How good is a five micron good plating on a watch?
salmonella
plate." Is this good, mediocre or bad, relatively speaking?
Salmonella Scripsit
SWG
A micron is a thousandth of a millimeter. In the days where brass was
the standard metal used for making most watch cases, the scale would go
from:
gilt (a flash of gold plating)
3 M GP
5 M GP
10 M GP*
20 M GP*
The first two steps were used for basic cheap watches, average priced
watches used to have 5 M and the branded quality watches used the
latter two, which could be certified by an official stamp.
Less used was the other method of rolled gold, which could reach higher
thicknesses, used especially for bracelets.
The thickness is not the only indication of quality. The gold grade
used is also very important: normally the total thickness should have a
gold content of 75% = 18 ct, to prevent oxydation. Also the methodology
is very important, starting from the preparation of the surface to be
gold plated, the composition of the gold bath, temperature, timing of
the operation, etc.
Richard Lueck
@d71g2000cwd.googlegroups.com:
Thanks for the info, I found it very interesting. So, where does gold-
filled fit into this?
SWG
I feel that in checking and perusing the following sites, you can
acquire quite a precise knowledge about electro-plating and rollgold
(goldfilled):
quote from:
http://www.artisanplating.com/articles/goldfilled.html#comparison
"introduction to gold filled applications
The joining of a base metal with an outer layer of gold has played an
important commercial role in the jewelry industry and their related
trades for over 150 years. Commonly referred to as "gold filled" this
process is also known in the industry as "rolled gold", "gold overlay",
or "metal cladding". The process for creating gold filled sheet stock,
wire and hollow tubing was developed by the industry to help reduce
costs for jewelry and houseware items without sacrificing their
perceived beauty, durability, and long term wear. Gold filled materials
are heavily utilized for watch cases, cigarette cases, mid-priced high
fashion jewelry, and numerous other decorative items.
One of the many advantages of gold filled materials is that the gauge
of the decorative gold sheet can be adjusted to any thickness, karat
purity and color. In addition, important working characteristics such
as formability, strength, and rigidity can be easily modified by using
a different base metal (i.e. mild steel or bronze) without changing the
surface beauty of the object."
The History of Electroplating
>From Mary Bellis,Your Guide to Inventors.
Luigi Brugnatelli invented electroplating in 1805.
Italian chemist, Luigi Brugnatelli invented electroplating in 1805.
Brugnatelli performed electrodeposition of gold using the Voltaic Pile,
discovered by his college Allessandro Volta in 1800. Luigi
Brugnatelli's work was rebuffed by the dictator Napoleon Bonaparte,
which caused Brugnatelli to suppress any further publication of his
work.
However, Luigi Brugnatelli did write about electroplating in the
Belgian Journal of Physics and Chemistry, "I have lately gilt in a
complete manner two large silver medals, by bringing them into
communication by means of a steel wire, with a negative pole of a
voltaic pile, and keeping them one after the other immersed in
ammoniuret of gold newly made and well saturated".
John Wright
Forty years later, John Wright of Birmingham, England discovered that
potassium cyanide was a suitable electrolyte for gold and silver
electroplating. According to the Birmingham Jewellery Quarter, "It was
a Birmingham doctor, John Wright, who first showed that items could be
electroplated by immersing them in a tank of silver held in solution,
through which an electric current was passed."
The Elkingtons
Others inventors were also carrying on similar work. Several patents
for electroplating processes were issued in 1840. However, cousins
Henry and George Richard Elkington patented the electroplating process
first. It should be noted that the Elkington's bought the patent rights
to John Wright's process. The Elkington's held a monopoly on
electroplating for many years due to their patent for an inexpensive
method of electroplating.
In 1857, the next new wonder in economical jewelry arrived called
electroplating - when the process was first applied to costume jewelry.
Electroplating: how it works:
http://www.finishing.com/faqs/howworks.html
Electroplating Wikipedia: http://en.wikipedia.org/wiki/Electroplating
Goldplating Wikipedia: http://en.wikipedia.org/wiki/Gold_plating
Now, in many instances gold plating and goldfiled have been replaced by
PVD (Physical Vapour Deposition) which offers many advantages, e.g.
oxydation, resistance to abrasion, increased adherence especially on
stainless steel, etc:
http://www.pvd-coatings.co.uk/
Balzers "ion plating" offers e.g. the possibilty of depositing very
stable very thin layers of material onto sapphire crystals
http://www.balzers.com/bhq/eng/01-products-services/03-coating-technology/06-ionplating/indexW3DnavidW261.php
many more informatin are available on the net!
Tony Stanford
wrote
>I just bought a watch that is labeled , "Trim is five micron gold
>plate." Is this good, mediocre or bad, relatively speaking?
>
>Salmonella Scripsit
>
was once told that so far as a watch is concerned, you could count on 1
micron per year of gold plate being rubbed off by friction against long
shirt sleeves (if worn).
I don't know if it's true, and no doubt member of the group will provide
the specialist knowledge. But a colleague bought a 5 micron gold plated
Seiko, and sure enough, 5 years later, you could see the underlying
white metal coming through in many places.
--
Tony Stanford
SWG
Tony Stanford wrote:
> I don't know anything about the technicalities of gold plating, but I
> was once told that so far as a watch is concerned, you could count on 1
> micron per year of gold plate being rubbed off by friction against long
> shirt sleeves (if worn).
>
> I don't know if it's true, and no doubt member of the group will provide
> the specialist knowledge. But a colleague bought a 5 micron gold plated
> Seiko, and sure enough, 5 years later, you could see the underlying
> white metal coming through in many places.
> --
> Tony Stanford
Fair enough assessment.
Richard Sexton
salmonella <salmon...@yahoo.com> wrote:
>I just bought a watch that is labeled , "Trim is five micron gold
>plate." Is this good, mediocre or bad, relatively speaking?
Uh, don't breathe on it too hard.
--
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