Scientific American 32, 1.5.1847
(Continued from No. 31)
Plain Painting in Oil Colors.
The beauty of this kind of painting depends principally on the uniformity of its finish; and this is effected by distributing the paint equally on every part of the work, and finishing by drawing the brush lightly and steadilu over the work, in the direction of the grain of the wood. Care is required to avoid leaving a superfluous quantity of paint in the quirks and corners; all such accumulations must be brushed out. In painting houses outside, the workman should be particularly careful to paint the edges of the clapboards and all the hollow corners; and for this purpose, the brush must be held with the handle inclining downward, that the brush part may work upward, filling the edges and corners. Paint, for inside work, usually requires and ingredient more drying than raw linseed oil; and for this purpose, and article called litharge, being finely ground, is added to the paint, in the proportion of one ounce to each pound of paint; more or less according to circumstances. This litgarge is evidently the best dryer for floor paint that is known; paints tempered with this, dry harder, and wear better, than any other: but painters have in general use a fluid article, called drying japan, which is very convenient as a dryer, and is excellent for carriage and ornamental work, but is in more general use than it should be in house painting. This japan consists of oil, hum shellac, litgarge and red lead, united by being boiled together. Red lead is, of itself, a good dryer, in such colors as are not injured by its use; but when a delicate white is required, a sulphate of zinc, known as white vitriol, must be used. It is a general custom with painters, however, to prepare a drying oil, by boiling it, that it may the more readily dry, even without any other dryer. The usual mode of boiling the oil, is to place several gallons in an iron kettle over a slow fire, and when it begins to boil, add four ounces of litharge and an equal quantity of red lead, to each gallon of oil: the oil is continued boiling, being almost constantly stirred with a stick, for about half an hour, or until it boils clear without frothing; it is then taken off to cool. This oil can be always procured ready boiled at the paint shops; but paints mixed with this, will not prove so durable when exposed to the weather or to wear, as those ground in raw oil, and having good opportunity to dry. Raw oil, with litharge for a dryer, is best for floors or other inside work, in warm, dry weather. In giving the work a second or third coat, however, it is requisite to mix spirits of turpentine with the oil, to prevent too sharp a gloss, and render the paint more firm and hard. The paint is first mixed with oil and the spirits of turpentine is added, in the proportion of a pint to two quarts of oil; the proportion varying, however, according to circumstances. If the paint is required to be left flat, or without any gloss, the spirits may be used in the proportion of one half, or even two to one: but such paint will not wear so well. Alcohol is sometimes used instead of spirits of turpentine; but neither of these should be used in any considerable quantity on outside work in warm weather: in cold weather they are convenient to make the paint flew more freely. As a general rule, after the first cost of paint is dry, and when the second is to be applied, the work must be examined, and all the cracks, seams and holes filled up smoothly with putty, (a simple mixture of oil and Spanish whiting,) and all the rough parts smoothed with sand-paper or glass-paper; and after smoothing, the dust must be carefully removed with a dry brush. A general, but improper custom, which prevails with most painters, is to apply the putty with the fingers merely, in filling the cavities of nails and brads; but instead of this, the putty should always be smoothed with a chisel-shaped piece of wood. When any uneven part of the surface is to be smoothed, the putty should have a little white lead paint mixed with it, to make it adhere better. If an old room is to be painted, such parts of the surface as have been discolored with smoke, or have been exposed to wear, should be washed over with a dilute mixture of lime and water, and allowed to dry before the paint is applied: and such parts of a floor as have become bare, or from which the paint is worn off, should be first painted with very thin or dilute paint, and become dry before the whole is painted: as the same paint cannot be suitable for the painted and the unpainted parts. We shall now proceed to instructions in
Producing and Compounding Colors.
White is considered as not only a principal color in painting, but the base or foundation of all light colored paints. White lead is the principal white in use, though a more delicate white called slake white, is used in ornamental work. Several common colors, known as lead color, slate color, &c., are produced by mixing lampblack with white lead in different proportions. A small quantity of Prussian blue, finely ground and added to white lead, constitutes the common sky blue. Minute quantities of blue and yellow added to white, produce the delicate pearl color, so much in vogue for parlors and halls. Straw color is produced by the addition of a little chrome yellow to white: and pead green by addition of Paris green. A beautiful light purple or peach blossom color is produced, by adding to white lead, small quantities of ultramarine blue, and drop lake. It is needless to specify the exact proportion of the ingredients in these compounds; the only rule being to add the coloring ingredients in minute quantities till the required color is produced. The most common color for floors, is composed of white lead and yellow ochre, in about equal quantities by weight, with the addition of one ounce of red lead to each pound of the mixture. In painting carriages or ships, a great variety of compound colors are used, a few of which may be here noticed. The best black is composed of lampblack and Prussian blue. A dark green consists of a mixture of chrome green and Prussian blue. A brilliant plum color is produced by a mixture of lampblack and vermillion. Olive color is produced by mixing lampblack and chrome yellow. A brilliant orange color is produced by mixing chrome yellow and orange lead - (a pigment similar to red lead, but more refined.) A stone brown is composed of lampblack, yellow ochre and Venetian red, equal parts: the addition of white to this compound reduces this color to a drab, or light stone color. A mixture of lamp black with Venetian red, constitute the chocolate color. A bright rose color, which is much used in ornamenting, is composed of white lead and drop lake. As a general rule, the colors should be mixed with oil and ground separately before being compounded, or mixed together; but should not be diluted any more than is required for grinding, until the color is perfected. We shall proceed with some instruction in carriage painting in our next number.
(To be continued.)
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