Original Prusa CW1S review

Have you ever tried to manage sticky resin prints with nothing but a salad spinner and misplaced optimism?

What I Bought and Why It Changed My Routine

When I picked up the Original Prusa CW1S Curing and Washing Machine, I wanted a way to stop my workshop from smelling like a combination of hospital corridor and art school sink trap. I wanted fewer jars, fewer drips, and far fewer regrets. This compact 4‑in‑1 box promised preheating the resin before printing, washing, drying, and curing—essentially the whole aftercare ritual for SLA prints. It’s made to pair with the Original Prusa SL1S, but I’ve used it alongside other tabletop SLA printers without so much as a raised eyebrow. If it could also pay my electric bill, I’d knit it a tiny sweater.

The CW1S is a small appliance with big intentions. It heats resin so it flows nicely, creates a magnet-driven vortex to wash prints, dries them, and then cures them with four UV LED strips. It also has an IR sensor that recognizes when the liquid container is inside and shows only the functions I can actually use. I appreciate a machine that knows I shouldn’t be trusted with too many buttons at once.

First Look: A Little Box That Wants to Help

I’m a sucker for tidy design, and the CW1S looks like it would apologize if it took up too much counter space. It’s compact, squared-off, and neat, the sort of machine you could set next to a coffee maker without the neighbors thinking you’re building a submarine. The metal body feels sturdy, the door swings open smoothly, and the front controls are direct—no NASA mission planning, just simple presets.

The Moment I Met the IR Sensor

The quiet star is the IR sensor that detects the container inside. If the liquid tub is present, the machine offers washing and drying. If it’s out, you see options like curing. It’s like a friend who hides the cookie jar when you’ve sworn off sugar. I didn’t have to remember which steps belonged to which setup; it simply showed me the right list and moved me along. I wish my oven worked like this. Imagine it refusing to broil when you’re standing there in a nylon shirt.

Setting It Up Without Inventing New Swear Words

Setting up the CW1S took less time than figuring out why my cat prefers the resin box to my lap. I unboxed it, placed the liquid container inside, dropped in the magnet-driven propeller, and filled it with washing solvent—typically isopropyl alcohol (IPA), though other compatible wash fluids work too. Then I plugged it in and told myself not to touch anything with gloves that also touched the resin. Within ten minutes, I was ready to run a test.

Where It Lives in My Workspace

I gave it a stable, ventilated spot near my printers but not right up against them. Washing and curing create odors, and I like my lungs. I keep paper towels, nitrile gloves, and a lidded IPA jug within reach. For what it does, the footprint feels generous without being greedy. If I had the space of a New York shoebox apartment, it would still fit. If I had the space of a Midwestern basement, I would buy two and see if they bred.

How the CW1S Handles the Whole Post-Print Ritual

I needed a tool that wouldn’t just clean my prints but would also help me start right. The CW1S is odd in a delightful way because it begins before the first layer is cured. That resin preheating feature seems small until you use it.

Step 1: Resin Preheat

Resin behaves better when it’s warm. Instead of pouring like cold maple syrup, it becomes smoother, bubbles less, and sticks to the print layers just as it should. I learned this from experience and from a bottle that shivered audibly on a winter morning. The CW1S warms resin to a consistent temperature so the printer can do its job without wrestling with sludge. If you’ve ever tried to print in a chilly garage, this is as close to a guarantee as you’ll get that your first layer won’t look like a topographical bruise.

Step 2: Washing With a Magnet-Driven Vortex

Once a print is fresh out of the vat, the CW1S handles the wash with a magnet-driven propeller. It generates a vortex that whirls around the model, lifting off the resin without you needing to shake anything like you’re trying to revive a 90s bottle of mustard. My prints come out consistently cleaner than my old two-jar method, and I don’t find floating clumps of cured gunk lurking in the corners the way I used to. The vortex is gentle enough for delicate details but assertive enough to scold resin out of crevices.

Step 3: Drying Without Guesswork

After washing, the drying step is the sort of thing I used to skip in my rush, which would then punish me with foggy, blotchy cures. The CW1S dries the surface so there’s no IPA residue glinting on the model. A few minutes later, my prints look ready to attend a very tiny wedding.

