Class Book COPYRFGHT DEPOSIT ELECTRO-PLATING MADE EASY. TSIE m hWi Had -Bo ok A CLEAR AND COMPREHENSIVE TREA- TISE ON THE ART OF .D, SILVER AND NIGKEL PLATmS, VITH OR WITHOUT THE AID-^^5[^^0F^ca,G^ THE ELECTRIC CURREN ^ ' ^^^'^^'^^^^'^ ' E37- T. -^r. :e^..^ib:e=e:k. COLUMBUS, OHIO: PUBLISHED BY THE AUTHOR. 1883. •• ^ 4 M- Copyrighted A. D. 1883, By T. V. Harper. I / r Press of Trautman & Palmer, columbus, ohio. INTEODUOTION. In the preparation of this little work, we have -^^ndeavored to make everything as plain and :omprehensive as possible, by avoiding as far as )racticable all technical terms and names that are horoughly understood only by those having a lair knowledge of chemistry and its application to electro-metallurgical operations, which it is fair to presum.e, is not possessed by more than one out of a hundred persons, and as this book is intended more particularly for the practical benefit of the masses, we have adopted the language, and style of expression, best calcu- lated, we think, to supply a want in the field of popular, and scientific Hterature, heretofore so sadly neglected. At the same time the ex- perienced electro-plater will find herein, facts which will prove not only interesting, but instructive to him. The history of the art of electro-metallurgy dates far back in the seventeenth century, but not much progress was made in practical 4 THE SILVER PLATER's HAND BOOK. application of the then Hmited knowledge of the art in plating articles in a substantial man- ner, until sometime after the discovery of voltaic or chemical electricity, which occurred in the year 1799. The first seven years of the eighteenth century, were fruitful in important discoveries in the art. In 1800 water was first decomposed into its two constituent gases, by means of the voltaic battery, and shortly afterwards it wa? discovered that silver, in contact with another, and a more positive metal, received a firmly adherent deposit of copper, when placed in a solution of that metal. In the years of 1804 and 1805, it was first noticed, that when a current of electricity was passed through a solution of sulphate of copper, or nitrate of silver, by means of silver, or platinum wires, the metal held in solution was deposited upon the wire connected with zinc pole of the battery. About a year later, gold was first successfully deposited by means of the electric current, and it was then first noticed, that the anode (or the pole or plate,) by which the electric current entered the solution was slowly dissolved, although it is not clearly THE SILVER PLATER S HAND BOOK. O shown that any advantage was taken of this fact at that time. This seems strange when we take into consideration the importance of the discovery, which plays so prominent a part in all electro-plating operations. From this time, until after the year 1831, when magneto-electricity was discovered by Faraday, but little Was done in the way of advancing the art of electro-metaUurgy. In the year 1834, Faraday conducted a num- ber of experiments, and discovered among other things, that the amount of salt in a solution decomposed by the electric current, was in direct proportion to the quantity of electricity, and that the quantity of electricity generated in a battery, depended upon the size of the plates the intensity of the current, or its power of overcoming resistence, depending upon the number of cells in circuit. In the year 1836, it was noticed that the copper pole of a battery somewhat similar to the present Daniell battery, became heavily coated with metallic copper, which constantly increased in thickness, and also that this deposit when removed, presented a faithful outline of 6 THE SILVER PLATER's HAND-BOOK. the original copper plate, every line and scratch, however fine, being faithfully reproduced. In the years 1837 and 1839, it occurred to several parties that this fact might be taken advantage of in the reproduction of copper plates, steel engravings, etc., and a great many experiments were conducted with this end in view. One experimentalist had occasion to use a small strip of copper, in a sulphate of copper solution, in conducting one of his experiments, and not having a Mtrip of sheet copper con- venient, attached a large copper coin to a wire, and immersed it in the solution, where it remained in circuit for quite a while, and received a heavy deposit of copper. Finally one day while conducting another experiment, it became necessary for him . to use the wire attached to the coin, and while removing it he detached a large piece of the deposited copper, and at once observed that it was an exact mold of that portion of the coin, every line, and let- ter being reproduced with remarkable fidelity. In the year i84o, the art of electroplating with goid and silver received a fresh impetuous, by the discovery of the suitability of alkaline solutions, and the hitherto unprecedented sue- THE SILVER PLATERS HANDBOOK. 7 cess attending their use. Great difficulty was still experienced in obtaining a good and firmly adherent deposit upon articles of brittania metal, which was finally remedied, by first coating the articles with copper. From this time forward, the art has been making rapid strides towards perfection, but in this age of progress and invention, wdio can gainsay the assertion that, perhaps, it is still in its infancy. So numerous are the wonderful inventions, and startling discoveries, that the more conservative would hesitate, at drawing the boundarly line beyond which inventive genius and scientific research may not proceed. It would seem to the practical electro plater that there is but little room or necessity for improvement in gold and silver plating solutions, as they are now about all that could be desired. It is with the electro-deposition of other more obscure metals and metalloids that the fields of scientific research lay invitingly open, the elec- trolysis of carbon being all the more interesting from the fact that it may probably result in the artificial formation of the diamond which, as the reader perhaps knows, is but pure crystalized carbon. 8 THE SILVER PLATER's HAND BOOK. One great obstacle in the way of much re- search in the way of electro deposition of carbon is difficulty experienced in obtaining solutions containing carbon that are conductors of elec- tricity. The fused or melted carbonates are about the only liquids that have been used with any degree of success so far. With the melted carbonates of potash and sodium a black and very hard deposit of carbon has been obtained. The melted carbonate of sodium (washing soda) is, perhaps, the best mixture that has been tried as yet, it being a fair conductor of elect ricty, and yields a better deposit of carbon than any of the other mixtures. In conclusion we would say that a strict observance of the rules and formulas contained in this book will be productive of the best of results. Much pains have been taken to give the reader the benefit of all the later discoveries in the art, and the language of the book so adapted that those with but a limited education may easily understand. GENERAL INFOEMATION, All the vessels used in containing the dif- ferent solutions, should be of glass, stone, or enameled ware; glass ware being preferred for operations on the small scale. Their size should be adapted to the number and size of the articles to be plated, but for convenience sake we would suggest, that they be capable of containing at least a gallon. They should be kept in a well ventilated room, and where the light can not fall directly upon them. The different acids, and other necessary chemicals, should be kept in well stoppered bottles, and placed carefully out of the reach of meddling hands, as many of them are the most violent poisons, and some of them are capable of producing almost