Black Japan is made after the manner of the gold size. Put 6 gallons of raw linseed oil into the set pot; boil it with a very slow fire. Have a 10-gallon cast-iron pot, with two handles or ears: this pot will fit into the plate of the boiling furnace, into which put 10 lbs. of Egyptian asphaltum, and keep under it a good regular fire all the time of fusion. During the time the asphaltum is fusing, have 2 gallons of oil getting hot to mix it with as soon as it is sufficiently melted. After it is oiled, leave it on the fire about ten minutes; then pour it into the set pot, Carry it out of doors, and with a handful of hay or straw clear it out, and afterwards wash it out with turpentine washings, and dry it with a rag. Proceed and finish three more separate runs like the first, until there are four runs in the set pot, that is, 40 lbs. of asphaltum and 14 gallons of raw linseed oil; then introduce exactly the same driers as for the gold size, and in the same irianner. Keep a regular, but moderate fire, so that the boiling continues at a moderate heat for four hours from the last run being poured in the set pot; then draw, and put out the fire for that day.
Next morning, as soon as it can be brought to a boil, try it upon a bit of glass; if it but strings strongly, it will not do; it must be boiled so strong, that when a piece is pinched from off the glass, after it has been left to cool, it will roll into a hard pill between the finger and thumb. When it forms hard, and scarcely sticks to the fingers, it is then boiled enough. Put out the fire, as directed before. Leave it one hour and a half before mixing. When cold enough, mix it with 30 gallons, at least, of turpentine, and strain it. If it is too thick when cold, heat and introduce as much turpentine as will bring it to a proper consistency. The japan will dry in 6 hours in summer, and 8 in winter. It is principally intended for and used by coach makers, japanners, or painters, and should be kept at least six months before it is used.
Another Black Japan is made by putting into the set pot 48 lbs. of Naples asphaltum; as soon as it is melted, pour in 10 gallons of raw linseed oil. Keep a moderate fire, and fuse 8 lbs. of dark gum anime in the gum pot: mix it with 2 gallons of oil, and pour it into the set pot. Afterwards fuse 10 lbs. of dark or sea amber in the iron pot. When it appears completely fused, pour in 2 gallons of hot oil, and pour it into the set pot; continue the boiling for three hours longer, and during that time introduce the same quantity of driers as before directed; draw out the fire, and let it remain until morning; then boil it until it rolls hard; leave it to coo|, and afterwords mix with turpentine. This japan will appear in colour like the other; but when applied on work, it will dry more hard, compact and glossy, and will not rub down or polish so soon as the other, which is occasioned by the toughness and durability of the amber.
Fuse 6 lbs. of fine-picked, very pale, transparent amber in the gum pot, and pour in 2 gallons of hot clarified oil. Boil it until it strings very strong. Mix with 4 gallons of turpentine. This will be as fine as body copal, will work free, and flow well upon any work it is applied to: it becomes very hard, is durable, and is excellent to mix in copal varnishes, to give them a hard and durable quality. Amber varnish will always require a long time before it is ready for polishing.
Brunswick Black. Best. - In an iron pot, over a slow fire, boil 45 lbs. of foreign asphaltum for at least 6 hours, and during the same time boil in another iron pot 6 gallons of oil which has been previously boiled; during the boiling of the 6 gallons introduce 6 lbs. of litharge gradually, and boil until it feels stringy between the fingers; then ladle it into the pot containing the boiling asphaltum. Let both boil until, upon trial, it will roll into hard pills; then cool, and mix with 25 gallons of turpentine, or until it is of a proper consistence.
Put 281bs.of common black pitch, and 28 lbs. of common asphaltum made from gas tar, into an iron pot, boil both for 8 or 10 hours, which will evaporate the gas and moisture; let it stand all night, and early next morning, as soon as it boils, put in 8 gallons of boiled oil; then introduce gradually 10 lbs. of red-lead and 10 lbs. of litharge, and boil for 3 hours, or until it will roll very hard. When ready for mixing, introduce 20 gallons of turpentine, until of a proper consistence. This is intended for engineers, founders, or ironmongers; it will dry in half an hour, or less, if properly boiled.
Put 48 lbs. of foreign asphaltum into an iron pot, and boil for 4 hours; during the first 2 hours introduce 7 lbs, of red-lead, 7 lbs, of litharge, 3 lbs. of dried copperas, and 10 gallons of boiled oil; add one 8-lb.run of dark gum, with 2 gallons of hot oil. After pouring the oil and gum continue the boiling 2 hours, or until it will roll into hard pills, like japan. When cool, thin it off with 30 gallons of turpentine, or until it is of a proper consistence.
1. A piece of plate glass is heated, and, while yet warm, a little wax rubbed over it; water is then poured over the plate, and the moistened picture laid thereon and pressed closely down by means of a piece of filtering paper. When dry, the picture is removed, and will be found to possess a surface of great brilliancy, which is not injured by the process of mounting. 2. Boil Chio turpentine till brittle, powder and dissolve in oil of turpentine. 3. Canada balsam and clear white resin, of each 6 oz., oil of turpentine 1 quart; dissolve. 4. Digest gum sandarach, 20 parts; gum mastic, 8; camphor, 1; with alcohol, 48. The map or engraving must previously receive one or two coats of gelatine.
1. Boil clear parchment cuttings in water in a clean glazed pipkin till they produce a very clear size, strain it and keep it for use. Give any work two coats of the above size, passing quickly over the work not to disturb the colours; varnish with a paper varnish. 2. Dissolve 1 oz. of the best isinglass in about a pint of water, by simmering it over the fire; strain it through fine muslin, and keep it for use. Try the size on a piece of paper moderately warm; if it glistens, it is too thick, add more water; if it soaks into the paper, it is too thin, add or diminish the isinglass till it merely dulls the surface; then give the paper two or three coats, letting it dry between each, being careful (particularly in the first coat) to bear very lightly on the brush, which should be a flat tin camel-hair. The size should flow freely from the brush, otherwise the paper, if a drawing, may be damaged. Then take the best mastic varnish, and with it give at least three coats.