Coating

“ In connection with this subject, there is one fact worthy of notice; a plate with a very heavy coating of pure silver, will not produce an equally developed image, as a plate with a thinner coating, hence the thin coating, providing it entirely covers the surface, is the best, and is the one most to be desired. The experiment is plain and simple. Let the slate receive a heavy or thick coating by the electrotype, then polish, coat, expose in the usual manner, and the result will be a flat, ashy, indistinct impression ”

“ It has been emphasized that for durability and protection, the strength and imperviousness of a paint coating are vital factors. The protective value of the paint coating of course ceases with its chalking or disintegration, but, while it is true that the protecting or final life of the coating ceases with this disintegration, it is also true that a paint coating has always during its true life more or less porosity from the nature of the linoxin or oxidized linseed oil. ”

“ A piece of leather or of oilskin is stretched over a flat block, and a boy lays a coating of one of the colours to be used—say green—on the leather, with a brush. A man then takes that one of the carved blocks which is to stamp the green part of the device, and lays it down flat on the wet colour, by which a coating is transferred to all the raised parts of the block. This is then stamped down, with a firm and steady pressure, upon the piece of paper, by which the green device is permanently impressed. ”

“ Then, if we examine, with respect to strength, or depth of tone, and sharpness of impression, we see that the light coating, produces a very sharp but shallow impression; while the other extreme gives a deep but very dull one. Here, then, are still better reasons for avoiding either extreme. The changes through which the plate passes in coating may be considered a yellow straw color or dark orange yellow, a rose color more or less dark in tint, or red violet, steel blue or indigo, and lastly green. ”

“ This is to be attributed to the porous nature of the coating, whether it is applied by the hot or wet (acid) process. The lead does not bond to the plate as well as either of the other metals—zinc, tin, copper, or any alloys of them. The following table gives the increase in weight of different articles due to hot galvanizing:—
Tin is often added to the hot bath for the purpose of obtaining a smoother surface and larger facets, but it is found to shorten the life of the protective coating very considerably. ”

“ When a durable coating is to be applied to wood, the first solution must not be too strong, for if it be it will not be absorbed: it will not displace the air from the pores, and consequently will not adhere strongly. A more concentrated solution may be employed for the after-coats, but each coat must be dry before another is applied, and the drying, in the most favourable weather, will occupy at least twenty-four hours. When the glass is made with potash the coating is liable to crack: this defect does not apply to glass made with soda. ”

“ Coated-paper Troubles.—Coated papers have their characteristic shortcomings. The picking of small particles of the coating is perhaps the most common fault, and is caused by insufficient adhesive elements in the coating mixture. Other troubles are traceable to some of the defects of the body stock. Irregularity of the finish is sure to come from faulty application of the coating or careless calendering. Grit or bubbles in the coating is likely to result in a porous surface. The sour odor of some coated papers is due to decomposing casein or glue. ”

“ My invention relates to a process by which sheets of various material, such as leather, cloth, paper, etc, are covered by a coating applied in the form of a fluid, or a fluid solution, in such a manner that the resulting coating will be smooth and of uniform thickness, and so that when the solution applied contains chemical salts these will be equally distributed over the surface which is so covered. ”

“ When only a small quantity is required, it is the general practice to coat by hand.
In hand coating, the tissue compound may be strained through fine muslin into a flat tin dish placed on a water bath; the surface cleared of air bubbles by dragging over it a strip of stiff paper. The sheet of paper to be coated is held in an upright position at the further end of the dish with its bottom edge just touching the surface of the solution, gently lowered until the whole surface of the sheet is in contact with the solution. ”

“ Glazed paper is one of the most interesting and useful forms of coated paper. The glazing is done by two processes, known as friction and flint glazing. In either process the method of coating, up to and including the drying, is practically the same as that followed in the coating of other papers, except that wax is mixed with the coating to act as a lubricator, and to permit of securing the desired glassy finish. ”

“ A carborundum coating seems to be more durable than other coatings, not only because the carborundum can withstand high degrees of heat, but also because it seems to unite with the carbon better than any other material I have tried. A coating of zirconia or any other oxide, for instance, is far more quickly destroyed. ”

“ With care you may succeed in getting the paint on quite evenly all over, which is desirable. One coat will do. If it becomes necessary to remove this coating for renewal, it may be effected by an application of potash lye, or the old may be renewed by a coating of a mixture of 2 parts hydrochloric acid, 2 parts white vitriol, 1 part sulphate of copper (blue vitriol) and 1 part of gum arabic, applied by means of a brush.
Draw before Cutting
A detail drawing made of a piece of furniture before starting the work will often save time and mistakes. ”

“ The priming, or first coat, should be composed of equal parts of boiled linseed-oil and white-lead for outside, or zinc with some turpentine for inside work. When this is dry one or two coats are to be laid on, taking care to apply the paint evenly and to work it into all cracks, crevices, and corners. The secret of good work is not in daubing a whole lot of paint on the surface to be covered, but in laying it on evenly and in a thin coating, so that it will neither gum nor run. ”

“ It is a bad plan to put glaze on newly-spirited work, or to re-apply it on old bodies.
The following is another method for cheap work: A coating of clear size is first given in a warm state (this can be obtained at most oil-shops) , and when dry is rubbed down with fine glass-paper, after which a coating of varnish is applied with a sponge or a broad camel-hair brush, giving long sweeping strokes. ”

“ It is the aim in this system of painting to form a non-absorptive surface, and it will be seen that if the filler closed up the pores of the wood it will assuredly close up the pores of the leveling paint, therefore, a coating is applied to the rubbed surface of paint in the same manner as in priming the wood, wiping off all that will readily leave the surface, thus rendering the paint elastic, yet proof against the entrance of oil from all subsequent coats of color or of varnish. ”

