Paint Filling Laser Engraved Mirrors (for Art or Pleasure)

Hi guys, while I like to play around a bit creating things, this is the first Instructable I've ever published, so please be gentle.

I love trying to get a bit creative, and to try and make my place a bit classier. Unfortunately I've always been a bit clumsy with my hands, and have about as much artistic talent as a brick. But with modern tools there's no reason I can't make beautiful things.

In this project I'll show you how you can use a CO2 laser cutter to etchthe back of a plate mirror, and then use paint to contrast the engraving and make an eye catching art piece for your wall. I used a metal backed glass mirror, but a lot of mirrors these days use foil backed acryllic. That should work too, but be aware that your laser settings will need to be different.

You'll need:

- A CO2 laser cutter (I have access to a Trotec brand 100W system at work)

- A mirror (mine was sold as a candle stand at a cheap shop, and cost $5)

- Paint (any kind, spray or brush on, I used gold spraypaint)

- A PC with some kind of image editing software (I used CorelDraw)

- A ruler and a marker pen (this will be used to make sure your artwork is aligned on your mirror)

Something I also used in this project that you may or may not need, is aerosol furniture polish. I used this to remove adhesive residue on the back of the mirror prior to etching.

The first thing you'll need to do is make sure your mirror is flat for engraving. Fortunately, plane mirrors are the most common type of mirror, and the cheapest. Be aware that some mirrors made for applying makeup or other activities may have a slight curve on them, to exaggerate features. This probably won't be impossible to work with, but it's easier if your mirror is flat.

For this project you'll need to expose the back side of the mirror (the non-reflective side, not the glass covered side). That means you'll need to remove any frame or covering from the back of the mirror, and be sure you can lay your mirror flat reflective side down.

When I started doing this, I found two problems with my mirror. First, taking photos of mirrors is really hard. Second, my mirror had little rubber feet on the back attached with double sided tape. I just peeled these off with my fingernail. don't worry about fingerprints on the front of your mirror now, you'll clean it all up at the end.

After peeling back the rubber feet, I found this sticky tape residue left behind (see the pictures). Fortunately I had my secret weapon on hand: Aerosol furniture polish. Spraying with this and rubbing with paper towel removes pretty much any sticky residue I've ever come across (including the sticky left behind from old labels and stickers).

Once all the sticky is gone, give it a wipe with fresh paper towel so it's not too greasy from the polish, you want to be able to draw on it with a marker in the next step.

You'll need to plan where you're going to engrave your mirror. I'm planning on engraving across the entire mirror, but you don't have to (borders or small corners can be nice too). Because I'm using the whole mirror, I wanted to make sure my artwork was centered, so I had to mark the center of the mirror.

Marking the center point is easier on a square or rectangular mirror, but I (like a chump) am using a circle, so I have to mark the center point without any appropriate tools. In comes some classic maths: you can measure the cent re of any line you draw with a ruler, so you just need to make sure you can draw a line through the center point of a circle, then you know you can find the center of the circle.

Now we have a spot to align with.

You'll need to prepare an image to engrave into the back of your mirror. Because you'll be engraving deep and performing multiple passes, you'll want an image with high contrast in black and white. While you can engrave finer detail with grey scale images using high end laser cutters, this paint filling method won't really lend itself easily to that.

For this project, I used a photo I took of some local wall art in the Fish Lane district in Brisbane. The artwork was originally by an artist called sofles (sofles.com), and I hope he doesn't mind me working with it and putting it on my wall.

Firstly I imported the image into CorelDraw. Then I tweaked the brightness and contrast until it was copmposed of only black lines and white space, and most of the brickwork in the original image was gone.

I then cropped the image for engraving. Because I'm engraving on a circular mirror, I want the image to be circular as well. My mirror was 250mm in diameter, so I scaled the image to 260 so there was a slight overhang over the edges; I wasn't 100% on my center marking at this point, and wanted the image to go right up to the edge.

I then mirrored the image horizontally. We're engraving on the back of the mirror, so by reversing the image it will be facing the same way as the original painting when seen from the front.

Load your mirror into the laser cutter, with the back side (that you've marked) pointing up. Set the cutting height according to the method for your laser cutter (they can vary) and align the sighting laser with the center point you marked out earlier.

In your job control software, align your artwork so it's centred on the sighting laser, and manipulate the laser settings for glass etching. This was a 100w machine, and the default settings for this machine were 90% power and 90% speed. Even still it took 3-4 passes to fully penetrate the back mirrored layer.

Then etch away, repeating the etch until you can see through the engraved sections. I found that there was a progression of layers that got etched through, from the grey metallic back through a pinky-red colour, until finally an opaqueish white colour you could see through was achieved.

Give the etched surface a wipe with a wet paper towel, to remove any dust or particles (these can be hazardous if you breath them, so be careful).

Now we get to the fun part, paint filling the engraved section. Because I was spray painting the piece, I set up a mini "spray booth" for the job. I put the mirror face down on a rag, inside a thick paper bag. This prevented paint getting on the front of the mirror, and overspray getting on the rest of the work area. You can use a respirator if you want, but this is a small job and I was working outside and didn't bother. I then gave the piece a light, even spraying over the whole back, before letting it dry for 30 minutes. I then rotated the mirror 90 degrees, sprayed it again, and let it dry again. This gave me a reasonably even coverage, and looked great from the front.

I wanted this to be a wall hanging in my house (my wife has been hanging all her art up recently, and I wanted to compete a bit). I was worried about weight a bit so I used glue to glue 4 neodynium donut magnets (that I had lying around) to the back of the mirror. I then took an cheap steel ruler (from a cheap shop) and some adhesive picture hanging pads and stuck them to the wall. The magnets hold the mirror to the ruler, (hiding the ruler) and the pads hold the assembly to the wall. Plus when I move out I can remove these pads without damaging the paint.

How great does that look?

You don't have to use spray paint for this to work. Pretty much any method of marking will do. Here are two other paint fill mirror engraves I've done previously. One I filled with gold acryllic paint and a brush, the other one is literally just coloured in on the back with permanent marker (I actually really like the Vitruvian Man in Black on Mirror.

Again, taking photos of mirrors is really hard!

Let me know if you have a go at this!