by Virginia Vivier.
(Esprit Mystique Jewelry)
Acid Etching Metal Jewelry
Part 4a: Etching on Silver
Using Ferric Nitrate
Part 1 of this Acid Etching Metal Jewelry series covered how to transfer designs on metal.
Here in Part 4, the same techniques apply for etching on silver, except the acid is different. Please review Parts 1 – 3 to help understand the basic etching process.
Here’s my unscientific method for etching on silver, plus how you can avoid making the same mistakes I did.
Ferric nitrate provides a clean etch on sterling silver and fine silver.
You can buy ferric nitrate crystals at most chemical supply stores. I buy from Adchemco Scientific in Tucson, Arizona.
If you order ferric nitrate from an out-of-state supplier, the cost will include shipping and HAZMAT packing costs, so try to find a local supplier to save $$$. (When I was an ASU student I bought it through my local University Chemistry Store, but 9-11 may have changed that.)
Ferric nitrate crystals look like lumps of sugar with a light hues of purple. Ferric nitrate crystals should be combined with distilled water, but I confess, I use tap water and have not had any problems.
You may have more minerals in your water supply that could make a difference, but I apologize in that I haven’t researched those variables. So, to be safe, jot down “distilled water” on your grocery list and have it handy.
When it comes to a recipe for mixing a ferric nitrate solution, I have done a bit of research and experimenting. I found that a 50/50 mix works well. So, you don’t need to buy a gram scale if you don’t have one.
By now, you may be thinking, “She probably adds a “pinch of this” and a “dollop of that” when she cooks, rather than following a strict recipe.” Very true! I’m attempting to show where you can cut corners and where you must be careful.
Note: Please do not confuse ferric nitrate with ferric chloride. Ferric chloride works well on copper and brass, but does NOT work on silver.
Ferric chloride and ferric nitrate are corrosive iron salts. Although they are potentially harmful chemicals, they are much safer to use than acid. They do not have noxious fumes and are not absorbed through the skin. They will stain skin, counter tops, and clothes, so wear gloves, protect your working surfaces, and wear old clothes when etching.
To be safe, please read the precautions listed in the Goss Studios article on etching, sent courtesy of Art Chemicals.com. I have never experienced fumes or flammability, as mentioned in the article and am not cavalier about handling chemicals, but feel that some precautions are overkill.
I smile when I see a warning on a paper coffee cup: “Caution, hot liquid may cause severe burns.” (OK, I can see the steam – I get it. : )
Goss Design Studios – Ferric Nitrate Etching Recipe:
400 ml of distilled water
300 grams of Ferric Nitrate
Always add crystals to water!
NEVER water to crystals.
My Unscientific Etching Process:
Slowly add enough ferric nitrate crystals (about 2 cups) to make a total solution of 1 quart.
Mix carefully with a wooden or plastic spoon (DO NOT not use anything metal) until the crystals are dissolved.
The solution will turn a dark greenish color that is fairly clear compared to the thick, opaque, greenish ferric chloride, which is used straight out of the bottle.
(I feel like I should be chanting a “Spell” while stirring, as it reminds me of a Witch’s brew. : )
The instruction from Goss Studios says to “kick start” the solution with “a teaspoon of old, 5:1 diluted, nitric acid solution.”
I skipped that.
I have worked with nitric acid and it is very dangerous stuff. I avoid it whenever possible.
If you are more daring than I, please try the Goss recipe.
It may increase the strength of your ferric nitrate solution. I’d love to learn about your results.
Note on Nitric Acid Etching:
An accepted way of etching silver is to use nitric acid.
I tried etching silver, using 3:1 nitric acid solution, and was very disappointed in the results.
The acid quickly corroded the dry toner design and red Staedtler pen resist. The edges of the design came out fuzzy.
The fumes were so bad that I decided it was not something I wanted in my studio.
However, many professional jewelers swear by it as a clean etch method.
They use a stronger resist, like asphaultum, which I find messy and hard to work with.
I calculated that it costs less to use nitric acid than ferric nitrate, as it lasts longer and a smaller amount is required per etch.
Nitric acid concentration gets stronger as the water evaporates, unlike ferric nitrate, which is weakened by moisture.
It is necessary to follow safe OSHA disposal requirements. You can get more info on nitric acid etching on the internet.
You can etch about 20 pendant-sized pieces of silver in a quart solution of ferric nitrate before it starts to slow down and finally exhaust. I calculated that (in a perfect world) 5 pounds of ferric nitrate, at $60, should produce approximately 100 etched pendants at a cost of 60 cents per piece, just to etch.
This technique is better for creating your own special unique, one-of-a-kind designs. This may not be an economical way to create a wholesale line of jewelry. There are more economical ways of producing a jewelry design that appears to be etched, such as having a wax model cast by professionals.
This photo shows the original 4 inch x 2 inch, 16 gauge, piece of sterling silver intended to be a bracelet:
The design has been “ironed on” and the edges filled in with red Staedtler pen resist. The back of the silver is covered with clear plastic packing tape as a resist to the ferric nitrate.
The transfer design was made with of a sheet of IBM transparency acetate copied on my dry toner copy machine.
The copy machine transferred a thick layer of dry toner (dark black lines) on to the acetate.
The acetate was then placed (toner side down) on the squeaky clean piece of sterling silver.
I put a piece of paper towel on top of the acetate.
I placed a hot iron on top of the paper towel (for about 3 minutes) – this heated the acetate and melted the dry toner on to the silver.
When the hot metal cooled enough to touch, it was placed in a glass jar of water.
The acetate popped off easily, leaving the dry toner design on the silver.
I used a red Steadtler pen to touch up a couple of places that didn’t transfer fully to the silver.
The outside borders of the design were filled in with red Staedtler pen as a resist to the acid.
Also be sure to see the new page, Acid Etching Metal Jewelry – UPDATE before beginning your etching project!
Questions or comments on Part 4a? Please ask!
Superb – an awesome tutorial
Virginia, I so appreciate your publishing this great jewelry tutorial here on this site!
Thank you so much for sharing your expertise.
Virginia, you’ve got me so inspired to try this. I totally love the pieces you create! Thanks for sharing with us!
how long will solution mixture last?
wonderful tutorial! however, i am wondering how long the solution bath will last? also, what do you do with an old solution that needs to be thrown out? what is the safest method? thanks so much!
STERLING SILVER ETCHING
by: Dee Moro
Thank you for the great information about metal etching. What gauge do you use when etching sterling silvel?