Wood finishing refers to the process of purifying or protecting wood surfaces, especially in furniture production which typically represents between 5 and 30% of production costs.
Finishing is the final step of a manufacturing process that delivers desirable wood surface characteristics, including enhanced performance and increased resistance to moisture and other environmental agents. Finishing can also make wood easier to clean and stay sterilized, sealing the pores that can be a breeding ground for bacteria. Finishing can also affect other wood properties, such as the tone quality of musical instruments and floor hardness. In addition, finishing provides a way of delivering low value wood with an expensive and hard to get look.
Video Wood finishing
Planning to finish
Finishing timber requires careful planning to ensure that the finished parts look attractive, work well in service and meet safety and environmental requirements. Planning for finishing begins with furniture design. Care must be taken to ensure that the edges of the furniture are rounded to be adequately coated and able to resist wear and crack. Careful attention should also be given to the design and strength of wood connections to ensure they do not open the service and break the top layer. Care must also be taken to remove the niche in the furniture, which is difficult to solve with some systems, especially finished UV-cured.
Planning to complete wood also involves thinking about the properties of the wood you are about to finish, as this can greatly affect the appearance and performance of the finishing touches, as well as the type of finishing system that will give you the characteristics you are looking for. For example, wood that exhibits excellent color variations between pig and pith or inside a log may require an initial staining step to reduce color variations. Alternatively, wood can be bleached to remove natural wood color and then colored to the desired color. Roughly textured woods such as oak and other porous hardwoods may need to be filled before completion to ensure the layers can bridge the pores and resist cracks. The pores in the porous forest preferentially absorb pigmented dyes, and the benefits can be drawn from this to highlight the wood grain. Some tropical hardwoods, such as rosewood (Dalbergia nigra), cocobolo (Dalbergia retusa ) and African diuk ( Pterocarpus soyauxii ), contain extractives such as quinones, which inhibits the drying of the non-clear polyester film and UV-acrylic coating, and thus other finishing systems must be used with these species.
Planning for wood finishing also involves an awareness of how the finishing process affects the final result. Careful wood handling is required to avoid dents, scratches and dirt with dirt. The wood should be marked for cutting using a pencil rather than ink; However, avoid hard or soft pencils. HB is recommended for facial work and 2 hours for combined work. Care should be taken to avoid removal of glue from joints because the glue will reduce stain absorption and finish. Excess glue should be removed carefully to avoid further damage to the wood.
Wood water content affects wood dyeing. Changes in the water content of wood can cause swelling and shrinkage of wood that can cause stress and crack coating. Both problems can be avoided by storing wood indoors in an environment where it can balance to recommended moisture content (6 to 8%) similar to the intended end use of furniture.
Finally, consideration should be given to whether the finished wood will be in contact with food, in which case safe food should be used, local environmental regulations governing the use of the end result, and the recycling of finished wood at the end of life.
Maps Wood finishing
Sanding
Sanding is done before finishing to remove defects from the wood surface which will affect the appearance and finish performance which is then applied to the wood. These defects include cutter marks and burns, scratches and indents, small glue spots and raised grains. Sanding should not be used to remove larger defects such as gouges, and various forms of discoloration. Another technique is used to remove this defect (see below).
The key to setting up a defect-free surface is to develop a sanding schedule that will quickly remove the defect and leave the surface smooth enough so that the small scratches produced by the sanding can not be seen when the wood is finished. The sanding schedule usually starts with a fairly coarse sandpaper to remove larger defects (typically 80 or 100 grits, but sometimes higher if the surface is smooth enough), and progresses through a series of sandpaper values ​​gradually removes the sanding scratches made by the previous sanding step. A typical sanding schedule before wood finishing may involve sanding wood along the grain with the following grade of sandpaper, 80, 100, 120, 150 and finishing with 180 and sometimes 220 grit. The proper sanding schedule is a matter of trial and error because the appearance of a sanded surface depends on the wood you are sanding and finishing that will later be applied to the wood. According to Nagyszalanczy, rough-grained wood with large pores like oak hides sanding scratches better than fine-grained wood and hence with such species it is possible to use 180 or even 150 grit sandpaper as the final step in the sanding schedule. In contrast, sanding scratches is easier to see in finer, harder, and end-grain wood, and therefore, they require a finer sandpaper (220 grit) during the final sanding step. The sandpaper selected for the final sanding stage affects the color of the stained wood, and therefore when staining is part of finishing, avoid sanding wood for a very fine finish. On the other hand, according to Nagyszalanczy if you use an oil-based finish, you should sand the wood using a higher sandpaper (400 grit) because the oil tends to accentuate the sanding scratches.
