Most metals that are electroplated are ordinary, not to say boring, applications. When you have nickel-plated the hundred-thousandth tool and galvanized the one-millionth screw, very few surface coaters will jump for joy. The most exciting stories are to be found in precious metals.
The golden finger
The thriller "The Helsinki Conspiracy" by former Galvanotechnik editor-in-chief Heinz Käsinger is about a professor from Aalen whose gold-galvanized corpse leads to an exciting criminal caseWhen I was at vocational school, one of our teachers used to tell me that a former colleague of his electroplated one of his fingers when the James Bond film "Goldfinger" was released in 1964. Whether the story comes from the realm of galvanomysticism is impossible to say today, but it made our young eyes light up and showed one of the many extraordinary aspects of our profession. In 2020, the former editor-in-chief of Galvanotechnik, Heinz Käsinger, wrote the thriller "The Helsinki Conspiracy" [1]. The central theme was the electroplated gold-plated corpse of a professor.
Precious metals fascinate people, especially the eternally young gold. As an electroplater, you are confronted with the question of what you are actually doing for the rest of your life. Even during my training, I started using gold and silver plating as examples, even though I mainly did nickel and zinc plating. But when it comes to gold and silver, everyone has jewelry and other precious objects in mind. They not only have a timeless effect due to their chemical properties, but also culturally. The specific density alone creates the feeling of holding something very special in your hands.
The golden spider's web is a special challenge for the electroplater (Photo: Klaus Decker)
Gold on tungsten
In the 2010s, this gave me the idea, which never came to fruition, of making jewelry from tungsten, which would then be gold-plated. The idea was to create costume jewelry that felt as high-quality as possible and was also affordable. It wasn't until a few years later that I stumbled across the fact that gold-plating tungsten had been used for a long time, albeit as a scam. Given the almost identical density to gold, non-destructive proof was hardly possible for a long time, which is why some gold-plated tungsten bars ended up on the gold market in this way. Today, thanks to portable X-rays, proof is fortunately no longer a problem. A similar procedure is also postulated for the Baghdad battery. There is a theory that the battery, which is around 2000 years old, may have been used to gild silver coins - for the same reasons as the tungsten ingots [8].
Shoes, fruit and corpses
Art is the source of much more excitement than the frauds. A classic is the electroplating of first shoes - a fashion that emerged in the 1980s and was over a decade later [2]. Galvanic gilding and silver-plating of real plants, mainly roses, is still popular today [3, 4]. The electroplating of spider webs is truly exceptional. A suitable web must first be found, preferably in the corner of a room. It is then sprayed with clear varnish until the web is stable enough to be removed without damage. The rest follows the well-known laws of electroplating.
Silver electroplated children's shoes, here from the Leuze-Reichert family, are a popular souvenir of a child's childhood
The electroplating of organic objects is not new. The Technical Museum in Vienna has two extremely interesting exhibits, both dating from 1850: a pear and an apple that were silver-plated by the Christofle company (Paris). Research has shown that even today, the fruit still looks as if it has just been galvanized [5].
This silver-plated apple by the Parisian artist Christofle from 1850 is now on display in the Technical Museum in Vienna ...
... It was examined 160 years after electroplating. It was a completely gas-tight coating, so the apple is very well preserved under the silver layer. The core is clearly visible
The 19th century was a very experimental time in this respect anyway. As early as 1856, a Frenchman suggested galvanizing the dead as a substitute for embalming [6]. In 1887, the "Ann Arbor Courier" from Michigan/USA reported on a businessman who wanted to produce metal statues of the dead in order to preserve ancestors for centuries [7]. The idea lasted well into the 1930s, but was less successful in the long term than the galvanized first shoes.
