Part 12

Caoutchouc is partially soluble in carburetted sulphur, ether, pure petroleum, or benzole, but gutta-percha is perfectly so. In this state it may be applied as a varnish or coating for repairs, as it hardens by exposure to the air. When mixed with sulphur and exposed to a heat of 110° to 115° centigrade, gutta-percha becomes what is called “vulcanised,” assuming a very light grey colour, is more elastic, and retains this elasticity at a much lower grade than before. When the heat is raised to (maximum) 180° the mass becomes very hard, tough, and black, or like horn. The conditions of its toughness, elasticity, and hardness depend upon the amount of sulphur used; as in other combinations, the harder the material becomes the less elastic it is--that is, the more brittle.

EBONITE is extremely hardened caoutchouc. It is first treated with chlorine, washed with sulphate of soda infused in water, and finally mixed with hardening substances and submitted to severe pressure.

As indiarubber or “gum” shoes are in general use, most people would consider them the proper objects to begin with. To do this, first make two separate preparations as follows:

I.

Caoutchouc 10 Chloroform 280

II.

Caoutchouc 10 Resin 4 Turpentine 2 Oil of turpentine 40

No. I. is simply kept for a time in a bottle or tightly closed jar by itself. No. II. is made by cutting the gum very fine, mixing it with the resin, then adding the turpentine, and finally dissolving the whole in the oil of turpentine. Then combine I. and II. To repair the shoe, take a linen patch, steep it in the mixture, and place it over the rent. When this is dry apply one or more coats.

It may be observed that this preparation may be used not only for indiarubber shoes, but many other objects. Applied to the soles of leather boots, and then heated in, repeating the process a few times, they become perfectly waterproof. This is better when the shoemaker makes a coating of it between the two soles. I have tested this often. The inner sole may be made by simply dissolving the indiarubber in benzole or ether. A solution for ordinary repairing can be made by simply steeping the indiarubber in benzine.

Rents or holes in ordinary leather shoes or other objects can be very well repaired in this way. A piece of leather can in this case be substituted for the linen rag. Boots or shoes which will be very much exposed to wet should be warmed and then soaked or permeated with a solution of indiarubber. Preparations for the purpose can be bought of all dealers in gum and gutta-percha.

Cloth is generally waterproofed by steeping it in a slight solution of caoutchouc.

Another recipe (LEHNER) is as follows:--

Caoutchouc 150 Tallow 10 Slacked lime 10

This is used to cork or close bottles. To render it more resistant, substitute pipeclay for the lime. Or if in place of either we use red oxide of lead, it will form in time an extremely hard and perfectly waterproof cement of great value.

A STRONG INDIARUBBER CEMENT:--

Caoutchouc, about 90 Pulverised sulphur 10 Or from 6 to 12 of the latter.

This is specially commended as useful to close tins containing fruits, &c. It is simply vulcanised indiarubber.

MARINE GLUE is a very valuable and generally useful cement. It is so called because, being perfectly waterproof, it is used for many purposes in ships. It is applicable not only to repairing indiarubber or gutta-percha garments, but also to objects of metal, wood, glass, stone, paper, or cloth; as, for instance, umbrellas, on which, when torn, a patch or strip of silk or muslin may be gummed, which will last as long as the rest. It is also good for waterproofing shoes. It is sold by dealers in ships’ stores, chemists, and others. “It is a good thing to have in the country.”

