Liver of Sulfur Oxidizing Technique
For Silver Or Copper
While bright silver and copper are sometimes desirable, a more subtle finish looks terrific, especially with stones. Forced tarnishing, or oxidization of metal is a good way to create a nice antique finish.
Hard boiled eggs can be used for oxidizing, but the method does take time to complete. An alternate to using hard boiled eggs is Liver of Sulfur, a chemical compound. Liver of Sulfur (LoS) works very quickly, and I've found it leaves a more even finish than hard boiled eggs; however, LoS requires additional safety measures:
- Use in well-ventilated room or outdoors
- Take proper eye and skin safety precautions: goggles, gloves are recommended
- Containers and tongs used with Liver of Sulfur should not be used for any other purpose
- Store all materials out of reach of children
- Call poison control or 911 if ingested
LoS is available through several online jewelry suppliers, including Rio Grande, Thunderbird Supply Company, and Jatayu. Local rock and mineral stores may carry it as well. An 8oz supply runs about $15 (US) and will make many batches of solution.
Because the fumes from LoS are very strong, work outside or in a well-ventilated room. Use a glass or ceramic bowl or jar (I use an old canning jar) that will be used EXCLUSIVELY for LoS work. The mixture is 1 1/2 cups hot water (not boiling) to a pea-sized chunk of LoS.
Drop the LoS into the hot water and stir gently with a tongs, bamboo skewer or chopstick until dissolved. Dip piece to be oxidized in the solution; it will take a few seconds, but it will turn a greyish-black to black color. Using the tongs, skewer or chopsticks, remove item from the LoS and plunge into a cool water bath or rinse well with cool water. Your piece is now completely oxidized.
Remove topical tarnish from exposed surfaces by one of several methods:
- Fine grade steel wool (000) followed by polishing cloth
- Polishing cloth only
- Tumble, followed by polishing cloth if necessary
I have found that especially with copper, additional polishing is needed even after using a polishing cloth. I use a toothbrush with a mild baking soda and water paste or very small amounts of tarnish remover (you don't want to remove the tarnish in the recesses of your work!) and rinse well with clear water. The exposed metal will have a dull patina and recessed areas will be black. This is a great look, making details pop and accentuating the color of stones!
When I am making jewelry, I put anything to be oxidized in a separate bag after completion. Because LoS doesn't store all that well (it tends to break down in a short period of time), I make a fresh batch when I have several pieces to oxidize.
Note: Most stones will withstand the oxidation process — be cautious with polymer clay and porous stones, such as opals and pearls. Test first if you are not sure how it will affect your stones. If you are making jewelry with pieces that you do not want oxidized, or with components that will not hold up well to the process, oxidize prior to assembly.
