How to Store and Dry Your 3D Filament: A Complete Guide

A lot of people underestimate the role of filament in achieving high quality prints. There’s a few things to be aware of when storing, and drying your filament. Here is everything you need to know about drying and storing your filament.

The article is rather long, so here you can jump to a section that interests you. For complete knowledge and full experience, I recommend you to read the whole guide from A to Z instead. I tried my best to keep it short and informative.


Filament Moisture Absorption

Pretty much all 3D printing filaments like PETG or PLA are hygroscopic, meaning they absorb moisture from the air. Not all materials are equally hygroscopic, though.

Filament TypeHygroscopicityNotes
Nylon (Polyamide)HighNylon is extremely sensitive to moisture and requires drying measures during storage and prior to printing. (matterhackers.com)
PVA (Polyvinyl Alcohol)HighPVA is water-soluble and highly hygroscopic, necessitating storage in dry conditions. (en.wikipedia.org)
PETG (Polyethylene Terephthalate Glycol)ModeratePETG absorbs some moisture, which can lead to increased stringing if not properly dried. (toms3d.org)
PCTG* (Polycyclohexylenedimethylene Terephthalate Glycol)Low to ModeratePCTG absorbs significantly less moisture than PETG but still benefits from drying before printing.
PLA (Polylactic Acid)LowPLA is less hygroscopic but can still absorb moisture over time, potentially affecting print quality. (toms3d.org)
ABS (Acrylonitrile Butadiene Styrene)LowABS has a lower tendency to absorb moisture compared to other filaments but should still be stored properly to maintain quality. (en.wikipedia.org)

*Specific data on PCTG’s hygroscopicity is limited. However, it is generally considered to have lower moisture absorption compared to PETG.

Here’s a visual representation of Peter’s Filament Hygroscopicity Table™:

Moisture Absorption of 3D Printing Filaments: Comparison between different types of filament.
Comparison of different 3D printing filaments. Btw, this blog was never meant to be family friendly.

As you can see, the asexual ABS absorbs very little water, meanwhile the slutty Nylon is extremely sensitive to moisture and will absorb a lot of it.

Brief summary: filament sitting on a shelf absorbs moisture with time – just like that, because it can. This is not good, because the more moisture the filament absorbs, the worse the print quality.

It’s important to note that even a freshly opened filament might be wet. Some manufacturers use water in the filament manufacturing process and not necessarily dry it well. I recommend drying your filament after opening and storing it appropriately afterwards. This way you can be sure of your filament being dry and have it ready to use.


Symptoms of Wet Filament

Using wet filament has been a circlejerk on subreddits such as r/3dprinting or r/FixMyPrint for a long time now. Usually when someone posts about an issue of print quality, the first question being asked is “Is your filament wet? Did you dry your filament?”.

The most observable cause of wet filament is so called “stringing”.

Normal quality print (left) and print done with moist filament with visible stringing (right). Source: Reddit, posted by u/davidpp99.

Wet filament also usually causes small bubbles building up while melting the plastic, causing mini holes in your print. This can lead to brittleness and poor layer adhesion, meaning a print can break in half. Happened to me many times.

Object printed with wet filament with visible bubbling (left) and print done after drying the same filament (right). Source: Reddit, posted by u/ariannedonoghue.

In the picture above a Reddit user conducted a “study” where he printed the same object, first using wet filament (left) where you clearly see “bubbling”. After 8 hours of drying in a filament dryer, he printed the same object again (right). As he said:

(…) I bought this esun Gold Silk PLA a little while ago and it printed fine. All of a sudden, I couldn’t get good prints out of it (nozzle on the left).

Had the idea to dry it – even though it’s been stored in an airtight bag with dessicant. You can see the immediate difference on the Benchy – the first few layers are garbage, but once the filament that was in the dryer starts printing, the layers are smooth and clean.

Second nozzle in the image, on the right was printed with the exact same G-code. The only difference was 8 hours in a filament dryer.

Also: if you leave in a humid area with RH (Relative Humidity) levels of above 60%, your filament is more likely to absorb moisture from the environment quickly.


Drying Your Filament

Disclaimer: Beware of the fumes!!! The filament drying methods described are for informational purposes only. Heating certain filaments, like ABS, can release toxic fumes, which may be harmful if inhaled. Always ensure proper ventilation and follow safety guidelines when drying filaments. Use temperature-controlled equipment and monitor the drying process closely to prevent overheating, fire hazards, or filament deformation.