HARD MARINE GLUE:--

Caoutchouc 10 Rectified petroleum 120 Asphalt 20

To prepare this, the caoutchouc should be hung in a linen bag in a cask with a very large bung, or in a large jar, so that the bag shall be only half immersed. This is kept in a warm place for from ten to fourteen days, till the solution is effected. Then the asphaltum may be melted in an iron kettle. Let the rubber solution slowly run into the kettle over a gentle heat, and stir in the one to the other till the mass is thoroughly preserved are put in the bag; the edge is then turned incorporated. When this is effected pour the mixture into moulds which have been oiled to prevent adhesion. The result is dark brown or black thin cakes, which are broken with difficulty. The excellence of this cement is somewhat counteracted by the difficulty or care which must be observed in using it. To do this, put the vessel in which it is to be melted in another or a _balneum mariæ_, as for glue, filled with boiling water. When fluid take the kettle from the fire and subject it directly to heat till it attains a temperature of 150° centigrade. When it is possible, heat the object to be glued to 100°. The thinner the coat and the hotter the surface the better will it adhere, unless the objects be such as hard boards. In all cases as strong a pressure as possible should be employed to bring the two parts together, which should be continued till the glue has dried. Boxes which are cemented together by means of marine glue and are also nailed are of extraordinary strength, and may be thus made air-tight and waterproof. Those who intend to send articles which can be affected by sea-air, such as silks and tea, which change their colour and quality even when packed in the tightest ordinary cases, should employ boxes well secured with good marine glue. It is also invaluable to secure clothing against moths, for if anything be very thoroughly dusted and there are no moths in it, none can get in if it be enclosed in a box rendered air-tight.

_Apropos_ of which I would say that in America moths, which are far more of a pest than in Europe, are effectively excluded by means of bags of strong paper, well tarpaulined or tarred. The objects to be over and warmed, so that it seals itself up. Strong paper bags are better than any trunks to exclude moths, but they must always be well gummed up. Tobacco is no protection at all against these insects. I have even had an old woollen Turkish tobacco-bag which had been in use ten years, and which was partly full of tobacco, almost devoured by moths, which must have eaten no small quantity of tobacco in so doing. Nor is camphor or any other scent half as effective as hermetic closing in some substance which insects will not eat.

LEHNER gives a suggestion regarding the rendering walls air-tight which is of such remarkable practical utility that it ought to be enforced by health laws in every house. Whenever walls have any tendency to absorb dampness--and all have it in damp weather, especially in underground rooms--it is _far_ more dangerous than is generally supposed to put paper on them. This is so much the case that where workmen, from carelessness, paste one coat of paper over another on a damp wall, the mass in time gives out a very poisonous exhalation, so that an instance is recorded in which several people died, one after the other, in consequence of sleeping in such a room. To prevent this take the following waterproof cement:--

Caoutchouc 10 Washed chalk 10 Oil of turpentine 20 Bisulphide of carbon 10 Resin (colophonium) 5 Asphalt 5

These are combined in a large flask, kept in a moderately warm place, and often shaken till well incorporated. The wall to be covered should be brushed and wiped, and in some cases heated, until extremely dry. Then, using the cement, apply the paper in the ordinary way. It will stick with great tenacity, this being a very tight and strong glue. All wall-paper whatever is more or less productive of malaria in damp weather, as is the smell of a _damp_ library, or one where the scent of old paper is rankly and offensively perceptible. Therefore every precaution should be taken to render it innocuous.

Even if no paper be applied, this cement is very valuable when simply used to coat the interior or exterior of damp walls. It can, of course, be used to repair many articles of indiarubber, and to mend shoes, tan garments, &c. _Apropos_ of which latter I may here remark that all persons who intend to rough it in the bush as colonists, or go into any region where mending or getting mended is difficult--as I myself have many a time experienced--would do well to carry a tight tin box of waterproof glue, with which torn shoes, and very often torn clothes, can be promptly repaired. In fact, with the aid of a little rough stitching, or even without it, garments of leather, muslin, and even of cloth can be made to hold together with certain cements, which will literally bind anything.