instan death ; and others, when mixed, producing the most powerful explosives. Too much care can not be observed in this respect, as many are the sad, and fatal results, of an incautious manner in 10 THE SILVER PTATER's HAND BOOK. the handling of dangerous chemicals, or care- lessly leaving them where unthoughtful hands may bring about the most disastrous conse- quences. Articles to be re-plated, should first have the old deposit removed, either by the aid of different chemicals, ^vhich will be mentioned further along, or by filing and scraping, or scouring with emery paper. When removed by means of acids, the metal may be re covered with but small loss, and where the operation is carefully conducted, with no less at all, and used over again; where a great deal of re plating is done this is quite an important item in the economical management of the business. The prevailing opinion that electro-plating is necessarily a very expensive operation, is er- roneous, although w^e confess that the high prices at wdiich plated goods are usually sold, would tend to further that impression, and often when the purchaser has used the articles a short time, and worn off the thin plating, thus expos- ing the baser metal underneath, he would naturally conclude that what little precious metal there was there, had been deposited at great expense. But where the business is con- LHE SjiLVER ^LA.fEKa HANi^ }300J<:. H ducted economically, and understandingly, the total expense is but a very small percentnge over the intrinsic value of the metal depofited ; as an electro plating solution once properly made, and then carefully mana|f^, will last for years, or until it becomes^so clogged up wi-th impurities set free by the dissolving of the anode, that it will no longer deposit pure metal, and for this reason, great care should be taken in the selection of anodes, in order to obtain them as free as possible from all impurities. Anodes of silver generally contain traces of copper, and those of gold contain traces of both silver and copper, which being dissolved in the solution and deposited, greatly change the color and appearance of-the articles. When not in use, the vessels containing the depositing solu- tions should be carefully covered over to pre- vent accidents by poisoning, and also to keep out the dust, and other foreign substances which might be accidently introduced. The habit some platers have of dipping the hands in the solutions to recover articles that become detached from their supporting wires, is a very dangerous one to say the least of it, as some of the poison is apt to be absorbed 12 THE SILVER PLATER's HAND BOOK. through the pores of the skin, or by getting into cuts, or even sh'ght abrasions of the skin, causae troublesome and dangerous sores. The way to recover articles accidentally dropped in the solution, i* fey means of a wooden spoon or a bent wire. PREPARING ARTICLES TO BE PLATED. All articles to be plated must first be made scrupulously clean, in order to obtain a good firm deposit. A great many failures may be attributed to the neglect of this very important step. They should first be filed or scraped, or otherwise made as smooth as possible, then immersed for a short time, in a strong and hot solution of potash, (concentrated lye) and then rinsed well in clean water. A very good scraper can be easily made by gnnding down the sides of a three cornered file until it is perfectly smooth, and finishing up on an oil stone, thus leaving three sharp cutting edges. Articles that have been soldered, must not be allowed to remain long in the potash solution, or a portion of the tin contained in the solder will be dissolved, and deposited on the articles, should they be copper or brass, and blacken them. Articles of copper, or brass, require only a few seconds immersion, those of 14 THE SILVER PLATER'S HAND-BOOK. iron, or steel, a somewhat longer time. All articles should be well washed in clean water, immediately after taking them out of the potash solution, after which they should be treated with some of the different acid solutions, in order to more fully prepare the surface for the depositing solution. Ail articles of copper, brass, or German silver, should be dipped into a solution consisting of water four parts, sulphuric acid four parts, nitric acid two parts, to which a very small quantity of muriatic acid may be added. Articles of iron should be dipped in a mixture composed of one part of sulphuric acid and fifteen or twenty parts of water, and then well washed. Articles of lead, brittannia metal, or pewter, after having been treated with the potash solution and rinsed may be placed at once in the plating solution. It is a much better plan, however, to coat them, and articles of iron and steel also, with a thin film, of copper by means of one of the following solutions before attempting to plate them with cither gold, silver or nickel. For depositing a thin coating of copper on iron or steel use a weak and slightly acidulated solution of sulphate of copper, (blue vitriol) rub the itrfkles briskly • THE SILVER PLATER S HAND-BOOK. 15 with a cloth moistened with this Hquid, and as soon as tliey have thj desired appearance, wash them well and dry them quickly ; or they may simply be immersed in the liquid for a short time, and then thoroughly washed, and dried. This solution is not adapted for any other metals except iron and steel, and is not always certain in its operation. The surest, and best way is to use a battery and an alkaline solution, which may be prepared in the following manner: Add to a solution of sulphate of copper, a solution of cyanide of potassium just as long, but no longer than it forms a precipitate ; the cyanide solution should be added slowly, and towards the last in small quantities at a time, with frequent stirring, carefully observing when it no longer forms a precipitate, which is cyanide of copper. Allow it to settle, and pour off the clear liquid, wash the precipitate well by filling the vessel with water, stirring it up, and aftei it has settled again pouring off the water, repeating the operation several times, in order to remove all traces of acid, then add to the wet cyanide of copper, a little more of a solution of cyanide of potassium than is required simply to dissolve it, that is, add thej:yanide of potassium solution, to 16 THE SILVER PLATER's HAND BOOK, the wet cyanide of copper^ until it is all dis- solved ; then add a little more of the cyanide solution to form what is termed "free cyanide/' This solution should be used at a temperature of about 150*^ Fahr. A battery of from one to three cells, such as are used in all telegraph offices, will be sufficient for all ordinary opera tions. To use this solution, in'kmerse in it a clean sheet of copper and attach it to the wire leading from the copper pole of the battery, and the previously well cleaned articles of iron, steel, lead, brittannia metal, and in fact almost any tnetal to the wire leading from the zinc pole of the battery. The articles should be im- mersed in the solution before being connected to the battery, and the wire should be detached from them before taking them out of it, The amount of battery should be adjusted to the amount of surface presented by the articles to be plated. The smaller the articles, the less battery power will be required. A number of small articles may be attached to each other, or to the same wire, and be plated at one time. If too much battery be used, the copper will be deposited in the form of a dark metallic powder. This solution is rather difficult to manage, and is THE SILVER plater's HAND BOOK. IT more expensive than a simple acidulated solution of sulphate of copper. This latter solution, however, cannot be used to plate iron, steel, lead, brittannia metal, etc, unless they have previously