Imagens da página
PDF
ePub

become.

Recollect, when it is taken out, not to disturb or raise up the bottoms.

the gum begins to fuse and steam, stir | to fill the pouring pot, begin and pour it with the copper stirrer, and keep out with a small stream, gradually incutting and stirring the gum to assist creasing, and if the varnish rises rapidly its fusion; if it feels lumpy and not in the pot, keep stirring it constantly at fluid, and rises to the middle of the pot, the surface with the stirrer to break the lift it from the fire and set it on the ash-bubbles, taking care not to let the stirrer bed, and keep stirring until it goes down touch the bottom of the pot, for if it (meantime let the fire be kept briskly should, the cil of turpentine would be in up); then set on the gum pot again, and part converted into vapour, and the keep stirring until the gum appears varnish would run over the pot in a fluid like oil, which is to be known by moment; therefore, during the mixing, lifting up the stirrer so far as to see the keep constantly stirring as well as pourblade. Observe, that if the gum does ing in at the same time. Have also a not appear quite fluid as oil, carry it out copper ladle at hand, and if it should so whenever it rises to the middle of the far rise as to be unmanageable, let the pot, and stir it down again, keeping up assistant take the ladle and cool it down a brisk fire; put on the pot, and keep with it, lifting up one ladleful after stirring until the gum rises above the another, and letting it fall into the pot. blade of the stirrer. Then the copper As soon as the varnish is mixed put the pouring jack is charged with boiled oil, varnish sieve in the copper funnel placed and held over the edge of the gum pot; in the carrying tin, and strain the when the gum rises within 5 inches of varnish immediately; empty it into the pot-mouth, the assistant is to pour open-mouthed jars, tins, or cisterns; in the oil very slowly until towards the there let it remain to settle, and the last, the maker stirring during the pour-longer it remains the better it will ing. If the fire at this time is strong and regular, in about eight or ten minutes the gum and oil will concentrate and become quite clear; this is to be tested by taking a piece of glass and dropping a portion of the varnish on it; if it appears clear and transparent, the oil and gum are become concentrated or joined together. It is now to be further boiled until it will string between the finger and thumb; this is known by once every minute dropping a portion on the glass, and taking a little between the forefinger and thumb; pinch it first, then extend wide the finger and thumb; if it is boiled enough, it will stick strong and string out into fine filaments, like birdlime; but when not boiled enough, it is soft, thick, and greasy, without being stringy. It is a safe plan to have ready a thick piece of carpet large enough to cover the mouth of the boiling pot should it catch fire during the pouring. The moment it is boiled enough, carry it from the fire to the ash-bed, where let it remain from fifteen to twenty minutes, or until it is cold enough to be mixed; have at hand a sufficient quantity of oil of turpentine

LINSEED OIL.-The choice of linseed oil is of peculiar consequence to the varnish maker, as upon its quality, to a great extent, depends the beauty and durability of the varnish. Oil expressed from green unripe seed always abounds with watery, acidulous particles. The quality of oil may be determined in the following manner:-Fill a phial with oil, and hold it up to the light; if bad, it will appear opaque, turbid, and thick; its taste is acid and bitter upon the tongue, and it sinells rancid and strong: this ought to be rejected. Oil from fine full-grown ripe seed, when viewed in a phial, will appear limpid, pale, and brilliant; it is mellow and sweet to the taste, has very little smell, is specifically lighter than impure oil, and when boiled or clarified dries quickly and firmly, and does not materially change the colour of the varnish when made, but appears limpid and brilliant.

SPIRITS OF TURPENTINE.-That which is used for mixing varnish ought to be procured and chosen as pure, strong and

free from acid as possible. Some turpentine being drawn from green trees abounds with a pyroligneous acid, which rises and comes over with the spirit in distillation; it is strong and bitter to the taste, and appears milky, particularly towards the bottom, after standing to settle. Therefore, the longer turpentine is kept before it is used, the purer it will be.

COPAL VARNISHES FOR FINE PAINTINGS. Fuse 8 lbs. of very clean pale African gum copal, and when completely fluid, pour in 2 gallons of hot oil; let it boil until it will string very strong; and in about fifteen minutes, or while it is yet very hot, pour in 3 gallons of turpentine. Perhaps, during the mixing, a considerable quantity of the turpentine will escape, but the varnish will be so much the brighter, transparent, and fluid; and will work freer, dry quickly, and be very solid and durable when dry. After the varnish has been strained, if it is found too thick, before it is quite cold heat as much turpentine and mix with it as will bring it to a proper consistence.

