Warning
Metal etching can be dangerous! If you’re going to try this, make sure to read all red the warning
text at the bottom of the Edinburgh Etch
page first!
Also note that copper is reflective. Laser forum users warn that there’s a risk of the beam
bouncing off the copper and back into the laser head. I scuffed the copper prior to lasering to
avoid this, but I’m not certain how big of a risk this is.
One thing I’d been really excited to try on my Glowforge was etching metal. Of course the Glowforge
doesn’t etch metal directly, but there are a lot of posts on the Glowforge forums where people had
spray painted metal and then etched it. I was really curious if it was easier to do than the laser
transferred resists I’d been using. So I searched the forums for all the information I could find on
methods people were using, and gave it a shot.
I started by using a matte black spray paint to spray paint some flat pieces of copper and brass.
I let it dry for 24 hours.
I found settings by etching and scoring a test piece. The settings that worked best for me were:
Engrave: 2 passes, 1000 speed 20 power
Score: 2 passes, 500 speed 15 power
Test engraving on the glowforge. Engraves on the left are too low power.
As I’d seen on the forums, after engraving there was a thin residue of paint left over. I started
rubbing a spot in the middle with fine synthetic steel wool; you can see a shiny spot where I
removed the residue.
You can see the sanded spot shining on the boy's head.
I kept going until I had gotten all the residue. I wasn’t able to preserve all the fine details
while polishing, but I did remove the pixellation in the etch:
After fully sanding with synthetic steel wool, some of the detail is lost, but so is some of the pixellation.
Since I had spray painted both sides of the copper and brass pieces, I didn’t need to add any
additional resist. I put them into some Edinburgh
Etch for a few hours.
After removing from the etch, I used acetone to remove the spray paint. At this point I saw that
the photo etch looked really cool from some angles, but really incomprehensible from others.
After etching and removing spraypaint, the way the light hits the etch on the top looks great, but the way the light hits the etch on the bottom it's too hard to see what the picture is.
I realized I could put a patina on the metal before removing the spraypaint, and it would only
darken the etched area. I did this with JAX Brown.
Trying again with a third piece, I applied JAX Brown before removing the spraypaint.
After drying the patina and using acetone to remove the paint, I finished with clear Krylon
spray.
After removing the paint, you can see the image is darker, which makes it a lot clearer from every angle.
