Part 2

I have truly said that, while breaking and decay are universal, there are literally nowhere any generally accomplished repairers--that is to say, experts who know and can practise even what is set forth in this book. Certain menders of broken china there are, of whom the great authority on fictile restoration, RIS-PASQUOT, declares that none can be trusted with anything valuable. There are so few needle-women who can sew up a rent perfectly that a lady “to the manor born” paid in Rome _two pounds_, or _fifty lire_, for being taught the stitch, described in this book, by which it can be done. That it was a great secret to an expert and accomplished needle-woman proves that it cannot be generally known. A house-furnisher in London doing a large business once explained to me with manifest pride how he had, by dint of persuasion and treating, obtained from another what is really one of the simplest recipes for restoring a brown stain. All of this being true, it is apparent enough that any accomplished mender and restorer, lady or gentleman, can hardly fail to make a living by the art; and I sincerely believe that it is the simple truth that it is set forth in the following pages so fully and clearly that any one who will make the experiment can learn from it how to make a living. This is effectively, in all its fulness, a new art and a new calling, and it is time that it were established.

It is a great mistake to suppose that manufacturers are necessarily good menders of what they make. I have found, as have my readers, that it is not the great watchmaker who oversees the production of thousands of watches to whom a watch can be most safely trusted for rehabilitation. For, in nine cases out of ten, it is some extremely humble brother of the craft, who does nothing but mend in a small shop, who restores your chronometer most admirably. The same is true as regards trunks anywhere out of England, since in Germany and France anything of the kind is invariably botched with incredible want of skill. This runs through most trades; for which reason I believe that a really well-accomplished general _mender_, earnestly devoted to the calling in every detail and resolved to be perfect in it, could ere long repair better than most manufacturers, since the latter, in these days, all work by machinery or by vast subdivision of labour, and not, so to speak, by hand. But all repairing _must_ be by hand. We can make every detail of a watch or of a gun by machinery, but the machine cannot mend it when broken, much less a clock or a pistol!

The value of this book will appear to any one who knows how little really good repairing there is in Europe. Since writing the foregoing pages I have gone through the galleries of the Vatican and many other museums, and been amazed at the coarse, ignorant, and bungling manner in which the _great majority_ of antique statues and other objects of immense value have been mended up. There is in most cases no pretence whatever to conceal the lines of repair, and when this has been attempted it has failed through ignorance of recipes and instructions which may be found in this work.

A MANUAL OF

MENDING AND REPAIRING

MATERIALS USED IN MENDING

“_There are full many admirable and practical recipes_ (Hausmitteln), _which are often known only in certain families_.”--Die Natürliche Magie. By JOHANN C. WIEGLEB, 1782.

The art of mending or of repairing may be broadly stated as being effected, firstly, by mechanical processes, such as those employed by carpenters in nailing and joining, in embroidery with the needle, and in metal-work with clumps, or soldering; and, secondly, by chemical means. The latter consist of _cements_ and _adhesives_, which are, however, effectively the same thing. This glue, or gum, is an adhesive or _sticker_; that is, a simple substance which causes two objects to adhere. The same, when combined with powder of chalk or glass, would be a CEMENT. This latter term is again applied somewhat generally and loosely by many, not only to all adhesives, but also more correctly to all soft substances which harden, such as Portland cement, mortar, and putty, and which are often used by themselves to form objects, such as “bricks” and castings; but these latter, having also the quality of acting as adhesives or stickers, are naturally regarded as being the same.

As will be speedily observed in the great number of recipes for mending which will be given in this book, there are many which occur frequently in different combinations; therefore it will be advisable and indispensable for those who wish to master mending as an art to indicate these as a basis.

As SIGMUND LEHNER has observed in his valuable work on _Die Kitte- und Klebemittel_, there have been such vast numbers of recipes published of late years for adhesives in various technological works, that the combination of the usual materials depends almost on the judgment of the experimenter, and every practical operator will soon learn to make inventions of his own. These materials, according to STOHMANN, may be classified as follows:--

I. Those in which OIL is the basis. II. Resin or pitch. III. Caoutchouc (indiarubber) or gutta-percha. IV. Gum or starch. V. Lime and chalk.

