Okay, here goes…I intend to try cutting metal for wall art. What type and where can I purchase or beg for free? Lucie.
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That is basically impossible with consumer-grade CO₂ lasers, because metals very effectively reflect the infrared laser beam: no absorption = no heating = no nothing. Bonus: the reflected energy can damage the focus lens.
You can cut / engrave acrylic mirrors (from the back side) and cut / engrave metallic-looking Trolase, but real metals are off the table.
You should have spent your money on a plasma cutter.
Too! 
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Just Google local metal suppliers, but an 80W CO2 won’t get you where you want to go. Scissors would be faster and yield better results.
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I had asked my brother earlier and his response “You CAN’T”.
Can’t what?
I have a dozen or more metal suppliers within 45 minutes of me. Anything from wire to I-beams and shim stock to plate as thick as maybe 6". Pipe. Barstock. Aluminum, steel, titanium, brass, copper…pretty much whatever.
… always get what you want, but …
For small-scale wall art, various shades of Trolase Foil might work pretty well as a decorative surface treatment, rather than a structural element.
Their Thins line of acrylic has fewer colors, but would be self-supporting across small areas.
The Metallics line is more substantial.
All of those are intended for signs / labels with engraved text, but you don’t have to tell anybody they’re not really metal.
Their site layout makes it difficult to see the entire assortment at once, but if you spend some time rummaging around, … you just might get what you need.
(Which will be stuck in my head for the rest of the day.)
My dad was a commercial artist. What i want to do is etch some of his sketches on metal. The attached file is one I found Googling Metal Art. What metal does one use on a CO2 Rudia laser?
One of my Dad’s sketches:
You won’t be able to engrave directly to metal with that laser. Some workarounds:
- Use something like Cermark to pretreat metal. This will allow you to get a durable dark mark onto metal. You’ll need to experiment with shading but you won’t get colors this way.
- You could try painting the metal first with one or multiple layers of colors… then carefully setting your speed and power settings to reveal different layers of colors.
- Looking at the illustration it might be a good candidate to experiment with lasering powder coating powder. I’ve not seen anyone attempt this onto metal but the muted colors may be an interesting fit.
As I said above, you don’t.
Metal is highly reflective in the IR wavelengths of CO₂ lasers; different metals have different reflectivity values, but they’re all reflective.
Lasering painted metal depends on removing the coating to expose the bare metal underneath, whereupon reflectivity happens.
The problem is that reflecting the IR energy back into the laser optics is a Bad Idea™ that can damage everything from the focus lens back to the tube itself. IIRC, @jkwilborn has a fried lens resulting from doing exactly that.
(Industrial metal-cutting CO₂ laser machines exist. They are a completely different breed than the consumer-grade CO₂ lasers we civilians can afford.)
Lasering Cermark and powder-coat paint leaves the coating intact, so it’s (in principle) not risky behavior. You must pay close attention to the speed & power to avoid torching through the pigment down to the metal.
If it is your laser, sure, go ahead. If the laser belongs to the Rochester Makerspace, definitely get their permission first …