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What Solution for Etching sterling silver?
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Q. Dear Dr Gary Callon
Can you tell me the science behind this etching solution, I mean the possible reaction
40 ml methanol
[affil links],
10 ml hydrogen peroxide,
10 ml ammonium hydroxide.
I tried myself and it works really good
- Birmingham, UK
April 28, 2009
A. Deidre, It should be easily possible to do on your discs but it could be time consuming doing them all. As you are in California, there is probably a good chance of there being a microelectronics company that does photo lithography that might be able to do them for you.
Anil, Sorry but I'm not a chemist and don't know what the possible reaction might be. The only guess I could make is silver peroxide or silver hydroxide maybe being formed? I work in microelectronics and came across the recipe in a book that we commonly use here. It has an A to Z of materials and what they can be etched with. The hydrogen peroxide, methanol and ammonia
[on
eBay or
Amazon] solution worked well but I found it not so good when trying to etch small features. It was also much more active when first mixed together and it gradually became less and less active over a few days. I found the ferric nitrate solution by far the best to work with.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
Q. Dear Dr. Gary Callon
Thanks for your reply. Could you please let me know the book name you are talking about for etching.
- Birmingham, UK
May 5, 2009
A. Thin Film Processes [affil link on Amazon] by John Vossen and Werner Kern
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
June 24, 2009
Q. Your suggestions for etching silver are interesting and very easy to understand.Please tell me how long the etching solution can be allowed before silverware is washed. How long is the process of etching takes place?
Sri Vishwakar- Coimbatore, India
February 13, 2010
Q. Dear colleagues,
I am trying to selectively etch 30nm of a silver film in presence of gold pads (also around 30 nm). Do you know any silver etchant that does not affect gold?.
Thank you very much!
researcher - Barcelona
February 18, 2010
Hi, Maria. Gold is very inert. Do you have any reason to suspect that any of the silver etchants described on this page would etch it?
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
A. From recollection, the ferric nitrate solution and the hydrogen peroxide/ammonia/methanol solution do not etch gold so it should be possible to etch silver without attacking any gold that you have there. A potassium iodide and iodine solution is a common preference for etching gold and this will also etch silver. Etching times for up to a few hundred nanometers are fairly quick from a few seconds up to 10s of seconds and the speed is related to how fresh the solution is.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
April 27, 2010
"Sherri Haab Jewelry"
on
AbeBooks
or
Amazon
(affil links)
Q. Hi Gary
I have been happily etching brass and copper with ferric chloride [on
eBay or
Amazon], but would like to etch silver. I have bought some ferric nitrate, but have read that, unlike the ferric chloride[on
eBay or
Amazon]solution which will last for years, as soon as it is exposed to air its power starts to deplete. This chemical is quite expensive so not good for doing just one-offs. I haven't dared open it as I only make a few pieces of silver jewellery. I have been reading on the net that you can electro etch with silver nitrate. Do you know anything about this? I know that I can get this chemical fairly cheaply in the UK.
There is a site in the US (www.sherrihaab.com/etch/) that sells a hobby electro etching kit which uses copper chloride for etching copper and silver nitrate for etching silver. This kit would cost too much to ship by the time you add everything together taxes, etc. Do you have any info on this method as I am sure I could set up a homemade version.
Thanks
Maxine
- Midlands UK
May 4, 2010
A. Hi Maxine,
I have never experienced any problems with the ferric nitrate getting 'old', in fact I am pretty sure that the first time I tried to etch with it, the chemical was donated by a colleague who had it among some others and it had been sitting around for 2 or 3 years. I also regularly made up small amounts of solution such as 100 or 200ml which also kept and were still etching a few weeks later. There is definitely an aging thing with hydrogen peroxide/methanol/ammonia solutions and I found these to be very good when fresh but quite poor after a couple of days. Potassium iodide and iodine solution also does not seem to be affected by ageing and I would imagine would be quite easy to get hold of. I have read that electro etching can be done with a mixture of 3 parts nitric acid to 19 parts deionised water and 2V stainless steel cathode. don't know much about it other than photoresist is generally attacked by nitric acid.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
Q. Dear Gary,
I have purchased Ferric Nitrate in dry form but am unsure at what strength I should use it for etching silver. Could you please advise me?
