#Dueber coin pocket watch serial number how to

While this process produced a thicker layer of gold than electro-plating, the gold content was still no more than 5-10% of the total case weight. The gold layers could consist of 10-karat, 14-karat or 18-karat gold. The composite 3-layer bar was then rolled through high-pressure rolling mills until the desired thickness was reached. The 3 bars were soldered together under high pressure and high temperature in specially constructed ovens. Gold-filled cases were made by sandwiching together 2 bars of gold (typically about 1/2' thick) on either side of a bar of base-metal, usually brass or brass-alloy (typically 3/4' thick). After Keystone achieved success with gold-filled cases, many other case manufacturers began producing gold-filled cases. Boss' watch cases were the first widely adopted and commercially successful gold-filled watch cases, and are still commonly found on vintage watches today. Although James Boss certainly didn't invent the process of making rolled gold plate, Keystone 'J. James Boss, an early partner in the company that was to become the Keystone Watch Case Company, is credited with the development of the gold-filled watch case which was patented in 1859. Below are examples of markings on solid-gold watch cases. A good jeweler or goldsmith should be able to acid-test your case for gold-purity. Markings on the case are sometimes ambiguous, and counterfeit or 'upgraded' assay marks, while certainly not common, are known to exist. Proper case-marks are usually a good indication of gold-content, but gold-testing is advised if you want to be sure. If a watch case is solid-gold it will usually be hallmarked or stamped with a karat symbol or assay mark, like 'WARRANTED U.S. Most solid-gold watch cases sold in the USA were 10K - 14K (41.6% and 58.3%, respectively). Gold coins are about 22K (91.6%), and the highest purity typically found in jewelry or watch cases is 18K (75%) which was fashionable in Europe. The purity of gold is expressed as a fraction of 'pure' 24 karat gold, so if something is marked as 12-karat gold, that means it is 12/24ths or 50% gold. Gold must be mixed or 'alloyed' with other metals to make it hard enough to be usable. Pure gold (100%) with no other metals added is called 24-karat, but pure gold would be much too soft to be useful as a metal for making watch cases. Solid-gold means the case is gold all the way through. It's important to understand the difference between 'solid-gold' and 'pure gold'. So if you have a vintage watch that's housed in a solid-gold case, consider yourself lucky! But there were some beautiful, solid-gold cases made over the years and some of them have survived intact. These days, solid-gold cases have become even more scarce because so many of the large gold cases have been sold or melted-down for their gold-value (a practice we abhor and discourage, by the way).

in fact, it is estimated that only about 5% of cases produced were solid gold. There were far more gold-filled cases made than solid-gold 'karat cases'. If your vintage pocket watch is in a gold-colored case, odds are pretty good that your case is gold-plated or gold-filled, or even just gold-colored metal. What metals were commonly used to make watch cases? Is every gold-colored case watch case made of gold? Are all silver-colored watch cases made of silver? Answers to these and many other questions about watch case materials can be found below.

#Dueber coin pocket watch serial number how to

Pocketwatch 101 в„ вЂ“ Learn about Vintage and Antique Pocket Watches Materials Used to Make Vintage Watch Cases How to tell if your vintage watch case is gold or gold-plated?