THE ALLOYING OF GOLD

Gold above 18-Karat Used Only for Special Order Work— Variegated Gold Work—Alloys for Yellow, Green and Red Gold—High Grade Stock for Enamel Work—Hard and Soft Alloys—Standard 10-Karat Formula—Copper Shot vs. Copper Wire.
/^~^ OLD of a quality better than 18-karat is seldom

used in the manufacture of jewelry, and then
only on special order work. The so-called variegated gold work, wherein is seen, say, a fancy bracelet, ornamented with green, yellow, red or blue (platinum) trimming, is made by cutting out the shapes and sweating them on to a plate of gold.
These little ornaments may be cut out in the foot press or shears, as desired, and are usually cut out of 20 stock, dial screw gauge, and soldered on a back of 40 stock. After soldering, of course using best grade of solder for this work, the plate is put in the drop press and a sharp blow flattens and gives a smooth, blended effect. The piece of stock is now ready to be shaped into any pattern desired. In leaf or flower work, where the petals or leaves are of one color gold, the edges only showing variegation, the stock is made by taking a plate of gold 600 points thick for the backing, and soldering on the green, yellow and red in strips 250 points thick, then rolling down to the desired thickness, 60 points being customary for leaf and small work. In order to break the straight line effect where one color is joined to the other, after rolling, little odd shapes or zigzag pellets of green, red or yellow gold are applied on the seam and soldered, a sharp blow under the drop hammer blending them in flush. Fine wires of platinum, used in "veining" leaves, are also applied in this way.
Years ago blue gold, an alloy of 18 parts gold and 6 of iron, was used in place of the platinum. This is, however, an extremely difficult alloy to avoid getting brittle and is best effected by first dipping fine iron wire in sulphuric acid and water to take off the black oxide or scale, or by drawing it through emery paper until it is bright. The gold is first melted under a good layer of charcoal powder, the iron wire carefully added a little at a time and poked well under the charcoal. The bar must be annealed and carefully hammered after pouring and before putting through the rolls.
Some houses use fine or 24-karat for yellow gold. A 22-karat made of 22 pennyweights fine gold, i$i penny-weights silver, and % pennyweight copper, shows up as well and is of course not quite so expensive. Green gold is made of various proportions of gold and silver, 19 pennyweights of gold to 5 of silver giving a very deep, rich green. For most purposes, however, an alloy of 17 pennyweights of fine gold to 7 pennyweights of silver is used. The red gold lasting the longest in lustre and presenting the best finish is made of 22 parts gold to 2 of best shot copper, but all proportions are used and an alloy of 14 parts gold to 10 of copper is frequently employed. The writer does not advise using less than 18-karat red gold or 18 parts gold to 6 of copper, as under some conditions the alloyed metal will turn black.
Houses making 14-karat jewelry use different qualities of stock for the backing. Some figure that a 12-karat back will average up the 22-karat, 18-karat, or 17-karat front, as the case may be, so that if goods were assayed the test would show 14-karat as per stamp. Others, to be on the safe side, use a plump 14-karat backing. Of course, there is the solder (usually about 12-karat) which must be reckoned with. However, as the varicolored front is seldom or never less than 17-karat for the green and 22-karat for the yellow, a backing of 12^-karats will assay 14-karat in most cases. A large manufacturer of 10-karat goods with green gold (18-karat) front uses a back stock of 8-karat and finds his scrap to stand the io-karat test.
An 18-karat alloy much used to-day in fine diamond work, is made of 18 parts gold, 4 parts silver and 2 of copper. This is a very rich yellow. To get a red, sim¬ply reverse the figures of the silver and copper. In the making of enamel work, certain jewelers, in order to reduce the danger of chipping or breaking of the enamel, have used high alloys of gold, in some instances even fine or pure gold, figuring that they are in pocket by eliminating the frequent cost of re-enameling. This, in the case of painted work or finely veined and shaded flower work, where probably the labor is mostly in the enameling and 'painting, is a practical move and is thoroughly com¬mended. On the other hand, there is a tendency some¬times on the part of the manufacturer to make every¬thing of the higher alloy for enamel goods, and here is where he is going to the bad. One concern, employing indifferent help, went behind considerably by indiscriminately using a 15-karat alloy for their enamel goods and stamping it 14-karat. The fact that it was figured as 15-karat simply caused the customer to wonder at the cost of the goods and to look elsewhere when buying.
An alloy of 14-karat for enameling, of 14 parts gold, 7 of silver and 3 of copper, is recommended for all plain work, and is used for painted flower work in some shops as well. For shell or die work, or for work requiring bending or shaping, a 14-karat polished alloy is made of 14 parts gold, 3 parts silver, 2 of copper and 5 of pale Guinea gold. This alloy needs melting only once, and the scrap should be added to a fresh alloy for remelting.