Step 4: UV Curing With Four LED Strips

The curing chamber is lined with four UV LED strips that bathe the model in light. It’s an even cure, and the turntable-style platform helps ensure all sides get the same treatment. I’ve noticed dramatically fewer cases of uneven brittleness, and supports snap off more predictably. This is the step where the print stops being a suggestion and becomes a firm statement.

The CW1S Workflow in Practice

Here’s how a typical session goes for me—one small figure, one mid-sized bracket, and one large prop part if I’m feeling lucky. I preheat the resin if the room feels cold. I print. I carry the build plate over like a flight attendant handling soup in turbulence. I wash the part, dry it, and cure it. Then I manage supports and post-cure if needed. The whole routine is integrated enough that I no longer talk to myself while cleaning, which my family appreciates.

My Typical Time Budget

Different resins call for different times, but this is what I use as a starting place for Standard ABS-like resin:

• Preheat: 10 to 15 minutes (if needed)
• Wash: 3 to 6 minutes, sometimes 2 cycles for intricate pieces
• Dry: 2 to 5 minutes
• Cure: 5 to 12 minutes depending on thickness and resin

I still check parts by touch: if they feel slightly tacky, I add a minute or two. If they feel like a snack you’d regret, they probably need more washing.

A Quick Reference Table for Daily Use

Sometimes I need a cheat sheet because time has become a flat circle.

Mode	What It Does	Typical Duration	My Notes
Resin Preheat	Warms resin for smoother printing	10–15 min	Mandatory in winter, optional in summer
Wash	Magnet-driven vortex removes uncured resin	3–6 min	Two cycles for complex geometries
Dry	Evaporates solvent residue	2–5 min	Improves surface before cure
Cure	Four UV LED strips finish the print	5–12 min	Adjust based on resin/manufacturer

This is the routine I follow for 90% of my prints, and it has cut back on rework dramatically. Before, I was curing optimism more than resin.

Performance: What I Actually Noticed in Use

I’m not a laboratory. I’m a person with cabinets that never close the same way twice. Still, I noticed certain improvements.

Washing Quality

The vortex wash lifted resin out of nooks that once required a toothbrush, cold patience, and me mumbling about surface tension. Tiny details—scale mail, engraved text, and filigree—emerged sharper. I didn’t see the telltale cloudy areas I used to get when residue lingered. The magnet-driven propeller doesn’t grind away at the model; it moves the solvent across the surface quickly enough to dislodge resin without turning the tub into a turbulent soup.

Curing Evenness

The four UV LED strips distribute light consistently. I didn’t see the zebra striping effect I sometimes saw with my DIY light bucket. Edges felt uniformly strong, not crunchy in one spot and gummy in another. The turntable is subtle, but the combination of motion and multi-angle light adds up to a better cure. I’ve cured minis standing on their bases and tall brackets hung upside down; both came out predictably tough.

Noise, Smell, and Heat

It hums gently during washing and drying—louder than a phone, quieter than a hair dryer. The smell depends on your solvent and resin, but the closed design tamps down the aroma nicely. As for heat, it gets warm, never alarming, and the chassis feels well-insulated. I still ventilate the room, but I no longer feel like my workshop is cosplaying as a nail salon.

Energy Usage

I didn’t whip out a watt meter, but an afternoon of washing and curing didn’t upset my electric bill any more than a baking session. Preheating, washing, drying, and curing are all short bursts. If you’re printing production runs, you’ll notice it; for hobbyists and small businesses, it’s reasonable.

Design Touches That Made Me Smile

Some machines feel like they were built to keep you on your toes. The CW1S feels like it wants you to sit down and relax, within reason.

The IR Sensor That Nudges Me Along

The IR sensor that detects whether the liquid container is inside effectively greys out the steps I can’t use. Put the container in, and washing appears. Take it out, and the machine suggests curing. It’s the lightest form of hand-holding and exactly what I need when I’ve been touching resin and my brain is halfway to a shower.

The Magnet-Driven Propeller

The magnet-driven propeller means fewer moving parts getting stuck, less gunk building up on a shaft, and a swirl that’s assertive but not violent. It’s the difference between a polite mixer and an enthusiastic blender. I’ve washed thin lattice structures without bending them, which never happened in my old jar-and-hand-shake routine.

Compact Build, Thoughtful Internals

Everything inside feels purposeful—no wasted corners, no spaghetti wiring. The door seals well. The inner surfaces are wipeable. The container pulls out without catching my sleeves, and the basket and platform are easy to rinse. If I don’t swat resin across the room like a fly, it’s often due to the machine—not a change in my personality.

