March 13, 2011

Oxidizing Sterling Silver: A Multitude of Methods

Call me crazy, but I adore the look of oxidized silver. There’s something very romantic and organic about aged silver, not to mention that you never have to worry about polishing it!

What do I mean by oxidized? Oxidation is the dark coloration that forms on silver over time, also known as tarnish. It is caused by a chemical reaction between the metal and chemicals in the environment. Usually, oxidation occurs over time and is something that people generally try to prevent or correct by polishing silver to a high sheen. However, the antiqued look of oxidized silver can be very attractive in a jewelry application (not so sure I’d want to eat off of oxidized silverware, though).

Since I hadn’t really worked with sterling silver until I decided to create my own craft business, I had never really thought about oxidizing it on purpose. When I finally realized what I had been missing out on, I searched and searched to find different techniques for hand oxidizing. There are several different methods (it is only a chemical reaction, after all), but I never really found one good place that compared the most popular ones. I’m going to try to do that now!

Liver of Sulfur (LOS)
This is the most common method of oxidizing sterling silver. LOS is a potent chemical used by jewelers to create the dark patina on silver. It can be used to achieve several different shades of oxidization. I haven’t tried this yet for a few reasons: it is a hazardous chemical making it expensive to ship and it has a short shelf life. Since I’m just experimenting at this point, I don't really want to invest in something that goes bad quickly! However, if you simply search for “oxidizing silver”, this will be the most common method you will find. I think it is considered the industry standard, so I know it will work. If I don’t find any of the other methods to be adequate, I will probably go with LOS.

LOS comes in several different forms such as pellets, premixed liquid, and a gel. It generally needs to be diluted in warm water before applying to your silver.

Lime Sulfur
While reading forums about using LOS, I noted a few posts that mentioned lime sulfur, which is a chemical used in gardening for pest control on plants. This chemical has a longer shelf life than LOS, is a bit more economical ,and is easy to find in a local hardware store or garden center.

Lime sulfur comes in a liquid form. The information that I found said to dilute a few drops of lime sulphur in a larger portion of hot water, then soak the silver.

Hard Boiled Egg
There are tons of tutorials out there for oxidizing silver with a boiled egg. I tried this method with a few headpins and earwires. I boiled a large egg (it had been in the fridge for a while), broke up the yolk and placed it in a plastic container with some findings. According to the tutorial I read, I should have noticed some oxidation after five or so minutes, but I had nothing after 10. Bummer. I thought my yolk cooled off too much, so I heated it up (without the silver!) in the microwave and placed it back in with the silver. Ten more minutes passed and my findings were merely eggy. Then I thought that maybe I just didn’t have enough yolk to do the job, so I boiled up another egg (a little fresher than the previous egg) and added it to the container. After another 10 minutes I still had nothing. What the heck? Everything I had read said that it works great, takes a bit longer to achieve a black patina, but you should be able to see oxidation after a little while. Maybe my container isn’t airtight, I thought. So I switched everything out to a ziplock bag and forgot about it until the next day.

Disappointment. I noticed just a very small amount of very light uneven oxidation after a full 24 hours and stinky eggs. It just didn’t work for me this time, but I do plan to try this again because I would rather oxidize my silver without having to use harsh (and toxic, I might add) chemicals. Unfortunately I did not take any photos of my findings after this process, but I will the next time I try this method.

Household Bleach
I found very little information about using this method, but it does seem to work. I tried oxidizing a ring I don't wear anymore in straight bleach, and it oxidized to a nice dark black. I’ve read in a few other places to make a 50/50 bleach/water solution as a straight bleach solution may damage the metal.

Next time I’ll post the photos from my experiment with lime sulfur.

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