This section is from the book "A Treatise On Architecture And Building Construction Vol4: Plumbing And Gas-Fitting, Heating And Ventilation, Painting And Decorating, Estimating And Calculating Quantities", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
New Work. It is necessary, before entering on the process of painting, to clean off all glue spots, etc. In this operation, the painter uses the stopping knife (Fig. 4), care always being taken not to score or dent the surface of the wood. The dusting brush should, in this part of the work, be freely used.
Knotting. The next operation is called knotting, to guard against the. appearance of knots in the finished work, by arresting their absorbent quality, or closing the apertures of the fiber and thus preventing the effusion of gum or sap. Wood should, before use, be thoroughly dry, but as this is a matter not within the painter's control, he must employ all skill and industry to counteract any neglect in the choice of properly seasoned wood. The object of painting being to preserve the more perishable parts of the structure from the deleterious effect of weather, heat, gases, etc., it is well to note that paint, applied to unseasoned wood, confines the sap and moisture, and thus surely hastens decay. Patent knotting is a specially prepared composition readily purchasable. The following receipts are, however, given for the preparation of like compositions:
1. Mix together 1/4 pint of japanner's gold size, 1 tea-spoonful of red lead, 1 pint of vegetable naphtha, and 7 ounces of orange shellac. Keep in a warm place till the shellac dissolves; this mixture must be frequently shaken.
2. Mix together, with glue size, a small quantity of white and red lead powder, and apply while warm.
The knots should, in certain extreme cases, be covered with silver leaf.
106. In all well built structures, the woodwork receives at least four coats of paint. The first process of painting is called priming, applied for the special purpose of diminishing the absorbent quality of 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 colors are to be of somber hue, the priming coat may be dark green, dark brown, etc. The painting may be done with a dull 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 linseed oil for indoor, work, adding, in either case, a small quantity of turpentine, the proportion being three parts of oil to one of turpentine. For rapid absorption by the new wood or plaster, the priming coat should be thin. Some painters adopt the reprehensible practice of laying a coat of charcoal size over the wood. No durable effect is thereby obtained. The size, to a great extent, arrests the absorbent powers of the wood or plaster, but prevents the proper adhesion of oil paint, which splits and peels off. Charcoal may, however, be used with advantage on old work, where the grease prevents the proper drying of oil paint, but, even in such cases, it is better, when possible, to remove old paint from the wood or plaster, until the surface is reached, on -which a coat of oil color may be successfully applied.
When thoroughly dry, the priming is to be rubbed down with glass paper. This operation, although in itself simple, requires care to make the rubbing equally effective over the entire surface. To obtain this result, glass paper should be wrapped around a flat piece of wood or cork (cork to be preferred), say 4 in. X 6 in. and 1 inch thick. This should be rubbed equally over the whole surface which will thus be smoothed without injury.
For use on the edges of panels and similar situations, glass paper may be wrapped over a piece of chisel-shaped wood, while for the curves of moldings, a piece of cloth around the end of the finger is used. All the dust caused by the glass paper having been carefully removed with the duster, the next operation is that of stopping.
107. Stopping is the filling in and making good all nail holes, bad joints, splits, etc. with putty, or with a paste made of putty and white lead, called hard stopping, which is done with the stopping knife. This is another of the operations, simple in themselves, which, in execution, demand care and attention. It is not sufficient to merely press a small quantity of stopping into the interstices and then smooth it over; for, as the stopping dries, it contracts and sinks below the surface, leaving openings quite as great an eyesore as ever. With the stopping knife slightly raised above the surface, the stopping should be forced as far into the crack as possible. In a day or two before the second coat is laid, the stopping will-owing to shrinkage-be found nearly level with the panel, and may then be smoothed with the stopping knife.
Where a panel or other part of the work receives a blow, and a dent or shallow concavity is formed, it must be clear that the mere film of stopping required to level such a spot, is almost certain to peel off, leaving a place totally uncovered by paint. To avoid such a result, the best way is to deepen the recess in parts, by pricking holes in it with a brad awl, which should incline in different directions. Deep fissures are thus formed into which the stopping is to be forced, and the portions spread over the delves will thus be, as it were, nailed to the wood by the filaments penetrating these openings. The surface having been again smoothed off with glass paper, the second painting is proceeded with.