ARTISTS' VIRGIN COPAL.-From a select parcel of scraped African gum copal, pick out the fine transparent pieces which appear round and pale like drops of crystal; break these small; dry them in the sun, or by a very gentle fire. Afterwards, when cool, bruise or pound them into a course powder; then procure some broken bottles or flint glass, and boil the same in soft water and soda, then bruise it into coarse powder like the gum; boil it a second time, and strain the water from it, washing it with three or four waters, that it may be perfectly clean and free from grease or any impurity; dry it before the fire, or upon a plate; set it in an oven. When it is thoroughly dry, mix 2 lbs. of it with 3 lbs. of the powdered copal; after mixing them well, put them into the gum pot and fuse the gum; keep stirring all the time; the glass will prevent the gum from adhering together, so that a very moderate fire will cause the gum to fuse. When it appears sufficiently run, have ready

3 quarts of clarified oil, very hot, to pour in. Afterwards let it boil until it strings freely between the fingers; begin and mix it rather hotter than if it were body-varnish; pour in 5 quarts of old turpentine, strain it immediately, and pour it into an open jar or large glass bottle; expose it to the air and light, but keep it both from the sun and wet, and from moisture, until it is of a sufficient age for use. This is the finest copal varnish for fine paintings or pictures.

CABINET VARNISH.-Fuse 7 lbs. of fine African gum copal, and pour in half a gallon of clarified oil; in three or four minutes after, if it feels stringy, take it out of doors, and mix with it 3 gallons of turpentine; afterwards strain it, and put it aside for use. This, if properly boiled, will dry in ten minutes, but if too strongly boiled will not mix at all with the turpentine; and sometimes, when boiled with the turpentine, will mix, and yet refuse to amalgamate with any other varnish less boiled than itself; therefore it requires a nicety which is only to be learned from practice. This varnish is chiefly intended for the use of japanners, cabinet painters, and coach painters.

FOR

BEST BODY COPAL VARNISH COACH MAKERS. Fuse 8 lbs. of fine African gum copal; add 2 gallons of clarified oil; boil very slowly for four or five hours, until quite stringy; mix off with 33 gallons of turpentine; strain off, and pour it into a cistern.

QUICK DRYING CARRIAGE VARNISH. -8 lbs. of fine pale gum anime, 2 gallons of clarified oil, 3 gallons of turpentine; to be boiled four hours. This, after being strained, is put into the two former pots, and well mixed together; its effect is to cause the whole to dry quicker and firmer, and enable it to take the polish much sooner.

COMMON BODY VARNISH FOR CARRIAGES.-8 lbs. of the best African copal, 3 gallons of clarified oil, 3 gallons of turpentine; boiled four hours, or until stringy; mixed and strained, will produce about 5 gallons. 8 lbs. of the best gum anime, 2 gallons of clarified oil, 3 gallons of turpentine; boiled as

usual; mixed and strained hot, and put | into the former pot of African gum varnish. Put two pots of this anime varnish to one of copal; it will dry quicker and harder than the best body copal, and will polish very soon, but not wear either so well or so long.

QUICK DRYING BODY COPAL VARNISH. --8 lbs. of the best African copal, 2 gallons of clarified oil, lb. of dried sugar of lead, 3 gallons of turpentine; boiled till stringy, and mixed and strained; 8 lbs. of fine gum anime, 2 gallons of clarified oil, lb. of white copperas, 3 gallons of turpentine; boiled as before; to be mixed, and strained while hot, into the other pot. These two pots mixed together will dry in six nours in winter, and in four in summer; it is very useful for varnishing old work on dark colours.

BEST PALE CARRIAGE VARNISH.8 lbs. of 2nd sorted African copal, 2 gallons of clarified oil; boil till very stringy. lb. of dried copperas, lb. of litharge, 5 gallons of turpentine; strained. 8 lbs. of 2nd sorted gum anime, 2 gallons of clarified oil, lb. of dried sugar of lead, lb. of litharge, 5 gallons of turpentine; mix with the first while hot. This varnish will dry hard, if well boiled, in four hours in summer, and six in winter. As its name denotes, this is intended for the varnishing of the wheels, springs, and carriage parts of coaches, chaises, and so on; also it is that description of varnish which is generally sold to and used by house painters and decorators, as from its drying quality and strong gloss it suits their general purposes well.

SECOND CARRIAGE VARNISH.-8 lbs. of 2nd sorted gum anime, 2 gallons of fine clarified oil, 5 gallons of turpentine, lb. of litharge, lb. of dried sugar of lead, lb. of dried copperas; boiled and mixed as before. When three runs are poured into the boiling pot, the regular proportion of driers put in, and well boiled, this varnish will dry hard and firm in four hours in winter, and in two in summer: it is principally intended for varnishing dark carriage- |

work or black japan, and is also used by house painters for dark work.

WAINSCOT VARNISH.-8 lbs. of 2nd sorted gum anime, 3 gallons of clarified oil, lb. of litharge, lb. of dried copperas, lb. of dried sugar of lead, 5 gallons of turpentine; to be all well boiled until it strings very strong, and then mixed and strained. Where large quantities are required, it will always be found best to boil off the three runs in the boiling pot. This varnish is principally intended for house painters, grainers, builders, and japanners: it will dry in two hours in summer, and in four in winter.

Mahogany Varnish is either made in the same proportions, with a little darker gum; otherwise it is wainscot varnish, with a small portion of gold size.

