Glowforge Aura Wattage, Plasma Cutters, and Granite Engraving: Lessons From a Shop Owner

I've been running a small fabrication shop for six years. In that time I've burned a decent amount of money on the learning curve—especially when I expected one tool to do the job of another. I got a Glowforge Aura in 2024, and I've used a CNC plasma cutting table since 2021. So when someone asks whether a Glowforge Aura Craft Laser™ cutting machine can replace a plasma cutter, or whether anyone actually laser engraves granite, I have a practical answer and a couple of failure stories.

Here are the questions I answer most often.

The Questions I Answer Most Often

What is the Glowforge Aura Craft Laser™ cutting machine?

The Glowforge Aura Craft Laser™ cutting machine is a desktop CO2 laser cutter and engraver. It's built for smaller jobs and detailed work on wood, acrylic, leather, paper, and some stone. I use it for products like custom keychains, engraved slate coasters, acrylic signs, and leather tags. The 'craft' in the name is accurate: this isn't a heavy industrial flatbed cutter. It's a machine that lets you go from design file to finished piece in a few minutes.

The thing that sold me was the workflow. The Aura has a camera and autofocus system, so I can place a material inside, let the machine scan it, and drop my design where I want it. No manual focus, no guesswork about where the beam will land. The software also includes a design library, which is useful when a client says 'I need a simple logo, make it look nice.'

What is the Glowforge Aura laser wattage?

According to Glowforge's official specifications, the Aura uses a 20W CO2 laser tube. That places it below the Glowforge Plus and Pro models, which use 40W and 45W tubes, respectively. For many craft projects, 20W is enough. I cut 3mm birch plywood regularly and engrave slate, stone, and coated metal. The bigger limitation isn't the wattage itself; it's speed and cutting depth. If I need to cut 12mm acrylic, the Aura is going to be slow, and I'd rather move that job to a larger machine.

Does wattage matter? Yes, but only up to a point. For engraving, power matters less than focus and material consistency. For cutting, wattage determines how many passes you need. I'd take a 20W laser with accurate software control over a 60W laser with poor software any day. That's not a fashionable opinion, but it's the one I've earned by redoing jobs.

Can you laser engrave granite?

Yes, you can laser engrave granite. A CO2 laser can create a permanent mark on granite by heating the surface and causing tiny fractures. The result is usually a light, frosted mark. I've made granite coasters and memorial tiles with this method. The Glowforge Aura can handle engraving on granite because the laser doesn't need to cut through the stone—it just needs to alter the surface.

You should not expect to cut granite with a desktop laser. I've seen people ask if a Glowforge Aura can slice a granite slab. It can't. A 20W CO2 laser will produce a shallow mark, not a cut. Even if you try multiple passes, you're spending hours and exhausting the air assist for no real benefit. The right approach is to engrave, then use a waterjet or diamond tooling if you need a physical cut.

Can you engrave granite with a plasma cutter instead?

No. A plasma cutter needs electrically conductive metal. Granite is not conductive. Trying to use a plasma cutter on granite will do nothing except damage your consumables. This is one of those questions that sounds silly until you see a shop owner stare at a stone slab and wonder if all that plasma power can do what a laser does.

My rule is simple: if the material is organic or a poor conductor, think laser. If the material is steel or aluminum, think plasma. That rule would have saved me a lot of time in the beginning.

What is CNC plasma cutting actually good for?

CNC plasma cutting is for cutting conductive metals quickly and accurately. The process involves an electric arc and compressed gas that turns into plasma, which melts the metal and blows it away. I use my table for steel brackets, frames, and metal signs. It cuts through steel sheet that a CO2 laser would never handle. That's the main strength: raw material thickness.

But there's a common misconception. People hear CNC plasma cutting and think it's a detail tool. It's not. The cut edge has a heat-affected zone, and there's often dross on the underside. On thin metal, a plasma cutter can warp the piece if you're not careful. For parts that need a finished appearance, I budget extra time for grinding or sanding. The plasma cutter gets the shape close; the finishing gets it to a quality standard.

So: using a plasma cutter vs the Glowforge Aura—which one do you need?

That depends on what you make. If your shop produces custom steel brackets, gates, or structural parts, you need a plasma cutter. If you're producing engraved gifts, acrylic awards, leather goods, or granite keepsakes, you need a laser. Many shops end up with both. They solve different problems.

I once had a job that required both. A client ordered 120 steel keychains with a laser-engraved logo. The keychains themselves came from a CNC plasma cutting process because they were steel. The logo was laser engraved because we wanted a crisp mark with fine letters. Could one tool have done both? No. The plasma cutter would have made the logo look like a rough weld. The laser couldn't cut the steel shape.

I told a client 'we can handle both' on a mixed material order. They heard 'one magic machine will do all of it.' Result: a confused phone call when they saw a plasma cutter in one corner and a laser in the other. It was my fault, not theirs. I learned to say 'we use two different processes depending on material.' This is where quality perception becomes real: the customer didn't care that we used two machines. They cared that the finished keychain looked sharp and expensive. If we had forced the plasma cutter to do the engraving, the result would have felt crude and unprofessional.

Can the Glowforge Aura cut any metal?

No. This is the most dangerous myth I see online. The Glowforge Aura, like other CO2 lasers, can only mark specially coated metal sheets or anodized aluminum. It cannot cut aluminum, brass, or steel. A CO2 laser wavelength is not well absorbed by bare metal, which is why metal-cutting lasers are usually fiber lasers. A plasma cutter, not a laser, is the right tool for cutting steel.

I bring this up because I nearly made the mistake myself. In 2023, before I understood the difference, I considered selling custom metal engraving using only the Aura. A more experienced fabricator explained that I'd need to order pre-coated metal blanks or use a fiber laser. That conversation saved me from a very public failure.

What was the biggest mistake you made with the Glowforge Aura?

The biggest one happened in September 2024, on a $3,200 order for 140 acrylic keychains. I traced a corporate logo, ran a quick test on a scrap piece from a different sheet, and started the full run. The pieces looked acceptable until I checked the edges closely. The masking on the acrylic was identical on the outside, but the material below was different: one roll was cast, the other extruded. The extruded pieces melted around the edges and caught light, making the text look fuzzy. I had already boxed 90 pieces before I noticed.

I stood there with a box of unusable product and did a quick risk calculation. I could ship the good pieces and remake the rest, or I could remake the entire order. The upside of shipping partially was saving a few days. The risk was losing a client who might see the difference and assume it was my normal quality. I chose to remake everything. That decision hurt in the short term, but it preserved the relationship. The wasted material and labor cost me around $1,100.

The lesson stuck. Now I have a checklist for every laser job: same sheet, same masking, same settings, test piece checked under good light before the run. It has caught 47 potential errors in the past 18 months. None of them were as expensive as that first one, but every one of them would have made me look sloppy.