" " wisno wood furniture finishing: Wood veneer.

Friday, October 7, 2011

Wood veneer.

What is wood veneer?

Wood veneer is a thin layer of wood. It is made of log of timber that is sliced in thin sheet of wood. Wood veneer then is attached at core panel and widely used to make panel board in the furniture industry. Most of the big and wide panels for furniture are made from veneer. With the proper gluing of the correct technique then the panel of veneer panel or plywood is more stable than solid wood panel.
The main properties of wood veneer as:  base color, grains and pores character and the absorption to the finishing material is determined by the type of wood used to make veneer. The character of the wood veneer is also determined by the thickness of the veneer and how is wood sliced. Wood veneer is available in various thicknesses.

The veneer type and quality.

The veneer is widely available in the woodworking industry. The main properties of the veneer such as: the wood base color, the pores and grain character of the veneer is determined by the wood type that is sliced.  The furniture industry can select the veneer type in accordance to the appearance of wood panel board he needs to make furniture. Veneer is available in almost all type of wood,  so we can choose the type of veneer we need quite easy.
Veneer is also available in various grades of quality and thickness. The selection of the veneer is also should consider the thickness and grade of the veneer. To produce the panel boards normally we use the 0.2 mm to 0.5 mm thick. Thick veneer is expensive, while too thin veneer has high risk to get problem in the woodworking process. Thin veneer has the risk of glue bleeding at the gluing and  the “cut off”  at the sanding process.
Other things to be considered are the quality and grade of the veneer. Veneer is made from wood that could have varied properties. The quality of the veneer is according to the quality of the wood that was sliced to made the veneer. Same with the wood the wood veneer is classified according to the veneer grade. But as an engineered wood product the veneer quality can be controlled easier then the wood log. Veneer with high grade to is used to the exposed part of panel board, while the veneer with lower grade mostly used to layer the back panel or the unexposed part.

The storage of the veneer.
 
The veneer is dried at the veneer manufacturer before it is marketed.  The wood veneer is always marketed at dry condition, but the veneer is hygroscopic material, he will absorb and release water according to its environment humidity. The veneer should be stored in a dry room that has a stable humidity. Veneer is usually stored in dehumidifier or conditioning room which is kept at low humidity.

wood veneer panel

The veneer attaching to make panel.

The veneer laminating requires precision work and skillful people is needed. The veneer are cut to the certain size to produce the desired shapes and patterns, then the pieces are jointed together according with the desired pattern. The grafting and unification of the pieces of veneer has to be done neatly, the imperfectness at the joint will be seen at the veneer panel.
The veneer pieces are unified glued together by using special tape or a yarn. The series of veneer is then glued to the core board and pressed until the glue is dry to make a “wood panel”.
According to the gluing process there two kinds of veneering, that are: the hot press and the cold press. Hot press is the veneer process when drying of the glue is done by heat. If the drying is done without heating, it is called cold press. In the hot press a steel panel plate is heated to press and heat the wood veneer, the glue can dry in just few minutes. The temperature of the plate is depend on the type of the wood and glue used, but usually ranging form 70 to 100 degree Celsius.
The cold press is simpler process, it does not use heat, the glue is dry in the room temperature but the longer drying time is needed.
There are many cores can be used i.e.: M.D.F., particle board and laminated wood. Particle board is the most inexpensive materials;  but he is not as strong as the laminated wood or M.D.F.  The veneered particle board panels will also produce "wood looked" panel board, but it will not as strong as wood or M.D.F. It mostly used to make low end furniture product.
M.D.F. is stronger engineered wood product because he is homogeneous and stronger, but it is more expensive material. The M.D.F. usually is used as core material for panel boards when  furniture with better quality is needed.
Laminated wood, or bare core is stronger and more natural. The laminated sengon wood is the most often wood used. Sengon wood is relatively lightweight, inexpensive and durable. The laminated wood should be stronger than the M.D.F. or particle, but since it is wood then it could has varied properties.

There is two important things at the core preparation, the moisture content and surface flatness. The moisture content of the cores should be as close as possible to the moisture content of the veneer. The moisture content should according to the standard of the moisture content of the wood product. The glue used is usually water based, since then gluing process will tend to raise the moisture content of the panel. The moisture content of the core and veneer should be kept at around 10%.
 
The core should has flat and even surface to make a well attachment with the wood veneer thereon. The sanding for surface calibration with wide belt sander is needed to produce the flat and even core panel. 

Sanding the veneer panel. 

After the cores are attached with veneer and a wood looked panel is made, then the proper sanding is required. The sanding is purposed to remove the tapes that is used to unify the veneer pieces, to clean the dirt or stain and also to produce a smooth and flat surfaces. Sanding to the veneer should be done carefully; too much sanding is risk to cut trough the veneer layer.  The veneer sanding process principally is very similar to the wood sanding. It should be started with # 100 or # 120 grade sandpaper and ended with the # 240 or # 180 grade sandpaper.

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