Compared With Other Options I’ve Tried

If you’ve gotten this far, you probably already know the dance. You can cobble together a system with plastic tubs, a salvaged UV lamp, and determination. Or you can get a dedicated machine like this. I’ve tried both and a couple of competitors.

DIY: Jars, a Paint Mixer, and a Sun-Lamp

I used to keep two IPA jars: dirty and dirtier. I swished parts around like they were tea bags, then waved a UV lamp over them while humming a spell. The results were inconsistent. Some days I nailed it; other days, supports welded themselves on like they were unionized. If you enjoy improvisation, DIY works. If you enjoy consistency, the CW1S wins.

Competitors I’ve Used in Parallel

I’ve used dedicated wash-and-cure machines from Elegoo and Anycubic. They’re solid, often cheaper, and plenty capable. But the CW1S wins for me in a few places: resin preheating, smarter mode switching via the IR sensor, overall build quality, and the wash vortex that seems tuned for detail preservation. It also looks like it got dressed before leaving the house.

A Head-to-Head Snapshot

Feature	Original Prusa CW1S	Elegoo Mercury Plus (various models)	Anycubic Wash & Cure 2.0
Functions	Preheat, Wash, Dry, Cure (4-in-1)	Wash, Cure	Wash, Cure
Sensor Smarts	IR sensor detects container and adjusts modes	Basic	Basic
Wash Mechanism	Magnet-driven propeller vortex	Rotating impeller	Rotating impeller
UV Setup	4 UV LED strips with reflective chamber	LED array and turntable	LED array and turntable
Build Quality	Metal chassis, compact, sturdy	Good, plastic-heavy	Good, plastic-heavy
Footprint	Compact	Compact	Compact
Price	Higher	Moderate	Moderate
Resin Preheat	Yes	No	No
Overall Feel	Workshop-grade, thoughtful	Hobby-friendly	Hobby-friendly

If resin preheat matters, the CW1S stands alone here. If budget is king, the others will suit. I’m rarely loyal, but the CW1S made me tidy and that counts for something.

What I Didn’t Love

No review is complete without a little list of irritations. Consider these small pebbles in an otherwise very nice shoe.

Cost

It’s not the cheapest wash-and-cure machine. You’re paying for the smart touches and the compact, workshop-grade build. If you’re a weekend-only printer who makes two minis a month, it might be more machine than you need. If you print like you mean it, the price feels justified.

Bath Size Limits

The container is sized for typical tabletop SLA prints. If you’re washing very large pieces, you’ll either split the models or wash in sections. I’m fine with this, but I had to adjust expectations—no cleaning a dragon the size of a feline in one go.

Solvent Management

No matter what machine you buy, you have to handle IPA or a compatible wash fluid. It gets dirty, it needs replacing, and you need a responsible disposal routine. The CW1S doesn’t change chemistry. It only makes the handling more civilized.

The “One More Minute” Habit

The cure stage is so easy that I sometimes over-cure, thinking more is more. It isn’t. Use the resin manufacturer’s guidance and resist the urge to turn everything into a rock.

Tips That Saved My Prints (and My Nerves)

I learned the following the hard way so you don’t have to re-enact my mistakes:

• Preheat when your room is under 22°C/72°F. Resin behaves like a happy dancer, not a sulky teenager.
• Wash delicate parts for shorter intervals, twice. The double cycle helps free resin without stressing thin features.
• Always dry before cure. Residual IPA is sneaky and causes surface haze.
• Cure with supports on if you need to preserve geometry. Remove supports after a brief partial cure to avoid scars, then finish-cure.
• Label your wash container by resin type. Mixing resins in the same solvent shortens the life of your bath.
• Skim cured residue from the wash liquid now and then. It keeps the vortex effective.
• Store the wash fluid in a sealed, clearly labeled container. Your future self—and any housemates—will be grateful.
• Keep a UV-safe trash bin for contaminated wipes and gloves.
• For translucent resins, use shorter cure times. They can over-cure into brittleness faster.
• If the part feels tacky after cure, test a 60–90 second increment rather than adding five minutes. Small steps help avoid overdoing it.

Maintenance: The Chore I Don’t Mind

Maintenance is straightforward, and I say that as someone whose houseplants wake up each day wondering if this is their last sunrise.

