THE MEANING OF ROLLED PLATE, GOLD FILLED AND SOLID GOLD
(Address by George G. Wheeler, Superintendent of W. & S. Blackinton Co., North Attleboro, Mass., before convention of Illinois Jewelers' Association, La Salle and Peru, Ill., May 19-21, 1913)
A Clear Cut Explanation Of Some Of The Forms Of Metal Stock Used In The Manufacture Of Jewelry
By George G. Wheeler
HOW ROLLED PLATE IS MADE
The purpose of this paper is to explain in simple language the difference between "rolled plate, goldfilled" and solid gold, by describing what each of these terms means. There is no intention of devoting any time to historical matters and the dates of discoveries and the names of discoverers of processes will be omitted. Jewelers may or may not be interested in history, but they are interested in practical matters concerning their trade.
"Rolled plate" is to many a misleading term. To those who understand it nothing could be plainer; but to one who has neither seen the process nor heard it clearly described it means comparatively little. Perhaps we can describe it so that its meaning will be apparent to all.
"Rolled plate" is made by soldering a sheet of alloyed gold to a bar of metal, of which copper is the principal constituent. The ingot thus made is rolled down to any desired gauge for use in the manufacture of jewelry and works of art. The rolling process gives rolled plate its name, but- in reality very poorly describes it.
The making of rolled plate is an exact science. It is always made or "plated" at a certain definite quality. So carefully is this figured out, that when an ingot is rolled down to, say 3 per cent, of its original thickness in the bar, it will assay the same percentage of gold that was plated to begin with.
Let us imagine we are making an ingot of rolled plate while the process is being described. In the first place, we need a high degree of skill, for a plater soon finds that the utmost pains and ingenuity are indispensable if he is to turn out perfect stock.
First the gold must be alloyed, melted and rolled to the required thickness. Rolled plate is ordinarily made of either 12-karat or 10-karat gold, although occasionally a higher karat is used for some special purpose. Let us make, for example, an ingot of 12-karat one-tenth stock. The gold nine parts of composition, or plater's metal, and one part of 12-karat gold. The plater must weigh his bar of composition and divide it by nine in order to find what his gold must weigh. At first thought one would say divide by ten; but that is wrong, since there would then be ten parts of composition and one part of gold, making one-eleventh instead of one-tenth plate.
The sheet of gold and bar of composition are carefully prepared and clamped together with an extremely thin sheet of solder between them. The ingot is soldered off in a plating furnace and is then ready for rolling to any desired gauge.
The first rolling operation is called breaking down and requires rolling mills of great power. After annealing the stock is rolled to the finish gauge in rolls lapped to a mirror finish, suitable appliances being used to prevent rolling dust into the gold and also to avoid scratching and damaging the surface. The protection of this surface is the ceaseless task of the manufacturer of plated jewelry.
For some work, where both sides of the stock are exposed, double plate is required. The plater then solders a corresponding sheet of gold on to the back side of his ingot. It will be seen that in double plate the gold value is doubled and an ingot of one-tenth double has the value of an ingot of one-fifth single.
SEAMLESS WIRE
Seamless wire is made from rolled plate, by cutting out a disc, drawing this disc up into a cup-shaped form with the gold on the outside. This cup is again drawn down by successive operations until the result is a tube of rolled plate with one end closed. This is still further reduced in size and at the same time lengthened in rotary reducers, and finally drawn down into wire which has a shell of gold all around it without break or seam.
Before the process of making seamless wire was developed it was customary to tube up a strip of rolled plate, bring the edges together and solder them. After soldering the tube was drawn down into wire and was called "Soldered seam" wire. Sometimes the seam was not soldered and the stock was known as "open seam" wire. Nearly all manufacturers today use seamless wire, though a few hold to the older methods as being more desirable.
It is apparent that rolled plate has a definite value, based upon the karat of the gold and the proportion of gold to composition. Furthermore, the durability of an article made of rolled plate depends upon the thickness of the gold. But we must go still further on this line, for the thickness of the gold on a finished piece of jewelry also depends upon the gauge of the stock from which it is cut or stamped.
If a given article is made of one-tenth rolled plate, another article which requires stock of double the thickness would be made of one-twentieth, and so on. The practical manufacturer learns from experience just what quality he must use for a given gauge and figures his costs accordingly.
"GOLD FILLED"
With the hope that we have explained "rolled plate" with some degree of clearness let us take up the term "gold-filled." It is pretty generally acknowledged that this term was coined in the watch case industry, and was applied to stock made from two sheets of gold with a filler or stiffener of composition between them. It was certainly a good name, but the stock it described was nothing new. We have just described it; for it was nothing more nor less than double plate. The value of the name was soon recognized throughout the trade, and its application to any article having an outer shell of gold with an interior filling of composition was inevitable.
