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3D Printing Guide

How To Dry Filament: A Step By Step Guide

Picture of Scott Gabdullin
Scott Gabdullin

Updated on January 31, 2025

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Drying filament might seem like a basic step, but it’s one of the most important parts of the workflow for consistency and good results. Unfortunately, any type of filament, such as PLA, PETG, and nylon, are hygroscopic and tend to absorb moisture from the air. This can throw off the precision we strive for, leading to stringy prints, uneven extrusion, or worse, failed projects.

In this guide, we’ll walk through the steps on filament drying using common and practical methods, temperatures, and some tips to make sure that every spool performs as it should.

What Happens If Your Filament Isn’t Dry?

When your filament absorbs moisture, it doesn’t just cause minor inconveniences. It can derail your entire workflow and undermine the quality of your projects, leading to subpar results or outright failures. 

In fact, here’s what happens when moisture sneaks into your spools.

Popping and Bubbling During Printing

When a filament containing moisture is fed into a heated nozzle, the absorbed water turns into steam, causing popping sounds and forming tiny bubbles in the molten plastic. This sudden evaporation disrupts the smooth flow of material, leading to inconsistent extrusion and uneven layer deposition. 

Additionally, the air pockets produced during this process weaken the layer bonding, compromising the structural integrity of the print and making it prone to breaking under stress. These issues are particularly problematic for functional prints or components where strength and durability are critical.

Stringing and Oozing 

Moisture in filament alters its viscosity as it melts, causing unpredictable flow rates that often lead to stringing and excessive oozing from the nozzle. Stringing leaves behind unwanted wisps of filament that connect parts of the model, creating surface imperfections that require extra cleanup and extended post-processing time. 

Excessive oozing can obscure fine details and edges, diminishing the professional finish of intricate designs. For professionals producing prototypes or detailed models for clients, these can result in the need for reprints and may even impact reputations if the final product fails to meet expectations.

Brittle and Weak Prints

Filaments like PLA and nylon are especially prone to absorbing moisture, and when they do, the impact on your prints can be significant. Wet filament results in brittleness, producing parts that are fragile and easily breakable. 

In our past projects, we also encountered stress failures, where moisture-affected prints give out at critical stress points, making functional parts unusable. These can cause costly delays and lead to wasted materials

Nozzle Clogging

Moisture doesn’t just affect your filament. It can also lead to nozzle clogs, disrupting your entire printing process. When moisture in the filament turns to steam, it often leaves behind residue that accumulates in the nozzle, causing blockages over time. 

Moreover, the erratic extrusion caused by wet filament can create temperature fluctuations, further increasing the likelihood of clogs, which force us to pause our work, clean or replace the nozzle, and lose valuable time that could have been spent printing high-quality parts.

Dimensional Inaccuracy

When we work with wet filament, inconsistent extrusion rates can wreak havoc on the dimensional accuracy of our prints, making it difficult to achieve the precision we need. 

Warping becomes a common issue as uneven cooling caused by poor layer adhesion can distort the shape of our prints, particularly with materials like ABS. Models with tight tolerances are also at risk, for they may not fit together as intended, making us spend extra time on reprints or even redesigns. 

Now, let’s explore the steps to properly dry filament and prevent these problems from occurring.

Step #1: Check Your Spool and Determine If Your Filament Needs Drying

The first step we always take before starting a print is to assess whether our filament is in optimal condition. Even the most carefully stored spools can absorb enough water to impact print quality.

Start by checking for visual cues. If the spool looks cloudy instead of smooth and shiny, it’s often a sign that moisture has infiltrated. Run your fingers along the filament to check if it feels rough or uneven. Texture change can indicate the presence of absorbed water.

Additionally, look for visible inconsistencies, like tiny cracks or deformities in the filament strand. These clues are often the first indicators that the spool has been compromised by moisture.

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Step #2: Choose a Drying Method

Once we’ve identified that our filament needs drying, the next step is selecting the best method to do so. The option we choose often depends on the tools we have available and the type of filament we’re working with.

Filament Dryer

Using a filament dryer machine is one of the most effective and reliable options. This machine is purpose-built for this task and is designed to control both temperature and humidity levels with precision. For those who print regularly or rely on consistent results, these devices are an excellent investment.

