A lot of 3D printing hobbyists wonder how to smooth PLA with ease so that their prints end up looking the best possible. That’s why I decided to write this article, to teach people how to smooth PLA 3D prints with ease.

To smooth PLA 3D prints with ease, you can either sand your model, with sandpaper of different grits or you can try the chemical smoothing method by doing an acetone vapor bath on your model. Coating your print with UV resin or XTC-3D epoxy are also viable solutions that will result in a smooth PLA print.

This is the basic answer, keep reading for more information on how to smooth PLA 3D prints with ease.

How to Smooth PLA 3D Prints with Ease

These are the main ways to smooth PLA 3D prints with ease:

1. Sanding
2. Chemical smoothing
3. 3D printing resin coating
4. XTC-3D

1. Sanding

The most popular method to smooth PLA 3D prints with ease is sanding as it is one of the most straightforward and effective methods for smoothing PLA 3D prints. 

Here’s how to do it:

• Purchase sandpaper
• Start with coarse grit
• Progress to finer grits
• Clean and finish

Purchase Sandpaper

The first step to smooth PLA 3D prints with ease is to purchase sandpaper. You will need sandpaper with varying grits, ranging from coarse (around 100-200) to fine (800-2000).

The HSYMQ 24PCS Sand Paper Variety Pack Sandpaper 12 Grits Assorted for Wood Metal Sanding can be found over at Amazon with great reviews.

Start with Coarse Grit

The next step is to begin sanding your 3D print with a course sandpaper of around 100 grit to remove obvious layer lines and imperfections. 

Some users recommend using a sanding block to ensure even pressure and avoid creating flat spots. You can find the BOSHCRFAT 10 Pack Sanding Block available at Amazon for a reasonable price.

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Progress to Finer Grits

Then, the next step is to gradually move to finer grits (higher number) as you smooth out the surface. Each finer grit will remove the scratches left by the previous coarser grit, resulting in a smoother finish.

One 3D printing hobbyist recommended starting with a relatively coarse grit, around 150, after the initial sanding he advised moving to a higher grit and sanding in a different direction. 

This allows you to detect the rest of the deeper scratch lines from the previous stage. 

By continuing to sand until these old lines disappear, users can progressively move up to finer grits for a smoother finish.

Take a look at the work in progress of one 3D printing hobbyist:

Always heard that you cant acetone smooth pla but…..
byu/optyumart in3Dprinting

Clean and Finish

After sanding, clean the print to remove dust and debris. You can then apply a primer or paint for a professional look.

One user recommends applying a plastic primer as you sand the model and leaving only the painting to be done after it. He thinks this is the best way to smooth out PLA 3D prints.

Another user stated that PLA can be smoothed easily with sandpaper, giving very good results. He suggests cleaning it with IPA after sanding it down. If you still think it needs work, only then he recommends using a plastic primer or a filler.

Check out the video below for more information about this method.

2. Chemical Smoothing

Another popular method to achieve a glass-like finish on PLA prints is by following the chemical smoothing method. 

To do it, just follow these steps:

• Choose your solvent
• Prepare a container and pour the solvent
• Suspend the print and seal the container
• Remove and dry

Choose your Solvent

The first step you’ll need to do is to choose your solvent. 

Acetone is commonly used for smoothing PLA. Ensure you are working in a well-ventilated area or under a fume hood when using it.

One user explained that sodium hydroxide should be used as a dip rather than a vapor bath, as it has an extremely low vapor pressure, likely one or two orders of magnitude less than solvents. 

For a safer and more accessible option, they recommended ethyl acetate, which can be readily obtained from non-acetone nail polish removers. 

Here is the DIY setup that one 3D printing hobbyist did to use ethyl acetate:

Ghetto PLA smoothing
byu/Garuda1_Talisman in3Dprinting

However, they cautioned that any vapor-based smoothing process might negatively impact the print’s quality, rounding off sharp edges and potentially causing the loss of small features before achieving the desired smoothing effect.

Prepare a Container and Pour the Solvent

The next step is to prepare a container and pour the solvent. Find a container large enough to accommodate your print. A glass jar with a sealing lid works well. 

Then you’ll need to pour a small amount of acetone into the container, just enough to cover the bottom.

You can find the mDesign Plastic Deep Storage Bin Box Container with Lid and Built-In Handle at Amazon for a great price.

Suspend the Print and Seal the Container

The next step consists of suspending the print and sealing the container. To do that, just place the print on a platform above the acetone, ensuring it does not touch the liquid. 