So general has the use of this term become, that today the method of applying the outer covering of gold is immaterial, so long as it is suitably applied and is of sufficient thickness to insure durability. The development of the electro-plating industry has made it possible to manufacture gold-filled articles with a great variety of beautiful finishes, ranging from Roman gold to dark green "antique" gold, and including rose gold, red gold, English finish, Colonial gold, sea green and even purple gold. These finishes are all made with various alloys of gold, and they have given to the jewelry industry an impetus which otherwise could never have been realized, owing to the beauty and variety of finishes obtainable.
THE ART OF ELECTRO-PLATING
It is taken for granted that the general principle of electro-plating is understood by all jewelers. In case there are some who do not understand it, let it be said that the gold to be applied is dissolved by chemical means, the work to be plated is suspended in the solution thus obtained, and the introduction of the electric current causes the gold to deposit upon the work by galvanic action.
There are other ways of making a gold-filled article. Besides making it from rolled plate or electro-plate, there is the process of fire-gilding, now little used, but once very common. Certain clever artisans have devised, or claim that they have a method of depositing a shell of gold upon a piece of jewelry and then fusing the gold to the article by heat. This process doubtless is capable of practical development, but is not used to any extent at this time.
The value of a gold-filled article, like a piece of rolled plate depends upon the amount of gold on it. A cheap electro-plated article has such a thin coating of gold that it is described in the trade as a "shade." No better term could be used to describe it. On the other hand we see plenty of higher priced goods that have a coating of gold of sufficient thickness to leave a perfect, unbroken shell, if the interior metal is eaten out by acid, thereby proving the value of an article beyond dispute. This distinction cannot be too strongly emphasized, for too frequently we hear the remark, "Why, I can buy those same goods of so and so for half that price." Do not be deceived in this matter. Take one of the cheap ones and one of the more expensive ones and make the test. Then, and then only, will you realize the difference.
One would hardly expect to find any chance for argument in describing "solid gold." And yet there are few subjects offering greater opportunity for discussion. Strictly speaking, solid gold would naturally mean pure gold. Well, practically all the gold used in the arts comes from Uncle Sam's Assay office and it is not pure. Government gold averages about 997 one-thousandths fine, or about 99 7/10 per cent. pure. Some commercial refiners offer for sale chemically pure gold, but it costs more than the government price and is seldom used.
ALLOYS OF GOLD
Fine gold, the stuff we are all after, is known in the arts as 24-karat gold. It is a very soft metal, totally unfit for use; even the United States Mint has to alloy the gold used for coinage, and gold coins are somewhere around 22-karat, the value being computed accordingly. Jewelry made of fine gold would be of no practical value, and could not be satisfactorily finished. Consequently, the practical jeweler alloys his gold down to a point where it becomes a durable metal, and anything better than 18-karat is rarely heard of. It may be well to explain in passing that 18-karat gold contains 18 parts of fine gold and six parts of alloy. Twelve-karat gold contains equal parts of gold and alloy. The stated karat denotes that a certain number of twenty-fourths of the article are fine gold and the remaining twenty-fourths are alloy.
Since gold is alloyed of necessity in order to make it workable and durable, it has come to be the usual practice to speak of articles made of alloyed gold as "solid gold." Certainly no harm can come from this practice, so long as it is perfectly understood. Of course the higher the karat, the higher the price, and a customer may suit his purse, knowing full well that a 10-karat article will save him much money on his purchase, and one of 18-karat will have the added intrinsic value resulting from the increased proportion of fine gold used. These are generalities, but they can hardly be ignored in treating this subject.
WHAT IS "SOLID GOLD"?
It seems perfectly fair and entirely honest to call an article "solid gold" provided it is of sufficient fineness to withstand the acid test, and avoid tarnishing in use. This point is held to be reached at 10-karat, and in this country 10-karat jewelry is honestly considered solid gold.
In Canada and in England 9-karat gold has official recognition, but we believe that 10-karat is as low an alloy as should receive the sanction of the jewelry trade. At the same time we believe that a 10-karat article is of such high merit that it is honestly entitled to be called "solid," and answers every requirement of beauty, durability and intrinsic value. The higher karats remain for those who seek the very best and have the means wherewith to pay for it.
In conclusion we are led to say what every jeweler will sooner or later attest; a low price is an indisputable evidence of inferiority. Rolled plate is worth the cost of the gold in it; gold-filled jewelry is worth more or less according to the coating of gold upon it; and solid gold is worth just what its fineness indicates it contains of the precious metal. From constantly dealing in jewelry in a common-place way, we overlook the fact that it is supposed to have gold in it or on it. We must be careful about making extravagant claims as to the value of articles that are sold so cheap that gold is an impossibility in their makeup. The laborer is worthy of his hire and the law says he must come first. Pay the price and you will get the goods. Your customers will get them in turn and they will be worth what you charge for them.
Source: The Metal Industry - June 1913
Trev.
The Meaning of Rolled Plate, Gold Filled and Solid Gold
Re: The Meaning of Rolled Plate, Gold Filled and Solid Gold
Standard British Trade Definitions
Adopted by the BIRMINGHAM JEWELLERS' & SILVERSMITHS' ASSOCIATION (Rolled Gold, Gilt and Imitation Jewelry Manufacturers' Trade Section), 27 Frederick Street, Birmingham, England.