Sanding is excellent for removing defects on wood surfaces, but creating surfaces that contain small scratches in the form of valleys and microscopic backs, as well as slices of wooden cell wall material attached to the underlying wood. These sanding ridges and wooden slivers swell and spring, respectively, when the sanded wood finishes with a water-based finish, creating a rough coarse surface. This defect is known as wheat milling. This can be removed by moistening the surface with water, allowing the wood to dry and then lightly sanding the wood to remove the 'elevated seed'.
Removing larger defects
Bigger flaws that interfere with wood finishing include dents, gouges, splits and glue and stains. These defects must also be discarded before they are finished, otherwise they will affect the quality of furniture or finished objects. However, it is difficult to completely eliminate major defects from the wood surface.
Removing the dent from the wood surface is quite easy as Flexner points out. Add a few drops of demineral water to the dent and let it sink. Then put a clean cloth over the hollow and place the hot iron tip on the fabric just above the curve, be careful not to burn wood.. The transfer of heat from iron to wood will cause the compressed fiber in the groove to restore its original dimensions. As a result the dent will decrease in size or even disappear completely, although large dent removal may require a number of wet and warming cycles. The wood on the restored buffer should be dried and finely sanded to fit the wood around it.
Gouges and holes in wood are more difficult to repair than dents because wood fibers have been cut, torn and removed from wood. Bigger gouges and splits are best improved by patching the void with a piece of wood that matches the color orientation and the wood grain being repaired. Patching wood requires skill, but when done right, it is possible to make repairs that are very hard to see. The alternative to patching is filling (sometimes known as stop). Many color fillers (putis and candles) are commercially produced and colored to match different wood species. The success of void filling in wood requires the filler to precisely match the color and pattern of the wood grain around the void, which is difficult to achieve in practice. Furthermore, filled voids do not behave like wood during the subsequent finishing steps, and they age differently from wood. Therefore, repairing wood using fillers may be apparent. Therefore, the stuffing is best used with an opaque finish rather than a complete semitransparent, which allows the wood grain to be seen.
Glue smears and droplets sometimes exist around furniture joints. They can be removed using a combination of friction, scrubbing and sanding. This approach removes surface glue, but not glue under the wood surface. Sub-surface glue will reduce the absorption of stains by wood, and can change the scratch pattern made by sanding. Both of these effects will affect the way the wood colors when the stain is used to finish the wood. To overcome this problem it may be necessary to spot local and touch areas previously covered by glue to ensure that the finish in such areas is compatible with the surrounding wood.
Bleaching and blotting removal
Wooden surfaces are sometimes influenced by various organic and inorganic blemishes. Sometimes such stains increase the color and appearance of the wood. For example, the oak that is affected by the beef steak mushroom has a rich, attractive brown color, and there is no reason to remove the stain from the wood before finishing. The same is true for spalted woods whose appearance is attractive once again due to the fungus. On the other hand some mold stains and which are caused by iron reactions with wood can damage the wood. This stain can be removed from wood using bleach. Bleach is also sometimes used to reduce the color difference between lightweight saplings and pith and also the color variation in the wood core. Such bleaching makes it easy to obtain uniform colored wood when the wood is subsequently stained with dye and pigment dye (see below). Furthermore, the natural color of the wood fades when the wood is exposed to the sun, and a more permanent color can be made with bleaching wood to remove its natural color and then re-color the wood using artificial, light, fast dye.
Bleaches used to remove unwanted wood fungus stains include two-part bleach peroxide and sodium hypochlorite solution. The first is very effective to remove the natural color of the wood before it is stained with dye or pigment dye. Oxalic acid is very effective for removing iron stains from wood.
Wood coloring
Wood can be colored to change its color or left unspotted before the lacquer application, or any other type of overcoat. Coloring should enhance the appearance of wood by reducing the color variations between and within the sapwood and pith. It also provides a way of giving wood that looks bland like poplars, the appearance of precious wood furniture such as ebony, mahogany or walnut. Wood can be colored using dyes or pigmented dyes. The end result is available in a variety of colors, many of which are not part of the natural wood color palette, for example, blue and green. Pigmented stains tend to highlight grains (as well as sanding scratches), whereas dyes do not have this effect and are more transparent. Wood can also be colored by exposing it to chemicals that react with wood to form colored compounds. Chemical staining in wood is rarely done because it is easier to dye wood using dyes or pigmented dyes, however, ammonia is a chemical staining method that is sometimes still used to darken woods like oaks that contain lots of tannins. Wood staining is difficult to control because some parts of the wood absorb more stains than others, leading to problems such as blotchiness and scratches. For this reason, as Flexner points out, many people prefer to eliminate the staining step when finishing the wood.