Thanks,
- Adelaide, South Australia
June 27, 2010
A. The book that I mentioned above Thin Film Processes [affil link on Amazon] by Vossen and Kern, lists 11 g of ferric nitrate to 9 ml of water which I think is a saturated solution and etch at 44 to 49 °C. From my experience, a more dilute solution will take longer to etch and I think the thickness of your silver that you wish to etch has a bearing on the concentration that you should go for. From my experiences, I was etching 200nm thick silver with a solution that was 20g of ferric nitrate in 100ml of water and this etched well in less than a minute. It may be a case of some experimentation on your part. Too concentrated a solution will mean too fast an etch, which could affect the resolution of the lines or shapes. I would suggest maybe starting with the 20 g in 100 ml solution and see how you get on.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
July 5, 2010
Q. I am attempting acid free etching using a saturated solution of cooking salt with copper electrodes and a 3V power supply. I have got a good etch on the anode after about 90 mins.
When trying this with a sterling silver anode, copper cathode and copper connectors, after 6 hours a black deposit had been made on the silver sheet. Any ideas what this may be and any comments about the possibility of etching silver by this process?
- Derby, England
September 5, 2010
A. As a guess I would say that you could be creating silver chloride during the reaction, which is depositing. AgCl quickly darkens on exposure to light by disintegrating into elemental chlorine and metallic silver. This reaction is used in photography and film.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
September 23, 2010
Q. Hi,
I try to etch silver plated copper (etched with cupric chloride and then stripped by sodium hydroxide), but after etching there are black dots and brown stain on the silver.
I would like to ask what is that and what causes it?
etcher - HK
March 24, 2011
Hi, Gary.
We appended your inquiry to a previous thread, and the response from Lisa in Portland Oregon probably answers your question. Good luck with a solution though :-)
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 25, 2011
Q. I have been etching with water saturated with salt and a battery charger [on eBay or Amazon] (20 AMP) but it only etches very faintly. So faintly it is easily removed with polishing.
I also tried with some vinegar
[in bulk on
eBay or
Amazon] in water and have varied the etching time from 30 minutes to 1 hour with no change of depth.
Any suggestions to why this would not be working. The battery charger is the same model that I used in college and similarly with he salt water (I even tried distilled water to mix with the salt tonight)
Many thanks
Christina
- renfrewshire, scotland
August 31, 2011
Hi, Christina.
Is the item that you want to etch connected to the red lead? What metal is the jewelry that you are trying to etch? What are you using for the cathode (the metal you are attaching the black lead to)? Can you estimate the amperage that is actually being drawn?
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 1, 2011
Q. Hi,
The sample being etched isn't attached in this picture but it is silver on both the cathode and anode and I don't have a way of reading the actual AMP while its working.
I was thinking the crocodile clips might not be touching the metal enough (as in surface area) with the teeth.
There are bubbles while it works but he results are so faint.
Thanks
Christina
- Renfrewshire, Scotland
September 1, 2011
Hi, Christina.
I haven't etched silver, so I can't say much except that your recollection of using salt water or vinegar in college may have applied to a different metal than silver. None of the previous contributors to the thread claimed that either of those solutions would work to etch silver. Alligator clips are used on high amperage battery cables for jump starting cars, so I doubt that the limited surface area of the teeth is an issue. The gas bubbles are hydrogen on the cathode, and oxygen on the anode; while they indicate that current is flowing, they also say that at least some of the current is being wasted liberating hydrogen and oxygen instead of dissolving metal.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 6, 2011
A. Christina, the reference source I referred to in this post has 6 solutions listed for etching silver but none of them refer to acetic acid (vinegar). Nitric acid is the only acid listed among the etches. There is one electrochemical etch among them with utilises 3 parts nitric acid to 19 parts water, 2 Volts with a stainless steel cathode. From my experience of etching other metals, I do know that acetic acid is an ingredient in an etch for aluminium, which I have also seen etch nickel if that helps with regards to previous work you mentioned. That etch consists of 80ml of orthophosphoric, 10ml of acetic and 10ml of nitric acids.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
October 7, 2011
Q. I am trying to find a way to make a rectifier with a computer power supply that is roughly 19 volts. Do you know what the amps needs to be and would this be a steady enough current to etch silver in silver nitrate?
I have a piece I etched with my jewelry teacher and it is just lovely. My issue is the expense of a rectifier 300-350$ for the 18 volt. Contenti/Pepe has one. Also Riogrande also sells one and it is about the same. How constant does the current need to be, what is the best electrode materials for opposing diode and are you aware of the best way to make your own rectifier? I do not want to use acid if I do not have to. Root killer works fine with a rectifier.