Then you’ll need to seal the container and leave it undisturbed for several hours or overnight. The acetone vapor will smooth the surface by melting and re-solidifying the PLA.

I wrote an article called How to Smooth 3D Prints with Acetone that may be helpful to you if you decide to follow this method.

Remove and Dry

After the desired smoothing level is achieved, carefully remove the print from the container and allow it to dry completely.

One user stated that this kind of method works better on clear and pure PLA as the colors may diminish the effectiveness of the chemical smoothing. 

You can find the Super Nail Pure Acetone on Amazon with great reviews and a reasonable value.

Check out the video below for more information about how to smooth PLA with acetone.

3. 3D Printing Resin Coating

Another popular method to smooth PLA is the 3D printing resin coating, which consists in using resin to coat your PLA print can give you a glossy, smooth finish. 

Here’s how to do it:

• Select a clear resin and prepare the print
• Apply resin
• Cure the resin
• Inspect and repeat

Select a Clear Resin and Prepare the Print

Choose a clear or transparent 3D printing resin and make sure that your PLA print is clean and free of dust and debris.

You can use the ANYCUBIC 3D Printer Resin SLA UV-Curing Resin which is highly recommended by different users for this method.

Apply Resin

Using a brush or dip-coating method, apply a thin layer of resin to the entire surface of the print. One user recommends using the same resin you can print with to apply a smoothed outer layer.

He stated that this method is really straightforward, consisting of just a clear coat of UV-reactive resin that is brushed on the part. He said you don’t need even a specific SLA resin.

As an example, he stated that he used a cheap automotive resin on his FDM prints and it took out all the layer lines perfectly.

Cure the Resin

Use UV light or follow the manufacturer’s curing instructions to harden the resin coating. This step can be done using a UV curing chamber or direct sunlight.

You can find the 3D Printer UV Resin Curing Light for SLA/DLP/LCD 3D Printing at Amazon for a great price.

Inspect and Repeat

Examine the print’s surface and repeat the resin application and curing process if necessary until you achieve the desired smoothness.

One user stated that while this smoothing method worked really well for him, after exposing his 3D printed parts to sunlight they started to yellow a bit.

Check out the video below for more information about 3D printing resin coating.

XTC-3D

Using XTC-3D is another popular method to smooth PLA. 

XTC-3D is a specialized epoxy coating designed to provide a smooth, glossy finish to 3D printed objects, including those made from PLA. 

This method is particularly popular among hobbyists and professionals for its ease of use and exceptional results. 

Here’s how to utilize XTC-3D to achieve seamless PLA smoothing:

• Purchase XTC-3D and prepare your PLA print
• Mix and apply the XTC-3D epoxy
• Allow for drying and curing

Purchase XTC-3D and Prepare your PLA Print

The first step is to purchase XTC-3D and prepare your PLA print. You can find the XTC-3D epoxy from its official website or from XTC-3D from Amazon.

It is recommended to wear appropriate safety gear, including gloves and eye protection when working with epoxy coatings.

Users also recommend having disposable stirring sticks or utensils handy for mixing. Brushes and foam applicators will be used to apply the epoxy smoothly and evenly.

Ensure your PLA print is clean and free from any dust, debris, or grease. 

Mix and Apply the XTC-3D Epoxy

The next step is to mix and apply the XTC-3D. It is recommended to follow the manufacturer’s instructions for mixing the XTC-3D epoxy. 

Typically, it involves combining equal parts of the resin and hardener. Stir the mixture thoroughly, but do so gently to minimize the introduction of air bubbles.

Using a disposable brush, carefully apply a thin, even coat of the XTC-3D epoxy onto your PLA print. Work methodically to ensure complete coverage while avoiding excess pooling or drips.

One 3D printing hobbyist stated that the key when using XTC-3D is to apply multiple thin coats. 

He said that it lasts for a while and recommends using synthetic brushes as they work a lot better than foam ones.

Allow for Drying and Curing

The next step is to allow for drying and curing. Once the epoxy is applied, place your coated print in a dust-free and well-ventilated area to dry and cure. 

The curing time may vary depending on factors such as temperature and humidity, so refer to the manufacturer’s guidelines. 

It can take a few hours to achieve a tack-free surface, but a full cure may take longer. 

One user recommends the XTC-3D to smooth PLA. He stated that although it isn’t a miracle fix, it can hide a lot without the need for sanding.

Another user suggests XTC-3D as the easiest way to smooth out PLA. He stated that it is not perfect but it helps a lot.

Check out the video below for more information about XTC-3D.