LEHNER extends the list as follows into adhesives, or cements:--

I. For glass and porcelain in every form.

II. For metals not exposed to changes of temperature.

III. For stoves and furnaces, or objects exposed to heat.

IV. For chemical apparatus and objects exposed to corrosive liquids.

V. Luting or cements, to protect glass or porcelain vessels from the action of fire.

VI. Cements for microscopic preparations, for filling teeth and similar work.

VII. Those for special objects, such as are made of tortoise-shell, meerschaum (ivory), &c.

OILS are divided into those (such as olive) which never become hard, and the linseed, which in time dries into a substance like gum. The latter combined with a great variety of mineral substances, such as plumbago, calcined lime, magnesia, chalk, red oxide of iron, soapstone, or with varnishes, forms insoluble “soaps,” which, as cements, resist water. They require a long time to _set_ or become hard.

RESINS and GUMS include a great number of substances, such as resin or hard pitch, which is distilled from pine-trees; shellac, mastic, elemi, copal, kauri gum, amber, gum arabic, dextrine made from flour, the gum of the peach and cherry, and of many other trees. To these may be added frankincense and tragacanth, which is less an adhesive than a stiffener and dresser. Gums are generally rather brittle; this is remedied by combination with oily substances, volatile oils, or caoutchouc. With these gums LEHNER includes asphaltum. The defect of such adhesives is, as he also remarks, that they will not resist _high_ temperatures. This, however, will apply to most objects.

VARNISH.--This belongs properly to the gums, but is technically regarded as a separate material. It is gum in solution in turpentine or spirits. For details vide _Die Fabrikation der Copal- Terpentinöl und Spiritus-Lacke_, by L. E. Andés; Leipzig, price 5 m. 40 pf.

CAOUTCHOUC and GUTTA-PERCHA are gums which when hard are still elastic, and resist the action of water. I have read that a perfect imitation or substitute for them has been made of turpentine, but have not seen it, though I have met with glue made with oil and turpentine, which very much resembled them in elasticity or flexibility. Reduced to a liquid form with ether, benzine, &c., these gums can be kept in a liquid state for a long time, and then hardened in any form by exposure to the air. They enter into a very great variety of cements, such as are meant to be tough or waterproof. Indiarubber is, on the whole, the best, and gutta-percha the cheapest, for cements.

GLUE.--This is made, by boiling, from horns and bones; it is essentially the same as gelatine. It is the most generally known of all adhesives, and may be modified by certain admixtures to suit almost any substance. It has the peculiarity that it must always be boiled in a _balneum mariæ_, or in a kettle in hot water in another kettle. Its strength is vastly increased by admixture with nitric acid or _strong_ vinegar. On the subject of glue in all its relations, the reader may consult _Die Leim- und Gelatine-Fabrikation_, or “The Manufacture of Glue and Gelatine,” by F. Dawidowsky; Vienna, price 3s.

FLOUR-PASTE AND STARCH-PASTE.--These mixtures, though generally used for weak work, such as to make papers adhere, can be very much strengthened by admixture with glue and gums. Combined with certain substances, such as paper, mineral powders, and _alum_, they, when submitted to pressure, become intensely hard, and resist not only water but heat, when not excessive. Also combined with varnishes they are decided resistants. LEHNER speaks of them as if they were perishable in any condition.

STURGEON’S BLADDER.--With this the bladders of several kinds of fish are classed. Cut in small pieces and dissolved in spirits it makes a very strong adhesive, which is mixed with many others.

LIME is the most extensively used cement in the world. Combined with water it forms mortar. It is united with many substances, such as caseine or cheese, the white of eggs, and silicate of soda, to make powerful minor cements. On the subject of lime the practical technologist should consult _Kalk und Luftmortel_, by Dr. Herrmann Zwick; Vienna, A. Hartleben, price 3s., in which all details of the subject are given in full.

