Gold Plating Problems with Jewelry, How to make gold plating last longer? PVD?

Hi Geno. Peeling is more often related to poor preparation than the thickness of the plating. It is possible to do 40 microns thick (for electroforms for example), but "nobody" does gold plating that thick. The world's most expensive watches have plating of 7-20 microns; vermeil is 2-1/2 microns; and good quality costume jewelry is 1 micron.

Regards,

A. Hi, We are 20 years in Gold plating. We were plating 10 micron / 5 micron hard gold plating, (even duplex coat of 18 kt followed by 23.5 kt hard gold) for watch parts. As the gold cost shot up over the years, the thickness specs gradually came down to 1 micron hard gold followed by clear EP coat of about 8 microns (no orange peel/drip marks).

Presently it is 0.5 micron of TiN PVD followed by 0.1 micron of gold PVD in the same PVD machine. We have been successful in EP coat on top of the PVD coats by which we are able to guarantee gold plating of watch parts, pen parts, Imitation jewellery, temple decorations etc., and make it LAST and NOT LOST!

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Ed. note: We assume that in this context EP stands for electro-phoretic, i.e., electrocoating.

Hi. Congratulations on reducing your use of gold by a factor of 100X while simultaneously improving the durability of the jewelry! However, I need to quibble because what you are guaranteeing is a "TiN based gold-ish tone/look"; you are clearly not guaranteeing the "gold plating" if you have only 10¢ worth of gold on it :-)

Regards,

Hello A. I don't think I agree at all with your assessment of this thread nor your conclusions about how other people produce and protect their gold-tone finishes.

Jim Teglio and others have told us that most gold-tone faucets don't use any gold -- just titanium nitride (TiN) Physical Deposition (PVD) coatings; and that good watches use TiN PVD coatings plus a little gold which wears off over time but still looks enough like gold. I believe them, and assume that "gold hand railings at a casino" are either TiN, solid brass, or brass plated -- not gold plated. TiN isn't a clearcoat, it's a nitride which looks like gold, but is much harder than gold and much much harder and more scratch resistant than a clearcoat.

Unfortunately, this brings the practical problem that small jewelry designers often can't apply that technology because it requires million dollar PVD vacuum chambers which is too capital intensive for them. Small jewelers are limited to such products as waxes like Renaissance, single-component clearcoats like Everbrite and ProtectaClear, 2-component coatings like automotive clearcoats, e-coatings like Kliar, and UV-hardened clearcoats such as are applied in manicure salons. These options would quickly be gone, rather than widely sold and widely used, if there actually was a secret formula "baked on clearcoat" which is manifestly better, and cannot be scratched (but baking does improve some of the mentioned clearcoats).

There is still another approach, but it is probably economically prohibitive: really heavy gold plating. Some gold plated pocket watches have lasted a century without any clearcoat at all. But gold of high thickness is generally considered cost-prohibitive these days. Good luck.

Regards,

Hi Jonathan. Fortunately, that one is easy :-)

A micron (µ or µm or micrometer) is one millionth of a meter, but a mil is one thousandth of an inch. So a mil is 25.4 microns, and a micron is 0.0394 mils.

Multiply mils by 25.4 to get microns; multiply microns by 0.0394 to get mils.

But be wary, because a small number of people will always try to mislead us for their personal gain, and they have apparently now invented the abbreviation "mills" for millionths of an inch so they can talk nonsense like "heavy 10 mill gold plating", which is actually only 1/100th of a mil :-)

Regards,

A. Hi Allison,

You can test for e-coating using the ohms range of an electric multimeter. Put the prods on the item to be tested. If there is no coating, you will get a very low resistance reading. If the item is coated, the resistance will be near infinity. If the meter has sharp pointed prods (they usually do) there is a danger the ends of the prods will push through the coating and give a false reading. So, use the sides of the prods or better still remove the points and grind a smooth, gentle radius on the ends.

I would introduce further quality controls.

1) check that the coating is sufficiently thick so as not produce iridescence (like oil an water)
2) do a solvent rub test (acetone or methyl ethyl ketone) to check that the coating is well cured
3) do a pencil hardness test, another test of mainly curing

If any of these tests are of interest to you I would be happy to provide more details of the procedures.

Harry

Gold test kit

on eBay or

Amazon

(affil links)

A. Hi Helen. Gold CAN be deposited by PVD techniques but it isn't customary because gold electroplating is far less capital intensive. Yes, one micron gold plating can be used on good quality costume jewelry.

It is possible to check the thickness of the gold plating with X-Ray fluorescence thickness testing machines, but they are by no means cheap (say $30K and up). Testing the karat is supposedly possible with inexpensive acid test kits, but I think this is destructive testing and cannot be done on clearcoated items.

Regards,

⇦this on eBay or Amazon [affil links] patented that sequence years ago for their watches. I'm not sure if they plated the gold or deposited it by PVD as well as the TiN PVD layer, so I don't know whether it is possible to gold plate the PVD coating. The more common method is to skip the gold layer and just apply a PVD coating that looks like gold.

Hi Nicole. For the 50 years that I've been in the plating industry a "mil" meant one thing: a thousandth of an inch, i.e., 25.4 microns --

www.dictionary.com: "... a unit of length equal to 0.001 of an inch ..."
www.merriam-webster.com: "... a unit of length equal to 0.001 of an inch ..."
www.thefreedictionary.com: "... a unit of length equal to 0.001 of an inch ..."
www.oxforddictionaries.com: "One thousandth of an inch ... Origin late 17th century from Latin millesimum 'thousandth', from mille 'thousand"

Lately, jewelry platers have been using "mil" or "mill" to mean a millionth of an inch, i.e., one thousand times thinner; sometimes they add an extra 'l', 'mill', perhaps for plausible deniability about their attempt to obfuscate :-)

So 6 of their "mills" is only .15 microns, and 20 of their "mills" is about 1/2 micron (1 micron used to be considered good quality costume jewelry; vermeil is 2-1/2 microns, and top quality plating on super premium watches is probably about 7 microns). What that means to you as a buyer is that the gold is only there for color and won't last a day without a clearcoat, so you must find a shop whose clearcoat doesn't peel. Whether the actual gold value is 1¢ vs. 4¢ shouldn't be much of a concern on $25-$185 jewelry.

Regards,

Hi Jeffrey. Thanks for continuing to do great quality gold plating. I think there are few people like you anymore :-)

Regards,