It is well worth while for those who propose to live in the wilderness, wherever it may be, to know how to prepare or make indiarubber garments. The recipe is very easily made:--

Gutta-percha 10 Benzine 100 Linseed-oil varnish 100

The gutta-percha is dissolved in the benzine; the solution, when clear, is poured into a bottle already containing the varnish, and all is then thoroughly shaken. This mixture, when spread on woven fabrics of any kind, renders them completely waterproof. The garments can then be cut out and “sewed;” that is, bound together with the same cement. According to LEHNER, this cement can be used for making the soles of shoes, and is marvellously elastic. All travellers, and assuredly all housekeepers, should have this cement among their possessions.

It may also happen to a traveller to find himself with an aching hollow tooth in a region where no dentist is accessible. Should he have with him some gutta-percha (bleached is best for this purpose) he may combine it with very finely pulverised glass. (To _levigate_ or powder anything as fine as flour, it must be pounded in a mortar, or on metal or hard stone _under water_.) Then warm and thoroughly mix the gutta-percha and glass. Make it into little pencils, which, when they are to be used, must be dipped in hot water. This cement may be also used for a great variety of other purposes.

A very admirable cement, which should be found in every stable and known to every one who owns a horse, is made as follows:--

Hartshorn and resin ammoniacum (_Ammoniakharz_) 10 Purified gutta-percha 20-25

Heat the gutta-percha to 90°-100° centigrade, and thoroughly incorporate it with the powdered resin. The chief use of this admirable composition is to fill up cracks or splits in horses’ hoofs. It may also be used for plaster on occasion. To apply it to hoofs, warm it and spread it in with a warmed knife. It sets so hard that it will hold nails.

In mending or making, it may be observed that a very little indiarubber or gutta-percha may be combined with benzole or ether, or rectified petroleum in large amount, which soon becomes dense. Therefore, to produce a surface or a skin, we first spread a _thin_ coat over the object or mould, and then apply another with a broad, soft brush or “dabber” with great care, so as to make it of uniform thickness. It is, therefore, best to have the preparation always rather thin, and use it at the right time, and not when it has become dense by long keeping. In the latter case add more of the solvent.

Glass bottles or vials containing liquids are often broken, even by the pressure of soft objects, such as clothing, when placed in trunks. It is therefore advisable to dip or coat them with this solution, which forms a bag which will contain the fluid; that is, unless it be of a nature which will soften it. I have known a bottle of hair-oil to be packed in a valuable cashmere shawl, which was almost ruined by its breaking, and which could have easily been prevented by this easy precaution.

Any apothecary will make up these recipes.

A very curious and valuable imitation of indiarubber waterproof cloth is made as follows:--Caseine is macerated with water and with borax to a solution. The cloth is dipped in this, and when quite dry, again dipped into a strong infusion of gall-apples. This is a kind of tanning.

For exhaustive information on the subject of indiarubber the technologist may consult _Kautschuk und Guttapercha_, by Raimund Hoffer, Leipzig, 1892, which is, I believe, the latest and best work on this important subject.

MENDING METAL-WORK OR REPAIRING BY MEANS OF IT

FIREPROOF CEMENTS, WITH IRON BINDERS

Metal-work, especially in iron, requires so much forging and so many appliances that it is to a certain extent beyond the ordinary mender, who must in most cases have resort to the smith or artificer. But there is still much within the capacity of the amateur to effect, and this I will describe.

One of the commonest requirements in repairing trunks and many other objects is to make a strap or strip of metal hold either to a surface or to itself. This is to be promptly effected by _riveting_. If the iron band on a trunk is broken, you cannot well nail it again into its place. A nail will not hold in the thin side, possibly of pasteboard. To learn how to repair in such a case, take a piece of common hoop iron, lay it on a block of wood or a board, and with a fine nail or brad-awl and hammer knock a hole in it. Then take a rivet or any flat-headed tack, put it through the hole, lay it with the head of the tack down on iron or stone if possible, and then give the point a blow, a little sideways. The result is that the point will be flattened and the tack firmly held. The result will be the same if the rivet passes through two thick pieces of metal. In this manner the two ends of an iron hoop for a box are fastened. Therefore, if we take a piece of tin or sheet-iron, put it in the trunk against the side, and bring down the broken strip on the outside, we can, with a little care, rivet it. It is advisable, when this is done, to paste a strong piece of muslin or leather over the tin to prevent it from cutting anything in the trunk. These riveted strips are _far_ better for surrounding and holding many bundles than cords. They are better for books, because they do not leave marks on the edges, neither do they untie nor are they hard to fasten, requiring no knotting.