received a thin deposit of copper in the cyanide solution. The sulphate solution is used in precisely the same manner as the cyan- ide solution, and where heavy deposits arc desired, it is much to be preferred. In copper- ing articles in this way, preparatory to plating them with another metal, a thin deposit will be sufficient, but as we have stated before, the sulphate solution will not answer, unless the articles have previously received a thin deposit of copper, and we must per force first use the cyanide solution, or in the case of iron and steel resort to the rather uncertain method of rubbing them with a rag, moistened with a slightly acidulated solution of the sulphate. After re- moving the articles from the solution, they should be well washed and examined, and if any imperfections be discovered, the cleaning and scouring operation will have to be done over again, and th*^ plating repeated, but by using a proper amount of care the first attempt will generally prove successful. NICKEL PLATING WITHOUT A BATTERY, The commonest salts of nickel are the nitrate, chloride, sulpliate and oxide. The nitrate is obtained by dissnlvini:^ tlie metal in warm dihited nitric acid, and evaporating the mixture by a gentle heat until the residue solidifies upon cooling. The oxide is made by adding to a solution of the nitrate, or other common salt of nickel, a solution of potash, or caustic soda, un- til it no longer forms a precipitate. There is no danger of adding too much o( either potash or soda, as the oxide it forms is not soluble in a solution of either of them ; the preci[)itate which is oxide of nickel, sliould be collected by means of a filter and dried. It is a black pow- der, insoluble in water, but dissolves readil}^ in nitric, muriatic or sulphu»-ic acid. The sulphate is obtained by dissolving either the nitrate, chloride or oxide in a quantity of diluted sulphuric acid, and evaporating the mixture nearly to dryness, when it will solidify upon THE SILVER Plater's hand-book. JO cooling. A solution of the nitrate of nickel may be obtained by passing a tolerably strong current of electricity through a very dilute solution of nitric acid, by means of two plates of nickel, or by using a dilute solution of muriatic acid, the chloride may be obtained, and with a dilute solution of sulphuric acid, a solu- tion of the sulphate is produced. Nickel is too highly electro positive a metal to be readily deposited upon other metals, unless they are more electro positive than itself. This consti- tutes one of the greatest difficulties in the way of successful nickel plating, but one which we think may be "overcome by a careful observance of the directions given. Thoroughly cleaned articles of copper, brass, and German silver, and articles of iron, steel, pewter, type metal etc., that have pre- viously received a deposit of copper by the battery process, may be coated with nickel very readily in the following solution : Add to a boiling solution of pure tin tarter, a small quan- tity of nickel oxide heated to redness, which will impart a greenish tint to the liquid. Use the solution hot, and stir the articles about in it with a brass rod until they have acquired a good 20 THE SILVER PLATER 's HAND BOOK. deposit, then take them out, wasli and dry them, and if necessary, polish them with finely powdered clialk This solution should yield a very brilliant deposit and is comparatively easy to manage, but the immersion of the least par- ticle of zinc or iron in it will greatly impair its action, and perhaps ruin it. ELEOTEO NICKEL PLATING, There are quite a number of solutions used by different platers, for depositing nickel by means of the electric current, any of which are capable of doing excellent work, but in the hands of an inexperienced person, they all prove rather difficult to manage. The simplest, and perhaps the best solution, is made by adding slowly to a solution of nitrate, or chloride of nickel, a solution of cyanide of potassium as long as a precipitate, or cloud is formed, pour off the clear liquid. Wash the precipitate, and dissolve it in a strong solution of cyanide of potassium, adding a very little more of the cyanide solution, than is required simply to dis- solve it. Another, and a very good solution for electro- nickel plating, is simply solution of chloride of nickel, and^yields a very white and brilliant de- posit. Still another solution is composed of sulphate of nickel two parts, tartaric acid (dis- 22 THE SILVER PLATER's HAND BOOK. solved in water) one part, and potash (concen- trated lye) one-tenth part, or the tartaric acid and potash may be a very little in excess of the figures given without injuring the solution. This solution we think is capable of giving bet- ter results than either ot the others, and is much more simple in its preparation. There are quite a number of other solutions used to a greater or less extent by different electro platers, but their preparation and maintenance involve difficult and complex operations that necessitate a thorough knowledge of chemistry and for that reason would be out of place here. MANAGEMENT OF NICKEL PLATING SO- LUTIONS. Nickel plating solutions are more difficult to manage than those of either copper, silver or gold. The amount of nickel salts held in the solution may vary considerably without materially affecting its working. From three to eight ounces of the combined salts per gal on of water makes a very good working solution. When it contains -less than this amount the working of the solution is retarded by the in- creased resistence it offers to the passage of the electric current, and when it contains more than the proper amount, the chemical action is im- peded by the solution being too nearly satu- rated. Electro plating is the product of electro chemical action, this phenomenon being called electro chemical action from the fact that a cur- rent of electricity passing through a suitable liquid produces a chemical change in it. Elec- tricity being the cause and chemical action the 24 THE SILVER PLATER's HAND BOOK. result, hence the importance of having a solu- tion that is a good conductor of electricity and at the same time one that is capable of sustain- ing the proper amount of chemical action neces- sary for its successful operation. Nickel beir-g a very brittle metal, it is rather difficult to obtain suitable anodes. They are generally composed of plates of cast nickel, and should present a surface considerably larger than that of the articles to be plated. Where anodes of cast nickel cannot be obtained small Iragments of nickel may be suspended in the solution by means ot a frame work of platinum wire. Nickel is a metal that is seldom obtained in its pure state. It generally containing traces of copper, carbon and other impurities which, dis- solving with the anode, are either deposited or fall to the bottom and form a black sediment. It is a difficult matter to obtain a heavy deposit of nickel, owing to its tendency to crack and scale off, but for ordinary work there is no par- ticular necessity in having a thick deposit, as it is so extremely hard that a very thin coating will, with ordinary usage, last for years where a deposit of silver equally as thick would scarcely last as many months. Nickel is not affected to THE SILVER PLATER's HANDBOOK. 