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How To Smooth PLA 3D Prints With a Heat Gun

Do you love making 3D prints and want to know how to make them even smoother? Using a heat gun lets you easily smooth out areas on your print and achieve outstanding final results. However, if you’re going to try this for the first time, you’ll need to know the steps!

Here are all the steps to smooth PLA 3D prints with a heat gun:

  1. Remove excess materials.
  2. Choose the proper heat gun. 
  3. Set the piece on a turntable.
  4. Set the heat gun to its lowest setting.
  5. Watch for overheating!
  6. Let the piece cool.
  7. Consider adding epoxy.

After reading this whole article, you’ll know how to smooth your PLA 3D prints like a pro! Doing so gives your objects a finished appearance and makes them look professional. As long as you follow these steps, you’re sure to get the results that you want!

1. Remove Excess Materials

It’s always best to remove the excess materials before you start using the heat gun. PLA melts quickly, so you’ll have less to worry about with the leftover parts out of the way. Often, pieces require additional support during the creation process- it wouldn’t make sense to smooth them!

No matter your final plans with your project, removing the supports and bridges should be your first step. You may already know how to do this if you’ve worked with 3D printing previously.

To do this, you’ll want to have a new utility knife sized for your project. Then, use the knife to cut out the excess plastic. Ensure that you work carefully, don’t apply too much pressure, and cut away from yourself to avoid injury.

You also may want to sand down your piece. Doing so helps remove a lot of the ridges before you get to the heat gun. Plus, it’s an excellent way to remove more material, if need be.

2. Choose the Proper Heat Gun

Next, you want to ensure that you have the proper heat gun for your projects! You should always choose one that can stand up on its own. That way, you can set it down if you need to. It’s also easier to work with this kind of setup.

You also need to make sure the heat gun can reach about 140°F (60°C) since PLA is the beginning melting point. 

You can see how the heat gun should sit in this YouTube video:

You also don’t need the heat gun to get extremely hot. Often, a smaller one tends to work best for many 3D pieces. I recommend using the Fujiwara Heat Gun Kit. It comes with everything you need and works well on a variety of crafts! Even the lowest setting gets extremely hot, so you’ll want to swipe the pieces through the hot air quickly.

However, just about any heat gun you have will work! Some people suggest using a hairdryer, but that won’t get hot enough to melt your PLA- so it won’t make your pieces any smoother. 

3. Set the Piece on a Turntable

If you don’t want to hold the piece up to the heat gun, setting it on a turntable is the next best method. Simply place your 3D print on the spinning table and point the heat gun at it. You want to make sure you’re spinning the table constantly, so your work doesn’t melt in one area!

You only want to have the heat on for short bursts of time. If you notice the piece getting too warm, you can let it cool for a few moments, then move it back into place. With PLA, the plastic holds its shape when it cools.

Overall, having a turntable to work on helps move the process along smoothly. If you don’t own one, you might want to consider getting one before using the heat gun on your projects. Something as simple as the RamPro Rotating Swivel will work perfectly! Make sure you don’t hold the heat against it for long.

4. Set the Heat Gun to Its Lowest Setting

Next, you’ll want to make sure you have the heat gun at its lowest heat setting. Some heat guns can get hotter than 1000 degrees- which you wouldn’t want to apply to your PLA works!

Usually, the lowest settings are between 120 and 160°F (about 49 to 71°C). PLA isn’t a heat-resistant material, meaning that you can easily melt your piece. You want to melt it very lightly to remove the ridges- but not enough to deform your object.

In short, never start with a high, or even medium, heat setting! You want to make sure to start very low and continue turning the piece. That way, it won’t deform in one place from being overexposed to the heat.

How To Use the Heat Gun

Always start by making sure you have heat-protecting gloves or a tool to hold your 3D object so that the hot air won’t blow on you. Then, set the heat gun to the lowest point where the PLA will still melt.

You’ll need to plug in the gun to turn it on. After that, every model has different mechanics. Some come with screens showing you their set temperatures, while others only have “low” and “high” indicators. It would help if you chose a heat gun that comes with the features you want.

You can turn on the heat gun by holding it in the trigger. Some models can run without you having to hold in the trigger for long periods. Make sure you also turn off the heat gun every once in a while not to overheat.

From there, make sure to rotate the piece in the hot air. Only one side will reach the heat and become smooth if you hold it still. Plus, you could melt your piece. Once finished, make sure to unplug the tool and allow it ample time to cool off before moving it!

