Review: Polymaker’s Polysher Makes Your 3D Prints Shiny and Smooth

As a maker, your 3D printer is probably one of the most important tools in your arsenal. The freedom to quickly and easily print your parts is indispensable, but we all experience the frustration of layer lines. They’re a dead giveaway that a part is just a prototype, and really detract from an otherwise professional-looking build. Polymaker’s Polysher device, when used with their PolySmooth or PolyCast filament, promises to remove those lines and give you a nice, smooth finish.

If you’re experienced with 3D printing, you’re probably familiar with how acetone can be used to smooth out ABS prints. The acetone starts to liquefy the surface of the print, which reduces the prominence of layer lines. The problem is that acetone only works on ABS. Even if you like printing in ABS, it’s difficult to apply acetone to the part in a controlled manner. The Polysher solves both problems.

The Polysher has a sealed enclosure, and inside is a nebulizer that creates a fine mist of alcohol. Don’t use acetone, it will damage the device. Just fill the reservoir with 70–90% isopropyl alcohol, put your part inside, and start the polishing process. The chamber will fill up with a misty cloud of alcohol, and your part will spin on its platform. The polishing time is up to you, but in roughly 30 minutes you should end up with a nice and smooth part.

This process only works with Polymaker’s proprietary PVB-based PolySmooth and PolyCast filaments. PolySmooth, which is what I tested the Polysher with, is a material with properties similar to PLA that can be printed with the same settings. It costs roughly twice as much as generic PLA, so you will probably only want to use it for the final revision of a design after testing with the cheap stuff. PolyCast is a material formulated specifically for investment casting.

The question on your mind, of course, is how well the Polysher actually works. To test it, I started with Thingiverse user Abei’s Fallout Vault Boy 3D model. I printed this in black PolySmooth on an Original Prusa i3 MK3, using the “Optimal” 0.15mm print settings with supports at 20%. Here is the result before smoothing, with supports removed:

This model is 80mm tall, and, as you can see, the results are pretty good even before smoothing. The overall quality is almost exactly the same as standard PLA. But, the layer lines are still visible, and some of the imperfections from the supports are apparent. Let’s see if the Polysher can take care of those:

Polymaker recommends 90% isopropyl alcohol, so that’s what I used. I set the Polysher for a 30 minute cycle, and left it to do its thing. After the process was finished, I removed the tray. Immediately after polishing, the surface of the part will be tacky. But, after about 30 minutes, it can be gently handled.

The results were quite good, and I was impressed by how smooth the surface was after a cycle in the Polysher. The layer lines were almost completely imperceptible, but most of the fine detail in the model remained. Polymaker says that it takes about 72 hours for the alcohol-exposed material to fully harden, but that’s a small price to pay for such a nice surface finish that doesn’t require any manual post-processing.

I was, however, curious if I could achieve similar results by simply spraying alcohol onto the part. Polymaker themselves say that’s a good way to handle touch-ups with the PolySmooth filament. So, I printed another vault boy and starting spritzing it with the alcohol.

Spraying the part with alcohol myself did work, but not nearly as well as the Polysher. I showered the vault boy liberally several times over the course of a couple of hours, and the layer lines were certainly reduced. But, they were still visible. You can clearly see the difference between regular, unfinished PLA, the manually-sprayed PolySmooth, and the Polysher-polished PolySmooth.

The Polysher-smoothed part is the obvious winner here. Not only were the results better, but I didn’t have to babysit the process with a spray bottle. That said, you can get nice results out of the PolySmooth filament even without a Polysher.

Figurines like the vault boy are a major use case for the Polysher, and many of you will purchase the device specifically for smoothing out models like that. But, personally, I’m far more interested in smoothing out enclosures and cases for my projects. The closer it looks to an injection-molded enclosure, the happier I am. So, I tested out the Polysher on a Raspberry Pi case designed by Thingiverse user Tripnutz.

Once again, the results were very nice. Some of the imperfections and layer lines were still visible, but it definitely looks more like an injection-molded part than a 3D-printed one. If you like to share your projects online, the professional appearance of a enclosure of processed in a Polysher is bound to score you some internet points.

As you can tell, my opinion of the Polysher is quite favorable. But, that doesn’t mean it doesn’t have some weaknesses. The most glaring to me was how slow the platform raises and lowers. I don’t know why Polymaker chose the motorized mechanism over a simple latching door, because it takes a painfully-slow 45 seconds to open and close.

For many of you, however, I think the $299 price tag will be the major sticking point. That’s a non-trivial amount of money, a lot of you probably spent less than that on your actual 3D printer. If you can’t swallow that price tag, you’ll probably want to consider using PolySmooth with an alcohol spray bottle. But, if smooth 3D-printed parts are important to you, the Polymaker Polysher could be well worth your money.