William Norman Brown

“ When it has been permitted to drain thoroughly, the work should be hung on the hooks on the rods in the oven as seen in the explanatory sketch, care being observed that no portion of the work is in such a position that any superfluous enamel cannot easily drain off—in other words, the work must lie or hang that it is always, as it were, on the slant. Always bear in mind when shutting the oven door to do so gently, as if a slam is indulged in all the gas jets will be blown out, and an explosion would probably result. ”

“ Japanning may be said to occupy a position midway between painting and porcelain enamelling, and a japanned surface differs from an ordinary painted surface in being far more brilliant, smoother, harder, and more durable, and also in retaining its gloss permanently, in not being easily injured by hot water or by being placed near a fire; while real good japanning is characterised by great lustre and adhesiveness to the metal to which it has been applied, and its non-liability to chipping—a fault which, as a rule, stamps the common article. ”

“ As zinc is one of the metals most readily attacked by acids, ordinary galvanized iron is not suitable for positions where it is to be much exposed to an atmosphere charged with acids sent into the air by some manufactories, or to the sulphuric acid fumes found in the products of combustion of rolling mills, iron, glass, and gas works, etc., and yet we see engineers of note covering-in important buildings with corrugated and other sheets of iron, and using galvanized iron tie rods, angles, and other constructive shapes in blind confidence of the protective power of the zinc coating ”

“ Common black japan grounds on metal by means of heat are procured in the following manner: The surface to be japanned must be coated over with drying oil, and when it is moderately dry must be put into a stove of such heat as will change the oil black without burning it. The stove should not be too hot when the oil is put into it nor the heat increased too fast, either which error would make it blister, but the slower the heat is increased and the longer it is continued, provided it be restrained within a due degree, the harder will be the coat of japan. ”

“ The best way to clean the work is to soak it in a strong "lye" of hot potash, when the softened enamel can be wiped or brushed off—this latter method being pursued in the more intricate and ungetatable portions of the work. New work, which has not been enamelled, can be treated in the same way for the removal of all grease, stains, finger-marks, etc., and too much attention cannot be paid to the initial preparation of the surface of the metal, to have it thoroughly even and smooth, as it adds so much to the ultimate finish and appearance of the work. ”

“ The best way of proceeding is to begin in the middle and pass the brush to one end, then with another stroke from the middle pass it to the other end, taking care that before each stroke the brush be well supplied with varnish; when one coat is dry another must be laid over it in like manner, and this must be continued five or six times. If on trial there be not a sufficient thickness of varnish to bear the polish without laying bare the painting or ground colour underneath more varnish must be applied. ”

“ The formation of a perfectly white japan ground and of the first degree of hardness has always been difficult to attain in the art of japanning, as there are few or no substances that can be so dissolved as to form a very hard varnish coat without being so darkened in the process as to quite degrade or spoil the whiteness of the colour. ”

“ To all intents and purposes the deposits obtained from acid solutions under favourable circumstances are fairly adhesive when great care has been exercised to thoroughly scale and clean the surface to be coated, which is found to be the principal difficulty in the application of any electro-chemical process for copper, lead, or tin, as well as for zinc, and that renders even the application of paint or other brush compounds to futile unless honestly complied with. ”

“ When pouring enamel by means of the ladle over pieces of work, do not agitate the liquid too much—at the same time taking care to keep it well mixed—so as to form air bubbles, as this will cause trouble, and in pouring over the work do it with an easy and gentle and not too hurried a motion. In japanning curved pieces, such as mud-guards, etc., in hanging up the work in the oven see that the liquid does not run to extremities and there form ugly blots or blotches of enamel. ”

“ Another plan preferred by some japanners is to have three rows of burners the full length of the stove, which, under some circumstances, due to structural conditions, will be found more suitable. Anyway, whatever the position of the stove, allowance must be made for a temperature up to 400° F. to be raised. In old-fashioned ovens the heat is applied by means of external flues, in which hot air or steam is circulated, but this system is generally unsatisfactory, the supply of heat having to be controlled by dampers or stop-cocks, and this has given place to the gas apparatus. ”

“ Electrolytes made by adding caustic potash or soda to a suitable zinc salt have been found to be unworkable in practice on account of the formation of an insoluble zinc oxide on the surface of the anode and the resultant increased electrical resistance; the electrolytes are also constantly getting out of order, as more metal is taken out of the solution than could possibly be dissolved from the anodes by the chemicals set free on account of this insoluble scale or furring up of the anodes, which sometimes reaches one-eighth of an inch in thickness. ”

“ Let the mixture continue to boil until it appears of a thick consistence, then strain the whole through a coarse cloth and keep it for use. The pigments are also sometimes applied in a gum-water vehicle, but work so done, it has been urged, is not nearly so durable as that done in varnish or oil. However, those who formerly condemned the practice of japanning water-coloured decorations allowed that amateurs, who practised japanning for their amusement only and thus might not find it convenient to stock the necessary preparations for the other methods, might paint with water-colours. ”

“ With equal amounts of zinc per unit of area, the zinc coating put on by the cold process is more resistant to the corroding action of a saturated solution of copper sulphate than is the case with steel coated by the ordinary hot galvanizing process; or, to put it in another form, articles coated by the cold process should have an equally long life under the same conditions of exposure that hot galvanized articles are exposed to, and with less zinc than would be necessary in the ordinary hot process. The hardness of a zinc surface is a matter of some importance. ”

“ When taken out of the stove, the articles must be allowed to get cold, after which they must be given a coat of super black japan, which, if necessary, must be thinned with turps, a stiff, short bristle brush being employed, and the varnish put on sparingly, so that it will not "run" when it gets warm. Two coats of this varnish on top of the vegetable black coating are usually sufficient, when done properly, but a third coating much improves the work, and from ten to twelve hours' hardening will be necessary between each coating. ”

