Ufl 



UNDULATORY FORCKS. ELECTRO-METALLURGY. 



[MOULDS, no. 



tho revolving wire bnuhes, exposing in succession dif- 

 ferent part* of the article to their action. Wire of dif- 

 ferent degree* of fineness is naod with different articles. 



8L Coniieding Wires. The depositor should provide 

 a large number (several pounds weight) of pieces of cop- 

 per wire, of about the size No. 18 or 20, of the Birming- 

 ham brass wire gauge, and about fifteen or twenty inches 

 long, for suspending the smaller and more numerous 

 articles to be coated in the depositing solutions ; a few 

 other pieces of a larger and stronger kind should be pro- 

 vided for tho heavier articles. Copper is the most suit- 

 able metal for connecting-wires, and the most generally 

 used, because it is one of the best conductors of electri- 

 city, being also flexible and not expensive ; next to it we 

 should select brass : silver is the best conductor, but is 

 too expensive. 



82. Di/iping Liquids, Pickling Liquids, <tc. The de- 

 positor wiU next prepare his various liquids for cleansing 

 articles for plating. For cleaning iron articles he will 

 require large stoneware pans and jars, containing a mix- 

 ture of one part of sulphuric acid, and twenty parts of 

 water ; a weaker solution may be used for some kinds of 

 metal ; smooth wronght-iron requires a weaker liquid 

 than rough cast-iron. For cleaning either copper, brass, 

 or German silver, he will require several stoneware pans, 

 one containing strong nitric acid, another filled with 

 "dipping" liquid (a mixture of 64 parts of water, 64 

 parts sulphuric acid, 32 parts nitric acid, and 1 part of 

 hydrochloric acid), and a third containing "spent" 

 liquid, i.e., cither nitric acid or dipping liquid, the power 

 of which has been partly exhausted. In addition to these, 

 he will require some glass-cutters' fine sand ; with several 

 small liana-brushes and pieces of old cloth, for brushing 

 and rubbing the sand upon the more rusty and refractory 

 parts of tho metals to be cleaned ; also a file and scraper 

 to further assist in cleaning them. Hydrofluoric acid, 

 contained in a small leaden or gutta-percha bottle, should 

 be at hand, to apply to the ' ' glazed " patches occasionally 

 met with upon cast-iron. 



83. Battery Liquids. Tho only kind of acid used by 

 electro-platers, to excite their batteries, is sulphuric acid. 

 For tho negative solution of Daniell's batteries, a stock 

 of sulphate of copper should bo provided. 



84. Liquid* for Canting A dhctive Uc/wntt. Solutions 

 of nitrate, or of cyanide of mercury, will be required for 

 preparing the surfaces of copper, brass, and German 

 silver, for receiving adhesive deposits of silver. The 

 nitrate solution is prepared by adding ono ounce of mer- 

 cury to sufficient nitric acid, diluted with three times its 

 bulk of distilled water to dissolve it : no more mercury 

 must be added than the liquid will dissolve : when tho- 

 roughly dissolved, dilute it with about ono gallon of 

 water. To prepare tho cyanide solution, dissolve ono 



ounce of mercuiy as stated, dilute it with water, and a. 1.1 

 a solution of cyanide of potassium to it, just as long as 

 a precipitate is produced ; filter it, add a small <|iu 

 of water to the precipitate in the filter, and, when tho- 

 roughly drained, take out tho precipitate, and add to it a 

 strong solution of cyanide of potassium until it is all un- 

 solved ; then add a little more cyanide solution, and finally 

 dilute it with water until the whole measures ono 

 gallon. Tho solution, when prepared, is kept in a large 

 stoneware pan, a pan of dipping liquid ana another of 

 water being near it, and each placed near the scratch- 

 brush lathe and depositing- vats in the silvering-room. 



85. Material* for Moulding. Tho electro-depositor who 

 includes in his business not only the ordinary electro- 

 plating, but also tho manufacture of works of art by 

 deposition, requires a number of substances for moulding, 

 and preparing the surface of tho moulds to receive a 

 deposit. For moulding ordinary metal objects, ho often 

 uses gutta-percha or a composition consisting of equal 

 parts of white wax and spermaceti ; but one of tin 

 substances wo have used for this purpose, lias been a 

 composition of our own, consisting of two parts of gutta- 

 percha, and ono part of Jeffery's marine glue : the glue 

 is cut up into small pieces, and molted at a gentle heat 

 in an iron ladle ; the gutta-percha, also cut very small, in 

 then added, and the mixture constantly and vigorously 

 stirred at a gentle heat until tho two are thoroughly 

 incorporated. This substance possesses several im- 

 portant advantages over gutta-percha alone as a moulding 

 material ; it is softer when heated, and takes a sharper 

 impression ; it contracts more in cooling, and is therefore 

 more easily removed from the original; and in taking 

 tho blacklead it is very superior to gutta-percha. With 

 ordinary care many copies may be taken by deposition 

 off one of these moulds ; we have taken upwards of ten 

 from one of them. 



86. Elastic Moulding Composition. When tho objects 

 to bo copied are much under-cut, or when we wish to 

 take a mould of a bust all in one piece, clastic moulding 

 composition is required. The best substance of this 

 kind, and almost the only ono used, is composed of four 

 parts of best Russian glue and one part of treacle ; tho 

 glue is broken into small pieces, and soaked for one or 

 two hours, or until it is quite soft, in sullicient cold 

 water to cover it ; when it is soft tho superfluous water 

 is thrown away, and tho glue, together with the troaclf, 

 is heated in a common glue-pot, like ordinary glue, to 

 nearly a boiling heat, and stirred until tho two sub- 

 stances arc thoroughly mixed : the use of the treacle is 

 to prevent the mould drying and shrinking too rapidly. 



87. Blacklead, Phosphorus, Liquid, etc. For rendering 

 the surfaces of non-conducting substances, such as gutta- 

 percha, wax, marine glue, etc., conductible, the follow- 

 ing substances are used : 



1st. The common powder blacklead for ordinary non- 

 elastic moulds: there is the greatest difference, howc 

 between various specimens of blacklead in their valuo 

 for this purpose, some causing the deposit to spread 

 over the moulds very quickly, whilst others scat. 

 cause it to spread at all ; the best we have found, and it 

 has been very good, is "Dix's," sold in twopenny 

 packets, one or two of which will serve tho operator a 

 long time for this purpose. 



2nd. For moulds of elastic composition (86), the de- 

 positor will require tho following liquids, patented by 

 Mr. Alexander Parkos : A, tho phosphorus solution : 

 to make nearly three ounces of which, melt 64 grains of 

 bees-wax or tallow; then dissolve eight grains of india- 

 rubber cut up very small, in 160 grains of bisulphide of 

 carbon ; and when it is dissolved, add to it very carefully 

 (as it is highly inflammable) tho melted wax, and shako 

 the mixture thoroughly. Then dissolve 04 grains of 

 phosphorus in 960 grains (about 21 ounces) of bisulphide 

 of carbon, and add to it 80 grains of spirit of turpoiu 

 and i/l grains of asphalto in fine powder: when dis- 

 solved, add this solution to the previous ono of india- 

 rubber and wax, and thoroughly mix thorn by shaking. 

 B, tho silver solution : to make twenty ounces (one 

 pint) of this liquid, dissolve about 18 or 19 grains of 



