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Topic: Etching copper plates (Read 1118 times)
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Nik Semenoff
Administrator
Newbie
Posts: 19
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Recently I have been working on a safer and cheaper way to produce a mordant that etches copper plates as effectively as ferric chloride or acids. It may not work quite as fast as these, but certainly fast enough for most printmakers. Having good results but trying to workout even a bit better process testing various materials. I presume etchers working in copper might be interested. It doesn't take much chemistry once setup and established. More later.
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Nik Semenoff
Administrator
Newbie
Posts: 19
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Hi Linda:
Somehow I missed there was another post in this section, so I must apologize. I have finished my research into etching copper using basically a variation of the copper sulfate mordant I developed years ago. In fact it can be modified to etch a copper plate, but I suggest making up a special bath. I had told Alfons Bytautas at Edinburgh Print Studio about the process and met with him recently while I was there giving a workshop on waterless lithography. He has taken one of the possible various formula and is already using it for etching copper plates. He will likely be teaching it there as well because of its' environmentally safer features. He and I will write an article for Printmaking Today for hopeful publication, but in the meantime I will do up a paper that will be posted on my blog here and at the university website with my other innovations.
I showed the process to printmakers at two Dublin print studios as well; they were very much impressed with the sharpness of the lines and ease of making up the bath.
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Alfons
Newbie
Posts: 5
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Nik
Had to describe the new etch to a friend who works in a university print department. she was concerned about having to use hydrochloric acid and so I wrote a reply to encourage her to use it. Thought I would put my reply on the site to encourage others to experiment too.
Alfons
Etching with Cupric Chloride
After consulting with Nik Semenoff (I was lucky enough to meet Nik personally during his trip to the UK), I’ve been experimenting using acrylic resists and biting the plates in a new etch. One of the ways in which this can be made is by using copper sulphate crystals and household salt with the addition of small amounts of hydrochloric acid and hydrogen peroxide.
Using the ingredients listed we can make the new mordant - cupric chloride. This is made using copper sulphate (which we already use) and adding salt and a small amount of hydrochloric acid and hydrogen peroxide (provides oxygen and is a contact lens cleaner, hair bleach and mouthwash!). This produces a bright green solution, which at about 36 degrees Baume can be used to bite copper. Diluted it appears blue (it looks exactly the same as the copper sulphate bath) and can be used to bite zinc and aluminium.
The beauty of cupric chloride is that it can be regenerated, so you will never need to dispose of the solutions. You can regenerate a bath by adding hydrogen peroxide and/or (small) amounts of hydrochloric acid. Although you need to use hydrochloric to make or regenerate the mix, the cupric chloride solution itself is pretty safe.
Making the solution this way is probably the safest & easiest, at least it was for me. You can also make cupric chloride by biting copper in a solution of hydrochloric acid (referred to as muriatic acid in the states and available in hardware stores) and hydrogen peroxide. Environmentally, because it can be regenerated, cupric chloride has much to recommend it and is used to etch printed circuits (PCB’s) - along with the now much used ferric chloride.
Etching copper, the solution produces a fine accurate bite and an excellent range of tone in aquatint. It looks and behaves similarly to the traditional “Dutch Mordant” etchant, allegedly used by Rembrandt. However it produces little in the way of fumes, similar to ferric chloride, as long as you don’t add too much hydrochloric acid to the bath.
Etching zinc (or aluminium) it behaves identically to the copper sulphate or “salt etch” baths – with an added bonus that the coppery residue produced when biting is re-absorbed back into the solution over time. Small amounts are absorbed quickly while the residue from heavy biting generally clears overnight. So far I’ve found the bath of cupric chloride lasts much longer (in our open access studio in Edinburgh) than an equivalent bath of copper sulphate solution – and this could then be regenerated too. This means the solution is now relatively low maintenance.
I made the change to using the cupric chloride for biting zinc without any of my fellow etchers noticing any difference – except that it seemed to perform better and we had nice residue-free baths most of the time.
This is a significant development in fine art etching chemistry and, although I’m still experimenting with the mixes and their dilutions (when I can find time), I enthusiastically recommend the use of this mordant. I’m grateful to Nik Semenoff for sharing his expert knowledge with me. His website contains a lot of information and is invaluable if you wish to find out more about this new etchant.
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Nik Semenoff
Administrator
Newbie
Posts: 19
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I have just received information from Alfons at Edinburgh Printstudio, who has been researching and testing the cupric chloride mordant I introduced him to. He is very positive about the advantages it has over traditional mordants, especially ferric chloride for copper. He is the etcher who is most knowledgeable on this process as I am not an etcher and only do interesting research into such matters. He and I will put together an article and hope to find a publisher. He hopes to assemble more data on his research so he can publish it on the home page of this site as one of my blogs. I look forward to his results and recommendations,as should all etchers. If others have begun to use this process, I would invite you all to give your impressions and any technical data that you think might be of use to the print community at large. That is why these forums have been set up.
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Nik Semenoff
Administrator
Newbie
Posts: 19
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To all etchers looking for safer processes
In the last couple of days, I have uploaded an article on how to remove all the harmful metal compounds from the spent mordant before pouring it down the drain. We must make these metal compounds insoluble to water, so I have found a cheap, safe and readily available product one can find in most communities. If you put all the recent posted articles on etching plates with variations of copper sulfate, this last one will allow you to use this mordant, which is the safest I know of, and still dispose of a clean liquid down the drain. There is no reason not to try in and use it like many are already.
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Nik Semenoff
Administrator
Newbie
Posts: 19
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Hi Peter:
If you are only etching zinc, I would suggest using copper sulfate and common salt with some sodium bisulfate so the bath will regenerate. All of that is on the home page of this blog site. There has been enough written about using copper sulfate on etching aluminium and zinc, you should have little problem finding the information. All the latest developments on this new mordant are on this blog site, but there is an article being published in Printmaking Today in the next edition. Alfons has one coming in the next edition. Alfons it the expert on etching metal and you can find what he thinks about the mordant.
I am glad you find this forum and blog helpful.
Cheers
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