A curious galvanoplasty that Leuze Verlag received on the occasion of its 100th anniversary in 2002 (Photo: Klaus Decker)
The golden car
DeLorean, model DMC 12, with a 24-carat gold-plated body, which was carried out in 1979 by the then Degussa (now Umicore) There are alsoconstantly fascinating projects in the field of precious metals in the inorganic sector. During my training, there was also repeated talk of the gold-plated DeLorean (model DMC 12) [8]. In 1979, American Express commissioned DeLorean Motor Cars Ltd. to produce a series of vehicles with a 24-carat gold coating for their Goldcard advertising campaign. The gold plating was carried out by Umicore (then Degussa) in cooperation with the company Karl Holder (now Holder GmbH Oberflächentechnik). In 1981, two gold DeLoreans were produced and offered in the American Express Christmas catalog. Today, these vehicles can be found in the Snyder National Bank in Texas and in the National Automobile Museum in Reno, Nevada. A third vehicle was later reassembled from spare parts after the DeLorean Motor Company went bankrupt. At the time, I was fascinated by the story, especially as I was a big fan of the "Back to the Future" films; today, it's more about the technology.
And so my personal highlight also has to do with a precious metal, namely silver and an underlying gold plating. It was a prototype for a stainless steel sealing ring that had a diameter of 1.2 meters and could only be silver-plated on the outermost edge. The coating had to meet the highest standards and we only had one trial. My task was to develop a suitable process technology and then to silver plate the ring with a small team using the tampon process. The attraction here was not even the sophisticated coating, but the intended use: the sealing ring was intended for ITER, the experimental nuclear fusion reactor in Saint-Paul-lez-Durance, France. For the first time, I was able to experience what it feels like to be a small part of a gigantic project.
Silver, mercury and gold
Gold-plated pacifier - there are no limits to the imagination when it comes to souvenirs when electroplating with precious metals (Photo: Klaus Decker)However, curiosities about coating techniques can also be found outside of electroplating, for example in the book "Neues einfachstes und vorteilhaftestes Verfahren der Vergoldung, Versilberung, Verplatinierung, Verkupferung und Zinnung, ohne Galvanismus und Apparate, durch blosses Eintauchen des zu vergolddenden Obstets in eine Flüssigkeit" (New simplest and most advantageous process of gold plating, silver plating, copper plating and tin plating, without electroplating and apparatus, by simply immersing the object to be gold-plated in a liquid) from 1845. The catchy title is a good indication of what the ninety-page book is about. Fans of occupational health and safety will particularly enjoy it. The book is not only interesting from a procedural point of view, but is also a treasure trove full of negative examples of employee training. One example on page 59: "Dissolve silver in nitric acid, soak old rags in it, dry them and burn them in a bowl, making sure that nothing is dispersed by draughts or in any other way. The silver is contained in metallic particles in the ash and is rubbed onto the object to be silver-plated using a cork dipped in salt water."
Today we can only smile wearily at this and possibly discuss whether this is even considered a "coating" according to current standards. Another very old process described in the book is fire gilding. Gold is first mixed with mercury to form a gold amalgam. This is applied to the surface - usually bronze, for example with a brush. After drying, the mercury is vaporized in an oven or with a gas burner. Due to the serious damage to health, this process has long been banned here - in France, for example, since around 1830. Nevertheless, there are still numerous videos on YouTube showing that this process is still used in some parts of the world today.
Take part!
Refined curiosities
Precious metals fascinate us in many ways - be it through their historical context, their versatile applications or innovative coating processes. We in the editorial team are convinced that our readers have many more exciting examples in store. Let us know your suggestions and we will turn them into another interesting article.
Literature
[1] The Helsinki Conspiracy; Heinz Käsinger; Eugen G. Leuze Verlag; ISBN 978-3-87480-366-3
[2] From the practice - for the practice 12/1985; copper plating of first shoes
[3] Gilding roses - How to gild roses; https://www.blumeideal.de/blog/rosen-vergolden
[4] OUR 60-STEP PROCESS; https://www.rosederewigkeit.de/60-schrittverfahren
[5] History[s] of electroplating; Galvanotechnik 01/2013; Eugen G. Leuze Verlag
[6] History of electroplating; 1959 edition; Eugen G. Leuze Verlag; ISBN 3-87480-077-6
[7] Bodies in metal; https://www.spiegel.de/wissenschaft/technik/tueftler-des-19-jahrhunderts-planten-galvanisierung-von-leichen-a-858401.html
[8] The battery of the Parthians; Eugen G. Leuze Verlag; ISBN 3-87480-206-X
