Smoothing Out Your 3D Prints With Acetone Vapor

3D Printing & Imaging
Smoothing Out Your 3D Prints With Acetone Vapor
final result vs starting product
final result vs starting product

3D printing allows us to make some incredible things in our homes and workshops. People are prototyping products, designing bits and pieces to make their lives better, and spitting out more amusing trinkets than ever before.

Unfortunately, for the bulk of us who have a typical filament based printer, we’re stuck with a common problem. The surface finish of even the nicest prints are covered in tiny ridges. This is simply due to the way the printer works, building layer by layer on top of each other.

The great thing about the 3D printing community is that, for the most part, everyone loves to share the methods and practices they used to achieve things. Surface finishing is no different.

Some time ago I saw a method for smoothing out prints that involved making a chamber to hold acetone, placing your print in the chamber, then heating everything up for a short period of time. Typically people were using the heated beds of their printers to do this. I tried it and it worked decently. However, this really seemed like an incredibly dangerous setup. Not only do you have the enclosed space of your workshop, you have a container of acetone that is being heated up, building up pressure. Not a good situation.

Since then, several people have realized that the heating aspect is unnecessary. This allows us to do acetone smoothing in a much safer fashion.

YouTube player


It should be noted that this process only works on ABS.

To build a smoothing chamber, you don’t need much.

– a container, not too large

– paper towels

– aluminum foil

– acetone

As you can see in the video, the paper towels serve to hold acetone and distribute it more evenly. The foil simply keeps your part from coming in direct contact with the acetone.

Timing will vary depending on the size of your container, the size of your part, and how much acetone you add. This will require trial and error, so it may be smart to print a few copies of a test piece to figure out what works for you.

It should be pointed out that the ridges on your model will still be visible to varying degrees, even after acetone smoothing. The head that I left in the chamber for the longest time is completely smooth to the touch on the vertical surfaces but you can still see the remnants of the layers. Sloping surfaces like the top of the head are still clearly visible.

My personal feelings about the finish are that it generally looks a little to melted for my tastes. I’ve seen a few situations where it was preferred, but most of the time I’m fine with the ridges. However, I wanted to learn this and get the process down because you never know when you’ll need it. I like having this “tool” in my toolbox of skills.

11 thoughts on “Smoothing Out Your 3D Prints With Acetone Vapor

  1. Nathan Guice says:

    This is how craftsman and husky screw driver handles are polished clear.

    The material they use is an extruded Tenite tenite butyrate (a cellulosic plastic made primarily from wood pulp). Once extruded into rods (coextruded with the stripes). they are machined on a lathe. Then taken through an Acetone chamber for polishing. really quite amazing.

    I think the best results from a print would be to sand down as much of the ridges as possible, then use the acetone.

  2. msilvia says:

    I get great results by dissolving ABS scraps in acetone, and painting the finished prints with it. No ridges, no melty appearance, and I’m able to use any number of multiple colors for the finish.

    1. Caleb Kraft says:

      I’ll have to try that!

      1. msilvia says:

        Good luck, and let us know how it goes!

    2. Jason Wright says:

      Cool! Can you give details of the sort of ratio and texture for the mixture?

      1. msilvia says:

        Sure, I usually guesstimate and adjust, but you want it slightly thicker than maple syrup. It sholud be thick enough to form a skin quickly, and thin enough to flow and not leave globs on your print.

  3. D H says:

    How much acetone do you add to the paper towels?

  4. Dotsie Watson says:

    Many years ago, when Bell actually owned the telephones, they would rework the returned ones, polishing out blemishes, etc. and then solvent polish them to make them shiny again. But the phones were ABS so I think they used MEK vapor.

  5. John D says:

    I have been searching for an alternative method of smoothing out any type of plastic printed part, without having to boil acetone :S Seems someone has finally come up with something! There is a new coating called XTC-3D Epoxy Coating, I haven’t been able to find many places that carry it, but there is a good place in Canada.

    This coating brushes on super thin, and smoothes out ridges like a dream. Depending on the layer height, sanding is typically not needed. Worth checking out.

  6. megablue says:

    isn’t it better to sand it to smooth the surface before applying the acetone vapor?

  7. Tony Acevedo says:

    What about PLA? The acetone method only works on ABS.

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I get ridiculously excited seeing people make things. I just want to revel in the creativity I see in makers. My favorite thing in the world is sharing a maker's story. You can find me on twitter at @calebkraft and on youtube

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