The easiest way to dry your filament is using a dedicated filament dryer, like this one from Creality. I will write more about this particular dryer later (in a separate post).

Creality Space Pi Plus. I recommend this dryer, I own it for 3 months now. It can dry two 1kg spools simultaneously.

How it works: filament is being held in a container, preferably one that allows a bit of ventilation to let the moist air out, and being circulated with hot air of certain temperature for a specific period of time.

Different filaments have different recommended drying temperatures.

Filament TypeRecommended Drying TemperatureDrying Time
PLA (Polylactic Acid)50°C – 55°C4 – 6 hours
ABS (Acrylonitrile Butadiene Styrene)
65°C – 70°C
3 – 6 hours
PETG (Polyethylene Terephthalate Glycol)50°C – 60°C6 – 8 hours
PCTG* (Polycyclohexylenedimethylene Terephthalate Glycol)55°C – 65°C3 – 6 hours
Nylon (Polyamide)80°C – 100°C8 – 12 hours
PVA (Polyvinyl Alcohol)80°C6 – 12 hours
TPU (Thermoplastic Polyurethane)65°C4 – 8 hours
PC (Polycarbonate)75°C – 100°C4 – 6 hours

Source: support.dremc.com.au

*Drying guidelines for PCTG (Polycyclohexylenedimethylene Terephthalate Glycol) filament are not extensively documented. However, considering its chemical similarity to PETG, we can infer suitable drying parameters based on PETG’s recommendations.

While those are the recommended temperatures for generic filament, I still recommend following the manufacturer’s guidelines.


Tips / Important Points for Drying 3D Filament

  • Ensure your drying equipment maintains a stable temperature to prevent filament deformation. Depending on your equipment, the temperature reading can be inaccurate. It is recommended to check the drying temperature with another thermometer to ensure the accuracy of the reading on your drying deice.
  • Ensure the equipment can maintain the required temperature range for the specific filament.
  • After drying, and once the filament cools off to room temperature (important), store filaments in airtight containers with desiccants to prevent re-absorption of moisture – more about that in a bit, this is another important topic we’re going to cover.
  • Repeatedly drying the filament will eventually degrade the plastic/polymers. To avoid the need for drying your filament, store it in sealed containers (more about Storage below). Ideal location would be where the humidity is between 5-15%.
  • If you need to dry your filament in temperatures above 80-100°C it is recommended to re-spool your filament onto a metal spool, as plastic spools themselves can melt or the glue in cardboard spools melt and leak out.
  • Aim for 15-20% RH (Relative Humidity) on the dryer’s indicator. The humidity level will keep dropping during drying, but keep in mind that surrounding air humidity ≠ filament humidity. I recommend keeping the dryer running for the full drying time, even if the humidity on the indicator drops before the drying cycle is finished.
  • The moisture that is released from the filament while drying must leave the dryer and not recirculate inside it. You can achieve that by leaving the dryer’s cover a little bit open (1-2mm space) for ventilation. There are 3D models that you can print that keep the lid open, like air vent gap spacers – just like this one for my dryer (Creality Space Pi Plus).
  • Beware of the fumes!!! Heating certain filaments, like ABS, can release toxic fumes, which may be harmful if inhaled. Always ensure proper ventilation and follow safety guidelines when drying filaments. Use temperature-controlled equipment and monitor the drying process closely to prevent overheating, fire hazards, or filament deformation.

Other Methods

There’s other methods to dry your filaments if you don’t have one, involving some DIY or passive methods of drying.

Disclaimer: I am not responsible for any accidents, damage, injury, or harm resulting from the use of these methods. By following these suggestions, you assume full responsibility for any risks involved. Always refer to the manufacturer’s recommendations for safe filament handling and drying procedures.


This method involves putting your filament into a kitchen oven. There’s a lot of things that can go wrong with that method, including bad molten plastic smell, inaccurate temperature readings that can cause the filament to melt (and become unusable) and toxic fumes in your oven, after drying some types of filaments like ABS. Toxic fumes. Where you usually prepare food. Food that you ingest.

