Editor’s Note: In our last article, we discussed why metal jewelry is plated. Calla Gold, a Santa Barbara jeweler specializing in custom jewelry design and jewelry repair, will talk about Gold Plating Best Practices in this article, and then explain How Gold Plating is Done, Step by Step in the next article.gold-plating, or electroplating, is the process of covering one metal with a thin layer of another (gold, in the case of gold-plating).
As we learned in the last article, plating is used to decorate objects, for corrosion inhibition, to improve solderability, to harden, to improve wearability, to reduce friction, to improve paint adhesion, to alter conductivity, to bring new life and ‘pizzazz’ to old gold and for other purposes.” Although not meant to deceive, gold-plated jewelry can fool some people into thinking a jewelry piece is solid gold, and there will be great disappointment if the pieces are being “cashed in for gold.” [A portable XRF analyzer is a nondestructive solution that can quickly measure the gold and precious metal content, distinguish between gold plating and solid gold, and determine the accurate karat (K) weight of gold jewelry.]
We’ll go over the gold plating steps in the next article, but to summarize the process…the item to be plated is immersed in a chemical solution containing the covering metal (for example gold), an electrical charge is applied, and by the process of electrolysis, the gold ions are transferred to the piece of jewelry. How long the jewelry is left in the solution determines the thickness of the plating.
To be a little more specific, the items to be plated are hung from a cathode bar, which is a pole with a negative electrical charge going through it. The pieces of jewelry connected to the cathode bar are also negatively charged. When the jewelry items are submerged in the tank the electricity is turned on and the negatively charged jewelry attracts the positively charged ions present in the solution. The positively charged metal ions are submersed in the liquid bath. When the cathode bar is lowered into the bath the metal jewelry gets plated. Different plating tanks are used to plate different karat amounts and different metal colors.
There are four basic best practices for the best plating results.
- Temperature control. Plating results are best when the temperature is kept at a constant high level, appropriate for the type of metal.
- Voltage control. Plating needs to occur at a certain voltage level, which must be tightly controlled. Different metals require different voltages.
- Liquid cleanliness. Plating baths should be constantly filtered to remove dirt and contaminants. When properly maintained, a plating bath can be used for years. After a number of years the plating water can be allowed to partially evaporate and the remaining unfilterable residue can be sent to a refinery to be further filtered. In this way plating services keep their workshops and chemical process as environmentally ethical as possible.
- Excellent ventilation. For the health of the plating professionals, there should be plenty of ventilation, and if possible, plating should be performed in a designated space. The U.S. EPA outlines electroplating emission factors in this document.
These four best practices will help ensure the integrity of the plating and help it last (as well as help keep everyone healthy). The plating on a ring typically wears off faster than on a pendant due to rubbing against the fingers and hand, and by coming into contact with what the hand is touching like soaps and lotions. A gold plated pendant would last longer than a gold plated ring before it had to be re-plated. But if you follow these best practices, you will get the most out of your plating treatment.
Editor’s Note: Watch for Calla’s next article: How Gold Plating is Done, Step by Step
About Calla Gold:
Calla Gold, owner of Calla Gold Jewelry, has been a Santa Barbara personal jeweler since 1983, specializing in custom wedding ring design, jewelry repair, ring resizing and antique jewelry restoration. Her motto is, “Wear it, don’t warehouse it!” Calla shares her tips and advice on the topic of jewelry regularly on her blog and social media. She is a contributor to MJSA (a leading resource in jewelry making and design). Calla Gold is a jeweler without walls, coming to your home and office by appointment or over distance on the Internet. For more information on Calla Gold Jewelry, visit http://www.callagold.com/.