Elements of woodwork

by Charles A. King

Wood Finishing

69. Filling.—(A.) After wood has been smoothed and made ready to receive the finish, it is prepared by filling, by which is meant the process of filling the grain so that the finish itself will not soak in. This, if well done, makes it possible to do as good a job of finishing with two or three coats as could be done on some kinds of wood with from five to eight coats without the filling. Open-grained woods, such as oak, ash, etc., especially need filling, as before the process of filling was discovered, the open grain, or cellular part of the wood, had to be filled by shellac, or other expensive material, before there was a surface suitable to receive the polish. (B.) There are two forms of filler—the paste, which is for use upon open-grained woods, and the liquid, which is adapted to filling the pores of close-grained woods like pine, poplar, cherry, etc., and which takes the place of one coat of the more expensive shellac or other finish. The paste may be purchased ready-made, and colored to suit the taste, or it may be made by using whiting, silex, or corn starch, and any dry colors necessary to secure the desired stain. The ingredients should be well ground, and thoroughly mixed with boiled linseed oil to a thick paste; to this should be added as much japan drier as there is of the oil, or one quarter as much as there is of the paste. The whole may then be thinned with turpentine, benzine, or gasolene to a consistency which will allow it to be spread easily, but it should still be quite thick.

(C.) Filler need not be spread very smoothly, but the surface of the wood must be covered, and the filling thoroughly worked into the grain. After this has been done, the wood should be allowed to stand a few minutes, until the filler has become dull or powdery, and seems to stick to the wood if rubbed lightly with the finger, when it should be rubbed off with shavings or excelsior, rubbing across the grain wherever possible. Do not use cloth until cleaning up after the filler is all off, as it is more apt to take the filling out of the grain than either excelsior or shavings. The corners should be cleaned out with a sharp stick, after which the work should stand for several hours, or over night, before the finish is applied, as otherwise the moisture in the filler may cause the finish to bubble. Care should be used that the filling does not stand too long before rubbing off, or it will be very difficult to remove it; hence, it is best not to spread any more than can be cleaned off before it gets too hard. Be sure that there is enough filling mixed to do the job before any is applied, as it is difficult to match colors.

(D.) Liquid filling should be spread as smoothly and as evenly as possible, as the laps will be apt to show through the finish which is spread over it.

70. Staining wood (A.) is for the purpose of imparting some other than the natural color to the wood.

(B.) In finishing open-grained woods, a stain often is used which will color the wood before it is filled, though upon general work, it is the custom to color the stain only. This does not make the work all of one color, as the cells of the wood will retain more filling than will the harder part of the grain. By this method the quarter grain may be made more prominent. If an open-grained wood is being treated, it should be filled after being stained. Close-grained woods are ready for the finish as soon as the stain has dried. Stains which will do the work satisfactorily may be made of various chemicals. There are also many satisfactory stains upon the market, which can be purchased in as small packages as desired, offering the student a large range of colors from which to select.

(C.) Stains for close-grained woods may be made by mixing dry colors with turpentine or benzine, and a little boiled oil and japan to bind the color. These stains should be applied the same as the filler, but not allowed to become so hard before cleaning off, or there will be light places rubbed in the finish. The rubbing or cleaning off should be done with a soft cloth, care being used that there are no places left uncleaned, especially in the corners, as the finish will make them muddy.

(D.) A very good old cherry stain may be made by mixing Venetian red and rose pink until the desired shade is produced.

(E.) Black walnut may be imitated by mixing burnt umber with turpentine, oil, and japan, and if a reddish tinge is desired, a little burnt sienna may be added; this is a much better color than can be produced by umber alone. Asphaltum, thinned to the desired color, makes a good walnut stain.

(F.) Many of the best stains are mixed with water as a vehicle, as a depth and brilliancy of color may be obtained which is impossible with any stain that has oil in it. The objection to using water is that the grain of the wood is lifted by the moisture, and has to be sanded smooth before it can be finished. Even with this serious objection, water stains are used extensively upon the best work.