This is basically what can happen if your oven gets a tad too hot. Credits: @fribbledom at Mastodon.

If despite this, you still want to give this method a try, here’s what you would do:

Precautions

  • Avoid exceeding 60°C (140°F) unless specified, as higher temperatures can cause the filament to soften or deform.
  • Ensure proper ventilation, as some filaments may emit fumes when heated.

  1. Set the temperature. Preheat the oven to a low temperature suitable for your filament type. For instance, PLA can be dried at around 50°C (122°F), while ABS may require approximately 65°C (149°F).
  2. Prepare the filament. Place the filament spool on an oven-safe surface, ensuring it doesn’t touch any hot oven components.
  3. Drying duration. Allow the filament to dry for 4 to 6 hours, depending on its moisture content.
  4. Monitor the temperature (important). Use an oven thermometer to ensure consistent temperature, as oven thermostats can be inaccurate.

Again, I personally do not recommend this method. Do it at your own risk and in controlled environment (see disclaimer above, written in thick, bloody-red font).


2. Food Dehydrator (Preferably Modified)

A food dehydrator offers controlled low-temperature drying and can be modified to fit one or more filament spools in it. It’s the best DIY solution, I’d say. Surely not as dangerous as using your kitchen oven (don’t), but still can emit toxic fumes, so you should ensure proper ventilation (again, see disclaimer).

An example DIY filament dryer utilizing a Rosewill food dehydrator and Walmart cake carrier. Now that’s interesting. Credits: u/InterstellarMisfit on Reddit.
Another concoction made by u/[deleted] (he sure does post a lot) on Reddit.

You can find a lot of cool guides on how to build one by modifying commercial food dehydrators. Here’s some links:

And again, here’s how you would proceed after building your dream filament dryer that you’ve been having wet dreams about:

  1. Set temperature. Adjust the dehydrator to the appropriate temperature for your filament. Consult my table or look at manufacturer’s recommendations.
  2. Place filament. Position the filament spool inside the dehydrator.
  3. Set drying time. Again, consult my table or look at the manufacturer’s recommended trying time. Use a pomodoro timer or an hour glass. A simple alarm on your phone would do the trick, too.

This method provides more or less precise temperature control and is a practical alternative to dedicated filament dryers. And better than using a kitchen oven, hehe (don’t).


3. Desiccant Packs in Airtight Containers

This is a passive drying method that more helps to maintain dryness of your filament rather than actually drying it. It still dries it a bit, but it takes way longer. A big plus of this method is lower electricity usage, and the drawbacks would be the time needed and effectiveness comparing to active drying. Still a viable option, though.

This is a nice DIY example, with holes and tubes to guide the filament out of the box. That way you can use it to print. This makes it more like a storage solution than drying solution, but well, it can be both.

Very cool solution using a plastic, sealed storage box made by Becky Stern. Source: beckystern.com.

See those tiny bags on the bottom of the box? Those are bags of desiccant (no idea how to pronounce that) filled with silica gel – those little beads that absorb moisture. More about them later.


4. Using the 3D Printer’s Heated Bed

This one is an interesting one. You can use your printer’s headbed to dry your filament! It’s not the most effective method, but beats printing with wet filament or using the drybox with desiccant. Bambu Lab (popular 3D printer manufacturer) even made a guide using this method on their official Wiki.

Picture taken from BambuLab’s guide. I’d recommend putting an additional piece of cardboard, or some sort of distancing tubes under the spool to avoid accidental melting. Source: BambuLab Wiki.

This procedure involves putting a piece of cardboard, preferably with holes to allow better heating, or some distancing tubes (to prevent filament melting) on the heatbed and placing your filament spool on it. If your 3D printer is enclosed, that’s already enough. If not, you can put a cardboard box over it to maximize efficiency.

Tip: Leave some small holes on top of the cardboard box for ventilation.

When adjusting your heatbed temperature, I recommend measuring the temperature of the filament, or the air temperature inside of the cardboard cover, to make sure it stays within the recommended range. You could put a digital thermometer in there. And again, you can look at the table above or refer to filament’s manufacturer’s guidelines.

There’s even some 3D models to print for devices you can place on the heatbed to dry your filament. Here’s one with a place for a fan to circulate the air. This makes it way more efficient. I recommend you printing something like this if you would like to use this as your primary drying method.

u/ChintzyPC came up with an idea to model an original design. Source: u/ChintzyPC on Reddit.

