Hier geht es zum Deutschen Beitrag
Christmas Ornaments have been around for almost 500 years. Hans Greier, a German, invented them. Originally, they were glass shapes of nuts and fruit that were hung up together with tin figurines. The technique of mirroring hadn’t been discovered yet and only came into use about 300 – 400 years ago.
This is technique also known as the Tollen’s Reagent.
These days most Christmas baubles are fashioned from plastic and shine because of a metallic lacquer layer. This is obviously much easier and more inexpensive than the mirroring of glass baubles.
How does galvanic mirroring work?
The Ball: It doesn’t matter if it was crafted by hand or mass manufactured. What counts is that it is completely clean. The best way to achieve this is to treat the ball in chromic-sulfuric acid for 24 hours. If it doesn’t properly wet after rinsing, the process must be repeated until it does.
First Solution: This one carries the silver salt, an ammoniacal solution of silver nitrate.
Dissolve 5 g of silver-nitrate (AgNo3) into 100 ml of water. Put about 1/3 of the solution to the side as reserve for later. Proceed with the larger part of the solution.
Using a burette, drip concentrated ammonia into the solution. The first few drops will cause the solution to turn yellow brown. Soon however, it will become chocolate brown, and after that clear up.
For this purpose, the solution needs to be light yellow brown. To achieve this, drip another 2 ml of ammonia into it to clear it up. Pick up the reserve solution and add it to the main solution until you can see sediment forming. This, again, gets cleared by dripping ammonia into it. Proceed with these steps until all the reserve solution is used up. The last step should be the addition of silver nitrate solution to leave some crystals floating inside the medium. The solution has a slight yellow brown coloration after all steps have been followed correctly.
Use distilled water to fill up the solution to 500 ml.
The solution may be decanted into a dark, tightly closing bottle. The rest of the turbidity can fall out in this vessel.
Second solution: This one causes the reduction of silver unto the glass surface.
Dissolve 0,9 g Potassium Sodium Tartrate (Seignette salt) into a little bit of water, infuse it with 500 ml scalding hot water and cook it up.
Dissolve 1,1 g AgNo3 into a little bit of water inside a test tube. Add it to the seignette salt solution. It’s gonna take on a brownish hue which is changes into a greyish green sediment.
The mirroring: Mix the two solutions in equal parts. The mirroring solution needs to be moved heavily during the process of reduction. After a few minutes black flakes start sedimenting and a thin layer of blueish shimmering silver forms on the glass. When the solution becomes opaque, it needs to be replaced with a new batch. This process must be repeated until the silver layer is satisfactory. Afterwards rinse very well and dry without heat exposure.