Handbook on Japanning Part 3

PAINTING ON ZINC OR ON GALVANIZED IRON.

Painting on zinc or galvanized iron is facilitated by employing a mordant of 1 quart of chloride of copper, 1 of nitrate of copper, and 1 of sal-ammoniac, dissolved in 64 parts of water. To thin mixture add 1 part of commercial hydrochloric acid. This is brushed over the zinc, and dries a dull-grey colour in from twelve to twenty-four hours, paint adhering perfectly to the surface thus formed.

BRONZING COMPOSITIONS.

The following are the formulae for a variety of baths, designed to impart to polished bra.s.s various colours. The bra.s.s objects are put into boiling solutions composed of different salts, and the intensity of the shade obtained is dependent upon duration of the immersion.

With a solution composed of sulphate of copper, 120 grains; hydrochlorate of ammonia, 30 grains; and water 1 quart, greenish shades are obtained. With the following solution, all the shades of brown, from orange-brown to cinnamon, are obtained: chlorate of potash, 150 grains; sulphate of copper, 150 grains; and water, 1 quart. The following solution gives the bra.s.s first a rosy tint, and then colours it violet and blue: sulphate of copper, 435 grains; hyposulphite of soda, 300 grains; cream of tartar, 150 grains; and water, 1 pint. Upon adding to this solution ammoniacal sulphate of iron, 300 grains, and hyposulphite of soda, 300 grains, there are obtained, according to the duration of the immersion, yellowish, orange, rosy, and then bluish shades. Upon polarizing the ebullition, the blue tint gives way to yellow, and finally to a pretty grey.

Silver, under the same circ.u.mstances, becomes very beautifully coloured. After a long ebullition in the following solution, we obtain a yellow-brown shade, and then a remarkable fire-red: chlorate of potash, 75 grains; carbonate of nickel, 30 grains; salt of nickel, 75 grains; and water, 10 oz. The following solution gives a beautiful dark-brown colour: chlorate of potash, 75 grains; salt of nickel, 150 grains; and water, 10 oz. The following gives in the first place, a red, which pa.s.ses to blue, then to pale lilac, and finally to white: orpiment, 75 grains; crystallized sal-sodae, 150 grains; and water, 10 oz. The following gives a yellow-brown: salt of nickel, 75 grains; sulphate of copper, 75 grains; chlorate of potash, 75 grains; and water, 10 oz. On mixing the following solutions, sulphur separates, and the bra.s.s becomes covered with iridescent crystallizations: (1) cream of tartar, 75 grains; sulphate of copper, 75 grains; and water, 10 oz. (2) Hyposulphite of soda, 225 grains; and water, 5 oz. Upon leaving the bra.s.s objects immersed in the following mixture, contained in corked vessels, they at length acquire a very beautiful blue colour: hepar of sulphur, 75 grains; ammonia, 75 grains; and water, 4 oz.

A GOLDEN VARNISH FOR METAL.

Take 2 oz. of gum sandarach, 1 oz. of litharge of gold, and 4 oz. of clarified linseed oil, which boil in a glazed earthenware vessel till the contents appear of a transparent yellow colour. This will make a good varnish for the final coating for enamelled and j.a.panned goods.

CARRIAGE VARNISH.

The following is used for the wheels, springs, and carriage parts of coaches and other vehicles: Take of pale African copal 8 lb.; fuse, and add 2-1/2 gallons of clarified linseed oil; boil until very stringy, then add 1/4 lb. each of dry copperas and litharge; boil, and thin with 5-1/2 gallons of turpentine; then mix while hot with the following varnish, and immediately strain the mixture into a covered vessel. Gum anime, 8 lb.; clarified linseed oil, 2-1/2 gallons; 1/4 lb. each of dried sugar of lead and litharge; boil, and thin with 5-1/2 gallons of turpentine; and mix it while hot as above directed.

Of course these quant.i.ties will only do for big jobs, and as it has to do with metal, it has been thought advisable to include the formula in this handbook.

METAL POLISHES.

The active const.i.tuent of all metal polishes is generally chalk, rouge, or tripoli, because these produce a polish on metallic surfaces. The following recipes give good polishing soaps:--

(1) 20 to 25 lb. liquid soap is intimately mixed with about 80 lb. of Swedish chalk and 1/2 lb. Pompeiian red. (2) 25 lb. liquid coco-nut oil soap is mixed with 2 lb. tripoli, and 1 lb. each alum, tartaric acid, and white lead. (3) 25 lb. liquid coco-nut oil soap is mixed with 5 lb. rouge and 1 lb. ammonium carbonate. (4) 24 lb. coco-nut oil are saponified with 12 lb. soda lye of 38 to 40 B., after which 3 lb. rouge, 3 lb. water, and 32 grammes ammonia are mixed in. Good recipes for polishing pomades are as follows: (1) 5 lb. lard and yellow vaseline is melted and mixed with 1 lb. fine rouge. (2) 2 lb.

