part II
.—Copper 35 parts Zinc 56.5 parts Nickel 8.5 parts
III.—German silver 5 parts Zinc 5 parts
Compositions I and II have analogous properties. In composition III “German silver” is to be considered as a mixture of copper, zinc, and nickel, for which reason it is necessary to know the exact composition of the German silver to be used. Otherwise it is advisable to experiment first with small quantities in order to ascertain how much zinc is to be added. The proper proportion of German silver to zinc is reached when the mixture reveals a brilliancy and condition which renders it possible to barely pulverize it while hot. A small quantity when brought in contact with the soldering iron should just fuse.
«Hard German-Silver or Steel Solder.»—
I.—Copper 35 parts Zinc 56.5 parts Nickel 9.5 parts
II.—Copper 38 parts Zinc 50 parts Nickel 12 parts
Composition I requires a fairly high temperature in order to be melted. Composition II requires a blow pipe.
«GOLD SOLDERS:»
«Hard Solder for Gold.»—The hard solder or gold solder which the jeweler frequently requires for the execution of various works, not only serves for soldering gold ware, but is also often employed for soldering fine steel goods, such as spectacles, etc. Fine gold is only used for soldering articles of platinum. The stronger the alloy of the gold, the more fusible must be the solder. Generally the gold solder is a composition of gold, silver, and copper. If it is to be very easily fusible, a little zinc may be added, but, on the other hand, even the copper is sometimes left out and a mixture consisting only of gold and silver (e. g., equal parts of both) is used. The shade of the solder also requires attention, which must be regulated by varying proportions of silver and copper, so that it may be as nearly as possible the same as that of the gold to be soldered.
I.—For 24-carat gold: Twenty-two parts gold (24 carat), 2 parts silver, and 1 part copper; refractory.
II.—For 18-carat gold: Nine parts gold (18 carat), 2 parts silver, and 1 part copper; refractory.
III.—For 16-carat gold: Twenty-four parts gold (16 carat), 10 parts silver, and 8 parts copper; refractory.
IV.—For 14-carat gold: Three parts gold (14 carat), 2 parts silver, and 1 part copper; more fusible.
V.—Gold solder for alloys containing smaller quantities of gold is composed {662} of 8 parts gold, 10.5 parts silver, and 5.5 parts copper, or,
VI.—Ten parts gold (13.5 carat), 5 parts silver, and 1 part zinc.
VII.—The following easily fusible solder is used for ordinary gold articles: Two parts gold, 9 parts silver, 1 part copper, and 1 part zinc. Articles soldered with this solder cannot be subjected to the usual process of coloring the gold, as the solder would become black.
VIII.—A refractory enamel solder for articles made of 20-carat and finer gold, which can bear the high temperature required in enameling, consists of 37 parts gold and 9 parts silver, or 16 parts gold (18 carat), 3 parts silver, and 1 part copper.
Which of these compositions should be employed depends upon the degree of the fusibility of the enamel to be applied. If it is very difficult of fusion only the first named can be used; otherwise it may happen that during the melting on of the enamel the soldering spots are so strongly heated that the solder itself melts. For ordinary articles, as a rule, only readily fusible enamels are employed, and consequently the readily fusible enameling solder may here be made use of. Soldering with the latter is readily accomplished with the aid of the soldering pipe. Although the more hardly fusible gold solders may also be melted by the use of the ordinary soldering pipe, the employment of a special small blowing apparatus is recommended on account of the resulting ease and rapidity of the work.
«SOLDERS FOR GLASS.»
I.—Melt tin, and add to the melted mass enough copper, with constant stirring, until the melted metal consists of 95 per cent of tin and 5 per cent of copper. In order to render the mixture more or less hard, add 1/2 to 1 per cent of zinc or lead.
II.—A compound of tin (95 parts) and zinc (5 parts) melts at 392° F., and can then be firmly united to glass. An alloy of 90 parts of tin and 10 parts of aluminum melts at 734° F., adheres, like the preceding, to glass, and is equally brilliant. With either of these alloys glass may be soldered as easily as metal, in two ways. In one, heat the pieces of glass in a furnace and rub a stick of soldering alloy over their surfaces. The alloy will melt, and can be easily spread by means of a roll of paper or a slip of aluminum. Press the pieces firmly together, and keep so until cool. In the other method a common soldering iron, or a rod of aluminum, is heated over a coal fire, a gas jet, or a flame supplied by petroleum. The hot iron is passed over the alloy and then over the pieces to be soldered, without the use of a dissolvent. Care should be taken that neither the soldering irons nor the glass be brought to a temperature above the melting point of the alloy, lest the latter should be oxidized, and prevented from adhering.
