This section is from the book "Cyclopedia Of Painting", by George D. Armstrong. Also available from Amazon: Cyclopedia of Painting.
The first process of painting is called priming, which consists of laying on a coat of paint for the special purpose of diminishing the absorbent quality of the wood or plaster. The paint used for this purpose is generally a mixture of white lead and red lead, with a proper proportion of driers; but when the finishing color is to be black, dark green or dark brown the priming may be done with a lead color made of vegetable black and white lead in equal quantities.
These colors should be mixed with boiled oil for out-of-door, and with linseed oil for in-door work, a small quantity of turpentine being added in either case, the proportions being three parts of oil to one of turpentine. The paint should be rather thin so that it may be well adapted for rapid absorption by the new wood or plaster.
Some painters, in order to save the oil coats, have resorted to the objectionable practice of spreading a coat of size mixed with water and whiting over the new work.
This may serve for temporary purposes, but it will soon be seen that it should not be adopted in good work or where durability is expected. To a certain extent the size stops the absorbent powers of the wood or plaster, but it prevents the proper adhesion of the oil paint, which soon cracks or peels off. It may, however, be used with advantage in old work, where the grease would prevent the proper drying of the oil paint, but even in such cases it is best, when possible, to scrape the wood or plaster until a new surface is reached, on which the oil paint may be successfully applied.
When the priming is thoroughly dry, it is to be rubbed down with glass paper and this operation, although in itself simple, requires a certain amount of care so that the rubbing may be equally effective over the whole surface. In order that this result may be attained, the glass paper used should not be a mere scrap, rubbed carelessly about in various directions, by which means some parts will be passed over oftener than others, and the paint may be nearly rubbed off in one spot whilst it is left almost untouched on another. A piece of the paper should be wrapped round a flat piece of wood, say 4 inches long by 3 inches wide and 1 inch thick, forming a kind of brush, and this should be rubbed equally over the whole surface, which will thus be nicely smoothed, whilst its perfectly level character will not be injured. A piece of glass paper which has been used several times in this way should be saved for use in the later stages of the work, when great refinement is required. A strip of glass paper may be wrapped over the edge of a piece of wood shaped like a chisel for use in the edges of panels and similar situations, or round the finger or a piece of rag for the curved parts of mouldings, great care being taken that a stiff edge, such as is formed by a sudden bend in the glass paper, may not come in contact with the work, producing scratches which are very troublesome to get rid of.
All the dust caused by the glass paper must be carefully removed by means of the duster. When the priming has been properly rubbed down the next operation is that of stopping.
Stopping consists in filling in and making good all nail-holes, bad joints and cracks with putty, or with a paste made of putty and white lead, called hard stopping; this is done with the stopping knife.
This is another of the operations which, although simple, require a certain amount of care, lest instead of contributing to, they may mar the success of the work. Thus let it be required to stop a crack in a panel; it will not be sufficient merely to press into the interstice a small quantity of stopping and then smooth it over, for as the stopping dries it contracts and sinks below the surface, and the crack becomes just as great an eye-sore as ever.
In such a case, the stopping should be forced as far down into the crack as possible; this may be done with the edge of the stopping knife, or with a thin piece of wood, leaving the stopping, however, slightly raised above the surface. In a day or two, before the second painting is proceeded with, the stopping will, owing to a certain amount of shrinking during drying, be found nearly level with the panel and may then be smoothed down with the stopping knife.
The circumstance calling for the greatest care in stopping, is where a panel or other part of the work has received a blow and a delve or shallow concavity is formed, for it will be clear that the mere skin of stopping required to level up such a spot, would be almost certain to crack off, leaving the place totally uncovered by paint. The best way to avoid such a result is to deepen the recess in parts by pricking holes in it with a bradawl and these should incline in different directions and should be more closely placed and more numerous near the edges than in the middle of the space. The point of the stopping-knife may be used for this purpose, and deep fissures will be formed thereby; into these fissures or holes the stopping is to be forced and the portion spread over the delve will thus be as it were nailed to the wood by the filaments penetrating into the holes.
This process should be slowly done, an interval being allowed to elapse between the first and second stopping, but this is supposing a condition which cannot always be fulfilled; the exigencies of business in these days of high pressure demanding that work shall be pushed on with the utmost rapidity; but it is desired to point out the means by which failure may be avoided, and the intelligent painter, knowing this, will be able in most cases to arrange his work in such a way that some portions may be proceeded with whilst the necessary delay is afforded to others, and thus, by economy of time, and proper organization of labor, the desired end may be accomplished.
The surface having been again touched off with the glass paper, the second painting is to be proceeded with. For the second coat, the same paint used for the priming, or white lead thinned with oil and a little turpentine and driers, may be employed, the proportion of driers for ordinary cases being 1 1/2 ounces to 10 pounds of white lead, but in winter, or in a damp climate, the proportion of driers must be increased. The following useful hints are here given:
It should be observed that second color for new work is made up chiefly with oil, as it best stops the suction of the wood, but second color for old work is made up chiefly with turpentine, because oil color would not dry or adhere to it so well.
The color should be spread on as evenly as possible, and to effect this as soon as the whole or a convenient quantity is covered, the brush should be passed over it in a direction contrary to that in which it is finally to be laid off; this is called crossing. After crossing it should be laid off softly and carefully in a direction contrary to the crossings, but with the grain of the wood, taking care that none of the cross brush marks be left visible. The criterion of good workmanship is, that the paint be laid evenly and the brush marks be not observed. In laying off, the brush should be laid into that portion of the work already done, that the joining may not be perceived. Every coat should be perfectly dry, and all dust carefully removed before the succeeding one is laid over it.
In the third painting some approach is made to the finishing color. Thus, if the finishing color is to be lavender, the third coat should consist of white, slightly tinted with that color. In some cases it is desirable that the coat preceding the finishing should be darker than that which is to be laid over it.
In the third painting, the oil and turpentine should be used in equal proportions.
The fourth may be considered as the finishing coat, although a fifth is often given, and always with great advantage. The finishing coat must not by any means be applied unless the third coat proves perfectly satisfactory; that is, unless the surface has dried absolutely uniform, as regards surface, for if one part is glossy and the other dull it will be clear that the absorbent quality is not stopped and the third painting must be repeated.
In commencing to repaint old work, the surface should, in the first case, be gone over with the stopping knife, removing all excrescences, and it is then to be rubbed with pumice stone and water, the greasy parts being well rubbed with turpentine.
Parts from which the paint has been entirely removed and decayed patches must then be gone over with a coat of priming color, and cracks and holes are to be made good with stopping. The first coat is then to be given and this is to be mixed with turpentine. The quality of the next coat will depend on the manner in which it is to be finished. If it is to be painted twice in oil and flatted, the next coat should be mixed up chiefly in oil, and tinted like the finishing color to form a ground for the flatting. The greater the gloss of the ground, the more dead will be the finishing coat, or flatting; likewise, the more dead the ground the better will the finishing oil shine. It is, therefore, a general rule, that for finishing in oil the undercoat should be turpentine, and for finishing flat the undercoat or ground color should be oil; but all turpentine grounds must have a little oil mixed with them, and all oil undercoats must have a small quantity of turpentine added to them, excepting the priming or first coat in new work.
In order to attain an absolutely solid appearance, some painters apply two coats of the finishing color, by which no doubt uniformity is secured, but the expense is, of course, materially increased thereby. There are, however, pigments of a cheaper but still permanent character, which approach in tone to the very best, and these may with advantage be used as a first finishing coat, over which the final color may be applied. Such colors must be carefully selected and must be well covered by the finishing coat.