25 any great extent by exposure to the air or coal smoke, and in this respect it possesses an ad- vantage over silver which is easily tarnished by exposure to sulphuretted gases. Nickel is very easily corroded by acids and lorms very poison- ous compounds, and for this reason should never be used for plating the interior of vessels used in cooking ; but for plating such articles as cream pitchers, sugar bowls, drinking cups, etc., it possesses the great advantage of being capable of retaining its polish and resisting rough usage for a long time. P'rom one to three cells of battery will gener- ally be sufficient ; too much battery causing the metal to be deposited in the form of a black powder. The anode, either in the form of a plate of nickel, or composed of fragments of nickel suspended in a platinum wire net work, should be attached to the wire leading from the copper pole of the battery, and the previously cleaned articles, after being placed in thc^^soju- tion, should be attached to the wire leading from the zinc pole of the battery and kept in gentle but constant motion and as near as pos- sible to the anode without coming in actual con- tact with i(, until they have acquired a sufficient 3 THE SILVER PLATER's HAND BOOK. '26 deposit, when they may be taken out and well rinsed in hot water and dried by rolling them about in hot sawdust. All the solutions we have given should be used at a temperature of from_ioo° to 150° Fahr. SILVEE PLATING WITHOUT A BATTERY. Quite a namber of the different salts of sil- ver have been used in forming preparations for silver plating by this method, which, by the way, hardly merits the name of silver plating, as but a very thin film of metal can be deposited with- out the aid of a battery, but for small articles of ornament not subject to much hard usage this process of silvering answers very well. Most of the salts of silver are made from the nitrate, which is formed by dissolving small fragments of silver in a warm mixture composed of one part of water and four or five parts of the strongest nitric acid. Care must be taken that the liquid is not too hot nor the silver added too rapidly, or it will boil over and a portion of it be lost. Should it threaten to do so, add a small quantity of cold water. The whole operation should be conducted in the open air or where there is sufficient draft to carry off the noxious fumes that arise from the mixture while 28 THE SILVER FLATEr's HAND BOOK. the silver is being dissolved. When it will dis- solve no more metal it should be evaporated and crystallized. The resultant' salt is nitrate of silver, which should be kept in a well stoppered bottle protected t'rom the light. The chloride is formed by adding a solution of common salt to a solution of nitrate of silver, until it will no longer form a precipitate, which should be care- fully filtered and washed and be protected from the light. This salt is more frequently used in making compounds for silvering without a bat^ tery, than any of the other salts. This process is more particularly adapted to the plating of small articles, where they are not subject to much wear, and consequently only a very thin coating of silver is required ; the deposit looking fully as well as at tides plated by the battery process. The following solutions we have selected from a large number as being the most economical ; and at the same time, simple and efficacious, and are used by adJing sufficient warm water to them to form a thin paste, and rubbing it over the articles with a soft rag, or stirring them about in it until they have become thoroughly coated. I St. Take equal parts of chloride of THE SILVE:R plater's HAND-BOOK. 29 silver and cream of tarter. 2d. Take common salt and cream of tarter each six parts, chloride of silver one part and about two parts of alum. A p^ood liquid solution is made by dissolving in boiling water a mixture composed of chloride of silver one part and cream of tarter sixty or eighty parts. The articles to be plated should be placed in a small basket and immersed and stirred around in the boiling liquid. The above mentioned solutions can only be used for plating articles of brass, copper or Ger- man silver, or articles of other metals that have previously received a coating of copper. The liquid solution, after continued use, becomes of a greenish color, caused by the presence of cop- per, dissolved from articles that have been plated in it. The presence of the least particle of iron, steel, lead or brittannia metal, causes the copper to be deposited, thus spoiling the appearance of the articles. An old solution, however, will work much better than a new one, provided it has been well taken care of and has been properly managed, and it may be renewed b> occasionally adding small quantities of chlo- ride of silver, and thus kept in good order for a 30 THE SILVER PLATEr's HANIVBOOK. long time. In using these solutions, as well as all other plating solutions, the articles to be plated must first be made very clean and smooth, and the solutions kept at a uniform temperature. SILVEE PLATING BY THE BATTEEY PEOCESS. Quite a number of the salts of silver have been used in forming solutions for silver plating by means of the electric current, all of which have proved more or less successful, but the solution that has the best stood the test of time and experience, is the commonly called cyanide solution, and which may be formed either by chemxal means, or by means of an electric cur- rent. The former method, we think, is to be preferred, especially when the operation is to be conducted by those havuig but little experience in such matters. To prepare the solution by this method, make a solution of nitrate of silver in the proportion of about one pint of water to each half ounce of nitrate of silver; also have prepared a solution of cyanide of potassium in the proportion of about two ounces of cyanide of potassium to one quart of water, which should be added to the solution of nitrate of 32 THE SILVER PLATER's HAND BOOK. silv^er as long as any precipitate is formed (which is the cyanide of silver.) Should too much be added some of this precipitate will be redis solved and wasted. This will be indicated by a clear and slightly di.scolored tint being imparted to the liquid, where the cyanide of potassium solution passes. Should this be the case, add a weak solution of nitrate of silver in small quan- tities at a time, and at the same time stirring the liquid gently as long as it produces a light cloudy appearance. This amount of care is necessary in order that all of the silver may be utilized, as when too much or too little of the cyanide solution is added, some of the silver remains held in the solution. In the former case, in the shape of the double cyanide of silver and potassium, and when too little is added the silver remains in the clear portion of the solution in the form of nitrate of silver, but when just the proper amount is added, all of the silver is precipitated in the form of the sim- ple cyanide of silver. After the exact neutral paint has been attained, allow the liquid to set- tle, and pour off the clear liquid, carefully pre- serving the precipitate which should be well washed by adding a quantity of water, stirring THE SILVER PLATER S HAND BOOK. deJ it up thoroughly, and after it has settled pour off the clear liquid, repeating the operation several times until all traces of acid have been removed. The wash waters, as well as ihe clear liquid first poured off should be preserved and tested in order to recover any traces of silver they may contain. Next add to the wet precipitate a strong solution of cyanide of po- tassium until barely the whole of it is dissolved, leaving a clear and light amber colored liquid. The cyanide solution should be added in small quantities at a time, and the solution thoroughly stirred upon each addition, then allow it to set- tle. Should any of the precipitate then remain undissolved, add a little more of the cyanide solution, stir briskly, and allow it to settle, re- peating the operation until barely the whole is dissolved, and finally having observed how much of tlie cyanide of potassium solution was required to merely dissolve the precipitate, add about one third to^one half as much more of it, in order to form what is called "free cyanide," and