I have a question about Acid Etching Copper & Silver that I haven’t seen an answer to in the other Acid Etching Posts:
I’m getting ready to give Acid Etching a try and have read up on it as much as I can, but I haven’t found the answer to these questions yet: Should you Acid Etch Copper and Silver pieces separately, before Soldering them together or Solder the pieces together and then Acid Etch them? I understand that Copper and Silver Acid Etch somewhat differently, but how differently, does one Etch much faster or slower than the other? Also, will Soldering the pieces together after Acid Etching affect the look of the Etched Metal or will it come out fine after Pickling? Lastly, has anyone tried Acid Etching a Copper & Silver object together before and if so, how did it turn out? Thank you so much for any thoughts, experiences or suggestions that you are willing to share!
The main thing is that you need two different acids. Copper will etch with ferric chloride- easy to get at any art store and relatively easy to neutralize. Silver however will require something else- nitric acid is the classic chemical but that’s pretty dangerous to use and I don’t know anyone who’s tried it. You’d need a hazmat disposal lined up. You probably want to electro-etch your silver. I have never done that myself, but there’s a lot of info out there on it.
OK, I apologize, I guess the wording of my questions were not what I should have written…
I do understand that to Etch Silver you need Ferric Nitrate and to Etch Copper you need Ferric Chloride, but what I was actually wanting to know is: Can you Etch a Copper & Silver Object that have been Soldered Together, or do you need to wait and Etch the Copper and or the Silver Pieces Separately and Then Solder them together? In other words, if I wanted to Acid Etch a Silver Disc that has a Copper Rim and Embellishments on it, can I do this Safely or will the Ferric Nitrate React/Eat-Through the Copper (and vise-versa: Copper with Silver Embellishments), even when it’s Covered with a Resist? I guess I’m just curious about How Ferric Nitrate Affects Copper and How Ferric Chloride Affects Silver and How both Acids Affect Solder and if the Metals will React Differently when they’re Soldered Together? Sorry for my confusing wording, though these questions may not be any better… Hopefully someone will understand what I’m asking… Thank you!
Just speculation on my part, the best way to find out is to run a test, but silver chloride is insoluble, so if it formed it would likely form a barrier to further reaction. Copper nitrate is soluble, so if it formed it would dissolve and leave the area to be etched further exposed to additional etching.
I’m going to speculate further, that if you did use an etchant that was effective on both metals the copper, being more reactive, would etch faster, and thus deeper than the silver. So it might be better to etch each metal separately.
Etching is done with a barrier such as lacquer to protect areas from being etched, and neither ferric chloride nor ferric nitrate would penetrate it. So you should be able to etch each metal separately by blocking, then exposing different areas.
Other than the cost of both reagents, there’s nothing to lose by trying each and seeing what happens. Part of the fun of what we do.
Thank you so much, I really appreciate your responses, that was what I was hoping for! I will do some experimenting, but I wasn’t sure if it was “Safe” to proceed - I didn’t want to produce any Deadly Gases or Explosions or anything - I never took Chemistry in school, I was able to talk my Counselors into letting me take Geology instead (I was preparing to study Architecture in College and then my Uncle talked me into trying out Jewellery Work…)… Anyway, I’m curious to see if the various Etching Acids will leave any Interesting Affects/Textures on the other Metals, other than the ones that they are meant to Etch, that would probably be Affected later by Soldering the pieces together… The fact that Copper would Etch faster than Silver with Ferric Nitrate, might give the piece an interesting multiple-depth design, if I can pull it off, I guess we’ll have to wait and see… Thanks again, I really do appreciate you taking the time to respond!
I do not know about the speed.
But for etching both Silver and Copper one have to avoid any Chloride based etches.
Copper will be etched by Copper or Iron Chloride, but as said, Silver will form Silver Chloride and passify.
Nitric will dissolve/etch both but needs 4 times as much Nitric for Copper than Silver.
The gases emitted by this is NOx and can be dangerous, (You do not want brown fumes)
but in a dilute solution with the amounts needed for this, it should not pose any problems.
Maybe one can use agricultural 3% Nitric for this, impossible to know without testing.
Just keep it in a closed container when not in use.
Ammonium Hydroxide can be used for Copper and maybe Silver too, but the smell is overwhelming.