A tough alloy, excellent for knife edge, screw wire, or open work, is 14 parts gold, 4 of silver, and 6 of copper. This should be melted twice to thoroughly mix. A, very hard 14-karat alloy, suitable for bracelet snaps, pin tongue stem's or stiffening pieces, is, fine gold, 14 parts; silver, 4^ parts; copper and pale Guinea alloy, 2^ parts each; total, 24. Another used to-day is, 14 parts gold, with 5 parts each of silver and copper. A fine 14-karat green gold is made of fine gold 14 parts, silver 8*4 parts and copper i$4 parts or pennyweights, total, 24. There are also formulas furnished by refiners who sell a special green gold alloy.
There are a number of white gold alloys on the market ranging from 20-karat down. In the better karat qualities palladium was used, but this made an expensive alloy, so that after some experimenting an 18-karat white gold was made out of 18 parts fine gold, 4 parts pure nickel and 2 parts fine iron wire. This is a rich blue-white alloy closely resembling platinum, but is a little hard. Baker & Co., of Newark, N. J., are now supplying a white alloy which works up very well for all karat qualities and is ductile. The basis of all white gold alloys is simply a fine grade of german silver with a high percentage of nickel. In melting white gold alloys the gold is put in last and covered with boracic acid crystals. More heat must be applied than in ordinary gold alloys. When melted, stir well with carbon stick and pour at once, roll as soon as cooled to about two-thirds of the thickness, then anneal, and proceed as in regular alloys. The gold may be plunged while warm (not red hot) in sulphuric acid pickle to remove the black.
In using alloys furnished by the refiners and supply houses no other metal is used, so that 14-karat white gold is simply 14 pennyweights fine gold to 10 penny¬weights white gold alloy; 10-karat white gold, 10 parts fine gold and 14 parts white gold alloy, etc.
To get a fine white appearance after a piece of white gold jewelry is made up it must be stripped in the following solution before polishing:
Cyanide copper, \]/2 ounces by weight; ammonia, 26%, 4 ounces; carbonate soda, 4 ounces; cyanide potassium, 6 ounces; water, 1 gallon.
Solution may be cold or slightly warm and the cathode a sheet of soft copper, which should, to get best results, entirely surround the jar, although an ordinary carbon will do for small lots. Hang the work, after steel-brushing in bran water, on the positive wire and keep moving.
In a few moments the work will strip bright as silver and may be polished in the usual way. This "strip" is also excellent for all gold alloys.
A point to remember in the making of alloys is that the nearer the proportions the alloys approach one another the harder will be the alloy, so that if an equal amount of silver and copper be found to be too hard the alloy may be made softer by using less copper, adding the amount taken off to the silver.
In the matter of alloys, there are a number on the market: thus we read of red gold alloy, pale yellow, pale gold, Guinea gold and others. The writer has found these very useful where gold is first alloyed, melting only once. But where there is a quantity of scrap to be re-melted (and it is not desired to add fresh gold), the resultant melts, especially if in wire form, are hard and brittle and a fierce thing to get up against. This is undoubtedly due to the zinc or other volatile metals used in the making of these alloys, the repeated melting burning them out.
A very good io-karat alloy that works well for nearly all purposes and stands remelting by reason of the small quantity of alloy used, is, fine gold, 10 parts; silver, 3 parts; copper, 7 parts, and pale gold alloy, 4 parts. A very soft alloy for dies and stamping consists of, fine gold, 10 parts; silver, 2 parts; copper, 3 parts, and alloy, 9 parts. A io-karat green gold alloy is, fine gold, 10 pennyweights; silver, 11 pennyweights; copper, 3 penny¬weights. As in the case of the 14-karat green gold an alloy is also sold by refiners especially made for green gold. Another io-karat pale gold, used for half-pearl work and for enameling, is, fine gold, 10 parts; silver, 6 parts; copper, 2 parts, and alloy, 6 parts. This last has a tendency to get hard and cracky during remelting, and should always be mixed with a new melt.
Some jewelers prefer to use the purified shot copper for everything in which they use copper. Others use it in wire form, and there are still other manufacturers who insist that the shot is best for polished gold work, whilethe wire is the better for enamel work and for the making of solders.* The writer uses the wire for all alloys, finding that the solder flows better. Certainly the


*At this present moment it is impossible to get the copper wire (pure lake copper), so we melt the shot copper and roll it into wire, as we find that for certain fine wires it has a better grain.
form of copper that most readily blends with the gold, either for polished or enamel work, should be used. The only argument in favor of using shot copper is that it is not (within a fine point or two) quite so apt to melt when being soldered.