Gold electroplating vs. gold-filling vs. PVD treatments for jewelry and watch cases

A. Some of the watch companies are using very cutting edge technology to apply finishes to their products and the following info is general.

Cost comparison for various methods of getting a layer of gold onto a watch case depends on the design, the market, the quantity (thousands? millions?), the thickness desired etc. Very often a combination of processes are used by manufacturers. Durability of a layer of gold is dependent mostly on the thickness of the layer and is improved some by increasing the hardness.

Gold filled material is made by heat and pressure bonding a layer of gold alloy to brass and then rolling it into sheet or drawing it into wire to the required thickness. This material is identified with a ratio and a karat mark, such as 1/20 12K gold filled or GF. The ratio is by weight and the actual thickness of the gold layer depends on the thickness of the wire sheet. If your watch case is made out of 0.010" 1/20 12K gold filled sheet then the gold alloy layer is about 1/40 the total thickness because 12K gold is about twice the weight of brass. So the gold alloy thickness is about 0.00025" or 6.25 microns. 14K gold filled material has a thinner layer of gold because the gold alloy is heavier than 12K.

Gold electroplating is a process of passing an electric current through a gold plating solution to deposit a layer of gold on an object. There are a great many chemical formulas for gold plating solutions and each is designed to produce a specific alloy or color or hardness or thickness or a combination of these attributes. There is almost no limit to the thickness gold can be plated with the right solution and equipment so 20 microns or more can certainly be achieved.

PVD is physical vapor deposition and is a process in which atoms of metal (or molecules of material) are vaporized in a vacuum and condenses on an object. The deposits are typically very thin, in the range of a few angstroms.

I hope this helps.

A. Many watch case/strap manufacturers are moving away from depositing gold. ZrN or TiN offer the same effect for a fraction of the price. Plus ,these coatings are much more wear resistant than electroplated gold.

A. Hi Rene. Although we're naturally in a hurry to move on to your question, any reference to Neil Bell's super-informative response, which went way beyond the call of duty, must start with a hearty thank you :-)

He told us that the principal thing determining how long the gold will last is the thickness, and that plating CAN easily be 3x thicker than gold-filling, so plating can certainly outlast gold-filling. However, unless you know the thickness of the gold plating, you have no guarantee that it's even as thick as the gold-filling, let alone thicker -- and it probably isn't. High quality costume jewelry is sometimes called "micron gold", which means the gold plating is one micron thick (much less than 6.5 microns thick). And in my experience gold plating is often actually shamefully thin today: 1/4 to 1/3 microns -- just thick enough to look good on the counter; but you'll also see century old gold plated pocket watches :-)

Good luck.

A. Yes, gold plated items can certainly be re-plated, Cathleen. If you search our Jobshops link you will find shops that offer gold plating. Mr. Bell's company does gold plating, but some companies are only set up to offer their services to manufacturers, so you would need to inquire of him whether he can work with consumers.

A. Regarding the gold thickness: 20 microinches would probably be a typical gold plating thickness today . Since a micron is 39.4 microinches, the thickness you mention would be 40x thicker than much of today's stuff. The gold thickness can be measured quickly and easily with an X-Ray fluorescence machine, but most jewelers are unlikely to have one. It can be measured destructively by cutting a section and examining with a microscope (conceptually it's very simple, but actually doing a good job of cross-sectioning takes practice because it's easy to smear the metal).

Chinese lacquer probably has little to do with gold, although gold foils and other materials may be inlaid in it

Mr Mooney, Thank you for the response. Yes, the units are microns, from all that I can find. These lighters were/are extremely expensive. They were/are made in FRANCE. Some going back to the 60's & 70's. Those I believe to be authentic. The ones I buy today are the ones I wonder about. The 20 micron stamp is on only some of the older gold lighters. Some of the older gold ones do not have the stamp. I presume these were their bargain models. None of the newer lighters have this stamp. I assume that 20 micron plating went by the boards at some point in time.
Again, I thank you for allowing me to take up your valuable time.

A. Hi, Aaron. "Micron gold" is one of those phrases with a fluid interpretation because, as far as I know, there is no legal body regulating what it means. To most people, most of the time, I believe it means jewelry with a gold plating of about 1 micron thick -- in other words reasonable quality costume jewelry. Sterling silver jewelry that is gold plated -- as might be given to a girlfriend by a college student or older high school student -- might be an example of something that could appropriately have 1 micron thick gold plating.

Regards,

Hi Bea. We appended your inquiry to a thread which explains gold plating vs. gold filling. It's a big world, run more by salespeople than linguists, so "galvanized gold" probably has no real meaning; my bet is it's a euphemism they coined for "gold tone" and that there is no gold in it at all.

Regards,

A. PVD stands for physical vapor deposition. It is a vacuum deposition process, requiring a very expensive (~$1,000,000) piece of equipment, but very extensively used to manufacture semiconductors and coat metal cutting tools and decorative hardware (faucets, doors, car parts, and jewelry). While it is possible to use PVD to deposit gold and rhodium, the more common idea is to deposit hard coatings that look like gold and rhodium, but are less expensive to deposit and have vastly superior wear resistance. The wear life is so great that many companies offer lifetime warranties on their PVD finishes.