" " wisno wood furniture finishing: How to make wood veneer panels.

Friday, May 11, 2012

How to make wood veneer panels.

The wood veneered panel is more used to replace the solid wood panel. The veneer that is layered to the particle board or m.d.f., will produce panel with wood looked that has very similar looked with the solid wood panel. With the proper processing the wood veneered panel gives some advantages compared with the solid wood panel. It is more stable, uniform in color, can be arranged with varied pattern and less expensive in price. The engineered wood product such as:  m.d.f., or particle board are homogenous and more stable since they are engineered product with some specific standard properties. Even the bare core, plywood and laminated wood are also have less risk to get warping or cracking problem since they are made from many pieces wood that is glued together. The tension of the wood pieces are eliminated each other result for more stable and stronger wood panel. Since that reason, then many woodworking industries prefer to use wood veneer than the solid wood panel. 

The process of making wood veneer actually is a simple process, but each process must be done in the right way. It is included the preparation of core panel, the veneer cutting and setting, the gluing process and the sanding of the veneer.

 wood veneered panel for furniture

Preparation of the core panel.
 
Core is a board where the veneer is going to be attached. The engineered wood products are used as the core; m.d.f., particle board, bare core, plywood or laminated wood. Each of them has their advantages and disadvantages but it won’t be discussed in here. Yoy can go see my previous article : (m.d.f.,  particle board, laminated wood, plywood).
No matter what is the type of core used, they need to be well prepared. First the core must be cut with the correct size and shape, according to the size and shape of the panel will be made. Then it needs to be properly sanded to make a flat and even surface core panel.
The flat panel usually is glued by the hot press machine. It is a press machine which is equipped with the heater to heat the glue to fasten the glue curing process. To produce strong bonds we need a core board with a flat and even surface. The uneven surface or panel which varied thickness could make the uneven pressure and uneven temperature in the panel and make the gluing is not well done.  The core surface must be cleaned form any dirt, and texture that may affect the gluing. The wide belt sanding is the best tool to sanding and calibrating the core panel to make the flat and even panel.  
For a curved panel, then the gluing is done with the vacuum press. It used vacuum to attract the veneer to keep stack with the core during the glue setting. It also need the clean and fairly smooth surface.  

The cutting and unification of the wood veneer.

 
Veneer is usually attached to make a wood looked with certain patterns. First the veneer is cut into the certain sizes and shapes according to the design. Wood veneer pieces are then put together to produce unified veneer with the desired pattern. To produce the tidy veneer, then each piece must be connected tightly. The right, neat and precision cutting is needed. A special machine called as guillotine knives is purposed to cut the veneers. The guillotine has a sharp knife with high pressure can cut the veneer with very sharp edges precisely, but it is limited to be used for the straight cutting. The laser knife is a modern tool to cut the veneer to make special shape and pattern. For small volume work, then a cutter which has sharp, and thin knife can also be used with very good results if it is carefully conducted with the skillful people.
The next process is the unification of the veneer pieces before glued to the core panels. The unification should be done precisely to make a tidy and tight connection for each piece. To form a simple and straight pattern veneer, then there is a veneer joint er machine. It can glue and connect the veneer edges automatically with very tight joint, but it only work for the straight connection. For the complex form then we need to join each pieces and then keep it with veneer tape or a thread. The manual hand work is needed in the jointing the veneer to make special pattern. 


Gluing veneer to the core.
 
Once the pieces of veneer are unified together forming the desired pattern then he can be placed and glued on its core. The glue used should be strong enough to produce a strong panel board. The chemical reaction is widely used. It forms the thermosetting bond which is strong, durable, high resistant to thinner and finishing materials that will be layered on
usually some ply of wood veneer is used to make a veneered  panel. The C or D grade veneer is used as the first layer that attached directly to the core. The on the veneer layer is attached the good performance veneer as the panel face.  The first and second layer veneer usually is set in a cross banding. The first veneer is layered with the cross direction grain while the top veneer is set with the grain direction according to the face panel designed. 
The cross banding will give you more strength to the wood veneer bonding. The special arrangement in the cross banding can be used to address some specific veneer problems. The crack problem in the crotch mahogany veneer can be minimized by set the cross banding veneer in the 60 angle with the core and face veneer.
For flat panel then the attachment is usually done with  by hot press machine. Hot press machine can heat the veneer layer with temperatures up to 100 C, thus the glue hardening process can quickly done; the glue dry in about 2-3 minutes. But the heating plate is flat; restricting the uses of the machine to board the flat panel only. To form the curved panel, then the vacuum press is needed. It used the vacuum force to suck to keep the veneer attached to the core until the glue is dry.  

Veneer sanding.
 
Veneer that has been attached will have rough and dirty surface. The tape at the veneer surface, the glue that sticks and stains that are stick at the surface must be cleaned to perform a smooth and even panel. The tapes can be cleaned by remove then with water or mineral spirit, but then it still need sanding process to make a smooth and even surface. The sanding with proper way can eliminate the tape, glue and stain at the veneer surface.  The veneer sanding can be done with # 150 or 120 grade sandpaper to clean the glue, tape and stain mark. Then the sanding with # 180 grade sandpaper is usually enough for last sanding to provide the clean and smooth unfinished surface for finishing.  Some type of veneer may need the # 240 as the last unfinished sanding before stain application.

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