• After washing sessions, I remove the container, put on gloves, and pour the used solvent through a fine mesh into a labeled bottle for settling and reuse.
• I wipe down the chamber walls with a paper towel lightly dampened with clean IPA. If anything sticky remains, I finish with a dry towel.
• I remove the magnet-driven propeller occasionally and rinse it. It takes seconds and prevents the “mystery sludge” effect.
• The UV chamber door and reflectors stay clear if you don’t touch them with resin hands. If you do, wipe gently—scratches are forever, and forever is too long to look at smudges.

I haven’t had to replace any internal parts. The machine behaves like it wants to last.

Safety Notes I Actually Follow

No machine can neutralize the realities of resin. I use PPE: nitrile gloves, safety glasses, and an apron I pretend is stylish. I ventilate the room. I keep IPA away from heat sources and label everything. I don’t cure parts in the same room as my pets because my pets are the type to investigate glowing things. The CW1S helps by confining the smells and the process, but it doesn’t replace common sense.

Real-World Use Cases That Won Me Over

I’ve run a few torture tests—my own small drama.

• Miniatures with capes and hair-thin spears: The vortex washed them clean without stress fractures. Supports came off like reluctant but polite guests.
• Functional parts like brackets: Edges stayed true after a measured cure. Over-cure made them brittle on an earlier attempt; the CW1S’s consistency helped me correct that on the next one by sticking to a shorter time.
• Translucent resin charms: Quick wash, careful dry, and a conservative cure kept them glassy rather than frosted.

The standout change is how predictable everything feels. I still have the occasional surprise, but it’s the sort of surprise like finding an extra fry in the bag, not discovering the bag is on fire.

A Closer Look at the Smart Design

If you need more reason than “it works,” the CW1S offers good hardware choices.

Resin Preheat That Feels Like Cheating

Preheating resin makes prints stick, reduces micro-bubbles, and improves layer adhesion. This is the step I didn’t know I needed, the way I didn’t know you could put salt on watermelon. I’ve had first layers go from patchy to uncompromised simply because the resin wasn’t shivering.

Container-Aware Modes and Sanity

The IR sensor doesn’t just detect the container; it streamlines the interface. I waste fewer seconds fumbling with the wrong mode. It’s like a car that refuses to let you open the trunk while driving. Annoying in theory, helpful in practice.

Four UV LED Strips and Even Light

A uniform cure is often the difference between “snaps together” and “snaps apart.” The LED arrangement and reflectivity of the chamber produce an all-around cure without hot spots. I suspect this is why my sharper edges no longer look like they were sanded by a raccoon.

Batch Printing and Throughput

If you’re churning out parts for a small shop or online storefront, time matters. I learned to queue prints so that as soon as one batch starts curing, I’m prepping the next wash. The drying step is quick enough that it doesn’t bottleneck. Using two wash containers—one for a first wash, one for a cleaner second—speeds things up further. Because the machine’s footprint is small, I can keep these containers ready without building a shelving unit that requires a zoning permit.

Common Questions I Asked Myself Before Buying

I had doubts; of course I did. Here are the answers I wish I had in one spot.

• Is it compatible only with the Original Prusa SL1S? No. It’s recommended for the SL1S, but it works with other tabletop SLA printers. I’ve used it with several brands without issue.
• Does preheating the resin really matter? Yes, especially in cooler rooms. It improves flow and layer bonding noticeably.
• Can I use water-washable resins? Yes, but follow the resin manufacturer’s guidelines. Water-washable doesn’t mean “bathroom sink washable.” Collect and dispose responsibly.
• How do I know when a part is fully cured? I touch a hidden area for tackiness and check for a consistent, satin finish. I also follow resin-specific cure times, adjusting in small increments.
• Is the wash container sealed? It has a lid for storage, but during operation it sits in the machine open. I store it sealed when not in use to limit evaporation and odor.
• Will it cure inside deep cavities? Light penetration has limits. For hollow parts, I cure longer and rotate the part, sometimes adding brief secondary cures to specific areas.
• How often do I change the wash fluid? When it looks like a dirty martini that’s offended by your presence. More practically, when residue begins to redeposit or wash times lengthen with worse results. Settling and filtering extend its life.
• Does it overheat small parts? No, but over-curing can make parts brittle. Use moderate cure times and test in increments.