Storage

When storing your filament, the general idea is to protect it from moisture and dust. There’s few ways to achieve a good storage.


1. Airtight Containers

I showed you a cool DIY storage system before that also dries your filament a bit. The idea here is to store your filament airtight with desiccant bags or loose silica gel. Rice also acts as a desiccant, but I don’t think it’d be effective.

You can make one yourself or purchase one. They usually come with thermometer and/or a hygrometer, which shows you how dry the air is inside the box, which gives you an idea of how dry the filament can be, but surrounding air humidity ≠ filament humidity.

Another nice low-cost DIY idea using silica gel balls instead of bags. Credits: 3D Print Files.

Before we saw a storage box using bags of silica gel for keeping the filament dry. You can also use loose silica gel beads, like in the example above. They are stored in this container near the lid.


2. Sealed (Vacuum) Reusable Bags

This is the method I use. You can pack your dry filaments in zipped reusable bags that have an air vent – using a handy pump (or a vacuum cleaner) you can vacuum all the air out of them. And the bags are reusable! A cherry on top is an additional desiccant bag inside to absorb moisture. Doubleplusgood.

You can get them cheap on Amazon and similar sites. I got an 12 piece set with a hand pump for 10$.

An example filament bags set by Elegoo. Credits: Amazon.

A big plus of this storage system is that they take up very little space in comparison to a dry box. I store my bagged filaments in their original cardboard packaging.


Desiccant Also Needs to Be Dry

Desiccant absorbs moisture, but only when it’s dry itself. Those bags and the loose silica beads need periodical drying themselves.

Desiccant bags with white silica gel (top), and indicating silica gel changing color (bottom). I’m pretty sure this image was AI-generated; which is weird, because I got it from Wikipedia.

You can buy those bags online, as well as loose version, or recycle them from various packaging (like shoe boxes, they almost always contain one). Some commercial silica bags have a visual indicator of when they needed to be dried. They simply change their color when they become too wet.

You can dry them similarly to the filament. But this time, drying those in the oven is generally a safe option (the disclaimer still applies, please don’t sue me).


1. Using The Filament Dryer

You can use your dedicated or DIY filament dryer to dry the bags or loose silica gel. For some dryers there are dedicated online 3D models of holders, trays and containers to store your desiccant and insert it into the dryer. An example tray for use with my dryer (Creality Space Pi Plus) can be found here.

A very cool idea. You can store your silica bags/gel in the filament-spool-like object. And you can print it yourself! Source: KYZ Design at MakerLab.

Important: The moisture that is released must leave the dryer and not recirculate inside it. If you get silica gel packs that have a color changing indicator dye, you will be able to tell when they are wet or dry.


2. Using Your Kitchen Oven

You can use your kitchen oven to dry your desiccant material. It uses a bit of electricity, but it’s a relatively good option, if you don’t have anything else.


Precautions

  • Avoid microwave use. Do not use a microwave oven for drying desiccants, as it can cause uneven heating and potential damage to the material.
  • Safety precautions. Ensure the area is well-ventilated during the drying process. Handle hot materials with care to prevent injuries. Also, see disclaimer above.
  • Desiccant type. Confirm that your desiccant is safe for oven drying. Some desiccants may contain substances that are not heat-stable.

Here’s how you would do it:

  1. Preheat oven. Set to 60°C (140°F).
  2. Prepare desiccant. Spread desiccant beads or packets evenly on a baking sheet lined with foil or parchment paper.
  3. Drying. Place the sheet in the oven for 6-8 hours (up to 12 hours if very saturated), checking occasionally. If they have a color-changing indicator, observe for color change.
  4. Cool down. Remove from the oven and let the desiccant cool to room temperature.
  5. Storage. Store in an airtight container to keep it dry.

Further tips

  • It’s a good idea to label your filament boxes or bags; sometimes the labels on the spools get covered up. Information such as print temperature, filament type and color would be useful.

Thanks for reading!

Thank you for taking your time to read the guide. I hope you learned something about drying your filament and could use the points listed here. If you have any questions, feel free to leave a comment or contact me.

I also appreciate your feedback. In case you think I got something wrong or something’s missing, please let me know. Thank you.