Part 427

III.—Fine gold, 1.555 parts; fine silver, 0.65 parts; and pure copper, 0.324 parts.

«SOLDER FOR IRON:»

See also under Silver Solders.

Copper, 67 parts; zinc, 33 parts; or, copper, 60 parts; zinc, 40 parts.

«TIN SOLDERS:»

See also Soft Solders.

Gold jewelry which has been rendered unsightly by tin solder may be freed from tin entirely by dipping the article for a few minutes into the following solution and then brushing off the tin: Pulverize 2 parts of green vitriol and 1 part of saltpeter and boil in a cast-iron pot with 10 parts of water until the larger part of the latter has evaporated. The crystals forming upon cooling are dissolved in hydrochloric acid (8 parts of hydrochloric acid to 1 part of crystals). If the articles in question have to be left in the liquid for some time, it is well to dilute it with 3 or 4 parts of water. The tin solder is dissolved by this solution without attacking or damaging the article in the least.

«VARIOUS RECIPES FOR SOLDERING:»

«To Conceal Soldering.»—Visible soldering may be obviated by the following methods: For copper goods a concentrated solution of blue vitriol is prepared and applied to the places by means of an iron rod or iron wire. The thickness of {666} the layer may be increased by a repetition of the process. In order to give the places thus coppered the appearance of the others, use a saturated solution of zinc vitriol, 1 part, and blue vitriol, 2 parts, and finish rubbing with a piece of zinc. By sprinkling on gold powder and subsequently polishing, the color is rendered deeper. In the case of gold articles the places are first coppered over, then covered with a thin layer of fish glue, after which bronze filings are thrown on. When the glue is dry rub off quickly to produce a fine polish. The places can, of course, also be electro-gilt, whereby a greater uniformity of the shade is obtained. In silver objects, the soldering seams, etc., are likewise coppered in the above-described manner; next they are rubbed with a brush dipped into silver powder and freshly polished.

«Solder for Articles which will not Bear a High Temperature.»—Take powdered copper, the precipitate of a solution of the sulphate by means of zinc, and mix it with concentrated sulphuric acid. According to the degree of hardness required, take from 20 to 30 or 36 parts of copper. Add, while constantly shaking, 70 parts of quicksilver, and when the amalgam is complete, wash with warm water to remove the acid; then allow it to cool. In 10 or 12 hours the composition will be hard enough to scratch tin. For use, warm it until it reaches the consistency of wax, and spread it where needed. When cold it will adhere with great tenacity.

«Soldering a Ring Containing a Jewel.»—I.—Fill a small crucible with wet sand and bury the part with the jewel in the sand. Now solder with soft gold solder, holding the crucible in the hand. The stone will remain uninjured.

II.—Take tissue paper, tear it into strips about 3 inches in width, and make them into ropes; wet them thoroughly and wrap the stone in them, passing around the stone and through the ring until the center of the latter is slightly more than half filled with paper, closely wound around. Now fix on charcoal, permitting the stone to protrude over the edge of the charcoal, and solder rapidly. The paper will not only protect the stone, but also prevent oxidation of the portion of the ring which is covered.

«Soldering without Heat.»—For soldering objects without heating, take a large copper wire filed to a point; dip into soldering water and rub the parts to be soldered. Then heat the copper wire and apply the solder, which melts on contact. It may then be applied to the desired spot without heating the object.

«COLD SOLDERING:»

See also Adhesives and Cements.

For soldering articles which cannot stand a high temperature, the following process may be employed:

I.—Take powdered copper precipitated from a solution of sulphate by means of zinc and mix it in a cast-iron or porcelain mortar with concentrated sulphuric acid. The number of parts of copper varies according to the degree of hardness which it is wished to obtain. Next add, stirring constantly, 70 parts of mercury, and when the amalgam is finished, allow to cool. At the end of 10 to 12 hours the composition is sufficiently hard. For use, heat until it acquires the consistency of wax. Apply to the surface. When cool it will adhere with great tenacity.

II.—Crush and mix 6 parts of sulphur, 6 parts of white lead, and 1 part of borax. Make a rather thick cement of this powder by triturating it with sulphuric acid. The paste is spread on the surfaces to be welded, and the articles pressed firmly together. In 6 or 7 days the soldering is so strong that the two pieces cannot be separated, even by striking them with a hammer.

«Cast-Iron Soldering.»—A new process consists in decarbonizing the surfaces of the cast iron to be soldered, the molten hard solder being at the same time brought into contact with the red-hot metallic surfaces. The admission of air, however, should be carefully guarded against. First pickle the surfaces of the pieces to be soldered, as usual, with acid and fasten the two pieces together. The place to be soldered is now covered with a metallic oxygen compound and any one of the customary fluxes and heated until red hot. The preparation best suited for this purpose is a paste made by intimately mingling together cuprous oxide and borax. The latter melts in soldering and protects the pickled surfaces as well as the cuprous oxide from oxidation through the action of the air. During the heating the cuprous oxide imparts its oxygen to the carbon contained in the cast iron and burns it. Metallic copper separates in fine subdivision. Now apply hard solder to the place to be united, which in melting forms an alloy with the eliminated copper, the alloy combining with the decarburized surfaces of the cast iron. {667}

«Soldering Block.»—This name is given to a very useful support for hard soldering and can be readily made. The ingredients are: Charcoal, asbestos, and plaster of Paris. These are powdered in equal parts, made into a thick paste with water, and poured into a suitable mold. Thus a sort of thick plate is obtained. When this mass has dried it is removed from the mold and a very thin cork plate is affixed on one surface by means of thin glue. The mission of this plate is to receive the points of the wire clamps with which the articles to be soldered are attached to the soldering block, the asbestos not affording sufficient hold for them.

SOLDERS FOR JEWELERS: See Jewelers’ Formulas.

SOLDER FROM GOLD, TO REMOVE: See Gold.

«SOLDERING PASTE.»

The semi-liquid mass termed soldering paste is produced by mixing zinc chloride solution or that of ammonia-zinc chloride with starch paste. For preparing this composition, ordinary potato starch is made with water into a milky liquid, the latter is heated to a boil with constant stirring, and enough of this mass, which becomes gelatinous after cooling, is added to the above-mentioned solutions as to cause a liquid resembling thin syrup to result. The use of all zinc preparations for soldering presents the drawback that vapors of a strongly acid odor are generated by the heat of the soldering iron, but this evil is offset by the extraordinary convenience afforded when working with these preparations. It is not necessary to subject the places to be soldered to any special cleaning or preparation. All that is required is to coat them with the soldering medium, to apply the solder to the seam, etc., and to wipe the places with a sponge or moistened rag after the solder has cooled. Since the solder adheres readily with the use of these substances, a skillful workman can soon reach such perfection that he has no, or very little, subsequent polishing to do on the soldering seams.

«Soft Soldering Paste.»—Small articles of any metals that would be very delicate to solder with a stick of solder, especially where parts fit into another and only require a little solder to hold them together, can best be joined with a soldering paste. This paste contains the solder and flux combined, and is easily applied to seams, or a little applied before the parts are put together. The soldering flame will cause the tin in the paste to amalgamate quickly. The paste is made out of starch paste mixed with a solution of chloride of tin to the consistency of syrup.

SOLUTIONS, PERCENTAGE: See Tables.

SOOTHING SYRUP: See Pain Killers.

SOUP HERB EXTRACT: See Condiments.