“ Dickson, "the craftsman trusts largely to his badger-hair brush to produce his effects of softness and marbly appearance; but in painting in water-colours, this softness, depth, and marbly appearance are produced mostly by the colour placed upon the surface, and left entirely untouched by badger or any other brush. The colour drying quickly, does not allow much time for working, and when dry it cannot be touched without spoiling the whole of the work. ”

“ Metals usually require from three to five coats, and between each application must be dried in an oven heated from 250° to 300° F.—about 270° being the average. It has already been seen that the best grounds for japanning are formed of shellac varnish, the necessary pigments for colouring being added thereto, being mixed with the shellac varnish after they have been ground into a high degree of smoothness and fineness in spirits of turpentine. In japanning it is best to have the oven at rather a lower temperature, increasing the heat after the work has been placed in the oven. ”

“ This is done sometimes in oil-colour in a marvellous manner, but even the best of oil-painting in marble cannot stand the comparison of water-colour, and it is only by comparison that any accurate judgment can be formed of any work. The production of marbles in water-colour has a depth, softness, and stoniness that defies oil-painting, and in some cases will defy detection unless by an expert of marbles. ”

“ So long as the zinc surface remains intact, the underlying metal is protected from corrosive action, but a mechanical or other injury to the zinc coating that exposes the metal beneath, in the presence of moisture causes a very rapid corrosion to be started, the galvanic action being changed from the zinc positive to zinc negative, and the iron, as the positive element in the circuit, is corroded instead of the zinc. ”

“ This beautiful ground, produced by heat, is valued not only for its hardness and its capacity to stand a heat greater than that of boiling water, but also for its fine appearance. It is made by means of a varnish prepared thus: Take one gallon of good linseed oil and half a pound of umber, boil them together until the oil becomes very brown and thick, strain it then through a coarse cloth and set it again to boil, in which state it must be continued until it acquires a consistency resembling that of pitch ”

“ For the first-mentioned class of work such high finish is not required as for bicycles, and consequently the enamel need not be applied with a brush, nor will it be necessary to rub down the work between each coat, but instead the pieces can be literally dipped in the tank of liquid, then allowed to drain on to the dripping-board—the superfluous enamel thus finding its way back into the trough or tank, the dripped articles being afterwards placed in the oven to harden. ”

“ It greatly improves all kinds of japan work to harden the varnish by means of heat, which, in every degree that can be applied short of what would burn or calcine the matter, tends to give it a firm and strong texture where metals form the body; therefore a very hot stove may be used, and the stoving may be continued for a considerable time, especially if the heat be gradually increased. ”

“ Japan work should be painted with real "enamel paints," that is with paints actually ground in varnish, and in that case all pigments may be used and the peculiar disadvantages, which attend several pigments with respect to oil or water, cease with this class of vehicle, for they are secured by it when properly handled from the least danger of changing or fading. The preparation of pigments for this purpose consists in bringing them to a due state of fineness by grinding them on a stone with turpentine. The best varnish for binding and preserving the pigments is shellac. ”

“ When galvanized iron is immersed in a corrosive liquid, the zinc is attacked in preference to the iron, provided both the exposed parts of the iron and the protected parts are immersed in the liquid. The zinc has not the same protective quality when the liquid is sprinkled over the surface and remains in isolated drops. Sea air, being charged with saline matters, is very destructive to galvanized surfaces, forming a soluble chloride by its action. ”

“ The seed-lac will give a slight tint to this varnish, but it cannot be omitted where the japanned surface must be hard, though where a softer surface will serve the purpose the proportion of seed-lac may be diminished and a little turpentine oleo-resin added to the gum anime to take off the brittleness. A very good varnish entirely free from brittleness may, it is said, be formed by dissolving gum anime in old nut or poppy oil, which must be made to boil gently when the gum is put into it. ”

“ The comparative inertia of lead to the chemical action of many acids has led to the contention that it should form as good, if not a better, protection of iron than zinc, but in practice it is found to be deficient as a protective coating against corrosion. ”

“ Large S hooks are about the handiest to use. A necessary adjunct of the stove is a pan, which can be made by any handy man or tinworker, which should be made to fit the bottom of the stove above the gas jets, it being arranged that it rests on two side ledges, or along some rods. One a couple of inches in depth will be found sufficient, and it will repay its cost in the saving of enamel, it being possible with its use to enamel a bicycle with as little as a gallon of enamel. ”

“ When the zinc is brushed over with this mixture it oxidizes the surface, turns black, and dries in from twelve to twenty-four hours, and may then be painted over without any danger of peeling. Another and more quickly applied coating consists of, bi-chloride of platinum, 1 part dissolved in 10 parts of distilled water, and applied either by a brush or sponge. It oxidizes at once, turns black, and resists the weak acids, rain, and the elements generally. ”

“ If the pigments are ground in an aqueous vehicle of strong isinglass size and honey instead of gum water the work would not be much inferior to that executed with other vehicles. Water-colours are sometimes applied on a ground of gold after the style of other paintings, and sometimes so as to produce an embossed effect. ”

“ Having thus prepared the varnish, clean well the surface which is to be japanned; then apply vermilion ground in shellac varnish or with drying oil, very thinly diluted with oil of turpentine, on the places intended to imitate the more transparent parts of the tortoise-shell. When the vermilion is dry, brush the whole over with the black varnish thinned to the right consistency with oil of turpentine. When set and firm put the work into a stove where it may undergo a very strong heat, which must be continued a considerable time, for three weeks or even a month so much the better. ”