EGGS.--The yolk, and more particularly the white, of eggs is sometimes used as an adhesive, and it enters into many very excellent cements. For details as to the chemistry and technology of this material consult _Die Fabrikationen von Albumin- und Eierkonserven_ (A Full Account of the Characteristics of all Egg Substances, the Fabrication of Egg, and Blood Albumen, &c.), by Karl Ruprecht; Vienna, A. Hartleben, price 2s. 3d.

NEUTRAL SUBSTANCES, OR BINDING MATERIALS.--Almost any substance not easily soluble in water, and many which are, from common dust or earth, or clay, sand, chalk, powdered egg-shells, sawdust, shell-powder, &c., when combined with certain adhesives, form cements. This is sometimes due to chemical combination, but more frequently to mechanical union. In the latter case the adhesive clinging to every separate grain has the more points of adhesion, just as a man by clinging with both hands to two posts is harder to remove than if he held by one.

CASEINE OR CHEESE.--This in several forms, but chiefly of curd in combination with several substances, but mostly with lime or borax, forms a very valuable cement. It is also combined with strong _lye_ and silicate of soda. It must not, however, be too much depended on as a resistant to water or heat.

BLOOD, generally of oxen or cows, combined with lime, alum, and coal ashes, forms a solid and durable cement.

GLYCERINE forms the basis, with plumbago, &c., of several cements. Like oil, it renders glue flexible and partly waterproof. For chemical details on this subject, vide _Das Glycerin_, by J. W. Koppe, Leipzig.

GYPSUM is combined with many substances to form cements, some of them of great and peculiar value.

IRON pulverised is the basis of a great number of very durable and strongly resistant cements.

ALUM may be included among the bases, as it is very important in several compositions, forming a powerful chemical aid. It is excellent as aiding resistance to both moisture and heat. For an exhaustive work on alum consult _Die Fabrikation des Alauns_, &c., by Frederic Junemann, which should be carefully studied by all who work in cements.

There is a very great number of “indifferent” or minor aids to these, such as sugar, milk, honey, spirits of wine, water, ochre, galbanum, tannin, ammonia, feldspar, plumbago, sulphur, vinegar, salt, zinc (white), umber, bismuth, tin, cadmium, clay, ashes, &c., which are essential in certain combinations.

DEXTRINE, the gum of flour or starch, or _Leiokom_, much resembles gum-arabic, but is more brittle. Its adhesiveness depends somewhat on the manner in which it is dissolved. “It is,” says LEHNER, “prepared by heating starch which has been moistened with nitric acid; also by warming paste with very much diluted sulphuric acid.”

WAX, including that of bees as well as paraffine, is used in repairs, and forms a part of several cements. On this subject consult _Das Wachs_, or “Wax and its Technical Applications,” by Ludwig Sedna; Leipzig, 2s. 6d.

SILICATE OF SODA, OR LIQUID GLASS.--This is generally sold in the form of a very dense liquid. It is prepared by mixing quartz or flint sand with soda, or more rarely with potash. “It is,” says LEHNER, “a glass which is distinguished from other glasses by being easily soluble in water. It is believed to be a very modern invention; but I have seen Venetian glasses of the fifteenth century which appeared to be painted with it, or something very similar; and I have found decided indications of a knowledge of it in two writers of the sixteenth century, WOLFGANG HILDEBRAND and VAN HELMONT. According to Wagner, there are three kinds of liquid glass. By itself liquid glass can only be used for mending glass; but when combined with other substances, such as cement, calcined lime, or clay, or glass, in powder, it forms a body as hard as stone, or a double silicate, which is strongly resistant to chemical influences.” It occupies the first position as an adhesive for glass, nor is it surpassed as a cement in solid form. On this subject vide _Wasserglas und Infusorienerde_, &c., by Hermann Krätzer; Vienna, 3s.

