The Art of Wood Finishing by Nita Hubbert download in iPad, ePub, pdf
French polishing is a finishing method of applying many thin coats of shellac using a rubbing pad, yielding a very fine glossy finish. The wood in the recovered dent should then be dried and sanded smooth to match the surrounding wood. Removing dents from wood surfaces is quite straightforward as pointed out by Flexner. Both these effects will influence the way in which the wood colours when stains are used to finish the wood. The pores in ring-porous woods preferentially absorb pigmented stain, and advantage can be taken of this to highlight the wood's grain.
Ammonia fuming is a traditional process for darkening and enriching the color of white oak. The following table compares the characteristics of different clear finishes. These finishes are available in a wide variety of colours, many of which are not part of the natural colour palette of wood, for example, blues and greens. Then put a clean cloth over the dent and place the tip of a hot iron on the cloth that lies immediately above the dent, taking great care not to burn the wood.
Hence, repairs to wood using fillers may noticeable. To overcome this problem it may be necessary to locally stain and touch-up areas previously covered by glue to ensure that the finish on such areas matches that of the surrounding wood. Water based finishes generally fall into the coalescing category.
An alternative to patching is filling sometimes known as stopping. Imperfections or nail holes on the surface may be filled using wood putty or pores may be filled using wood filler.
Once the wood surface is prepared and stained, the finish is applied. This defect is known as grain raising. It is used thinned with denatured alcohol as a finish and as a way to manipulate the wood's ability to absorb other finishes. Ammonia fumes react with the natural tannins in the wood and cause it to change colours.
For this reason, as pointed out by Flexner, many people prefer to omit the staining step when finishing wood. Macro photo of grit sandpaper Macro photo of grit sandpaper Macro photo of grit sandpaper Glue smears and droplets are sometimes present around the joints of furniture. As a result the dent will diminish in size or even disappear completely, although removal of large dents may require a number of wetting and heating cycles. Reactive finishes may use solvents such as white spirits and naphtha as a base. Furthermore, filled voids do not behave like wood during subsequent finishing steps, and they age differently to wood.
Tung oil and linseed oil are reactive finishes that cure by reacting with oxygen, but do not form a film. Successful filling of voids in wood requires the filler to precisely match the colour and grain pattern of the wood around the void, which is difficult to achieve in practice. However, it is difficult to completely eliminate large defects from wood surfaces. Wood can also be coloured by exposing it to chemicals that react with the wood to form coloured compounds.
The same applies to spalted wood whose attractive appearance is again caused by fungi. Often, a final coat of wax is applied over the finish to add a degree of protection. Choosing a clear finish for wood involves trade-offs between appearance, protection, durability, safety, requirements for cleaning, and ease of application. On the other hand some fungal stains and those caused by the reaction of iron with wood can disfigure wood.