«HARD SOLDERS.»
Hard solders are distinguished as brass, German silver, copper, gold, silver, etc., according to the alloys used (see Brass Solders, Copper Solders, etc., for other hard solders).
The designation “hard solder” is used to distinguish it from the easily running and softer solder used by tinsmiths, and it applies solely to a composition that will not flow under a red heat. For the purposes of the jeweler solder may be classified according to its composition and purpose, into gold or silver solder, which means a solder consisting of an alloy of gold with silver, copper, tin, or zinc-like metal or an alloy of silver with copper, tin, or zinc-like metal. According to the uses, the solder is made hard or soft; thus in gold solders there is added a greater amount of silver, whereas for silver solders there is added more tin or zinc-like metal.
In the production of solder for the enameler’s use, that is for combining gold with gold, gold with silver, or gold with copper, which must be enameled afterwards, it is necessary always to keep in mind that no solder can be used effectually that contains any tin, zinc, zinc alloys, or tin or zinc-like metals in any great quantities, since it is these very metals that contribute to the cracking of the enamel. Yet it is not possible to do without such an addition entirely, otherwise the solder would not flow under the melting point of the precious metals themselves and we should be unable to effect a union of the parts. It is therefore absolutely necessary to confine these additions to the lowest possible percentage, so that only a trace is apparent. Moreover, care must be taken to use for enameling purposes no base alloy, because the tenacity or durability of the compound will be affected thereby; in other words, it must come up to the standard.
In hard soldering with borax, direct, several obstacles are encountered that make the process somewhat difficult. In {663} the first place the salt forms great bubbles in contact with the soldering iron, and easily scales away from the surface of the parts to be soldered. Besides this, the parts must be carefully cleaned each time prior to applying the salt. All these difficulties vanish if instead of borax we use its component parts, boric acid and sodium carbonate. The heat of the soldering iron acting on these causes them to combine in such a way as to produce an excellent flux, free from the difficulties mentioned.
«Composition of Various Hard Solders.»—Yellow solders for brass, bronze, copper, and iron:
I.—Sheet-brass chips, 5 parts, and zinc, 3 to 5 parts, easily fusible.
II.—Sheet brass chips, 3 parts, and zinc, 1 part; refractory.
III.—Sheet-brass chips, 7 parts, and zinc, 1 part; very refractory and firm.
Semi-white solders, containing tin and consequently harder:
I.—Sheet brass, 12 parts; zinc, 4 to 7 parts, and tin, 1 part.
II.—Copper, 16 parts; zinc, 16 parts, and tin, 1 part.
III.—Yellow solder, 20 to 30 parts, and tin, 1 part.
White solders:
I.—Sheet brass, 20 parts; zinc, 1 part, and tin, 4 parts.
II.—Copper, 3 parts; zinc, 1 part, and tin, 1 part.
«To Hard-Solder Parts Formerly Soldered with Tin Solder.»—To repair gold or silver articles which have been spoiled with tin solder proceed as follows: Heating the object carefully by means of a small spirit lamp, brush the tin off as much as possible with a chalk brush; place the article in a diluted solution of hydrochloric acid for about 8 to 10 hours, as required. If much tin remains, perhaps 12 hours may be necessary. Next withdraw it, rinse off and dry; whereupon it is carefully annealed and finally put in a pickle of dilute sulphuric acid, to remove the annealing film. When the article has been dipped, it may be hard soldered again.
«SILVER SOLDERS.»
Silver solder is cast in the form of ingots, which are hammered or rolled into thin sheets. From these small chips or “links,” as they are called, are cut off. The melted solder can also be poured, when slightly cooled, into a dry iron mortar and pulverized while still warm. The solder can also be filed and the filings used for soldering.
Silver solders are used not only for soldering silver objects, but also for soldering metals of which great resistance is expected. A distinction must be drawn between silver solder consisting either of copper and silver alone, and silver solder to which tin has been added.
«Very Hard Silver Solder for Fine Silverware.»—
I.—Copper 1 part Silver 4 parts Hard silver solder.
II.—Copper 1 part Silver 20 parts Brass 9 parts
III.—Copper 2 parts Silver 28 parts Brass 10 parts Soft silver solder.
IV.—Silver 2 parts Brass 1 part
V .—Silver 3 parts Copper 2 parts Zinc 1