Improve your 3D prints with chemical smoothing

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FFF 3D printers like the Original Prusa i3 MK3S enable you to print fascinating models with a very good level of accuracy. Yet sometimes it’s not enough. There are things that require a perfectly smooth and shiny surface – either for aesthetic or functional reasons. With SLA 3D printers, it’s no difficult job. But what about FFF 3D prints? Layer lines are usually quite prominent. Smoothing them out can be accomplished only by proper postprocessing. You might have heard of it, or tried it on your own already – like smoothing ASA/ABS 3D prints with acetone vapors. We still receive a lot of questions about how to make various materials smooth, though. So let us walk you through our instructions on how to make your model perfectly smooth and glossy.

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Safety first:

First, we need to remind you that in all cases of chemical smoothing we’ll work with flammable organic dissolvents and/or their fumes. Please follow the recommended safety precautions to protect yourselves and the people around you. Remember that you work with these chemicals at your own risk. Do everything necessary to avoid direct contact with and inhalation of chemicals. Always work in well-ventilated areas, as far as possible from flammable objects and use protective equipment such as gloves and face protection (protective shield or protective glasses). Acetone vapors tend to be very prominent and may cause respiratory issues.

How to choose the right material

When chemical smoothing is mentioned, many users will probably remember ABS or ASA filaments as materials that can be smoothed easily. This is why we will pay attention mostly to these materials. However, these types of filament are not the only ones which can be smoothed to a certain level. Every material has its own dissolvent (you can find it in chemistry tables) that will smoothen the material sooner or later. However, not every process is recommended, because many dissolvents are usually hazardous materials that are unavailable to a vast majority of people (e.g. chloroform, dichloromethane, etc.). Moreover, dissolving some filaments takes way too long, which makes them impractical for this type of postprocessing. Let’s evaluate several basic combinations of filaments and dissolvents that are often recommended among makers and see what are their advantages and disadvantages.

ABS and ASA

By far, the most suitable materials for smoothing are ABS and ASA in combination with acetone. You should be able to buy acetone at your local drugstore or hardware store and use it in your home workroom. Prusament ASA, in particular, can be smoothed out easily. And using the right method, you’ll get a nice smooth and shiny surface in no time. We will pay more attention to ABS and ASA in the following chapters.

PVB

Another very popular material is PVB (PolyVinyl Butyral), because it’s also easy to use (like PLA), it’s not prone to warping and it can be smoothed with isopropyl alcohol (IPA). However, if you use IPA vapors for smoothing (as you would with ABS/acetone), the process might take up to several hours. To speed it up, IPA should be applied directly onto the surface of your 3D prints. It’s better to disperse it just like the Polymaker Polysher and Zortrax Apoller do it.

HIPS

HIPS, aka high-impact polystyrene is generally used as a support material

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