Riveted bands, corners, or bent pieces of sheet-metal are more generally applicable to broken furniture than is generally supposed. The plate thus applied can generally be concealed either by chiselling a place for it or by hammering it into the wood, and then cementing and painting it over.

Wire is also very useful for mending of many kinds, either in metal or wood. To manage it we need a pair of cutting pliers or pincers, as well as the long-nosed and flat pliers. Thus, to attach two bodies--for instance, the two parts of a broken gunstock--begin by fastening one end of the wire in one piece, and wind it round both, drawing it as tightly as possible with the flat pliers. When united, fasten the other end by driving it under the _twist_ or into the wood. This also can be so adroitly treated that the wire, flattened with a file and hammered down, can be concealed under paint and varnish. By means of wire passed through holes made with long brad-awls or fine gimlets, picture-frames can be firmly repaired. In many cases the wire should be brought round and the ends fastened or wound together; in others, make a double ring in one end of the wire and nail it down, then pass the wire through the hole and fasten the other end in the same way. Many kinds of broken implements may be thus mended. Endeavour to get strong, _flexible_ wire for such purposes.

Boxes containing goods will be doubly strong when protected by strips of iron nailed round them. Hoop-iron is generally used for this purpose.

Soldering is, however, the best and most usual means of repairing all kinds of metal-work, and this is very far from being so difficult as is generally supposed; indeed, a lady-writer on metal-work goes so far as to declare that it is fascinating. As every tinker and tinman knows how to “sodder,” and will willingly give instruction for a trifle (children, indeed, often behold the whole process admiringly for nothing), and, finally, as it is most unlikely that any reader of this work should be in a place where neither tinkers nor tinmen are to be found--for I have read that a gipsy tinker was once discovered mending a kettle seated in the shadow of the Great Wall of China--it is hardly necessary to describe in detail processes which any one can take in at a glance. The principle is this:--As in cementing glass, the glue which binds requires powdered glass to be mixed in it, so that it may establish a quicker and closer affinity with the glass; so to unite two metallic surfaces we must have a flux or some fusible substance as an intermediary. For this purpose various substances, such as resin and borax, are employed with the solder, which is a compound of metals, which melts very easily, takes a firm hold of other metals, and sets hard at once. There are many varieties of it, adapted to different metals. It is generally sold in small sticks for use.

I lay some stress on the fact that there should be some one in every family knowing how to repair, especially in metal, because there is no household in which there is not damage of tin and iron ware, trunks, kitchen utensils, and often even of jewellery, which a clever youth or young lady could easily restore. A pin is detached from a brooch. You could repair it yourself in five minutes, at a halfpenny’s expense; but no, it must be sent to a jeweller’s to be mended for a shilling. It is the same with earrings and chains and bracelets and clasps and securing-rings. When they become shaky you fasten them with thread. It will hold for the present, of course; and then comes an advertisement in the _Times_: “Lost--Twenty-five Pounds Reward!” All because you never learned how to repair or solder.

But, as ’tis never too late to mend, and no one should be a mend I-can’t, or go begging to others to do for him what he can do for himself, I trust that reflection on this subject will induce many to become practical repairers. If you have a valuable coin, do not take half the value out of it, as most people do, by boring a hole through it. Make a simple twist and eyelet of a bit of silver wire and solder it on the edge. Do not tie a gold chain with twine; mend it properly. Rivet your broken scissors, and when hinges come out screw them on again. If there were really anything _difficult_ in all this I would honestly say so, but there is not, and people who have received some education learn how to do it all with ease in a short time.

