xTool S1 40W Acrylic Cutting: $465 of Mistakes Later, Here's What Actually Works

I run a small laser engraving and cutting business out of my garage. Four years in, I've personally made—and documented—thirteen significant mistakes that cost roughly $4,600 in wasted budget. I keep the list because it's the only thing standing between me and a fourteenth.

October 2024 was the worst month on that list. That's when I unboxed the xTool S1 40W and learned that a capable machine doesn't automatically make you capable.

The machine that made me overconfident

Here's the thing about the xTool S1 40W: the marketing is mostly true. It does cut acrylic. It does a legitimately good job at laser engraving on aluminum, at least once you understand what's actually happening. And you can swap the xtool 20W laser module for S1 in five minutes, which is a big reason I picked it over a fixed-power machine. I wanted one frame that could handle thicker cutting jobs on Saturday and fine detail engraving on Sunday.

What the marketing didn't include was the learning curve. Or its price tag.

In my first three weeks with the S1, I ruined $120 of clear cast acrylic, gave a customer a stainless steel "engraving" that was basically a golden scratch, almost set the honeycomb on fire, and issued $180 in refunds. I keep a running damage total for every new tool. It sounds dramatic, but it's how I make sure lessons actually stick.

That total came to $465 in materials and consumables, not counting my time. Here's how I earned every cent of it.

Mistake #1: Clear cast acrylic is the wrong place to start

First real job on the new machine: wedding table numbers, the kind that stand up on a little base and catch the light. I bought three 18×24-inch sheets of clear cast acrylic—the premium stuff, protective paper still on, $120.

I was too proud to start with the manufacturer's material profiles. I'd watched a YouTube video where someone cut 10mm acrylic with a 40W laser in a single pass, so I decided to dial in my own settings. Classic overconfidence. I set 8mm/s at 85% power and hit start.

Ten seconds in, I knew something was wrong. There was no cut. There was a bubbled, brown smear and a smell I can only describe as a bad idea getting worse. Second pass didn't fix it. Third pass melted the sheet into a shape that wasn't a number, and a corner of the honeycomb started smoldering before I killed the machine.

My first instinct was to blame the laser. The real problem was physics. The S1 is a 450nm blue diode laser, and clear cast acrylic is, well, transparent to it. The beam passed through the material instead of being absorbed by it. What little energy the edges did absorb melted the material instead of vaporizing it cleanly.

I knew I should have tested on scrap before touching the good sheets. I thought, "what are the odds, really, that the machine can't do the one thing it's famous for?" The odds caught up with me. $120 in scrap and one near-miss with the smoke alarm.

What actually worked for acrylic (eventually)

Three days of forum reading later, I landed on the formula that most diode laser users eventually find:

• Use extruded acrylic for cutting, not cast. Cast acrylic cracks from thermal shock; extruded cuts cleaner and forgives small focus errors.
• Dark colors absorb 450nm light far better than clear. I cut a lot of black and dark green stock now.
• Air assist isn't optional. The difference between a frosted-looking edge and a clean one was, for me, mostly the air assist pointed exactly where the beam meets the material.
• Slow down. On my S1 with the 40W module, 6mm black extruded acrylic cuts at 6mm/s, 100% power, two passes, on the honeycomb bed. That's slower than the YouTube video promised, but it's repeatable.

When I switched to dark extruded stock and followed my own notes, the piece dropped out clean on the second pass. I just sat there for a minute. This whole disaster was because I was in a hurry to impress people I'd never met.

Mistake #2: "Laser engraving on aluminum" is a trap if you're not specific

Two weeks in, a local brewery asked if I could do laser engraving on aluminum—their logo on anodized aluminum pint cups. Twenty-four units. With the rotary attachment, each one spun under the laser head like a tiny planet.

Good news: the S1 does this beautifully. The anodized coating absorbs the diode beam and vaporizes, exposing the bare aluminum underneath. The result is a sharp, light-on-dark mark that looks genuinely premium. I was hitting crisp logos at 90mm/s and 35% power with the 20W module.