NATURAL CEMENT, OR HYDRAULIC LIME.--This is familiarly known to all readers as Portland cement, but it is found of different qualities in many countries, and is also made artificially. Certain mineral substances have the quality when powdered and combined with water of setting hard as stone; hence the name _hydraulic_. I have seen at Budapest articles of Portland cement made in Hungary which equalled in appearance fine black slate or marble, and, while much less brittle, were indeed in every respect more durable and resistant to exposure. These artificial cements can be largely incorporated with indifferent substances, such as sand; they, however, require intense baking, and may in consequence be regarded as a kind of fictile ware.

Portland cement is very thoroughly treated in _Hydraulischer Kalk und Portland Cement_ (in all their relations), by Dr. H. Zwick.

TRAGACANTH, though called a gum, is properly nothing of the kind, not being a true adhesive. It is the product of the _Astragalus verus_, a tree found in Asia. It swells out in water, and softens, but without dissolving. It is more of a glaze than a paste; hence it is used extensively by confectioners, bookbinders, or to stiffen laces. It enters, however, into the composition of several cements.

BREAD may be classed as a material by itself, as it derives certain peculiar virtues from the yeast which causes its fermentation. With certain combinations it becomes wax-like, or hard, and may be used to advantage in many repairs as well as for modelling. It has the great advantage of being easily worked and always at hand.

CELLULOID is treated of in this work under the head of Artificial Ivory. It is made from gun-cotton and camphor. For full information on this subject consult _Das Celluloid_, or “Celluloid, its Raw Materials, Manufacture, Peculiarities, and Technical Applications, &c.,” by Dr. Fr. Böckmann, Vienna and Leipzig.

POTATOES, peeled and mashed, and kept for thirty-six hours in a mixture of eight parts of sulphuric acid to a hundred of water, and then dried and pressed, form a white, hard substance very much like ivory, or, as one may say, like white boxwood. LEHNER expresses his doubt as to whether artificial meerschaum pipes were ever made of this substance, but I have seen them, and can testify that they looked like meerschaum, and certainly were much harder than _bruyere_, or briar-wood. Whether they will “colour” I cannot say.

The principle by which potatoes, paper, and many other substances can be hardened like parchment or horn is curious. Potatoes consist of about seventy per cent. water and twenty-five per cent. of starch, the remainder being salts and _cellulose_, which forms cells surrounded by the grains of starch. “When such a substance is for some time brought into contact with diluted sulphuric acid, that which results is simply a contraction of the cells” (_i.e._, a hardening), “or a kind of parchmenting.” Thus soft paper is converted into parchment.

It is evident that chemistry is as yet in its infancy as regards the conversion of cellulose by acid into hard substances. Since cotton, paper, and potatoes all produce by this process different substances, it is probable that hundreds of organic, or at least vegetable, substances will all yield new forms.

There is a marked difference between paste made of _starch_ or _flour_, each having its peculiar merits. The former is principally prepared from potatoes. To prepare the cement we mix it with a very little water, stirring it very thoroughly till it assumes a bluish appearance. A little more hot water is then added, and the mass left till an opal-like tinge indicates that it has formed. To this then add hot water _ad libitum_. As it is almost colourless in very thin coats, it is largely used to glaze and give body or weight to, and often to simply falsify, woven fabrics, which by its aid seem heavier. To increase this weight white lead and other substances are used.

To make the best flour-paste, flour should be kneaded in a bag under water till all the starch is washed away. What remains is a substance closely allied to caseine, or the white of egg. Combined with lime it forms a hard cement. A very slight admixture of carbolic acid (also oil of cloves) will keep paste from souring or decay. This acid has the property of destroying the growth of the minute vegetation which constitutes fermentation, just as other strong scents or perfumes are supposed to disinfect rooms, &c.

A very great number of other ingredients, such as the oxides of lead or zinc, manganese, baryta, sulphur, sal ammoniac, flint-sand, clay, salt, ochre, varnish, galbanum, or frankincense, enter into certain recipes, but those already given may be regarded as constituting by far the principal portion of all cements in ordinary use.