- San diego, California
August 11, 2012
Q. Hi. I just read a blog where the young lady etched using a resistant paper on a piece of silver backed with nail polish, and sea salt mixed with water, and cathode / anode of stainless steel, all hooked to a 9 Volt battery. She said it took two hours to etch. I see nice results.
Question:
Personally I have light sensitive paper used with photopolymer plates; I used photopolymer plates to make precious metal clay imprintables. I still have the films actually. I went into my darkened bedroom armed with a UV nail light and a copy of a design and made the film.
I wonder if I use the finished design film with a hot iron to push the design film to release the black pigment onto sterling or fine silver (I mean processing this film is one thing you must do it in a dark room at night with flash lights and it comes out really black). But can I transfer the image onto silver with an iron? Will this film melt?
Question #2:
Can I use plain transparency paper and adhere the design onto my metal with an iron? Here's the site where the young lady uses a 9 volt battery it's called green etching: www.inbarbareket.info/green-electro-etching
home jewelry enthusiast - New York, New York United States
November 10, 2012
August 4, 2013
I have had success etching copper, brass and bronze with a solution of 60% vinegar (regular 5% acidity white vinegar from the grocery), 40% hydrogen peroxide (regular 3% hydrogen peroxide from the drug store) and sea salt (1 Tbsp per cup of solution, more or less depending on how long it takes. Too much salt may remove the resist). I use sea salt because that's what I had on hand. Table salt would probably work as well, but my table salt was iodized and I didn't know if the iodine would affect the solution. I use heavy body acrylic paint as the resist (two coats) and usually work the piece as one would a scratchboard. (Don't forget to paint the sides and back or tape the back before etching). Sometimes I use a engraving pen to take off the paint, which helps the etch:
Copper takes up to 2 hours depending on the size of the piece. Brass takes 3 hours, and bronze can take 3-4 hours. To get the etching started, I put the plastic or glass container holding the etch solution and the piece in a hot water bath from the tap. When the etch is finished, I rinse the piece and put in baking soda bath. Then put the baking soda solution in the vinegar solution to neutralize it. I take off the resist with rubbing alcohol and a scotch-brite scrubbie. Then sand with 3000 grit sandpaper (from the auto parts store), then 8000 grit paper (from Rio Grande) to polish and remove the scrubbie marks.
I would like to graduate to Sterling, but don't want the traditional etching chemicals in my house. Would this solution work on Sterling without creating a chemical hazard!? I am new to metalsmithing, but it seems like silver is softer than copper, so it would take less time. Any thoughts? Thanks.
- St. Louis, Missouri, USA
Q. Hi Dr. Gary,
Thank you for sharing your insights of how to etch Silver and the concentration how to make the solution of it. I have been looking over the internet for sometime and this morning I able to come to this wonderful site. I just started to make Silver jewellery.
Here my question are:
1. How often I need to change the Ferric Nitrate solution after being used? What is the indication which tells me I should change it, and where do I deposit the old solution?
2. Dissolve Ferric Nitrate crystals in distilled water (300 mg of Ferric Nitrate to 400 ml water), someone suggested before, and I wonder if I use tape water and dissolve the Ferric Nitrate would be any different?
- Hong Kong, China
May 1, 2015
A. Hi, the solution works best when made up freshly and from my experience lasts a few weeks but will gradually become less and less reactive. My guess is that a solution with tap water would probably work the same but I have never tried it. As for disposal, this should be done properly and you may wish to see if your authorities have a disposal facility where it could be passed to.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
September 2, 2015
Q. Hi I am looking to use the ferric nitrate method to etch silver but am having trouble (I'm in far north Australia) accessing chemicals. Can you please tell me if it matters if I use Ferric Nitrate or Ferric Nitrate Nonahydrate? Thank you.
michael harrison- Cairns, QLD Australia
March 8, 2019
A. I don't think it would matter. Nonahydrate means the crystal contains 9 molecules of hydrate or water attached to it and its being dissolved in water anyway.
Dr. Gary Callon
University of Dundee
Arbroath, Scotland
July 23, 2019
Q. Has anyone else used the 60/40 vinegar, hydrogen peroxide, salt method? And what would the disposal be?
Isabelle McCollum- Northern Utah, USA
January 18, 2020
A. Hi Isabelle. The disposal method for a casual consumer is probably just neutralization with baking soda [on eBay or Amazon] . But factories, and sometimes even schools, have regional or national regulations on disposal of chemicals & waste. Thanks!
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
January 2020
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