10 Things You Should Know About Wood Finishing
Wood finishing today is a commercial art. With the greater appreciation of interior decoration by the great middle classes has come the realization that interior wood trim constitutes the frame of the picture, so to speak. Consequently the selection of color and texture of the finish for wood trim is being done with the same care that is exercised by the artist who chooses a frame for his painting. Here are 10 Things You Should Know About Wood Finishing.
Getting a surface ready for finishing is work which should be done with the utmost care when the finish is to be the finest possible and even for ordinary jobs. Unfortunately the price received for many jobs of finishing: is so low that it is quite impossible to do more than the most rapid cleaning and sandpapering, so that is where the responsibility must be placed for many muddy, cloudy natural and stained finishes.
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Woods to be finished in natural color as light as possible, maple, birch, etc., are often bleached before any finishing coats of filler, varnish or shellac are put on. The bleaching raises the grain of the wood and a thorough job of sandpapering must be done after that process.
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One of the very first considerations is whether the trim in a building or the wood used in a cabinet or piece of furniture is sufficiently uniform as to color, grain and figure to make it practical to finish it in the natural or a stained color, whether it might not be better to finish with paint or enamel. A skillful finisher can always bleach dark boards and stain light boards to tone in with the general appearance of the other wood, but it costs money and time to remedy defects.
Each of the various classes of stains is possessed of certain advantages and some disadvantages. Various kinds of wood take a single stain with different color effect. The difference may be only a lighter or darker shade of the same color or it may be a similar color with a different hue. The brown stain, for instance, which will give you an excellent walnut color on gum will produce only a light brownish yellow on birch and maple.
The rougher the surface, naturally or from rough sandpapering with coarse paper, the darker the color produced by a stain. Rough surfaces soak up more stain. And smooth surfaces, naturally hard, close-grain, and those made smooth with fine sandpapering take the stain with a lighter color.
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For the finest kind of finishing on interior wood trim of buildings, cabinets and furniture, water stains are easily the best type, particularly the aniline and coal tar dye group which comes in convenient dry and liquid form. When a finisher is anxious to build up a reputation he will be wise to use water stain as a rule and get a price which will cover the little extra labor of sandpapering the raised wood grain caused by the use of water on it.
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Speed is necessary in spreading any stain to distribute it evenly, especially on oak, chestnut and ash which have large open cells which soak up much stain making too dark a color in places. There is not so much danger on veneered wood in this respect; the stain can penetrate only as far as the glue. But on solid wood more stain may go deep into the wood, if you flood the surface by working too slowly, than can dry in the time allowed. Then when you seal up this wet stain with filler, shellac and varnish trouble may follow. Sometimes the wet stain generates gas and forces itself to the surface pushing filler and varnish ahead of it and disfigured surface results.
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Wood fillers are needed for the purpose of filling the open cells or tiny crevices in open-grain woods such as oak, ash, chestnut, butternut, elm, mahogany, walnut, etc. All woods are composed of fibers and cells. While growing these cells are filled with water, sap or resin. When the wood is seasoned and dried the cells are filled with air. The surface cells are little holes or pores. In the open-grain woods listed above they are fairly large. In close-grain woods like maple, birch, bass, beech, cherry, cypress, fir, pine, gum, poplar, redwood, spruce, sycamore and holly, the cells are very small, the fiber being closely woven together.
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Varnish is needed to protect surfaces from moisture which will warp, swell and raise the grain of the wood and from gases ever present in the air which discolor wood not protected. Varnish also protects stained colors from light and air which fade them, especially the oil and spirit anilines which must be covered immediately if they are to hold their color a reasonable length of time. Varnish protects wood from wear by surface abrasion to some extent.
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Painted and enameled wood trim is finished with very interesting, artistic effects by glazing it much in the same manner as walls are finished with the glazing, mottling and blending methods. The object of this treatment is sometimes to give a novelty finish in vivid color effects, but more often it is done to subdue the color of the wood trim and to make it harmonize in low tones with walls, furniture and the general furnishings of the room. The work is simple to do, yet it requires the use of good taste both in the selection of the glazing or stippling color and the strength of the pattern put on to the wood.