Metal etching tests

What do you do when etching resist is out of stock? Oh and it has toxicity concerns?
You do some tests, and write shit down, because Science™️.
I cut 20 gauge copper into roughly 1-inch squares, cleaned and prepped them for etching.

*edit*

Okay, writing on my phone is a pain. Let’s be more thorough!

Etching, in jewelry and metalworking terms, is the removal of surface metals by an acid. Areas that you don’t want removed are covered by a resist. Pretty straightforward, but because this is Science, and we respect and love Science and the Goddess O’Sha, we take all the necessary precautions to keep our meatsuit safe.

Preparing metal means removing oils and other debris from the surface, so I gave it a good scrub with some dish soap, dried it, then used some isopropyl alcohol to really make sure it was clean.

Resists

There is a plethora of materials that can be used for a resist out there, and boy howdy some of them are outright terrifying. I saw someone using tar and gas. No gloves, no mask, no eye protection.

Really.

Commercial resists can contain asphaltum or bitumen, which…is not really something I’m keen on keeping around the house. Additionally, it was out of stock when I tried to order it. So what to do? A woman must complete her jewelry project after all.

To the testing chamber, Batman!

So, resists need to stick to the metal in some fashion. Again, there are a variety of ways to do this, but I had to stick (hah) with what I had available in the studio. Here’s what I came up with:

  • Colored Pencil: can have a high wax content
  • Beeswax: is literal wax
  • Pigment ink
  • India ink
  • Sharpie pen
  • Adhesive vinyl

For beeswax and the India ink, you lay it down and scrape away what you want to be etched. Colored pencil and Sharpies, you just draw right on there. Pigment ink you can use stamps to apply, and adhesive vinyl you can cut in a multitude of shapes.

Results

I won’t bore you with the actual etching process, ’cause frankly, it’s…boring (away the metal). First thing is to put on all your protection, prepare a baking soda water solution (which will neutralize the acid we’re using). Heck, just keep the baking soda around, because it can be used to clean up any spills.

To etch copper (or brass or bronze), ferric chloride is…the solution. (Are you tired of my puns yet?) Now, this stuff is NOT GOOD for the environment, particular after it’s been used. Copper is absolutely lethal for the aquatic invertebrates that keep our ecosystem functioning. The local water here contains trace amounts of it, and watching your aquarium ecosystem entirely collapse because of it is sobering.

So. Be careful. Pay attention to Our Lady of Workplace Safety O’sha, and dispose of properly through local hazardous waste ordinances. Ferric chloride stains, so again, wear some protection.

How long to leave the pieces in the mordant (the ferric chloride) depends on how big your piece is, how deep you want the etch, and how new your mordant is. It come out a bright, bright orange, and will immediately take on a green color as it leaches away the copper.

I went about 20 minutes for these tests, and I will probably go longer for the next time that I do this–at least half an hour. Of the six different resists that I did, the vinyl and Sharpie tests were the top two. The india ink and beeswax have potential, but any results I got felt more like it was because I scratched into the metal rather than etched into it. The colored pencil and pigment ink didn’t work at all. Now, I have seen some folks get great result with *solvent* ink, but I don’t have any.

Yet.

So there you go! Definitely going to use vinyl for my jewelry project.

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