GOLD FRONTED Goods the fronts of which are made from a sheet of gold, which can be separated (by running the solder where necessary), and the front portion is then all gold.
ROLLED GOLD GOLD PLATE ROLLED GOLD PLATE A sheet of gold sweated or soldered to a thicker sheet or bar of base metal, and the whole rolled down together.
In the case of wire the definition shall be that of the whole of the bar of base metal is surrounded with gold, sweated or soldered on, and the whole drawn down together. This is known in the Optical Trade as "Gold Filled."
The test recommended is that the goods if annealed and pickled will show a surface of gold.
The same definition applies to all these terms, but the term "Rolled Gold" is recommended.
GOLD FILLED A term chiefly used by the makers of spectacle frames and other optical goods, and watch cases, and should be confined to the manufacture of these and similar goods, such as cigarette cases, sovereign purses, etc.
A sheet of base metal covered both sides with sheets of gold sweated or soldered on.
In the case of wire the same definition applies as that of rolled gold wire.
GOLD SHELL An article of base metal completely cased in gold by any process, so that if cut through (so as to expose the base metal) and immersed in acid until all the base metal is dissolved, a shell of gold is left.
GOLD CASED An electro-deposit of gold on base metal which must stand the pure nitric-acid test.
GILT A deposit of gold on base metal by chemical or electrodeposition process.
FIRE GILT OR MERCURIAL GILT Articles covered with gold dissolved in mercury which are put into the fire to burn out the mercury.
It must be clearly understood that the whole of the foregoing terms apply only to goods the base metals in which are non-ferrous. Where any ferrous metals are used, it must be distinctly stated in description, such as "Gilt on Iron." No other terms than those defined above should be used.
Imported articles corresponding with any or all of the foregoing descriptions, offered for sale should be made to comply in all respects with these descriptions.
These Standard Trade Definitions have been approved and adopted by:
The Birmingham Jewellers' and Silversmiths' Association.
The London Wholesale Jewellers' and Allied Trades' Association.
The National Association of Goldsmiths.
Source: The Metal Industry - April 1922
Trev.
Adopted by the BIRMINGHAM JEWELLERS' & SILVERSMITHS' ASSOCIATION (Rolled Gold, Gilt and Imitation Jewelry Manufacturers' Trade Section), 27 Frederick Street, Birmingham, England.
GOLD FRONTED Goods the fronts of which are made from a sheet of gold, which can be separated (by running the solder where necessary), and the front portion is then all gold.
ROLLED GOLD GOLD PLATE ROLLED GOLD PLATE A sheet of gold sweated or soldered to a thicker sheet or bar of base metal, and the whole rolled down together.
In the case of wire the definition shall be that of the whole of the bar of base metal is surrounded with gold, sweated or soldered on, and the whole drawn down together. This is known in the Optical Trade as "Gold Filled."
The test recommended is that the goods if annealed and pickled will show a surface of gold.
The same definition applies to all these terms, but the term "Rolled Gold" is recommended.
GOLD FILLED A term chiefly used by the makers of spectacle frames and other optical goods, and watch cases, and should be confined to the manufacture of these and similar goods, such as cigarette cases, sovereign purses, etc.
A sheet of base metal covered both sides with sheets of gold sweated or soldered on.
In the case of wire the same definition applies as that of rolled gold wire.
GOLD SHELL An article of base metal completely cased in gold by any process, so that if cut through (so as to expose the base metal) and immersed in acid until all the base metal is dissolved, a shell of gold is left.
GOLD CASED An electro-deposit of gold on base metal which must stand the pure nitric-acid test.
GILT A deposit of gold on base metal by chemical or electrodeposition process.
FIRE GILT OR MERCURIAL GILT Articles covered with gold dissolved in mercury which are put into the fire to burn out the mercury.
It must be clearly understood that the whole of the foregoing terms apply only to goods the base metals in which are non-ferrous. Where any ferrous metals are used, it must be distinctly stated in description, such as "Gilt on Iron." No other terms than those defined above should be used.
Imported articles corresponding with any or all of the foregoing descriptions, offered for sale should be made to comply in all respects with these descriptions.
These Standard Trade Definitions have been approved and adopted by:
The Birmingham Jewellers' and Silversmiths' Association.
The London Wholesale Jewellers' and Allied Trades' Association.
The National Association of Goldsmiths.
Source: The Metal Industry - April 1922
Trev.
Re: The Meaning of Rolled Plate, Gold Filled and Solid Gold
"Rolled Gold" as the term best fitted to describe articles composed of one or two plates of solid gold, with a metal filling between, has received the official sanction of the National Association of Goldsmiths of Great Britain. The subject was brought up at the twenty-first annual conference in London, when, after a long discussion, it was decided unanimously that "gold rolled" was not the term most acceptable to the trade.
Source: The Brass World - October 1915
Trev.
Source: The Brass World - October 1915
Trev.