Wood Bonding Test in the Woodworking Industry

Tests for wood bonding are very important to be done by the woodworking factory that does the wood gluing process. The wood bonding test can be done regularly for the sample product at the production process to control and check the quality of the products. The test is also needed at the R&D department to develop new products and processes. The test for wood bonding is also commonly held by the wood adhesive industry to ensure the quality of their products.

Ideally, the wood bonding test should be able to figure out the adhesion behavior of the wood product after being used for a certain period of time. The test could be done to see the condition of the bonding when it is exposed to extreme environmental conditions such as the high fluctuation in the temperature, humidity, moisture content of the wood, or strong pressure and stretch. A wood bonding test is also required to obtain a certificate that is required to enter the market in certain countries.

There are several tests that are commonly done for wood bonding:

• Chisel test.

A chisel test is a test that is often done by the wood adhesive supplier. The chisel test is also commonly done by the woodworking company. The chisel test is mainly purposed to find the physical condition of the wood bonding. The test is done by opening the wood bonding using chisel. Then we can see and observe the wood bond physically. The chisel test is the perfect toll to find out the condition of the wood bonding. In the woodworking factory or wood adhesive lab, the chisel test should be done first before other tests are held. The observation data found is used to find the best system for the gluing process.

• Cold check.

Cold check is a test to see the strength of adhesion when the temperature changes every time. This test is very important to ensure that the product is safe to be shipped to the overseas destination. The cold check is the simulation for the product when he faces the fluctuation of the temperature conditions in the container during the shipping. 

The cold check is done as follows:

Heat the sample to 50°C for 2 hours, then cool it to room temperature for about 30 minutes, and then continue cooling the product until -20°C for 2 hours. Check and observe the product. This process should be repeated for some cycles. At the time we find any defect for the sample product, we can stop the test. The quality of the wood bonding is mentioned as the amount of cycles that are passed by the sample product. 

• Dowel test.

Dowel test is a test to see the strength of adhesion at the wood assembly. A sample product, which could be a piece of product or just bonding wood, is assembled in the mouth on a device. Then 2 pairs of cylinders are pressing the wood alternately with a certain force. Every hit of the cylinder is calculated and recorded and called a cycle. The test result is expressed as the number or cycle that can be withstand with the connection. 

• Finger joint test.

It is especially for the finger joint. A finger joint is mounted on a pedestal, then a load is put on the wood. The bending strength is measured as the force of the load divided by the width and length of the gluing surface. 

 

• Climate test.

It is purposed to find the wood bonding behavior in the changes of the humidity and temperature. The wood joint is put in a climate chamber; it is a room where the temperature and humidity of the air can be set up. Objects were placed in the climate chamber, and we set the temperature and humidity at certain levels. After a certain time, the wood bonding is released and observed and checked. Any changes in the dimension of the wood bonding are measured and recorded.

• Gas emission test.

An emission test is held to find the gases that are emitted by the product of the glue. This test is mostly needed for the products that use glue in large amounts, such as plywood, bare core, or particle board.

There are many more tests that can be done for the wood-gluing product, depending on the product and the buyer's requirements. Some tests are specifically required to enter the market in a particular country or region. The standard tests for the US market usually refer to ASTM, while for Europe they refer to the EN standard, and JAS is for the Japanese market.