Finishing of solid wood jointed panels

It is not always possible to make furniture from a single piece of solid wood. Especially if the furniture is larger. The solution can come from panels made from solid wood that have been joined together, called solid carpet. These are narrow strips of wood that are joined both lengthways and widthways.

How to make solid wood panels

To lengthen the solid wood elements, you can make finger-joints or straight joints. The elements are prepared at the ends, glued together, usually with cold glue, and held in presses. In the case of finger-jointing, the elements to which glue has been applied are placed side by side and then cold-pressed until the glue has hardened. After removal from the press the panels are sanded to remove excess adhesive and to calibrate them.

These solid wood jointed panels are a solid wood variant widely used in industry. Due to the joining of several pieces of wood that may behave differently, some problems may occur during finishing. In the following you will find some tips for a flawless finish.

Staining of solid wood panels

The colouring carpet may stain due to different absorption. Lumber pieces come from different logs and have different densities. During staining, the berry is absorbed differently resulting in uneven staining. The absorption of the berry also highlights the joints in the teeth.

To reduce absorption, fast evaporating solvent-based wood stains can be used, which do not go deep into the wood. It is a handy method, but increasingly difficult to use because of environmental requirements related to the emission of volatile organic compounds (VOCs).

To eliminate the problem of VOCs, water soluble baths can be used. It is known, however, that water-based stains absorb deeply, highlighting the wood's grain. In the case of a solid wood carpet that absorbs differently is not the best option. That is why it is best to dilute the stains with a mixture of water and a special resin that reduces the absorption, thus achieving a uniform stain.

Also for a uniform look, staining can be done with coloured primer, with the recommendation to control very well the amount of stain in the primer and the thickness of the layer applied so that the finish does not look plastic.

Another drawback of using solid wood jointed panels is the discontinuity of the design. While solid wood is stained in such a way as to bring out the natural pattern of the wood, in the case of panels a discreet, uniform stain is usually chosen.

If the staining solution is not compatible with the adhesive used for gluing, a fine white line appears along the joint. The defect is not very common because the adhesives commonly used for gluing are compatible with most staining solutions. For rare cases where there is no compatibility it is recommended to use an isolator before staining the panel.

Defects that may occur after varnishing

Fine holes may appear along the solder lines following the application of film-forming materials. The defect resembles pore dropping of the finish and occurs due to the small amount of adhesive applied. In order to avoid holes the adhesive is applied in excess. When the solid elements are squeezed into the press to form the panel the excess must come out. This excess is removed by sanding.

If the defect still occurs, before finishing begins, the panels are grouted with a putty compatible with the staining solution and primer to be applied. If, however, fine holes have been observed at the end of the finishing process, an attempt can be made to repair them using touch-up putties of the same colour as the panels. This solution is valid for very small defects, otherwise the putty will make the situation worse.

Solid wood panels are a great solution for solid wood furniture. They are stable, easy to process and if a few rules are followed the finish can be very successful.