5. Watch for Overheating!

You need to periodically stop heating the 3D sculpture to check for signs of overheating. Suppose you notice that the plastic feels exceptionally soft and malleable. In that case, you’ll want to let it cool before continuing to heat it. 

The PLA can also bubble if it gets too hot. When that happens, deformities are sure to appear on your work! 

The best ways to avoid this situation are to hold the heat gun a reasonable distance away from your project. You also need to rotate it constantly in the hot air and give the 3D work “breaks” from the heat.

It’s challenging to learn how to evenly heat a piece of plastic without melting it or causing other types of damage. The more you practice, the better you’ll get! It also gets easier to notice when the PLA is about to melt.

6. Let the Piece Cool

You’ll also want to ensure that the piece has plenty of time to cool and solidify before moving on to the final step. If you don’t let it cool down first, the object could easily warp. You can also hold the piece in place during this stage, ensuring that it hardens correctly. 

It should take about 10 to 15 minutes for your project to cool down significantly after being under the heat gun. However, the longer you can give it to cool off, the better! You don’t want to risk damaging your hard work on the final step.

7. Consider Adding Epoxy

While you don’t have to add epoxy, some people give their print a finished, glossy appearance. You will need to mix two parts epoxy- yours should come with instructions specific to your brand.

You can apply epoxy in two ways. First, you can paint it across the surface using a brush. You’ll want to wait for the layer to dry thoroughly before adding another one. Secondly, you can dip the piece in the liquid, then hang it over a bucket. You won’t have as much control over where the epoxy builds up, but it’s better for making large batches of prints.

Epoxy works wonders when you want to have a piece that you want to smooth out thoroughly. Your piece must be cool since heat makes the epoxy cure faster- making it harder to work with.

Overall, adding a layer of epoxy is simple. It does take time, but you’re sure to appreciate the final results!

Using the Heat Gun for Repairs

You can also use the heat gun for making repairs to the piece. For example, you accidentally cut a hole into the object when removing excess material.

You start by heating a piece of scrap or filament until it’s incredibly soft. Press it into the hole, then sand it down after giving it time to cool. From there, you can heat the area again to give your project a smooth finish.

You can also use this to reconnect parts that fall off of the project. Overall, having a heat gun is extremely useful when you’re working with PLA! 

Why Do 3D Prints Have Grooves?

Your PLA projects consist of Polylactic Acid. This material is one of the most popular in the world of 3D printing! Many features make PLA worth using– it’s cheap, strong, and has a long shelf life.

Your printer is essentially a high-tech extruder, which pushes out the material into place. However, this can cause some ridges to be left behind. Some people enjoy the appearance of the grooves, while others want to get rid of them. This choice may also vary between projects.

In other words, your printer builds the object by layering very fine strips of filament on one another. Doing so does leave behind some grooves. Depending on the printer you have, the tracks could be more or less noticeable than with other brands.  

Why You Should Smooth Your Prints

Although many people do, you technically don’t have to smooth out your 3D prints. If you leave the ridges, the pieces tend to appear unfinished. If you want your objects to look their best, then smoothing them out can go a long way.

Additionally, your prints might have some blobs on them when they first come out. These blobs happen when the extruder starts and stops in the same place. They can stick out a lot and look all that nice when the bumps are enormous.

Overall, you’ll probably want to spend a little bit of time smoothing out your prints! You won’t need to do this for your test pieces unless you want the extra practice. 

Alternative Smoothing Methods To Consider

You also have more options available to you than just the heat gun! You’ll want to consider using chemical treatments. Ethyl Acetate and THF (Tetrahydrofuran) are both chemicals that work great for smoothing 3D pieces. Always make sure that you use protective equipment when using any chemicals! 

Ethyl Acetate is often the more popular option for smoothing. It dissolves the plastic fast, then evaporates. You want to use tiny amounts of the chemical at one time to focus on smoothening certain areas on your piece.

Some printers prefer to smooth their works with chemicals. Others prefer to sand down the piece and apply epoxy after. Using a heat gun is one of the best methods, but it might not be for everyone.

Finally, make sure to work in a well-ventilated area. You wouldn’t want to breathe these chemicals! 

Final Thoughts

In short, you can smooth your PLA 3D prints with the above guide. These prints often have many ridges when fresh off the printer since they consist of plastic filaments. Removing the excess then smoothing the piece makes it more impressive looking.

Overall, knowing how to use a heat gun is a valuable skill to have! Especially when you know you’ll use it often for smoothing your 3D prints. It can take a while to learn, but you’ll enjoy the experience of making the print your own.