Patina Reviewed & Removed

14-988z & aa w & w out Patina sm

Other than shown with and without patina, the two Wolf Pendants on the left are the same, as are the two on the right. I love patina. It seems the more I patina, the more I like it. I even like silver pieces that have been patinaed black with none of it removed. I’m such a patina snob that when I see metal-clay creations that are not patinaed, I think they are not finished. I mean, how can someone like that? See what I mean?

There are numerous kinds of patina. Some, like Liver of Sulfur, are slow to tarnish silver. Some, like Black Max, are fast. Did I say tarnish? Yes, I said tarnish. That is what a patina agent does: it tarnishes silver. Oxidize is another word for tarnish. If you look up the process of tarnishing you will most often find the explanation to read as follows. "The copper in sterling silver (7.5% copper) reacts to oxygen and sulfur in the air, causing the sterling silver to tarnish.” If this were true, then fine silver would not tarnish, would it, because it is 99.9% silver. Wrong. Fine silver tarnishes also. Even Argentium Silver with less than 7.5% copper tarnishes, just at a much slower rate. So sterling, Argentium, and fine silver tarnish, along with other metals, each at their own rate.

Silver tarnishes faster and thus more in environments with high humidity and air pollution. This is why some pieces in your studio or jewelry box can go months looking good then one day, they all need polishing.  

When silver (Ag) or other metals combine with ambient sulfur (H2S) and oxygen (O2), silver sulfide (Ag2S) and water (H2O) result.
Silver sulfide (Ag
2S) is black. Oxidation simply means the addition of oxygen.

4 Ag + 2 H2S + O2 —> 2Ag2S + 2 H2O

Tarnish then is a thin layer of oxidation or corrosion that forms on the surface of silver, copper, brass, aluminum, magnesium, and other similar metals as their outermost layer undergoes a chemical reaction. 

From this point forward, all discussion is about silver, ignoring the three hundred or more ways to patina and color other metals.

Manufacturers have discovered different ways to add black, brown, green, and more colors to silver. For black, Black Max and a new product called JAX are fast and efficient. Both of these also come in brown and green colorations.

Liver of Sulfur slowly turns silver from white to gold to blue to deep rainbows to grey to black. You can stop at any color, say the lovely rainbow coloration, by dipping your piece into a super-saturated, baking-soda solution. Don’t wait too many weeks or months to enjoy the colorful piece patinaed with Liver of Sulfur, because it will eventually tarnish to black over time. 

There are Gilders Pastes® that come in an array of colors. Gilders Paste® is a wax-based medium that you can apply to metal-clay silver to add color.  Application is easy, and you can blend colors.

Gilders Paste

The baking soda (NaHCO3) solution is used most often to stop the tarnishing and oxidizing process. I can’t find exactly how it does this, but likely it removes all the oxygen and oxides (O2) from the environment or surface thereby stopping further tarnish. The reaction gives off gas, mostly likely as carbon dioxide (CO2). A super-saturated solution means that you add more baking soda than will dissolve in the water. Baking soda in water stops the chemical reactions involved when you use Black Max, Liver of Sulfur, and JAX.

A couple of side notes are these. One. Never let your silver metal clay come into contact with aluminum other than anodized aluminum. Aluminum totally compromises the silver clay’s integrity. Two. You can polish your tarnished finished silver pieces with baking soda, hot water, and aluminum. See Cleaning & De-Tarnishing. You could actually remove all patina black and tarnish by this method; however, the aluminum does weaken your silver in the process.

Patina Process

Patinas are nasty solutions. Read the MSDSs and you will want two things immediately: One, to not touch the stuff and two, to not breathe the stuff. Really. Wear gloves. Open all windows and put on a fan. I draw a skull and cross bones on the patina container’s lid to remind myself.

My set up consists of all plastic containers, and if you try using a metal lid jar you will see why. I have two plastic jars, one for the patina agent and one for the baking soda solution. I keep these in a plastic tray-like container that has paper towel lining the bottom. Once in a while I pour fresh baking soda solution into the tray-like container so the paper towel soaks it up. It’s okay to dry out. Wet or dry, it neutralizes any spills. I will often also wipe the lids of both with baking soda solution. 