Japanners' Gold Size. - To make 40 gallons of gold size, put 10 gallons of oil into the iron set pot, Fig. 2, make a good fire under it, and boil for two hours; then introduce 7 lbs. of dry red-lead, 7 lbs. of litharge, and 3 lbs. of copperas, by sprinkling in a little at a time; let the oil keep boiling all the time, not in too great a heat. During the time of putting in the driers, keep stirring them from the bottom of the pot, and have the large iron ladle ready to cool it down, if it should appear to rise too high; have also at hand an empty pot-the copper boiling pot will do-into which immediately ladle part of the boiling oil, if it cannot otherwise be kept in the pot, while the assistant is damping the fire with wet sifted ashes, of which there always ought to be a wheelbarrowful at hand, in case of an accident. When the oil has boiled about three hours, and the driers are all in, fuse in the gum pot 10 lbs. of gum anime; and during the time of fusing, heat 2 gallons of raw linseed oil in the copper pouring jack, by placing it on the plate of the gum furnace. After the oil has been poured to the guin, and as soon as it appears boiled clear, take the gum pot from the fire; let it cool for a few minutes, then pour it into the oil in the set pot. Wash out the gum pot, and proceed with another run in

F

the same way. When both runs of gum are in the set pot, there are altogether 14 gallons of oil, 20 lbs. of gum, and 17 lbs. of driers; increase and keep up a regular fire in the front of the furnace, that it may be drawn out in a moment, if it should be necessary. The gold size will soon throw up a frothy head on the surface, which must be kept down by constantly plying with the ladle when it is likely to rise within four inches of the pot-edge. In about five hours from the beginning of the oil boiling, it will become stringy; but the boiling must continue until it hangs to the ladle, appears quite stringy, yet drops in lumps. When tried upon the| glass, if it feels sticky and strings strongly, then it is boiled enough. Draw out the fire, sprinkle it with plenty of water; leave not a spark of fire in the varnish house-not even a lighted pipe of tobacco. While the maker cooling down the pot, let the assistant have ready at the door 30 gallons of turpentine, fill the pouring pot ready, and have all the doors open. Endeavour to cool it as fast as possible, as it will require at the least one hour and a quarter after the fire has been put out before it will be ready to mix. When the mixing commences, continue the pouring without intermission, until all the froth at the surface disappears, never stirring it until the turpentine is all in. If pouring in the turpentine has commenced while it was too hot, there will be a great loss of turpentine by evaporation; but that will not injure the quality of the gold size. Place the carrying tin close to the side of the pot, lay on the tin saddle, and strain off as quickly as possible. When all the gold size is out, pour into the set pot about 3 gallons of turpentine washings, and with the swish, wash down the pot as quickly as possible; and if the pot is still so hot as to evaporate the turpentine, ladle it out into the washings again, and pour in about 3 gallons of raw linseed oil; and with a palette knife scrape it all round, washing and cleaning it down with a rag until it is quite cleansed all round, then ladle out the oil, and wipe it completely clean

| and dry. The gold size ought to dry in from fifteen to twenty-five minutes, and in fourteen days it is ready for use. Experienced makers can make gold size that will dry in five minutes, but that requires great practice.

VARNISH, COACH MAKERS' BLACK.Gum amber 16 oz.; melt inpint of boiling hot linseed oil; add 3 oz. of asphaltum, and 3 resin; mix thoroughly over a fire, and add when cooling 1 pint of oil of turpentine slightly warm.

ASPHALTE VARNISH.-Boil coal tar until it shows a disposition to harden on cooling; this can be ascertained by rubbing a little on a piece of metal. Then add about 20 per cent. of lump asphalte, stirring it with the boiling coal tar until all the lumps are melted, when it can be allowed to cool and kept for use. This makes a very bright varnish for sheet metals, and is cheap and durable.

VARNISH FOR IRONWORK.-Dissolve, in about 2 lbs. of tar oil, lb. of asphaltum, and a like quantity of pounded resin, mix hot in an iron kettle, care being taken to prevent any contact with the flame. When cold the varnish is ready for use. This varnish is for out-door wood and iron work.

VARNISH FOR COMMON WORK.-This varnish is intended for protecting surfaces against atmospheric exposure. It has been used for coating wood and iron work with great advantage. Take 3 lbs. of resin and powder it, place it in a tin can, and add 2 pints of spirits of turpentine, well shake, and let it stand, occasionally shaking it for a day or two. Then add of boiled oil 5 quarts, well shake altogether, and allow it to stand in a warm room till clear. The clear portion is decanted and used, or reduced with spirits of turpentine until of the proper consistency.

VARNISH FOR IRON PATTERNS.-A good varnish for iron is made as follows:-Take oil of turpentine and drop into it, drop by drop, strong commercial oil of vitriol; the acid will cause a dark syrupy precipitate in the oil of turpentine; keep adding drops of vitriol until the precipitate ceases taking place,

then pour out the liquid and wash the syrupy mass with water, and it is ready for use. Heat the iron to be varnished to a gentle heat, apply the syrupy product, and allow it to dry.

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 manner. 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 cool, and afterwards 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.

PALE AMBER VARNISH.-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.

« AnteriorContinuar »