I often get asked what's the difference between upgrade gold (also known as tree gold or rack gold) plating and normal gold plating.
My last trip to Taiwan, I went sight seeing to all the different factories to see how the pen kits that I sell are made. The plating factory was one of the factory that I really wanted to see, so I could see for myself. I had the impression that I was big vats of boiling gold or chrome and it was more like a foundry with hot kilns in action. Attached are 2 photos of what I saw.
Rack gold plating is a more expensive plating because each individual item being plated is soldered onto a rack or rod (see photo above). As opposed to the tumbled plating method (where all the pieces are tumbled in a metal basket or cage) the rack gold plating method is a technique that ensures an even coat of the plating over the item. This ensures that no section of the item has a thinner layer of gold that is otherwise specified.
Rack gold is the standard method of plating gold in Taiwan. Factories in Taiwan is reluctant to use the tumble method of plating gold as it is seen as an inferior method of plating. The tumble method is however common practice in Mainland China where as the rack gold plating is much less practiced. The rod is then lowered into a solution and an electric current then is passed through the rod to attract plating (see photo below).
The rod is then washed and plated with an epoxy coating. It is then is washed again and passed through an industrial drier to harden the plate (see photo above).