The Results That Sold Me

I like data, but I like peace of mind more. After a month of consistent use:

• My rewash rate dropped to nearly zero.
• Surface quality improved, especially on tiny features.
• Support removal felt more predictable and kinder to the model.
• My workspace got cleaner because the process lived in one tidy box.

Printing stopped being a series of sprints between jars and towels. I can now print on a weeknight without the household filing a complaint.

Pros and Cons, Because Life Is Balance

I keep lists. I keep them in places I forget. Here’s the list I won’t forget.

Pros:

• True 4-in-1: preheat, wash, dry, cure in one compact unit
• IR sensor that shows relevant modes and helps avoid mistakes
• Magnet-driven vortex wash that’s effective yet gentle
• Even curing with four UV LED strips and reflective chamber
• Solid build quality and small footprint
• Simple interface with sensible presets
• Great for consistent results across different resins

Cons:

• Higher price than budget competitors
• Wash container size limits giant single-piece prints
• You still have to manage solvent responsibly
• Easy to over-cure if you get zealous with the timer

Who I Think Should Buy This

If you print weekly or more, care about surface quality, and prefer your workshop to resemble a workspace rather than a chemistry accident, the Original Prusa CW1S is the right kind of friend. It’s especially helpful if you use the Original Prusa SL1S, but compatibility with other desktop SLA printers makes it a versatile pick. Small studios, Etsy sellers, engineering students, and hobbyists who like their sanity intact will appreciate it most. If you rarely print and love tinkering with DIY setups, you can get by without it—but you’ll miss the preheat feature the first time your winter resin acts like molasses.

A Second Table for the Practical Among Us

I like seeing benefits in cold print, even if I describe them with warm feelings.

Task Without CW1S	With CW1S	What Changed for Me
Room-temperature resin in winter	Resin preheat step	Fewer failed first layers
Jar swish wash	Magnet-driven vortex wash	Cleaner details, less residue
Air dry or paper towel dab	Timed dry cycle	No IPA splotches before cure
DIY UV lamp cure	Four UV LED strips, turntable	Even cure, fewer brittle spots
Post-processing spread over half a bench	One compact device	A neater, safer workspace

I didn’t expect the “one device” approach to matter so much. It did. It reduced the number of ways I could get something wrong.

Little Behaviors That Add Up

I’ve found that making the CW1S the natural “next step” reduces my tendency to put things off. I take the print out of the vat, into the CW1S it goes, then onto the curing platform, and finally to the shelf. There’s a rhythm. When a machine gives me a rhythm, I keep better habits—gloves on longer, lids closed, towels tossed in the right bin. It’s not just about prints. It’s about being a functional adult for twenty minutes at a time.

Edge Cases and Oddities

• Very small parts can wash so well that they hide in the basket. I use a fine parts strainer for mini bits.
• Very tall parts sometimes benefit from a rotate-and-cure approach. I split the cure time in half and flip the part.
• Flexible resins prefer shorter cures. Think of them like pancakes: once burnt, they don’t come back.

None of these are faults of the CW1S; they’re quirks of resin printing. The machine simply makes the quirks manageable.

What I Wish It Had (But Don’t Miss Much)

A built-in filter for the wash fluid would be nice, but it would also complicate a device that currently feels straightforward. An automatic lift for dunking parts would be theatrical, but that’s what my hands are for. A scent diffuser that emits whiffs of fresh bread would be perfect, though probably not advisable near solvents.

The Bottom Line I’m Happy to Stand On

The Original Prusa CW1S does something rarer than it seems: it reduces friction. From resin preheating to IS-washing to drying and even curing, it removes the parts of the process where I would lose time, patience, and occasionally a part to user error. It treats prints gently but efficiently. It looks good without trying too hard. It is, in short, the appliance my resin workflow didn’t know it was waiting for.

I started using it because I wanted less mess. I keep using it because I want more predictability. And because it introduced me to the quiet joy of preheating resin, which feels like a magic trick I can do before coffee. If what you want is a compact, thoughtfully designed, 4‑in‑1 machine that knows when the tub is in place and what step comes next, this is the one.

If the budget allows, I’d buy it again. If mine wandered off, I would look for it on missing posters and offer a reward. And if anyone asked whether it’s worth making room for in a small workshop, I would say the same thing I say when asked about owning a proper kettle: once you have it, you wonder why you waited.

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