Testing of this wood is done to determine the value of water content and specific gravity, and to remove water contained in wood. In this test is expected also students can use tools and materials in accordance with the needs and can understand the determination of the calculation of test objects correctly.
Wood as a building material can bind also release the water it contains. This depends on the ambient air temperature, where the wood is located. Basically wood drying aims to remove water contained in wood. The advantage of drying it is to maintain the stability of the wood dimension and increase the strength of the wood.
So it is clear that testing the water content is needed to know the strength and quality of wood, because the lower the water content the stronger the wood. Water content is the difference between the weight of the wood before it is dried with the weight of the wood after it is dried over the weight of dry wood, expressed as a percentage. Formulated as follows:
Water content (M) = (B-B1) / B1 x 100%
Where: B = Initial weight (gr)
B1 = Dry weight after dioven (gr)
In addition to the water content of wood also has a different density ranging from a minimum of 0.20 (wet wood) to 1.28 (wood nani). Wood density is generally proportional to the strength of the wood or its mechanical properties. The higher the weight of wood, the higher the wood strength.
Specific gravity is determined, among other things, by the thickness of the cell wall, the smallness of the cell cavity that forms the pores. Specific gravity is obtained from the comparison between the volume of a certain timber with the same volume of water at the standard temperature. Generally, the specific gravity of wood is determined based on the weight of dry wood oven or dry air and the volume of wood at the position of the water content. Wood density can be searched with the following formula:
Bj = B / ((1+ M/100) .L)
Where: Bj = Wood density
B = Initial weight
M = moisture content
L = Area
Tools and materials for testing
Chainsaws
Elbows
0.01 gram precision scales
Temperature adjustable dryer oven 1030c ± 20c (equipped with Vantilator) To remove steam
- Wood 5 x 5 x 5 cm
WORK STEPS
Steps to be done first is to provide wood size 5 x 5 x 5 cm as much as 3 pieces and give no on the wood, then weigh the weight of wood by using the scales of 0.01 grams of accuracy record the results of the three wood scales, then put into the oven at a temperature fixed 1030c ± 20c for ± 24 hours. After that remove and cool first then weigh back the weight of wood after the oven.
After all steps of work done and the data obtained count the water content of the three woods with the formula of water content. Specific gravity can be determined after the moisture content is obtained. Calculation of specific gravity can be sought by using the specific gravity formula.
Wood 1
Dik:
V = p x l x t initial weight = 59.70 gr
= 5 x 5 x 5 = 125 dry weight = 52.37 gr
Dit: water content and specific gravity?
Jwb:
Water content
Water content (M) = (B-B1) / B1 x 100%
M = (59.70-52.37) / 52.37 × 100% = 13.99%
Specific weight / content
Bj = B / ((1+ M/100) .V)
Bj = 59.70 / ((1 + 13.99 / 100) 125) = 0.41 g / cm³
Wood 2
Dik:
V = p x l x t initial weight = 61.33 gr
= 5 x 5 x 5 = 125 dry weight = 53.92 gr
Dit: water content and specific gravity?
Jwb:
Water content
Water content (M) = (B-B1) / B1 x 100%
M = (61.33-53.92) / 53.92 × 100% = 13.74%
Specific weight / content
Bj = B / ((1+ M/100) .V)
Bj = 61.33 / ((1 + 13,74 / 100) 125) = 0.43 g / cm³
Wood 3
Dik:
V = p x l x t initial weight = 59.96 gr
= 5 x 5 x 5 = 125 dry weight = 52.52 gr
Dit: water content and specific gravity?
Jwb:
Water content
Water content (M) = (B-B1) / B1 x 100%
M = (59.96-52.52) / 52.52 × 100% = 14.16%
Specific weight / content
Bj = B / ((1+ M/100) .V)
Bj = 59.96 / ((1 + 14,16 / 100) 125) = 0.42 gr / cm³
Average BJ = (0.41 + 0.43 + 0.42) / 3 = 0.42 gr / cm³
CONCLUSION
From the results of this test can be concluded that the average weight of wood species obtained is 0.42 gr / cm³. PKKI wood is classified into 3rd grade wood.
I think you might be interested: I read this week on BBC page that two engineers invented a wood stronger than steel. In the article, they explain briefly the treatment applied to traditional woods to harden it.
The link is this but it is in spanish: http://www.bbc.com/mundo/noticias-43073561 I found a similar information in english: https://www.tecnologics-site.com/super-wood-material-strong-steel/