then add enough water to dilute the whole to the proportion of about two ounces of nitrate of silver per gallon or more of the solution. The solution is then ready for immediate use. 34 THE SILVER PLATER's HAND-BOOK. There are also quite a number of methods other than this ot making the cyanide solution, but all of them necessitate the introduction of various impurities that are often highly detri- mental ; for instance, suppose we add a solution of cyanide of potassium to a solution of oxide of silver as long as it will dissolve, and then add the usual amount of free cyanide part of the cyanide of potassium will be converted into caustic potash, or if chloride of silvei be used instead of th ^ oxide, part of the cyanide of potassium will be converted into chloride of potash, or if the nitrate of silver be used, it will produce almost an equal amount of the nitrate of potash as an impurity in the solution. Nor is this process an economical one by any means, as it requires exactly the same amount of cyanide of potassium to convert it into the plating solution as where the solution is made by the method we have first given, and besides it has the very great disadvantage of introduc- ing impurities very detrimental to the satisfac- tory working of the solution. The strength of silver plating solutions may vary greatly without materially affecting their operation, some platers doing excellent work THE SILVER PLATEr's HANDBOOK. 35 with solutions containing half an ounce of silver per gallon, and others using solutions containing several ounces of silver, and almost as many pounds of cyanide of potassium. A good working solution should contain from one to three ounces of silver per gallon, converted into cyanide, and from thirty to fifty per cent, of free cyanide. A good solution should not have a corroding effect on the base metals because it is those metals we wish to plate, and if the solution should have a corroding effect upon them, it will infallibly cause the deposit to strip and scale off. The cyanide silver plating solu- tion may be made by the battery process, with but very little trouble, and some electro platers prefer this method to any other, but while it possesses the advantage of simplicity, it also has the disadvantage of forming a small quan- tity of potash in the solution. This, however, may be remedied by the addition of a small quantity of the strongest prussic acid, which converts the caustic potash into cyanide. To make the solution by this process, make a moderately strong solution of cyanide of potas- sium and suspend in it a large anode and a small cathode of silver and then pass a strong 36 THE SILVER PLATEr's HAND-BOOK. current of electricity through it until a clean sheet of copper substituted for a short time for the small silver cathode, receives a oood deposit of silver, or until the solution contains about one ounce of silver per gallon which may be determined by weighing both the anode and the cathode before placing them in the solution and then weighing them from time to time, until the proper amount of silver is known to have been diss;>lved, the solution is then ready for use. The silver deposited by these solutions has a frosted appearance, and must be burnished in order to make them bright, or they may be placed in a specially prepared solution in order to deposit a coating of bright silver upon them. This brightening solution is prepared by tak- ing one pint of the ordinary silver plating solu- tion, containing about two pounds of cyanide of potassium per gallon, and add to it two ounces of bisulphide of carbon, two of strong liquor ammonia and one of ether, and shake well. Let it stand at least twenty-four hours, shaking it occasionally, and then add the clear liquid to the ordinary silver plating solution, with gentle stirring in the proportion of one ounce to every ten gallons. This would make less than a THE SILVER PLATER's HAND-BOOK. 37 small teaspooiifuU per gallon. This brightening mixture should be added in the above propor- tions about every other day, but great care must be observed that too much is not used, as more solutions have been ruined by the excess of the brightening solution, than by all other causes put together. It is best to add but very little at first, and if from the \Vorking of the solution, you conclude it needs more, then add a very little more taking care to use only the very least possible amount necessary to produce the desired effect. If too much is added, it will cause the articles to have a dull and dark ap- pearance, and perhaps to have dark streaks or spots on them. As often as a quantity of the brightening liquid is used, add a similar amount of the ordinary plating solution, or the same amount of a solution of cyanide of potassium, containing two pounds of cyanide of potas- sium per gallon. Another brightening solution is prepared by taking one quart of ordinary silver plating liquid containing about a half pound of cyanide of potassium, and adding to it two ounces of bisulphide of carbon, shaking well, and then set aside for a day or two, and adding to the ordinary plating solution in the 38 THE SILVER PLATER'S HAND-BOOK. same proportion as the first liquid we mention, always replacing the amount used by a similar amount of the ordinary silver plating solution, and shaking well. The "bright" solution is only used to finish articles in they having pre- viously received a deposit in the ordinary plat- ing solution, and then transferred immediately to the "bright" solution. Now having de- scribed the different methods of making the solutions, we will give the reader a few practical hints as to their management. Copper, brass, and German silver become coated with silver much easier than any other metal, and for this reason all articles of other metals should, if possible, first receive a deposit of copper before attempting to plate them with silver. This, however, is not absolutely neces- sary, when plating by means of the electric cur- rent. All articles must of course be made per- fectly clean before attempting to plate them and when the cleaning operation has been con- cluded, great care must be taken to prevent them coming in contact with anything that would tarnish them in the least, handling them only with metallic hooks or tongs and never with the naked hand. THE SILVER PLATER's HAND BOOK. 39 Articles of iron and steel are first immersed in a hot and strong- potash solution, then dipped for a short time only in a liquid prepared as follows - Take one pint of water, add to it slowly two ounces of sulphuric acid that has had a small piece of zinc dissolved in it and then add one ounce of nitric acid ; This should give the articles a clean bright appearance. They may then be plated with copper in a cyanide solution as previously described or they may be placed in the ordinary silver plating solution, using a strong battery of considerable "quantity" at first, or until they have acquired a thin deposit, when the battery should be re- duced to the ordinary strength, until the deposit is sufficiently heavy. All articles should be suspended in the solu- tion by means of a wire or hook of the same or similar metal, small articles may be strung on a wire of the same metal as the contact of different metals in the solution is apt to leave a stain. Articles of copper, brass and German silver, after being thoroughly cleaned by means of the potash and acid solutions, should be immersed in the following solution and then well rinsed in 40 THE SILVER PLATER's HAND-BOOK. clean water just previous to placing them in the silver solution : Dissolve one ounce of mercury in a mixture composed of nitric acid one part and water three parts, add no more mercury than the acid will dissolve, dilute it with as much more water and add a strong solution of cyanide of