Can You Use Spackle On 3D Prints? How To Smooth A 3D Print!

Finishing a print is possibly the most rewarding part of 3D printing. It is literally where you make your print shine. There is no greater joy than seeing a finished project in all its glory. 

But how do you get to that point? There are a couple of post-processes for 3D printing. In this guide, we want to focus on fixing the gaps in your prints and how to smooth out PLA prints. We also look at how to use a body filler like Bondo on 3D prints. 

Before we get to all that, however, let’s talk a little about spackle. Can you use it on 3D prints?

Spackle is a general purpose putty typically used to fill holes, cracks, and other blemishes in a wall or furniture before applying any paint to it. In that sense, it is similar to something like a joint compound used for the same thing.  Unlike joint compound, spackle has less shrinkage, is quick drying and is more suited for smaller jobs. This is what makes it ideal for filling gaps in 3D prints. One could use joint compound or drywall mud as it is also called, if one don’t mind waiting since joint compound dries slower than spackle.

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This printer is an upgraded version of the popular Ender 3 model, with a range of new features and improvements that make it even easier and more convenient to use.

The Ender 3 V2 is an excellent choice for beginners, kids, and experienced users.


How To Use Spackle On A 3D Print ?

Working with spackle is fairly simple. The first and most important thing to do is clean your print. You need to remove any oil or dust that might be on the print. Petroleum will do the trick and without damaging your print. 

Once you’ve removed any dirt from the surface, the next step is to mix the spackle until you get a good consistency. Then apply the spackle on the areas you want to work on. Once the spackle is dry, you can proceed to sand it down. 

What To Use To Fill In Gaps On 3D Prints ? (Substitutes)

Almost any general purpose putty or filler can be used to fill holes and repair cracks in a 3D print. Some of the most common fixes include using wood filler and automotive filler. 3D pens are also an excellent alternative.

Wood Fillers

Wood fillers are a popular DIY choice for most users. They’re cheap, easy to use and dry in between 15 to 30 minutes. Also, if you’re looking for a filler that will not clog up your nostrils, go with a wood filler since they are odorless.

Also, check out “Can You Stain 3D Printed Wood Filament? 5 Simple Steps!

Automotive Fillers

Automotive body fillers are used to repair minor damage and smooth out the surface of a vehicle. Similar to how you would use spackle on your walls, you would use body filler on the body of your car. 

Body fillers are not just for cars as you can also use them on your prints. Later in the article, we take a look at one of the most popular body fillers used to fill gaps in 3D prints. 

3D Pens

While they are not talked about as much, 3D pens are a great way to fix the gaps in your 3D prints. 3D pens are like handheld 3D printers. Typically used for creating 3D art, they’re a handy tool for welding, fixing joints and hinges for 3D prints. 

The downside to this method of fixing gaps is the expense. Fillers are cheap. Buying a 3D pen if you do not already have one will cost you up to $200. With that said, a 3D pen is a great tool to have if you can get past the cost. 

What Causes Gaps In 3D Prints?

There are different types of gaps that can form on a 3D print. They could be holes, layer separation or lines across layers. Most of these flaws are the result of incorrect printer settings. Some are caused by faulty material. 

The first place to check when troubleshooting your 3D prints is the material. Using poor quality filament or not storing it properly will almost always lead to bad prints. It’s much better to pay a little extra for good quality filament than to buy cheap filament that will not produce good prints.

Filament is hygroscopic. It absorbs moisture and when it does, this will cause poor layer bonding and holes in your prints. Always store your filament away from direct sunlight and in airtight containers. Consider getting a dry box to store your filament. 

As far as printer settings go, it all depends on the material you are working with. Finding the optimal settings is down to following the manufacturer’s recommended settings and experimenting to find the right calibration. Source

How Do You Smooth Out 3D PLA Prints?

Smoothing out a PLA print requires a combination of adding and subtracting material. The goal is to add just enough material to hide the layer lines while also filling in the gaps. This is generally done using filler. The filler will then be sanded down until the desired finish is obtained.

In theory, smoothing out your prints is as simple as adding and taking away filler. In practice, this requires a practiced eye and a patient hand because you will be doing this continuously until you get the finish you’re looking for. Sanding is the most common way to smooth a print.


The first step is applying your filler of choice. This could be any of the fillers we discussed above. Whichever filler you decide to use, you want to make sure to apply it quickly as most fillers are quick drying.

Once your filler is dry, then starts the process of sanding it down. You want to start with coarse sandpaper and work your way down as you get closer to your desired finish. 

Can You Use Bondo On 3D Prints?

Bondo is primarily used as an automotive body filler. An alternative use for it is post-processing 3D prints. Bondo can be used to either fill or repair gaps or for smoothing out prints to remove any visible layer lines. 

Like most fillers, Bondo dries quickly allowing you to work on your print within 30 minutes of applying it. Bondo does have a strong odor however, so wearing a dust mask is advisable when working with it to process your prints. 

For more on this, we recommend that you check out our post “Can You Use Bondo On 3D Prints? Guide To Fixing Print Gaps!


I am a very well experienced techie civil engineer who's extensively interested in 3D printing technology and even more captivated by the potential of 3D printing livable structures

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