Basic wood finishing procedures
Wood finishing begins by sanding by hand, usually using a sanding block or a sander's strength, friction, or planning. The imperfections or nail holes on the surface can be filled with putty or wood pores can be filled using a wooden filler. Often, the color of wood changes with coloring, bleaching, or a number of other techniques.
Once the wood surface is prepared and colored, it is finished. It usually consists of several layers of wax, lacquer, oil dryer, varnish, varnish, or paint, and each layer is usually followed by sanding.
Finally, the surface can be polished or polished using steel wool, pumice, rotten stone or other materials, depending on the desired sheen. Often, the last layer of wax is applied above the end to increase the level of protection.
French polishing is a finishing method for applying many thin layers of lacquered using abrasive pads, resulting in a very fine finish.
Ammonia anger is a traditional process to darken and enrich the color of white oak trees. Ammonia fumes react with natural tannins in wood and cause them to change color. The resulting product is known as "burnt oaks".
End types
There are three main types of solutions:
- Blur
- Reactive
- Merge
Wax is an evaporative coating because it is dissolved in a turpentine or petroleum distillation to form a soft paste. After this distillate evaporates, the remaining wax will remain.
Reactive can finish using solvents like white spirit and naphtha as a base. Varnish, linseed oil and tung oil are reactive end products, which means they change chemically when they heal, unlike the evaporating results. This chemical change is usually polymerized, and the resulting material is less soluble in the solvent.
Mite oil and linseed oil are the reactive end products that heal by reacting with oxygen, but do not form films.
Water-based finishes generally fall into the merge category.
Comparison of different distinct views
Clear finishing is meant to make the wood look good and meet the demands to be placed at the finish. Choosing a clear end to wood involves a trade-off between appearance, protection, durability, security, requirements for cleaning, and ease of application. The following table compares the characteristics of the obvious final differences. 'Scrubbing qualities' indicate the ease with which an end result can be manipulated to produce the desired end. Lak should be considered in two different ways. It is used diluted with denatured alcohol as finish and as a way to manipulate the ability of the wood to absorb other finishes. Alcohol evaporates almost instantly to produce a final coating that will stick on almost any surface, even glass, and almost any other end product can be used on it.
1 accentuates visual properties due to differences in wood fiber.
Automatic wood finishing method
Manufacturers who produce bulk products apply automatic flat line finish system. The system consists of a series of processing stations that may include sanding, dust removal, coloring, sealer and topcoat applications. As the name implies, the main part of the form is flat. Finishing of molten wood is applied through automatic spray guns in enclosed environments or spray cabins. The material can then enter the oven or sanded again depending on the factory settings. The material can also be recycled through the line to apply another finished layer or proceed in a system that adds a sequential coat depending on the layout of the production line. Systems typically use one of two approaches to production.
Hangline Approach
In the hangline approach, wood items that are being completed are hung by carriers or hangers attached to conveyor systems that move objects above or above the floor. The conveyor itself can be mounted on the ceiling, mounted on a wall or supported by a floor holder. A simple overhead conveyor system can be designed to move wood products through multiple wood finishing processes in one continuous round. The hangline approach for automatic wood finishing also allows the option of moving items into warmer air at the ceiling level to speed up the drying process.
Towline Approach
Drag approaches to automate wood finishing using wheelbarrows driven by conveyors mounted on or on the floor. This approach is useful for removing large and strange wood products that are difficult or impossible to lift or hang on top, such as wooden furniture of four feet. Mobile carts used in the drag approach can be designed with a rotating top plate either manually or automatically. The rotating top plate allows the operator to have easy access to all sides of woodwork in various wood finishing processes such as sanding, painting and sealing.
See also
- Wood stains
- Refinishing
- Depressing
- Danish Oil
- Xylotechnigraphy
References
- Michael Dresdner (1992). The Woodfinishing Book . Taunton Press. ISBNÃ, 1-56158-037-6
- Bob Flexner (1994). Understanding Wood Finishing: How to Choose and Apply the Right Edge . Rodale Press ISBNÃ, 0-87596-566-0
External links
- Shellac app
- Finish in Antique Wood Furniture
- For Fixed or Not Fixed (Antique Furniture)
- Finishing for First-Timers
- Homeshop finished working it
- Water based
Source of the article : Wikipedia
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