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topic 9370

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


(2001)

Q. Greetings from a jewelry salesman who has received conflicting information from his watch manufacturers concerning the pros and cons of gold electroplating, gold-fill, and PVD treatments on watch cases.

What are the general processes of each treatment? Can electro-plating achieve 20 microns; or is 17 to 19 microns with PVD the best finishing available? Which achieves the "most durable" finish? And what are the cost comparisons for mass production, generally?

Mark C [last name deleted for privacy by Editor]
- Seattle, Washington, USA


Sometimes readers try to follow along who aren't familiar with all of the lingo & concepts discussed. We'll try to make this page more accessible by explaining some things that Mark didn't need to ask, so Neil didn't need to tell him :-)

Tutorial: The main reason that production volume is such an important issue has to do with the cost of the equipment: While a jeweler can do gold electroplating with as little equipment as a small beaker and a power supply, so it's well suited to very short runs, PVD is a vacuum process that requires a fairly exotic machine that can cost several million dollars, and the rolling mills needed for gold filling are a factory-only process.

(2001)

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.

Neil Bell
Red Sky Plating

supporting advertiser
Albuquerque, New Mexico
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(2002)

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.

Mark Jarratt
- Kidderminster, Worcestershire, UK

Tutorial: While PVD machines can deposit gold, they can also deposit TiN (titanium nitride), a very hard material that looks a lot like gold in lieu of it, or ZrN (zirconium nitride), a material that looks like brass. Sometimes PVD machines are used to lay down a deliberately rough layer of TiN followed by a thin layer of gold so the TiN "mountain peaks" protect the gold in the "valleys" from wearing away.



(2003)

Q. Mark C was not completely addressed, so I am left wondering how durable are the different finishes? More specifically, how the Gold fill method stands in comparison to the new plating methods.

Rene A [last name deleted for privacy by Editor]
- Newport Beach, California, USA


(2003)

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.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



(2007)

RFQ: Very useful information. I am curious if a gold-plated item that is showing signs of wear can be re-plated? If so, any suggestions on companies that re-plate? Thanks.

Cathleen Candey
- St. Clair Shores, Michigan USA
outdated


(2007)

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.

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



(2005)

Q. I collect Dupont lighters. Dupont says 20 microns gold plate. Sounds really great! I wondered what that meant. I found out via this & other finishing sites on the web. I suspect some of these lighters are fake. Can ANY jeweler tell me the thickness of the gold plate (assuming it turns out to be gold)? What about Chinese Lacquer? What's with that? Dupont says it's a living plant. Any of you pros know anything about that stuff?

John Zerblis
- Conyers, Georgia, USA


(2005)

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

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2005)

thumbs up signMr 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.

John Zerblis [returning]
- Conyers, Georgia, USA



(2007)

Q. Hoping those who have inquired about S.T. Dupont Lighters are still reading these posts. After reading several articles containing various scientific terms that were beyond me (lol), I am under the impression that Micron Gold is a type of Gold not the plating. Is this correct?
As for the lighters, my S.T. Dupont has the 20 micron stamp which seems to be very rare. I have never seen a gold plated object that can be dented by the change in your pocket like the lighter. Also it seems that what's considered a pure gold S.T. Dupont would be unlikely as the working parts would wear out within days. My lighter is approx. (2.25" h, 1.25" w, .5" d) and weighs about 6 oz. when empty. I've been trying to identify this lighter for quite some time, so anyone that has any knowledge that relates to any of the above please feel free to throw your two cents in. All info will be appreciated.
Thanks

Aaron Abbott
- Arlington, Texas, U.S.


March 12, 2013

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,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



April 12, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hi,
I would like to know the differences between the term Galvanised Gold, gold plating and gold filled.
What should I ask a manufacturer who uses the term 'galvanised gold' - to define the amount of gold used, and its durability. The product in question is a ring.
Thanks

Bea South
buyer/hobbyist - Australia

April 13, 2013

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,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



July 4, 2015

Q. Dear Neil Bell,
That is interesting, Can you tell me the process of PVD in detail a bit. What type of machinery & Chemicals is required for this PVD process?? How quick is this process, if one wants to use it in jewelry manufacturing? Can this process be used for RHODIUM plating the finished jewelry?
Awaiting for your reply,
Best regards,

PRAKASH V PAI
- navi mumbai,maharashtra,india


July 21, 2015

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.

jim treglio portrait
Jim Treglio
- Vista, California



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