Using a filament dryer is straightforward. We simply place the spool inside the machine, set the appropriate temperature based on the filament type, and let it run for the recommended duration. This process will make the filament dry evenly and thoroughly, minimizing the risk of moisture-related print issues.

The advantages of filament dryer machines are clear. They’re incredibly user-friendly, and once we set the parameters, we can let the machine do its work without constant supervision. Some models even double as storage units, keeping the filament dry until we’re ready to use it. 

That said, filament dryers are not without drawbacks. For one, they can be expensive, which may be a barrier for beginners or occasional users. Additionally, they require dedicated space in your work area, which can be a challenge if your setup is limited. 

Food Dehydrators

For those who don’t have a dedicated filament dryer machine, a food dehydrator can be an excellent alternative. These devices, typically used to dry fruits, vegetables, and meats, can also work effectively to remove moisture from filaments, provided that they can reach and maintain the necessary temperatures for your material.

While not specifically designed for 3D printing, food dehydrators offer a practical and affordable option, especially for those looking for a budget-friendly solution.

Using a food dehydrator to dry filament is relatively simple. Most filaments, like PLA or PETG, require a range between 40°C and 70°C (104°F–158°F), but filaments like nylon may need even higher temperatures. If the dehydrator meets this requirement, we start by removing any non-heat-resistant components, such as plastic trays, that could warp or melt during the process. Once prepped, we place the filament spool inside the dehydrator, set the appropriate temperature, and let it run for several hours.

However, there are some limitations to keep in mind. Aside from temperature, not all food dehydrators can accommodate larger spools. Additionally, since food dehydrators aren’t specifically made for filament, the drying process might not be as precise or consistent as with a filament dryer machine. For example, some models may have uneven heat distribution, which could leave certain sections of the spool still retaining moisture.

Oven Drying

Another cost-effective way to dry filaments is to use a household oven. Like food dehydrators, which are not specifically designed for filament drying, an oven can serve as a viable option that can remove moisture effectively. However, this method requires careful monitoring and precise temperature control.

Oven drying has its advantages, particularly in its accessibility since most of us already have a household oven, so there’s no need for additional equipment. However, there are risks involved. Ovens are designed for cooking, not precision temperature control, and even slight temperature spikes can cause filaments to soften, warp, or fuse together on the spool.

Step #3: Set the Right Temperature

When it comes to drying filaments, setting the right temperature is a critical step that we can’t afford to overlook. Each type has its own ideal drying temperature, and getting this wrong can result in warped, melted, or even completely ruined spools.

For PLA, the ideal drying range is 40–50°C (104–122°F). This temperature is just enough to remove moisture without risking deformation, as PLA has a relatively low softening point. Going too high can cause the filament to soften and stick together on the spool.

PETG, on the other hand, needs a slightly higher range of 60–70°C (140–158°F) to remove moisture effectively. Its heat tolerance allows for more aggressive drying, but precision is still key to preventing deformation.

For those who frequently work with functional parts, ABS is a popular choice. However, improper drying can lead to filament inconsistencies that compromise the quality of prints. ABS filament requires a temperature of 70–80°C (158–176°F) for optimal results.

Nylon is among the most hygroscopic filaments, absorbing moisture at a much faster rate than other materials. Drying nylon often requires a higher temperature range of 70–90°C (158–194°F) to fully eliminate moisture. However, this higher range also increases the risk of overheating, so we have to be extra cautious when drying nylon, especially in ovens or food dehydrators where temperature fluctuations are more likely.

TPU, being a flexible filament, is a bit more sensitive to heat and typically dries best at the same range as PLA, between 40–50°C (104–122°F). This preserves its elasticity while removing any absorbed moisture.

Always make it a point to check the manufacturer’s recommendations for the specific filament brand and type you’re using. Some manufacturers provide detailed guidelines for drying, and these are invaluable in preventing accidental damage. If you’re unsure or dealing with a new type of filament, it’s better to start at the lower end of the recommended range and adjust upward if needed.

Step #4: Monitor the Drying Time

Getting the timing right is just as important as setting the correct temperature. The drying time depends on two main factors: the type of filament and how much moisture it has absorbed. While it’s tempting to set a timer and walk away, taking a more hands-on approach helps us achieve the best results. 