potassium as long as it forms a pre- cipitate but no longer. Collect the precipitate and wash it two or three times with clear water, then add to it with occasional stirring a strong solution of cyanide of potassium until it is all dissolved, then add a little more of the cyanide solution and enough water to make the whole measure a gallon. This solution will cover the articles with a thin coating of mercury and will generally insure a firm adherent deposit. Th<^ articles should not remain in the mur- curic solution any longer than is necessary to make them look white, and should be well rinsed in water after taking them out, in order to remove all excess of it. The solution will last a long time, but it final- ly becomes weak and impure from continued use, and blackens the articles immersed in it. It is then better to make a new solution than to try to revive the old one, almost any salt of THE SILVER PLATER's HAND BOOK. 41 mcixury may be dissolved in a solution of cyanide of potassium to be used as a "quick- ing" solution. For instance, dissolve a quan- tity of red precipitate in an excess of a solution of cyanide of potassium ; that is, add the red precipitate as long as the cyanide solution will dissolve it; then add a small quantity of the cyanide solution. The mercuric solution may be prepared in a number of ways, but the result is practically the same, viz. : The forming of a solution of the double cyanide of mercury and potassium. The brightening solution works slower and requires a stronger battery than the ordinary solution ; it generally requiring from ten to twenty minutes for the articles to become wholly bright. The deposit is also much harder. When the articles are once placed in the solu- tion they must not be moved or disturbed until the operation is completed, and where a num- ber of articles are being brightened at the same time none of them must be taken out or dis- turbed in any way until all of them have be- come bright. When the articles have become sufficiently bright disconnect them from the battery and 4 42 THE SILVER PLATER's HAND-BOOK. remove them from the solution and place them immediately in boiling water and allow them to remain there a few minutes, then take them out and dry them. GOLD PLATING WITHOUT A BATTERY. Chloride of gold is the salt generally used in making gilding solutions and in preparing the other salts of gold. The chloride of gold is prepared by dissolving gold in a warm aqua- regia which is a mixture composed of one part of nitric acid and two or three of muriatic acid. The gold should be cut up in small pieces and added slowly, care beii^taken not to inhale the gases that arise from the mixture. The gold dissolves very slowly but by gently heating the mixture its action is quickened. Four ounces of this liquid will dissolve about one ounce of gold, and form nearly one and a third ounces of chloride of gold. When the solution has dissolved all the gold it can, evaporate it with gentle heat to a small bulk which will solidify when cooled. The re- sultant yellow salt is the chloride of gold which is soluble in water. Almost all articles of gold contain traces of silver and this metal may now be observed m 44 THE SILVER PLATER's HAND BOOK. the solution in the form of chloride of silver, which is a white substance and insoluble in water, which may be removed, if desired, by pouring ofT the clear liquid, which holas the gold in solution, leaving behind the white chloride of silver, which should be preserved. Any dark or brownish substance that will not dissolve is very likely metallic gold formed by the chloride being over heated and should be re- converted into chloride. A solution of gold forms upon the addition of ammonia, a brown precipitate which, when dry, is one of the most po\^rful and dangerous ex plosives known, and ^ffich detonates with the least friction or percussion. One little accident of this kind will put a sudden stop to any fur- ther experiments, therefore great care should be taken to prevent its formation, or if formed to prevent its becoming dry. The gilding solution is prepared as follows; Dissolve one pennyweight of chloride of gold in a gallon and a half of water ; add nine ounces of caustic potash, one ounce of carbon- ate of potash, and half an ounce of cyanide of potash. This solution should be used very hot, but not quite at the boiling point. THE SILVER PLATEr's HAND BOOK. 45 The previously cleaned articles of copper or brass are immersed for a short time in this solution, when they should be taken out and dried. Should a thicker coating be desired they should then be dipped in the cyanide of mercury solution (see page 40) and then after rinsing them, be immersed in the gilding solu. tion again. By repeating this operation several tinses a very thick deposit may be obtained capable of resisting the action of tlie strongest acids for a long time. This process of gold plating is more particu- larly adapted to tlie plating of articles not sub- ject to much handling, as generally only a very thin coating is obtained by it. The work done by this method, however, looks fully as well as that done by the battery process, and to those having no knowledge ot the art of electro- metallurgy is somewhat more simple. The solution also improves with constant usage, acquiring a greenish tint from the pres- ence of copper dissolved t'rom the articles that I'.ave been plated in it. This however, does not interfere with its working unless there is a great deal of it held in solution , then it may be 46 THE SILVER PLATEr's HAND BOOK. deposited with the gold, and impart a darker color to it. As the solution gradually loses its gold by- being deposited, it is necessary to add, from time to time, a small quantity of chloride of gold dissolved in a little water, ^ in order to strengthen it, and after three or four such additions it may be necessary to add a small amount of the other salts, always preserving the proper proportions. By this means the solution may be kept in good working order for an in- definite length of time. GOLD PLATING BY THE BATTERY PRO- CESS. Solutions for gold plating by means of the electric current may, like those for silver plating be made either by the aid of a battery, or by the chemical process ; that made by the chemi- cal process being more quickly made and we think capable of giving better satisfaction to the inexperienced. Tiie solution made by the battery process has the advantage of being perhaps a trifle more economical, and for this reason is often preferred by the experienced electro plater. To make the solution by the chemical process, dissolve about one and a half ounces of chloride of gold in water or convert a little over an ounce of gold into chloride and dissolve in water, and add a solution of cyanide of potas- sium, slowly and at intervals with frequent stirring just as long as it produces a precipitate, but no longer. Great care must be taken to 48 THE SILVER PLATER's HAND BOOK. attain the exact neutral paint, that is, when it no longer produces a precipitate upon the addi- tion of a very small quantity of either the cyanide or the chloride of gold solution. A small quantity of the chloride of gold solution should be reserved and slightly diluted for this purpose, and if it is not all used it may be set away and protected fiom the^light for future use. Should the solution contain an excess of either the chloride or the cyanide some of the gold will be held in the clear solution and be poured off, hence the importance of exercising great care in this respect. When the exact neutral paint has been at- tained, allow it to settle and pour off the clear liquid, which should be preserved in order to recover any traces of gold it may contain. Then wash the precipitate well by adding water, stirring briskly, and after it has