Nitric acid etching of silver jewelry
April 28, 2008
I am a 63 year old man who is in his 2nd year Metalsmith course in the UK. I want to chemically etch onto silver. I would appreciate a formula that I can make up and get the chemicals at high street stores, or at a push chemical wholesaler. What type of stop-off do I use -- any form of lacquer or do I have to purchase a special stopoff?
I await your replies
Thank you very much
training to be a metalsmith - Kings Lynn, England
April 30, 2008
A. Nitric acid attacks silver. Adhesive vinyl or wax resist nitric very well.Guillermo Marrufo
Monterrey, NL, Mexico
Q. I am a jewelry student and I have heard that nitric acid is the best thing to use for etching silver. I am familiar with using ferric chloride for copper but I would like to step it up a bit.
What concentration of nitric acid should I buy?
Should I etch in a glass container (I use tupperware for my copper etchings)?
How much baking soda should I use to neutralize it when I am finished?
Any help would be appreciated.
Student - NYC, New York
A. I have done some silver etching. It's very different than ferric chloride and a very big step "up". But, the results are very nice and you can get just as clean an etch in the silver as you can with the ferric chloride.
The nitric acid is 1 part to 3 parts water .... remember: add acid to water. I am told (we used premix in the class) that if you add the nitric to the water too fast, an explosion is possible. Wear goggles and all your other protective gear if you choose to make your own solution and do it under a hood. Unlike ferric chloride, nitric acid is nasty stuff. Premix is available at Rio - and there is a hazmat charge for shipping.
We used a 12-volt battery and titanium wire in a glass dish. Attach a titanium wire to a sheet of titanium (about 22 or 24 ga) that is about the size of your piece and the other end to the positive terminal. Curl the other wire a bit so that you can put your silver piece on top of it. Attach the other end of the wire to the negative battery terminal.
Submerge the titanium sheet and the wire coil in the nitric acid (glass dish). Place your silver piece on the coil. Bubbles form on top of your piece as the etching takes place. They interfere with the etching and must be gently brushed away. We used cheap artist's brushes with no metal (do not use any metals in this solution other than the titanium). When the nitric melted the bristles too much we changed to a new brush. If I remember right, fresh solution gave us a good etch in about 15 to 20 minutes.
Good luck with your etching.
- Shrewsbury, Massachusetts
July 6, 2008
Q. Is there neutralizer that is needed to use at the end of acid etching on silver? How is the nitric acid disposed of safely once you are done with the etching process?
- Asheville, North Carolina
July 7, 2008
A. Hi, Valerie. Nitric acid can be diluted, then mixed with baking soda until litmus paper (pH paper) says the solution is neutral. Safety issues and environmentally responsible disposal are topics rather large to be dispatched with in a public forum though. I would suggest that you start with the EPA website and search it for appropriate terms. The EPA writes volume 40 of the Code of Federal Regulations, so you can often find those regulations by including "40CFR" in your string of search terms. Good luck.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
May 14, 2010
Q. I am a jewelry designer from in Bali
Until now, I made our jewelry with handmade method and I want combine with etching method.
Who has the circuit picture/equipment settings for silver etching?
- Gianyar, Bali - Indonesia
Ed. note: Hi Ari. We appended your inquiry to a thread where Cheryl B has already answered it. Good luck.
May 26, 2011
A. I've used nitric at higher strengths, usually y 1-2, for years.
The resist I've found most useful is a roofing spray asphalt. I've sprayed several thin layers to cover the whole piece.
I make sure my sterling is absolutely clean so the resist can stick to it.
It's a pretty thin layer and the acid doesn't creep under it so much.
I can achieve very fine lines with it; maybe not too deep, but deep enough.
I never throw my mordant away because I can use it for later etching if I just add a few drops of fresh acid to it. And it's great for a bright dip.
Why throw it away?
I've never brushed the bubbles off either. I did today. Let's see what happens. I hope it didn't loosen the resist. The resist getting brittle is the thing to watch, IMO.
If you'll note, the bubbles form and then disperse, so the acid is still working.
I'm sure a lot of jeweler's have more experience with this technique than I do, but this works for me.
That roofing asphalt spray is the key.
Good luck to us all!