Liver of Sulfur 101: What Is It, How to Use It to Create Patina on Silver and Copper Jewelry
Whenever I teach hand-finishing jewelry workshops and we get towards the end of the class, I mix up a small solution of liver of sulfur, and someone always asks “What’s that stinky stuff?”
Well, to me, it’s the stuff that gives my silver jewelry designs so much character. It’s a patina that sinks into the recesses of metal textures and shows nice contrast when I remove it and polish it off the high areas. It’s what gives my silver jewelry soul. Do I like the smell of it? NO WAY! But do I like the results? ABSOLUTELY!
What is Liver of Sulfur?
Liver of sulfur (LOS) is a potassium sulfide. It brings out the textural details in metal jewelry and can be used to make the pieces look antiqued. It is most commonly referred to as oxidizing, though that term is used erroneously, but just go with it—it’s got way too much stuff to do with chemistry to go into here. Most jewelers just call it oxidizing.
It gives gorgeous results on silver and copper; I find it a bit more difficult to get a good patina on brass, and it has no effect on gold. Colors achieved with liver of sulfur can range from a golden yellow to dark gray/black. You control this with your application of the patina.
It comes in several forms: liquid, lump, and gel form. For years I used the lump form, and it works fine, but I have found the gel form much easier, with the same or even better results. My personal least favorite is the liquid form, and this is because when used in a classroom setting, students use way too much and it gets wasted. Plus, I don’t think it lasts as long or is effective as long as the other two forms. I have found that many people, even when using the lump form, make way too much solution. You only need the size of half of a green pea and about a quarter cup of water to make a good solution.
Liver of sulfur will deteriorate in sunlight, so if you make up a batch, keep it tightly covered and in a dark, cool place. Also, keep it away from tools and other acids, like pickle.
Liver of Sulfur Prep
First, the metal needs some “tooth.” A textured or lightly sanded finish works best. Liver of sulfur will work on a polished surface, but a surface finished with rouge to a high polish may take several applications and a lot of patience. A slight tooth, even with the 9- or 15-grit 3M Finishing Films, will work. The piece must be very clean, so I scrub it with a paste of pumice and water and then rinse it. Then I don’t touch the part I wish to patina. Also, get a #5 soft, round, medium-priced watercolor brush. No need to mess up a real pricey brush, but neither do you want to leave brush hairs all over your jewelry. That’s a really unfashionable look. Use the brush only for your liver of sulfur treatments. Also use rubber gloves, and try not to breathe the “stinky stuff.” Safety glasses are a must. You don’t want this “stinky stuff” in your eyes. And keep away from food!
Liver of Sulfur Application Techniques
There are as many opinions of how to apply LOS as there are jewelry artists. Basically, it’s whatever works for you—it’s not rocket science. Experiment, but here are some pointers.
Application depends on your desired finish. If you want a yellowish-colored silver, dissolve a tiny piece of LOS, either lump or gel, in a small glass container of cold water. As you apply the solution, it will go through stages of colors, from yellow to magenta to purple to dark blue. These changes can happen rapidly, so watch carefully. You may add a tiny bit of ammonia and a drop of liquid Dawn detergent to sometimes get more vivid colors. The addition of an everyday iron tablet (yep just like the vitamin) can give you a rich blue. When you get to the color you want, dip the piece immediately into cold water. That will help “set” the color.
Another application process is to run hot water over the piece and then either dip it into a small glass container of LOS or use the paintbrush to paint it on where you want it. This will give you a gray to black finish.
Finishing After Applying Liver of Sulfur
To finish the process I use a soft brass brush (not the one you clean your BBQ grill with!) and Dawn detergent (isn’t this stuff wonderful!), which acts as a lubricant, to brush vigorously over the entire piece. This will even out the finish (and also give a gunmetal look on silver jewelry that I find extremely attractive). If I want to remove more, I use a polishing cloth or a flex shaft with a muslin buff and some Zam or rouge. Sometimes I use three or four pink 3M bristle discs (what I call spiders—who can say “3M radial bristle discs” in class all the time?) stacked on a mandrel with a flex shaft on the areas I want highlighted. A light finishing film or a green kitchen scrubby with a little pumice and Dawn detergent will work too. An old kitchen scrubby that is not so stiff works best. (Just don’t use it for cleaning pots and pans after using it for LOS! Yuck!)
Now keeping the color can be another matter. Here in Colorado this unprotected finish can last longer than it will in a humid or metropolitan area. But a light spraying with Krylon Low-Odor Clear Finish, available at most art supply stores, or even hairspray will work for a while, but it will wear off. Nikolas Lacquer has proven to work well but may need to be reapplied after several years wear. You could also use a clear powder coat, which may last forever. The powder-coated stuff I have has lasted for at least three years now. It’s a bit more pricey.
Anyway, have fun, experiment, and if you don’t like the results, liver of sulfur can be removed by placing the item in warm pickle for a few hours, by sanding, with pink pumice spiders, or heating with a torch. Then you can start all over and try it again. Nothing teaches like experience! Whatever you do, have fun and be safe.
You can learn more from Lexi Erickson when you subscribe to Lapidary Journal Jewelry Artist, where she is a contributing editor and frequently writes about silver jewelry-making topics like soldering, hand-finishing jewelry, jewelry design, and more. Her gorgeous silver jewelry is often featured in (and on the cover of!) the magazine.
Nikolas Lacquer: Finish1.com or Allcraft Tools 800-645-7124
Brass brushes: Allcraft Tools 800-645-7124