settled, pouring off the clear liquid, repeating the operation a number of times so as. to thoroughly remove all traces of acid. The wash waters should be preserved as they also are liable to contain traces of gold. THE SILVER PLATER's HAND BOOK. 49 After the last wash water has been poured off pour the precipitate into a paper filter, add a small quantity of water and allow it to drain thoroughly, but not to become dry, as it may possibly contain a small amount of the fulmi- nate of gold which is an extremely dangerous substance, and detonates with terrible violence upon the slightest friction or percussion. When the precipitate has thoroughly drained, collect it in a suitable vessel and add to it a strong solution of cyanide of potassium until barely the whole of it is dissolved, then, having observed the amount of cyanide solution neces sary to merely dissolve the precipitate, add about one-fourth as much more to form what is termed by electro platers "free cyanide" and finally dilute the whole with clean water to one gallon. The amount of gold in the solution may vary greatly from the amount we have given without injury to its working, but in order to obtain the best results it should not contain less than one half an ounce, nor more than ten ounces of gold per gallon. A rather dilute solution gives a somewhat better deposit but is less rapid in its operation than a stronger one. .00 THE SILVER PLATEr's HAND BOOK. To prepare the gilding solution by means of a battery, dissolve two pounds of cyanide of potassium in one gallon of warm water, im- merse two sheets of pure gold in this solution and connect them to a moderately strong bat- tery, and allow them to remain in this position and occasionally stirring the liquid, until the proper amount of gold has been dissolved and held in solution. This may be determined by weighing both sheets of gold before placing them in the solution, and then by taking them out of the solution occasionally and weighing them, the amount of gold held in solution may be very easily determined. Still another and a better means of ascertain- ing when the solution is ready for use, is to occasionally substitute for a short time a bright and clean sheet of copper, or light colored brass for the gold cathode, until it finally receives a satisfactory deposit. The solution is then ready for work and should be used at a temperature of about 150^ Fahr. PMOTIOAL OPERATION OF GILDING SO. LUTIONS. All solutions for gold plating should be used at a temperature of about 150° Fahr., and when not in use should be carefully covered over to protect it from the dust and other im- purities. The amount of gold held in the solu- tion may vary greatly without materially affect- ing it working, provided always, that it also contains a proportionate amount of cyanide of potassium. The proportions of gold and cyan- ide of potassium in the solution may vary within certain limits, generally from twent>-five to fifty per cent, more than is required to simply dissolve the cyanide of gold (see page 49) without impairing its usefulness. Too much cyanide of potassium causes the deposit to have a dirty discolored appearance. After the solution has been in use for some time it often works badly in consequence of the proportions of gold and cyanide becoming dis- K7 THE SILVER PLATER S HAND-BOOK. arranged. This is caused sometimes by using anodes with greater or less surface than the articles to be plated. When the anode presents a larger surface in the solution than the articles to be plated, the solution rapidly becomes richer in gold, which uniting with the free cyanide, soon uses it all up in forming the double cyanide of gold and potassium, leaving but very little or none at all to form the "free cyanide" so essential to its perfect working. This condition is indicated by the anode becoming covered v^ith crust or sediment, and is remedied by using an anode with smaller sur- face than the articles to be plated, or a sufficient amount of a solution of cyanide of potassium may be added. When the anode becomes black, and has a slimy appearance, the solution needs more gold, which may be supplied by using an anode of greater surface until the solution is again prop- erly proportioned, which will be indicated by the anode remaining bright and clean and giv- ing a good deposit. By carefully observing these indications, and applying the proper remedy, the solution may be kept in order THE SILVER PLATEr's HAND BOOK. 53 almost indefinitely, but after very long continued use it becomes contaminated with various im- purities, some of them accidentally introduced, and others set free by the dissolving of the anode. Gold anodes invariably contain traces of sil- ver, which is dissolved in the solution, and by being deposited with the gold increases its paleness of color. When from any of these reasons the solution ceases to work satisfactorily, all the metal held in solution may be recovered separately, and used to start out anew. DEPOSITING DIFFEEENT SHADES OF GOLD. The color of the deposit may be regulated in quite a number of ways, pure gold having too light a color to be admired by many. An old solution, in which a great many copper articles have been plated, is capable of yielding different colored deposits by means of regulating the size of the anodes, temperature of the solution, the strength of the battery, and, in a degree, the strength of the solution also. An old solution, that yields a pale yellow deposit, when but a small portion of the anode touches the solution, will yield a darker deposit when the anode is further immersed, and finally, when it is entirely immersed, the deposit will be of a red color. The temperature of the solution effects the color of the deposit, it being much darker and richer when the solution is used hot than when it is used cold, and it is claimed by a great many electro-platers, and justly too, that a THE SILVER PLATER's HAND BOOK. 55 metal deposited from a warm solution is harder, and consequently more durable, than a metal deposited from a cold solution. The strength of the battery also has a great deal to do with the color of the deposit, a moderately weak current producing a much lighter colored deposit than that produced by a much stronger battery. There are, however, certain limits regulating both the temperature and battery power, beyond which it is not safe to venture. The temperature should never be allowed to greatly exceed 160° Fahr. The amount of battery power is a more difficult matter to determine, as it varies with the amount of surface presented by the articles to be plated. Generally speaking, three cups of the ordinary Callaud or gravity battery will be amply sufficient for operations on the larger scale, while one, or, perhaps, two cups will answer for the gilding of small articles, or electro-plating on a small scale. Gold deposited by the electric current is not always pure gold, as other metals are often deposited with it in order to produce the desired color or tint, and in large electro plating estab- lishments, or where a great variety of work is 56 THE SILVER PLATER's HAND-BOOK. (lone, a number of gilding solutions are used, each of them yielding a different colored de- posit. However, one solution is capable of yielding, with careful and judicious manage- ment, a deposit of gold varying in color from the light yellow of almost pure gold, to a deposit so alloyed with copper as to resemble 14 karat gold, and which it really is. In order to accomplish this, the solution must contain a small amount of copper. This metal is always present in old gilding solutions, caused by a very minute portion of the metal being dis- solved from each article of copper that has been plated in the solution. Of course the amount of metal dissolved from each individual article is very small indeed, but