MENDING BROKEN CHINA, PORCELAIN, CROCKERY, MAJOLICA, TERRA-COTTA, BRICK AND TILE WORK.

Fictile or Ceramic ware embraces, roughly speaking, all that is made of clay, or mineral bases or materials, and which is subsequently baked to give it hardness. The better the material and the more intense the heat, or the greater the number of bakings to which most kinds are subjected, the harder and more lasting will they be. The old china ware which preceded porcelain, a great many specimens of old Roman vessels, and, for a more modern example, old Italian majolica and Hungarian wine-pitchers, made all within a century, are as hard as stone. They chip a great deal before they break, just as agate might do.

TERRA-COTTA is simply earth or clay “baked.” In most of the examples known as terra-cotta, earth predominates. Pure fine clay well fired is superior to what is generally called terra-cotta. Neither can we really class with it articles made of superior Portland cement, of which, as I have said, I have seen many made at Budapest which were like the finest hard slate.

Many writers confuse majolica with faïence; others regard the latter as what we should call crockery, or such ware as ranges between glazed terra-cotta and porcelain.

MAJOLICA consists generally of terra-cotta covered with a glaze. A glaze is a fusible substance, we may say a kind of glass, mixed with colouring matter, which is at the same time a protection and an ornament. Enamel is glass in fine powder melted, used generally on metal or by itself. The base of the paint is a substance fusible by heat which is mixed with colours also fusible. Therefore when the painting is submitted to heat it melts, adheres, and is permanent. Glazing, enamelling, and china painting are essentially the same.

Terra-cotta is not difficult to mend. I can best illustrate this by an example. A friend once gave me a terra-cotta vase from the Pyramid of Cholula, in Mexico. These are supposed to be of very great antiquity. This contained a fragment of pottery, probably a sacred relic of ruder style, and I suppose of far earlier times. The vase, however, had been broken to fragments, and the owner was about to throw it away as worthless. I begged it of him. Firstly, I put the principal pieces together, using, to make them adhere, glue with nitric acid. For finer work I should have used Turkish cement or the best gum-mastic dissolved in spirit or fish glue. Piece by piece with care I reconstructed the whole.

There was wanting, however, one piece about three inches square. I pasted with great care a piece of paper inside the vase for a _back_, and then poured on it plaster of Paris liquefied with water. To make this _set_ hard, the plaster or _gesso_ should be made with burnt alum-water and dissolved gum-arabic. This exactly supplied the missing piece.

When it was finished, I filled in all the broken edges and other cavities with the plaster-paste, which set even harder than the terra-cotta. The outer colour of the vase was of reddish rusty black. I painted the whole over with a corresponding colour; that is to say, I rubbed it in by thumb, which is very different from mere painting. By cementing and rubbing I so restored the whole that the repair was hardly perceptible. This process is carried to great perfection in Italy with broken Etruscan ware.

I may here remark as regards _rubbing in_ oil or water colours, that it is little known or practised, but it is of great value in restoration when we wish to produce certain curious antique-looking effects. I once knew in Rome an artist who had bought for a trifle an old carved _baule_ or chest. By rubbing in with care on it Naples yellow and brown shades, and subsequent friction, he had made it look strangely like old ivory. Mere painting, however skilfully performed, would not have given it its antique ivory look. The same artist had purchased one or two common, large, yellowish terra-cotta wine-jars. He drew on them classical figures, cut out the outlines a little with chisel and file, and smoothing the figures with sandpaper, also ivoried the whole by _rubbing in_ colour. This was but a few hours’ work, yet the effect was startling. What had cost but a few francs would have sold for hundreds. I should add that with the aid of fine retouching flexible varnish this process could be very much facilitated. Any one who can draw or paint at all can try this experiment on any old piece of wood-carving, or on a common yellow coarse earthenware. Smooth the latter first with sandpaper, then rub in the colours. The same is applicable to old carving in marble.