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.

HINTS ON MELTING

How to Obtain Clean, Smooth Ingots—Crucibles Must be Warmed—Placing the Ingredients—Use of Sal Ammoniac and Charcoal—Importance of Thorough Mixing—Casting the Ingot—Location of Melting Room— A "Kink" in Wire Coiling—Silver Melting.
I
T is just as easy to get a good, clean, smooth ingot of gold or silver as it is a bar that is full of holes, grooves or blisters. The poor "melts" are gotten by indifferent or careless workmen, who figure that the sub¬sequent rolling will smooth out everything. As a matter of fact, where the bar is uneven the thinner spots simply stretch, and after rolling to a certain thickness, your plate is full of seams, or cracks and holes, necessitating a cutting out of these portions for remelting. This, of course, is double work and a useless waste of crucibles and gas, to say nothing of the time. Then again the melter may not have a technical knowledge of the principles of melting and is simply following some formula furnished him, or that he has acquired, or he has drifted into the melting room by force of circumstances. To those manufacturers and melters who have met with varying results, the writer proposes to give some little "kinks."
All crucibles, whether sand or black lead, should be first warmed before putting in the metal for melting. The alloy should be put in first, then the copper, then silver, and lastly the gold. The reasons for this are, first, that the alloy and the copper melt first, and secondly, they are protected by the silver and gold from contact with the gases of the furnace, thus greatly eliminating oxides from being formed. Sal ammoniac and powdered charcoal are the agents used to neutralize the gases that form in the crucible, the charcoal acting as a coating cover and the sal ammoniac to purify the alloy while in a molten state. The official melter of the United States assay office at New York uses powdered sal ammoniac and a very fine powder of charcoal which he obtains from the collections on the beams of his melt¬ing room. The powdered sal ammoniac is probably bought fresh often, hence is as good as the lump form. For the average jeweler the lump is better, as the strength remains in longer, a little piece being broken off and pulverized as needed. For charcoal the powdered willow, purchased from leading drug stores, is as good as any. Berge, of New York (the crucible manufacturer), handles a charcoal powder which is very good, but under a good stiff flame blows out of the furnace to a great extent and is wasted. It is also a trifle more expensive than the willow charcoal.
The sal ammoniac should be mixed with the charcoal in about equal proportions and enough should be put on top of the gold to cover well before placing in the fur¬nace. Have flame just show through the cover, starting rather scant and increasing the force just as metal is melting. Add a little more of the sal ammoniac and charcoal. When the gold begins to sink to the bottom of the crucible, showing that the other metals are melted, it should be gently pressed down with an iron rod. Some¬times the gold, especially if it is in plate form, will stick for some time as a sort of roof before finally dropping of its own accord into the molten mass in the crucible. As soon as it is melted, which is ascertained by inserting an iron rod or poker, the mass is well stirred.
If a crucible cover, in addition to the furnace cover, is not used, it is well to add a little more of the sal ammoniac and charcoal, stirring just before pouring.
Right here the writer wishes to emphasize the necessity of thoroughly mixing the melts. The old-time melters swear by the rolling down of the stock and cutting up of same and remelting to get a perfect alloy. This method undoubtedly helps, but is slow, involving as it does a double melting. Stir the liquid mass well, two or three times, or even more, keeping it well covered with charcoal. First stir to the right, then rapidly to the left, and then pour rapidly into your plate or wire ingot. In case of 18-karat gold do not pour too hot; let the crucible commence to show a dull, almost blackish-red be¬fore pouring. The 14-karat alloys and lower should be poured as quickly as possible to prevent the base metals from oxidizing by contact with the air. Just before pouring some melters blow in a pinch of saltpetre, placed in the end of a long brass tube. This clears up the surface of the molten metal and perhaps helps a little in getting a cleaner ingot.
Within the last four or five years, and since the first edition was printed, there have come into use a number of green gold alloys in 14-karat and 10-karat, and as the principal alloy used is silver, the melt must be held as in pouring the 18-karat.
The ingot should be well warmed and just moistened with oil to prevent the gold from sticking. Avoid an excess of oil, as it will cause holes or fissures in your bar. In getting bars for wire the writer recommends the open wire ingot. The bar should be well hammered, with annealings frequently to prevent cracks. In 18-karat do not anneal until you have given the gold two or three very heavy drafts in rolls to close the grain. This applies also to all other soft alloys, whether wire or plate. In melting spring gold or hard alloys for snaps, pin tongues, etc., where the base metals added are of nearly the same weight, the ingot bar or plate must first be annealed and allowed to cool off slowly before rolling. Do not hammer any hard alloys, but in rolling force the drafts, do not "baby" the stock. This starts a good grain in the metal.
The farther away or the better protected the melting room is from drafts or windows, the better will be the general results. The adding of saltpetre is very hard on the crucibles and is hardly worth while in the long run.
An old pair of canvas gloves will be found handy in facilitating the handling of the furnace cover, ingots, etc.
In rolling wire it may be interesting to the beginner to know that a close, even coil is obtained for annealing, or for convenience in putting in gold box, by pulling the end of wire back over the top roll. When the wire has all passed through, an even coil of about the diameter of the roll is the result. It is surprising that a number of melters to-day who have been in the business for years have not gotten on to this little "stunt" and are still bending the long strip into a coil by hand, getting an uneven coil and risking burning or melting the projecting strands in the subsequent annealing.
Silver is melted and poured pretty much like 18-karat gold. The points to remember are, that it should not be poured any hotter than is necessary and that it should be well stirred with an iron poker. Borax or boracic acid crystals are used in place of sal ammoniac; keep extra well covered with charcoal, add a little more borax as soon as silver is melted. Poke or shove the borax under the charcoal with a long, narrow pair of tongs. The ingot should be just hot enough to permit of the finger touching it for a moment. In annealing after rolling, do not get too bright a red heat, as this will cause air blisters, condemning many a good bar that un¬til then had been all right.