Huh it’s still not that far off.
I wonder what would happen if you used a resist that is applied as a liquid? You could engrave it off the copper. Is there a resist like that for etching?
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Years ago I had some photo-etching done to create masters to make rubber molds for the lost wax casting process, and I hung out to pick the guy’s brain and witness the operation. The copper plates come with a photo-sensitive coating, and after exposure to an arc lamp the piece is mounted in a dishwasher-sized cabinet on a rotating base, and the mordant is sprayed in a stream on the surface. During the process, the reaction creates tiny bubbles on the surface and if not removed they can prevent an even etch, so the spray eliminates that variable. Etching at home in the shop, you use a small brush to constantly sweep the bubbles away. The etching time is about 15 minutes and the detail is amazing.
It’s the same process that is used to make the plates they print money with, so anyone buying the equipment and chemicals is known to the FBI.
Here is a positive and negative of one design, A logo for a live aboard dive boat that was called Wave Dancer. I cast these in silver.
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People commonly use sharpie pens or nail polish. Also works for non-acid etching via salt water and electrolysis.
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I’ve got one underway right now using acrylic paint as a resist. Had to do it that way as my blank is domed, not flat. It engraves off pretty well but you still have to scrape off a residue with a toothpick.
I’ve actually done the photo etching process at home, it’s not terribly difficult. You use a resist like this stuff and iron it on (I actually used a laminator) to the copper. Then do the exposure with a negative in front of it and wash it out. My results were really pretty good, but creating a good negative is messy and I wanted to see how the Aura would do. It’s certainly a quicker process.
Here is the same design I did about 8 years ago using the photo process:
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Wow! Beautiful!!
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Very cool! Is that paint, or a patina? Thanks for the link!
Yeah, the whole process fascinated me, and the guy led me through each step as he prepared the image. This was the first time I ever saw an image digitally manipulated (a long time ago) and I was amazed he could scan in the art as a vector and blow it up to a foot tall where I could make any adjustments, scale it back, expose it, and the master was - perfect, a goal when you plan to make a mold and reproduce an item at scale.
The detail the process is capable of is what drew me… the same with the glowforge.
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Neither! It is a base layer of gesso mixed with pumice powder (to give it tooth), then colored with a bunch of colored pencils. The whole thing was sealed with acrylic spray.
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excited to see more of this. I don’t actually know much about the aura since i already have a pro, what exactly makes this a aura only project? is the laser a different power? is it shielded different? also curious how its doing oracal without offgassing the icky stuff that usually occurs with vinyls in the other lasers.
my main question comes from my printmaking background - have you thought about putting on a traditional etching ground like hardground (if you have access to ventilation) or one of the more modern waterbased grounds (i know one is made by Golden acrylics but we haven’t had the best luck at my work for etching printmaking plates and we have amazing HVAC so we just use old school. there’s another one ive seen making the uk printmaker rounds BIG or Baldwin’s Ink Ground).
it might help with the edge issue as it’s paint on instead of adhesive. I don’t know if it will cause any problems as far as reflection, but all grounds are quite dark, so its kind of like the spray you can use on metals to allow for metal etching (brown for asphatlum based hard ground, and i think BIG is black) you need to see where you have broken the surface for the etch to get to the copper, so any etching coating is going to make it dark and not reflected.
so curious to see how this goes and if any of it could work for the students at my work incorporating more technology with their copper plates.
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That is explained in my original posting here:
This particular Oracal is polyester-based, not PVC-based, so you don’t get the offgassing of hydrogen chloride that permanent PVC vinyls can give you.
About the printmaking grounds you refer to: I know nothing at all of those, but it seems like a really good thing to look into—thanks for the heads up! Because the diode laser responds best to dark and opaque materials, that BIG might do the trick.
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For those still following this thread: I thought you might like to see the results on the domed pieces using acrylic paint as a resist.
A cloudy residue is left on the surface after engraving that has to be rubbed off with a toothpick or pointy swab.
After etching. Gorilla tape works pretty well to remove the resist.
Closeup of the etching. Pretty knarly. This is a fairly tiny piece, though, only 14 mm tall.
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Thanks for sharing these.
I’m not inclined to do this myself but I love seeing the process!
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Nice. So, Ferric chloride is the mordant? How long was the etch time?
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Edinburgh Etch is a mixture of Ferric Chloride solution and citric acid solution. The citric acid helps keep the etched parts free of sediment.
I left them in there for 90 minutes.
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Thank you 
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Very interesting!
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