For filament that’s only mildly damp, we typically dry it for 4–6 hours. This is often the case with spools that have been stored in slightly humid conditions but haven’t been exposed to extreme moisture. On the other hand, severely wet filament, like a spool left out in high humidity for days or weeks, may need 8–12 hours to fully dry.

For highly hygroscopic filaments like nylon, which can absorb significant amounts of water, drying overnight is often necessary. Nylon tends to hold onto moisture more than other materials, so giving it extra time means that every trace of water is removed.

If you’re using a filament drying machine, here’s a quick reference table with recommended temperatures and drying times for different filament types. 

 

Hygroscopicity 
(moisture sensitivity)

Min Temp (°C)

Max Temp (°C)

Drying Time

PLA

Low

40 °C

50 °C

4 – 8 hours

PETG

Low

60°C

70°C

4 – 8 hours

ABS

Mid

70°C

80°C

4 – 8 hours

TPU

Mid

40°C

50°C

4 – 16 hours

Nylon

High

70°C

90°C

24+ hours

Keep in mind that these are general recommendations. Always double-check your filament manufacturer’s guidelines for the best results.

Step #5: Store Filament Properly

After drying filaments, proper storage becomes a priority to make sure they stay dry and ready for future use. Without the right storage practices, your filament can quickly absorb moisture again, undoing all the effort you’ve put into drying it.

Storing filament in airtight containers is one of the most effective ways to keep moisture out. Add silica gel packs or other desiccant bags to the container to absorb any residual moisture. These are inexpensive, easy to find, and can make a significant difference in keeping your filament in top condition. Place a few packets directly with the spool to create a low-humidity environment inside the container.

If you want long-term protection, vacuum-sealing your filament is an excellent method. This is useful if you live in an area with high humidity. Many vacuum-sealing kits are affordable and easy to use. For added protection, include desiccant packs in the vacuum-sealing bags before sealing.

Lastly, pay attention to where you store your filament. Choose a cool, dry place away from direct sunlight or heat sources, as excessive heat can degrade the material over time. Humid environments should be avoided as much as possible, as even the smallest exposure to moisture can compromise the filament’s quality.

Step #6: Do a Test Run After Drying

Once you’ve dried your filament, it’s always a good idea to put it to the test before diving into a full-scale project. Start by printing a small, simple test model. This allows you to check if the filament is performing as it should without wasting time or material on a larger print.

Pay close attention to the results of the test print. Look for common issues like stringing, bubbling, or weak layer adhesion. If the print quality is still not up to par, it’s possible that the filament hasn’t fully dried. If that’s the case, return the filament to your drying setup and extend the drying time for an additional couple of hours to remove residual moisture.

Achieve Optimal Prints with Perfectly Dry Filament

We’ve all been there, dealing with brittle prints, frustrating stringing, annoying warping, or weak layer adhesion caused by moisture. But here’s the good part: with the right techniques and tools, you can avoid these headaches entirely. Just follow the steps we’ve laid out!

For more detailed guides, practical tips, and expert recommendations, explore the resources available at 3DGearZone, helping you bring your ideas to life with precision and reliability.

FAQs

Can I use a microwave oven for filament drying?

You technically can, but we don’t recommend it. Microwaves don’t heat evenly, and they can cause the filament to overheat in some areas while leaving other parts unaffected. This uneven heating can warp or even melt your spool, effectively ruining it. Worse, the filament could release fumes or start burning if things go wrong. It’s safer and more reliable to use a method designed for gradual, controlled heating, like a filament dryer, food dehydrator, or even a regular oven (if monitored carefully).

Is an air fryer a safe option?

Air fryers aren’t ideal for drying filaments either. They’re designed to cook food quickly using very high temperatures and rapid air circulation, which makes it really hard to control the heat at a low, steady level. Even if you set the air fryer to its lowest temperature, there’s still a risk of overheating or deforming the filament.

Is there a way to skip or speed up the drying times?

We wish there were, but drying filament takes time, and it’s one step you don’t want to rush. Patience is the key. Properly dried filaments will save you from frustration and wasted materials.

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