the oil from the wood to let the anti-insect and anti-fungal optimally fill the wood cells. Some vacuum is also equipped with the equipment to let the preservative solution is forced deep into the wood under high pressure.