The bad news is I didn't understand why it worked. I told the brewery "yes" when they asked if we could do bare aluminum tumblers later. Bare aluminum reflects blue light. It doesn't engrave with a diode laser, at least not with enough contrast to look professional. My "one more pass will fix it" strategy produced a smudgy gray ghost and a week of delay.

The lesson had two parts. First, know whether you're marking the coating or the metal. Second, don't say yes to a material before the machine has proven it can handle it.

Mistake #3: Stainless steel laser engraving needs a different toolkit

Then came the stainless steel order. A corporate gift run: twenty stainless steel tumblers with names engraved. I accepted the job without testing a single one.

The 40W module on bare stainless steel produced a faint, peachy-gold tint that came off with a fingernail. More power and slower speed turned it into a darker gold tint that was still less "engraving" and more "very slightly toasted." Customers paying for stainless steel laser engraving want a permanent dark mark, not a heat stain you can polish off.

The fix was laser marking spray. Coat the steel, let it dry, run the beam. The laser bonds the sprayed compound to the surface and leaves a dark, permanent oxide mark that survives handwashing. It adds a step, a consumable cost, and a smell, but it's the difference between a finished product and an awkward refund.

I told the client three days. It took nine. That cost me more than money—referrals like that don't come back.

The real cost, or the part nobody prints on the spec sheet

Let me break down what October actually cost:

1. $120 – three sheets of clear cast acrylic that became a modern art project.
2. $85 – assorted acrylic, wood, and plastic test pieces. Mostly tuition.
3. $35 – marking spray for the stainless steel redo.
4. $45 – replacement honeycomb after I realized scorched cells can't be fully cleaned.
5. $180 – refunds and partial refunds for the delayed tumbler orders.

Total: $465, plus two weeks of evenings spent troubleshooting instead of building the business.

Here's the part I now tell anyone considering an S1. The box price is the beginning of the conversation. Air assist, rotary bundle, marking sprays, replacement beds, exhaust and filtration—they're all right there in the store, and they're not hidden. But I didn't ask "what's not included?" before I paid. That's on me.

I've learned to ask that question with every purchase since. The vendor who lists everything upfront, even when the total looks higher, usually costs less in the end.

So: is the xTool S1 the best laser for cutting acrylic?

I get asked this constantly, and the honest answer is: it depends on what "best" means to your business.

If acrylic cutting is most of your workload and you mainly cut clear cast sheets, a CO₂ laser is still the more appropriate tool—the 10.6μm wavelength is absorbed by clear acrylic instead of passing through it, which gives cleaner edges with less trial and error. I'm not going to pretend the S1 replaces that.

But if you need one machine that cuts dark extruded acrylic, engraves anodized aluminum, marks stainless steel with the right prep, handles wood and leather, and lets you switch between a 40W cutting module and the xtool 20W laser module for s1, then the S1 is a legitimately strong answer. It's not the best laser for cutting acrylic in a dedicated acrylic shop. It's a versatile multi-material laser that can cut acrylic when you respect the material. Those are two different statements, and the second one is exactly what I wish I'd understood in October.

"The machine doesn't lose money. The gap between what you assume and what you verify—that's where the money goes."

My checklist now runs: material type, extruded or cast, color, air assist confirmed, focus verified, scrap test before the real part, and one line at the bottom that says "what's not included in this process?" It has caught 12 potential errors in the three months since I wrote it. That's $465 worth of lessons paying rent.

One last note on safety, because I do not want anyone to skip the boring part: the S1 is a Class 1 enclosed laser product under IEC 60825-1, which is exactly why it's workable in a garage shop. Keep the enclosure intact, don't bypass interlocks, and still vent the exhaust outside or through a filter. Enclosed doesn't mean fume-free. Trust me—I smelled the evidence.

Looking back, I should have spent a weekend reading before I spent an afternoon cutting. At the time, I was in a hurry to prove the new tool would pay for itself. It has, since then. But the bill for the learning curve came due first.