A recipe for a cement to attach metal to any other substance is made as follows:--

Purified flint-sand (or glass-powder) 10 Caseine or curd 8 Slacked lime 10

Mix thoroughly, and add water to a creamy consistency.

The following for metals is also very strong:--

Sturgeon’s bladder solution 100 Nitric acid 1

The acid is stirred in at the same time with the cement, which should be as dense as possible, and with this mixture the surfaces of the metal are covered. “The nitric acid is intended to make the surfaces of the metal rough, but it has the drawback that it hinders the drying of the glue” (LEHNER). This slowly drying is, however, a great advantage. The same is found when it is mixed with common glue, which generally dries too rapidly. Cements which dry rather slowly take hold the most firmly and permanently. The acid hardens the mass by contracting the cellular tissue. To hasten the drying, the metallic parts, which should be very strongly compressed together, must be exposed to heat.

A simpler method for light articles of metal is to wet the surfaces with nitric acid for a few minutes till they are roughened, then wash away the acid in water, and cement the metal with sturgeon’s bladder cement.

A special cement for zinc is made by thickening very strong dense glue with powdered slacked lime, into which is kneaded one-tenth part of flowers of sulphur.

A so-called Jeweller’s Cement, which holds firmly, is the so-called Diamond, elsewhere given; also the following:--

Sturgeon’s bladder 100 Gum mastic varnish 50

The sturgeon’s bladder is dissolved in as little water as possible with strong spirits of wine (equivalent to ordinary spirits). To prepare the mastic varnish, mix finely powdered mastic with the most highly rectified spirits of wine and benzine, and use as little liquid as possible. The two mixtures must be then rubbed as intimately as possible together. When carefully made this cement will serve for anything--glass or china, &c.

A CEMENT FOR ZINC, especially for ornaments and small work:--In ten parts by weight of silicate of soda (solution) stir two parts of cleansed chalk and three of zinc in powder. This is kneaded for some time into a putty, with which defects, roughnesses, &c., can be remedied. After twenty-four hours, when polished with agate, this cement has all the appearance of zinc.

It may be observed that other metals in fine powder may be substituted for the zinc, and that with bronze powders, oxides of metals, and indeed with all the range of painters’ colours, combinations may be formed of infinite application in the arts. According to LEHNER the silicate of soda should be of 33°.

A specially strong and valuable cement, capable of many uses in metal, wood, glass, or china, or to fasten glass to metal, is made as follows:--Take best purified litharge, stir it with glycerine until it becomes a thin homogeneous mass, which in less than an hour will become a very hard mass, which is of almost universal application. It is not affected by water, and resists the action (according to LEHNER) of almost all acids, the strongest alkalies, as well as etherised oils and the fumes of chlorine and alcohol. The surfaces which are to be united with it must first be covered with pure, thick glycerine.

It will readily occur to the reader that in or to this, as in every recipe given in this book, modifications, alterations, and additions can be made, of very great value, adaptable to a great variety of substances. It is to be observed that in such cases as this, where one cannot be sure of the exact result, it is best, _e.g._, to first experiment with a very little finest pulverised oxide of lead with the glycerine.

Another form of this powerful metallic cement is given as follows:--

Concentrated glycerine ½ litre Litharge 5 kilogs.

To make a cement to fill or close joints in zinc-work:--Soak three parts by weight of glue in water, pour off the superfluous water, dissolve the glue in warm water, stir into it six parts of slacked lime and one of flowers of sulphur.

When ironwork, as, for instance, window-bars, is to be set in stone, the following is commended as taking a firm hold:--

Calcined gypsum 30 Finely powdered iron 10 Vinegar 20

The following recipes, though I have found many of them in other works, are here taken, with acknowledgment, from LEHNER, as his proportions are invariably accurate, or confirmed by experiment.