palm oil and 2 lb. vaseline are melted together, and then 1 lb. rouge, 400 grains tripoli, and 20 grains oxalic acid are stirred in. (3) 4 lb. fatty petroleum and 1 lb. lard are heated and mixed with 1 lb. of rouge. The polishing pomades are generally perfumed with essence of myrbane. Polishing powders are prepared as follows: (1) 4 lb.

magnesium carbonate, 4 lb. chalk, and 7 lb. rouge are intimately mixed. (2) 4 lb. magnesium carbonate are mixed with 150 grains fine rouge. An excellent and harmless polishing water is prepared by shaking together 250 grains floated chalk, 1 lb. alcohol, and 20 grains ammonia. Gilded articles are most readily cleansed with a solution of 5 grains borax in 100 parts water, by means of a sponge or soft brush. The articles are then washed in pure water, and dried with a soft linen rag. Silverware is cleansed by rubbing with a solution of sodium hyposulphite.

BLACK PAINTS.

Carbon, in one form or another, is the base of all black pigments. By far the most common of these, as used in structural plants, is graphite. Other black pigments are lamp-black (including carbon black) and bone-black, the former being produced in many grades, varying in price from twopence to half a crown per pound. Bone-black, which is refuse from the sugar-house black, varies in the percentage of carbon contained, which is usually about 10 or 12 per cent, the remainder being the mineral matter originally present in the bone, and containing 3 or 4 per cent of carbonate, whilst most of the remainder is phosphate of lime. Lamp-black is an absolutely impalpable powder, which having a small amount of greasy matter in it, greatly r.e.t.a.r.ds the drying of the oil with which it may be mixed. For this reason it is not used by itself, but is added in small quant.i.ty to other paints, which it affects by changing their colour, and probably their durability. For example, it is a common practice to add it to red lead, in order to tone down its brilliant colour, and also to correct the tendency it has to turn white, due to the conversion of the red oxide of lead into the carbonate.

BLACK STAIN FOR IRON.

For colouring iron and steel a dead black of superior appearance and permanency, the following is a good formula: 1 part bis.m.u.th chloride, 2 parts mercury bi-chloride, 1 part copper chloride, 6 parts hydrochloric acid, 5 parts alcohol, and 50 parts lamp-black, these being all well mixed. To use this preparation successfully--the article to be blacked or bronzed being first made clean and free from grease--it is applied with a swab or brush, or, better still, the object may be dipped into it; the liquid is allowed to dry on the metal, and the latter is then placed in boiling water, the temperature being maintained for half an hour. If, after this, the colour is not so dark as is desired, the operation has simply to be repeated, and the result will be found satisfactory. After obtaining the desired degree of colour, the latter is fixed, as well as much improved generally, by placing for a few minutes in a bath of boiling oil, or by coating the surface with oil, and heating the object till the oil is completely driven off The intense black obtained by this method is admirable.

Another black coating for ironwork, which is really a lacquer, is obtained by melting ozokerite, which becomes a brown resinous ma.s.s, with a melting-point at 140 F. The melted ma.s.s is then further heated to 212 F., the boiling-point of water. The objects to be lacquered are scoured clean by rubbing with dry sand, and are dipped in the melted ma.s.s. They are then allowed to drip, and the ozokerite is ignited by the objects being held over a fire. After the ozokerite has burned away, the flame is extinguished, and the iron acquires a firmly adhering black coating, which resists atmospheric influences, as well as acids and alkalies. If the black iron vessels are to contain alkaline liquids, the above operation is repeated.

A good cheap stock black paint or varnish for ironwork is prepared, as follows: Clear (solid) wood tar, 10 lb.; lamp black or mineral black, 1-1/4 lb.; oil of turpentine, 5-1/2 quarts. The tar is first heated in a large iron pot to boiling-point, or nearly so, and the heat is continued for about 4 hours. The pot is then removed from the fire out of doors, and while still warm, and not hot, the turpentine, mixed with the black, is stirred in. If the varnish is too thick to dry quickly, add more turpentine. Benzine can be used instead of turpentine, but the results are not so good. Asphaltum is preferable to the cheap tar.

To make another good black varnish for ironwork, take 8 lb. of asphaltum and fuse it in an iron kettle, then add 2 gallons of boiled linseed oil, 1 lb. of litharge, 1/2 lb. of sulphate of zinc (add these slowly, or the mixture will boil over), and boil them for about 3 hours. Then, add 1-1/2 lb. of dark gum amber, and boil for 2 hours longer, or until the ma.s.s will become quite thick when cool. After this it should be thinned with turpentine to the proper consistency.

VARNISHES FOR IRONWORK.