when in the course of time a great many of them have been plated, the aggregate of the dissolved copper is con- siderable, and quite sufficient to change the color of the deposit. A freshly made solution used quite hot, with a large gold anode and a toler- ably strong battery, will generally give a satis- factory deposit, but should it still be of too light a color, remove the gold anode and substitute in its place a clean one of copper and work the solution with it until the deposit begins to THE SILVER PLATER's HAND-BOOK. 57 slightly change its color, and then replace it with the gold anode. If the copper anode has been weighed before, and again just after using it, as above mentioned, it will be discovered that a portion of it has been dissolved in the solution, which by being deposited with the gold gives it a richer and darker color. To obtain a green colored deposit, add a small quantity of the ordinary silver plating solution to the gilding solution, with gentle stirring, taking care to add just enough to produce the desired effect, as where too much of the silver solution is added it is liable to spoil it. White gilding is produced by adding a solu- tion of nitrate of silver to the gilding solution, until the desired colored deposit is obtained, which must be ascertained by actual trial. Pink gold is obtained by first plating the articles in a cold and weak solution, with a weak battery, then giving them another coat in a hot and strong solution that has considerable copper in it, using a more powerful battery in order to obtain a dark colored deposit, then give them an exceedingly thin coating in the ordinary silver plating solution, and finally burnish them. The coatine of silver should be barelv sufficient to 58 THE SILVER PLATEr's HAND BOOK. impart a lighter tinge to the deposit which, if the operation has been successful, will be of a beautiful pink color when burnished. To gild the inside surface of articles, such as cups, cream pitchers, and similar articles, fill them with the solution, and suspend a gold anode in them, and attach the article itself to the wire leading from the zinc pole of the battery. The lips of the pitcher, and other portions that the solution does not touch, may be plated by laying a rag wetted with the gilding solution upon the part, leaving a portion of it immersed in the solution contained in the vessel. The outside surface of the article, or that portion of it you may not want to gold plate, may be coated with a solution of sealing wax dissolved in naptha, or simply painted over with melted beeswax, and the articles placed in the gilding solution in the ordinary way, and after the gilding operation has been completed, the wax is easily removed. EEPLATING OLD AETIOLES. In order to obtain a good satisfactory deposit upon old articles, the old plating must first be entirely removed, or they will be apt to show lines, where ti:e old and the new plating join. The removing of the old deposit may be accomplished, by making them the anode in a solution composed of one pound of cyanide of potassium in one gallon of water, using a sheet of copper for the cathode. This process is always used for articles of iron, steel, lead, brittania metal, and pewter and sometimes for articles of copper, brass and German silver. Articles made of the latter metals are generally "stripped" of their old deposit in an acid solu- tion, which is made by adding a small quantity of saltpetre (nitrate of soda) to a quantity of hot and strong sulphuric acid sufficient to cover the articles. Should action become slow, it may be quickened by adding more saltpetre, and using the solution at a higher temperture. 60 THE SILVER PLATER's HAND-BOOK. After the old plating has been removed, they should be well washed in clean water, scratch brushed, and treated with the various acid and mercuric solutions as described on page 39, in order to prepare the surface for the gilding solution. The "stripping" solution will not act upon the copper or brass base of the articles to any very great extent, unless they are allowed to remain in it too long. The articles should be perfectly dried before immersing them, in order to keep the solution as free from water as possible. This solution is probably the best for opera- tions on a small scale, as the amount, or bulk of it, need not be much more than barely sufficient to cover the articles. Another solution is prepared by adding ten parts of strong sulphuric acid to one of nitric acid. A large quantity of this solution is re^ quired, which should be kept as free from water as possible by taking care that the articles to be "stripped" are first thoroughly dried, and by keeping the vessel containing it closely covered to prevent its aborbing moisture from the air. This solution should be used cold, and as it be- comes weaker, add very small quantities of nitric THE SILVER PLATER's HAND BOOK. 61 acid to it. The addition of a small quantity of water will cause it to attack the copper base of the articles. In stripping old articles to be replated, care must be taken to remove every traces of the old d posit, in order that the new one may present a clean, smooth and evenly colored appearance. Some platers, however, replate old articles without first removing the old plating, by wash- ing and scouring them well, then brushing them tlioroughly with a wire scratch brush, (see page 72), and finally, after treating them with the acid and mercuric solution, (see page 40), placing them at once in a tolerable strong silver solution, and using a battery of considerable strength at first, diminishing the battery power as the plating operation progresses. This plan is not an economical one, as the deposit is doubled upon that portion of the articles subject to the least wear, and giving the other portions a much lighter coat, where they need it the most. This process also requires that a thicker plating be deposited, in order to cover up the lines that are liable to occur where the old and the new deposits join, and which by the way, is an extremely difficult matter to 62 THE SILVER FLATEr's HAND BOOK. do, as scratches and lines have a tendency to magnify themselves during the platin^^ process, and where a very thick deposit is obtained, a slight scratch often becomes a crack of consid erable size. ^ About the only remedy for this is to take them out of the plating solution quite often and brush them well, and while in the solution they should be kept in gentle but constant motion. In re-gilding old articles, the old deposit should first be removed by making them the anode in a warm solution composed of one pound of cyanide of potassium in one gallon of water, using a battery of considerable strength until all of the old plating has all been dissolved. They should then be well washed and brushed in clean water and prepared for the plating solution by treating them with the various acid and mercuric solutions described on pages 39 and 40. HOW TO MAKE A BATTERY. One of the best batteries for electro-plating purposes is the ordinary gravity battery, of which there are various styles, all of them, however, being made on the same general plan. To construct a battery of this kind, procure two or three pieces of sheet copper five or six inches long, and about two inches wide and fasten them together by means of a copper rivet through the center; to the end of one of the strips fasten a copper wire about a foot long by means of another copper rivet. The wire must be well insulated except at its two ex- tremities, in order to prevent its being corroded at the surface of the solution. India rubber is the best substance for this purpose and is generally used in batteries of this description, but where wire already coated with rubber cannot be procured, a very good substitute may be obtained by wrapping th