“ The coating may be done in a good light, not bright sunlight, but it must be dried in the dark, because, although insensitive while in a moist condition, it becomes sensitive immediately on desiccation. ”

“ Protection of Surfaces:—The protection and coloration of metals and alloys includes a large number of industries. The engineer uses paints for his iron and steel. A small amount of work is treated by the Bower-Barff and allied processes, by which a coating of magnetic oxide is left on the metal. Hot tar—Angus Smith’s process—is used for water-pipes. Boiled linseed-oil is employed as a non-corrosive coating preceding the application of the lead and iron oxide paints. ”

“ Never apply paint or any other coating to green or unseasoned timber. If the wood was not well dried or seasoned, the coat will only hasten decay. Good coatings consist of oily or resinous substances which make a smooth coat capable of being uniformly applied. They must cover every part, must not crack, and possess a certain amount of plasticity after drying. Coal-tar, with or without sand or plaster, and pitch, especially if mixed with oil of turpentine and applied hot (thus penetrating more deeply) , answer best. ”

“ The coated wire is treated in the same way as the copper strand—the die D, or another of the same size, being placed at the back of the cylinder and a larger one substituted at the front. A second coating is then laid on, and after it passes through a similar process of examination a third coating is applied, and so on until the requisite number is completed. The finished core changes rapidly in its electric qualities at first, and is generally kept for a stated interval of time before being subjected to the specified tests. ”

“ The sheet intended to receive the image, the CF sheet, is treated on the front with a clay or resin that is alkaline on the surface but acidic inside, or with an alternative reactive coating [Calnan 1979] . In Europe, the color developer system is typically based on clays, whereas phenolic resins are most commonly used in the United States and Japan [Murray 1991] . The coating is spread in a mixture, dried, and adhered with a styrene-butadiene-latex or one of the binders listed above. ”

“ To the second coat add some wax. A very durable coating is obtained, which looks so pleasing that it is only necessary to draw some stripes with a darker paint so as to divide the surface into fields.
Cement, To Paint Over Fresh.—The wall should be washed with dilute sulphuric acid several days before painting. This will change the surplus caustic lime to sulphate of lime or gypsum. The acid should be about one-half chamber acid and one-half water. This should be repeated before painting, and a coat of raw linseed oil flowed on freely should be given for the first coat. ”

“ White Coating For Signs, Etc.—A white color for signs and articles exposed to the air is prepared as follows for the last coat: Thin so-called Dutch “stand” oil with oil of turpentine to working consistency, and grind in it equal parts of zinc white and white lead, not adding much siccative, as the white lead assists the drying considerably. If the paint is smoothed well with a badger brush, a very durable white color of great gloss is obtained. Linseed oil, or varnish which has thickened like “stand” oil by long open storing, will answer equally well. ”

“ The adhesion of the linoxin to the coarse group of particles and to the underlying material is vital to the life of the paint coating. If the coating parts from the surface beneath, we have scaling or peeling. It is universally admitted that this will result from use of zinc oxide as the sole pigment. ”

“ Glass made in this way is called "coated," and sometimes "flashed" glass, and is extremely useful for ornamental purposes, for by the action upon the coloured surface of hydrofluoric acid, the ruby coating can be eaten away, and the white glass beneath left entire. ”

“ His application of the law permits the paint manufacturers to design a paint formula with full knowledge of the controlling conditions, so that it shall produce a coating neither too thick, and therefore uneconomical and subject to excessive internal strains, nor too thin, and thus weak and inefficient for protection. ”

“ One or two coats of cement having I then been laid over the centering, a stratum of the square tubes laid side by side, and breaking joint, is next embedded in fine cement, and the interstices between them also filled in with that material. One thin coating of cement is then laid over the whole stratum; and in a week, when this is dry, another stratum of tubes is laid over the first in a contrary direction, bedded and filled in with cement as before, and finished by a coating of the same material. ”

“ A light coating is thus formed. For a second coating acetic or formic acid is used preferably for aluminum, nickel, and copper; but for iron and steel, muriatic or nitric acid. After cleaning, the article is placed in a solution of tannin or gallic acid, and is then dried in a warm place as before. The second coating is of a yellowish-brown color. On placing it near the fire, the color can be deepened until it becomes completely black; care must be taken to withdraw it when the desired shade is produced. Instead of the acids employed for the first coating, ammonia may be used. ”

“ The purpose of the coating is to give a perfectly smooth surface, obliterating entirely the marks of the machine wire and felts, and to do this effectively the consistency of the mixture is regulated so that it may enter the minute depressions and deposit sufficient matter to take a good finish. An ingenious overhead railway carries the web forward in a series of loops supported on a series of rods, hot air driven forward by mechanical fans effecting the drying. If the paper is two-sided art, it is reeled and the operations repeated on the other side of the paper. ”

“ If metal molding, couplings, outlet boxes, junction boxes, cabinets, or fittings having protective coating of non-conducting material such as enamel are used, such coating must be thoroughly removed from threads of couplings and metal moldings, and from the surfaces of boxes, cabinets, and fittings, where the metal molding or ground clamp is secured in order to obtain the requisite good connection. ”

“ This pigment has the property of forming with linseed oil a hard elastic coating, clinging with great tenacity to the metal. It has no oxidising effect on iron, and does not act as a carrier of oxygen from the atmosphere after the paint has set, neither does it render the oil brittle nor promote rust. When red lead fails, it is principally by gradual wear or friction from the outside. It does not scale or blister, which both asphalt and iron oxide paints will do, thereby requiring a thorough scraping and removal of old material before a new coat can be applied. ”