A reliable authority gives the following as a very good recipe for ironwork varnish. Take 2 lb. of tar oil, 1/2 lb. of pounded resin, and 1/2 lb. of asphaltum, and dissolve together, and then mix while hot in an iron kettle, taking all care to prevent the flames getting into contact with the mixture. When cold the varnish is ready for application to outdoor ironwork. Another recipe is to take 3 lb. of powdered resin, place it in a tin or iron vessel, and add thereto 2-1/2 pints of spirits of turpentine, which well shake, and then let it stand for a day or two, giving it an occasional shake. Then add to it 5 quarts of boiled oil, shake it thoroughly well all together, afterwards letting it stand in a warm room till it gets clear. The clear portion can then be drawn off and used, or reduced with spirits of turpentine till of the requisite consistency. For making a varnish suitable for iron patterns, take sufficient oil of turpentine for the purpose of the job in hand, and drop into it, drop by drop, some strong commercial oil of vitriol, when the acid will cause a dark syrupy precipitate in the oil of turpentine, and continue to add the drops of vitriol till the precipitate ceases to act, after which pour off the liquid and wash the syrupy ma.s.s with water, when it will be ready for use. When the iron pattern is to be varnished, it must be heated to a gentle degree, the syrupy product applied, and then the article allowed to dry.

A fine black varnish suitable for the covering of broken places in sewing machines and similar articles, where the j.a.panned surface has become injured or scratched, can be made by taking some fine lamp-black or ivory-black, and thoroughly mixing it with copal varnish. The black must be in a very fine powder, and to mix the more readily it should be made into a pasty ma.s.s with turpentine. For the ordinary repairing shop this will be found very handy.

The following is a simple way for tarring sheet-iron pipes to prevent rusting. The sections as made should be coated with coal tar, and then filled with light wood shavings, and the latter set alight. The effect of this treatment will be to render the iron practically proof against rust for an indefinite period, rendering future painting unnecessary.

It is important, of course, that the iron should not be made too hot, or kept hot for too long a time, lest the tar should be burnt off.

The following is a varnish for iron and steel given by a recognized authority: 5 parts of camphor and elemi, 15 parts of sandarach, and 10 parts of clear grains of mastic, are dissolved in the requisite quant.i.ty of alcohol, and applied cold.

Another good black enamel for small articles can be made by mixing 1 lb. of asphaltum with 1 lb. of resin in 4 lb. of tar oil, well heating the whole in an iron vessel before applying.

A good brown j.a.pan can be prepared by separately heating equal quant.i.ties of amber and asphaltum, and adding to each one-half the quant.i.ty by weight of boiled linseed oil. Both compounds are then mixed together. Copal resin may be subst.i.tuted for the amber, but it is not so durable. Oil varnish made from amber is highly elastic. If it is used to protect tin-plate printing, when the plates after stoving have been subsequently rolled so as to distort the letters, the varnish has in no way suffered, and its surface remains unbroken.

A bronzing composition for coating iron consists of 120 parts mercury, 10 parts tin, 20 parts green vitriol, 120 parts water, and 15 parts hydrochloric acid of 1.2 specific gravity.

SECTION VI.

PROCESSES FOR TIN-PLATING.

In these days of making everything look what it is not, perhaps the best and cheapest subst.i.tute for silver as a white coating for table ware, culinary vessels, and the many articles requiring such a coating, is pure tin. It does not compare favourably with silver in point of hardness or wearing qualities, but it costs very much less than silver, is readily applied, and can be easily kept clean and bright. In tinning hollow ware on the inside the metal article is first thoroughly cleansed by pickling it in dilute muriatic or sulphuric acid and then scouring it with fine sand. It is then heated over a fire to about the melting-point of tin, sprinkled with powdered resin, and partly filled with melted pure grain tin covered with resin to prevent its oxidation. The vessel is then quickly turned and rolled about in every direction, so as to bring every part of the surface to be covered in contact with the molten metal. The greater part of the tin is then thrown out and the surface rubbed over with a brush of tow to equalize the coating; and if not satisfactory the operation must be repeated. The vessels usually tinned in this manner are of copper and bra.s.s, but with a little care in cleaning and manipulating, iron can also be satisfactorily tinned by this means. The vessels to be tinned must always be sufficiently hot to keep the metal contained in them thoroughly fused. This is covering by contact with melted tin.

The amalgam process is not so much used as it was formerly. It consists in applying to the clean and dry metallic surface a film of a pasty amalgam of tin with mercury, and then exposing the surface to heat, which volatilizes the latter, leaving the tin adhering to the metal.

The immersion process is the best adapted to coating articles of bra.s.s or copper. When immersed in a hot solution of tin properly prepared the metal is precipitated upon their surfaces. One of the best solutions for this purpose is the following:--

Ammonia alum 17-1/4 oz.

Boiling 12-1/2 lb.

Protochloride of tin 1 oz.

The articles to be tinned must be first thoroughly cleansed, and then kept in the hot solution until properly whitened. A better result will be obtained by using the following bath, and placing the pieces in contact with a strip of clean zinc, also immersed:--

Bitartrate of pota.s.sium 14 oz.

Soft water 24 "

Protochloride of tin 1 "

It should be boiled for a few minutes before using.

The following is one of the best solutions for plating with tin by the battery process:--

Pota.s.sium pyrophosphate 12 oz.

Protochloride of tin 4-1/2 "

Water 20 "

The anode or feeding-plate used in this bath consists of pure Banca tin. This plate is joined to the positive (copper or carbon) pole of the battery, while the work is suspended from a wire connected with the negative (zinc) pole. A moderately strong battery is required, and the work is finished by scratch-brushing.