Patina Set Up

The patina process is easy as hang, dip, rinse.

Hang. I hang my pieces on an S-shaped floral wire. Why floral wire? Because if you use a metal wire, non-silver, this metal will react with your patina agent. Over time, your patina agent weakens. You might see black specks in it, and it will lose its potency. The floral wire is plastic coated; thus, no chemical reaction takes place in the patina agent or in the area that the wire touches your silver-metal-clay piece.

Dip. I lower the piece in slowly, swirl it around, tap the sides of the container to remove air bubbles, and pull it out. I tap it to the side of the container, which typically removes the last drop of patina agent. 

Rinse. Immediately, I lower the piece on the same wire into the baking soda solution. I swirl and tap this. I will often hang the piece on the edge of the container and let it sit, especially if I have more pieces to patina.

I change my baking soda solution when it becomes full of silt and/or discolored. I can use the patina agent endlessly, it seems, adding more when the amount decreases to the point that my pieces won’t fully submerge.

Tips. Your textures may be of the kind that traps tiny air bubbles, leaving you with un-patinaed white spots. To prevent this, wet your piece first, blot it dry, then patina it before it dries completely. If you still have air bubbles or forgot to do this, I usually dip the tip of a toothpick in the patina and poke the white spot, which turns black promptly. Rinse again.

Before and After the Patina

I do some things in my overall process that I was not taught in metal clay school, whatever that is these days. Before I patina, which is after my firing and brass brush steps, I tumble my pieces. See Tumble — A Second One? Why? Besides work hardening them, tumbling compresses the silver on the surface the most. To me this translates into closing the pores that exist in the silver. You do know that metal clay silver is way more porous than manufactured sheet, wire, or other pieces of silver, right? That is also why it is more brittle. So in my mind, a tumble at this point closes the surface pores, which will let the patina agent penetrate the least amount possible. Why is this important? Do you want a tarnishing agent in the pores of your piece? Would this not cause the piece to tarnish even faster? My theory says yes. This tumble is done in steel shot and polishing solution. Why? Because this is what I want in the pores and former air pockets of my silver. After this tumble, I rinse the pieces in water, which removes the polishing solution from the surface. If I don’t rinse them, the patina does not work.

I then patina and finish the piece in terms of polishing and shining. To completion, almost.

I then tumble the pieces again. Why? For one, a quick little tumble evens out patina. Remember, I like patina so have a lot of dark areas on my pieces. This tumbling also shines all areas, from the mirror shiny finished parts to the black patinaed parts. Then, a tumble cleans the piece of my finger oils and most of the polishing filings. Some polishing crumbs and filings actually have to be scrubbed out with a toothbrush. Lastly, the last solution my pieces come in contact with intimately is polishing solution. So the chances of any patina agent remaining on the surface or in the pores are remote. Since I use the polishing solution in steel shot about a week or less depending on how dirty and dark it is, I rinse my pieces in polishing solution and wipe them dry. That is the last step, really.

Patina 3

When I removed the two pendants from the first tumble, I placed them on the paper towel that has the black stains from the tumbling solution.
Then I rinsed them well with water and this is how they looked, ready for patina.

Patina 4

Floral wire is the best for dipping in the patina solution because it is plastic covered; thus, no undesirable chemical reactions take place.

Patina 5

I use Black Max with doors and windows open, ceiling fan on high, and rubber gloves on my hands.

Patina 6

One patinaed Jaguar

16-1095j 1 - Version 2

Finished Jaguar Pendant

Removal of Patina

To remove patina put your piece on a firebrick and heat evenly with a butane torch flame until the color or black disappears. Or re-fire your piece in a kiln. After this step, finish your piece as if it were just fired, kiln or torch.

I have not worked with Gilders Paste® but would imagine you could burn it off or remove it with paint thinner. Avoid a combination of the two; otherwise, you might blow up.

To learn more about patinas in an online course with detailed videos and photos, go to Patina — Everything You Want to Know.

For online courses in metal clay, go to I Love Silver, where you learn how to design and create your own silver creations.

© Kris A Kramer 2018