Moisture can wreak havoc on 3D printing filaments, leading to poor prints, stringing, and brittle material. Whether you're working with PLA, ABS, PETG, or other materials, understanding how to dry filament is a critical skill for any 3D printing enthusiast.

In this guide, we'll explore the importance of filament drying, the tools you can use, and step-by-step methods to help you restore your filament to optimal condition.

Why Properly Drying Filament is Essential?

3D printer filament is hygroscopic, which means it absorbs moisture from the atmosphere like a sponge. Extruding "wet" filament causes excess moisture to vaporize, creating tiny air pockets in the filament as it extrudes, which lead to bubbling, stringing, and inconsistent extrusion during printing. Avoiding these problems is why it's necessary to keep your 3D printer filament dry and to store it properly.

How to Identify Wet Filament?

Identifying wet 3D printing filament is essential for maintaining high-quality 3D prints. Here are common signs to look for:

• Popping or Cracking Noises: While printing, wet filament can release moisture as steam, causing audible pops or cracks during extrusion.

• Stringing or Oozing: Excess moisture leads to inconsistent extrusion, resulting in stringy prints or blobs on the surface.

• Poor Surface Finish: Wet filament often produces prints with a rough or bubbly surface due to steam escaping during extrusion.

• Brittle Filament: If the filament breaks easily when unspooled, it may have absorbed moisture and become brittle.

• Dimensional Inconsistencies:Moisture can cause swelling, leading to uneven extrusion and dimensional inaccuracies in prints.

• Cloudy or Discolored Filament: Some filaments visibly change in appearance when they absorb water, appearing cloudy or less glossy.

How To Dry Out Filament?

Drying filament is a straightforward process. The hardest part is remaining patient during the drying time. That said, here are three ways we recommend drying your 3D printer filament.

Dry Filament with a Filament Dryer

This purpose-built device represents the most sophisticated approach to filament drying, offering precision and convenience. The dryer creates a controlled, warm environment that eliminates moisture through consistent heating. Many models allow users to adjust the temperature and drying time based on the filament type.

Pros:

• Purpose-built for filament drying

• Precise temperature control

• Safe and dedicated solution

• Can store and dry simultaneously

• Often includes humidity monitoring

• Some models can dry while printing

Cons:

• Most expensive option

• Limited capacity

• Takes up storage space

• Quality varies between brands

• Higher-end models can be costly

Dry Filament in Oven

A conventional oven is a budget-friendly alternative for filament drying, but requires careful handling.

You need to preheat the oven to a low temperature and allow the filament spool to sit for several hours. The heat drives out absorbed moisture.

Since all filaments have a glass transition temperature, which is when a filament turns from hard state to a leathery state, you need to be careful when using this method. Always make sure to keep the oven temperature below the glass transition temperature using a thermometer, and keep the oven door slightly open.

Pros:

• Most accessible option

• No additional equipment needed

• Can handle multiple spools

• Fastest heating capability

• Largest capacity

Cons:

• Least precise temperature control

• Risk of melting filament

• Ties up kitchen appliance

• Potential food contamination

• Uneven heating

• Some ovens don't go low enough

Image: Unsplash

Dry Out Filament with a Food Dehydrator

If you own a food dehydrator, you can use it as a makeshift filament dehydrator. You'll need to clean it out before and after, and you'll want to remove any trays or grates that are used for food preparation.

Note: Mixing industrial plastics with food preparation equipment isn't always the best idea. If you're going to be drying a large amount of filament, we recommend spending the money on a dedicated filament dryer.

Pros:

• More affordable than filament dryers

• Good airflow

• Temperature control

• Multiple racks for batch drying

• Can be used for food when not drying filament

Cons:

• May require modification for spools

• Temperature accuracy varies

• Not designed specifically for filament

• May not fit larger spools

• Risk of overheating

The Temperature and Time to Dry Filament

Now that we've known the simple ways to dry out the filament at home, but how long to dry them and which temperature should you use for each type of filament?

Below is the recommended temperatures and time chart for different filaments:

Filament Type	Filament Dryer Temp/Time	Oven Temp/Time	Food Dehydrator Temp/Time
PLA	40-50°C (4-6 hrs)	40-50°C (4-6 hrs)	40-50°C (5-7 hrs)
ABS	70-80°C (4-6 hrs)	70-80°C (4-6 hrs)	70-80°C (6-8 hrs)
PETG	60-70°C (4-6 hrs)	60-65°C (4-6 hrs)	60-65°C (5-7 hrs)
Nylon	70-90°C (6-12 hrs)	70-80°C (6-12 hrs)	70-80°C (8-12 hrs)
TPU	40-50°C (4-6 hrs)	40-50°C (4-6 hrs)	45-55°C (6-8 hrs)

 

How to Store Filament?

Besides drying wet filament for 3D printing, you'll also need to store it properly to prevent it from taking on moisture again. Here are a few ways to store filament so that it stays dry and is ready for your next project:

• Use an airtight container and keep it away from potential sources of humidity, such as leaky sinks and damp basements.

• Filament dry boxes or dedicated filament storage bags work well. You can even save the bags your filament comes in and reuse them if they are airtight.

• Place desiccant or absorbent moisture beads into your filament storage container.

As long as you dry and store your filament according to this guide and use a reliable 3D printer, your 3D prints should come out looking great.

Safety Tips For Drying 3D Printing Filament

Since the filament drying process requires relatively high temperatures, it can create harmful gases or present a fire hazard. Therefore, when drying 3D printing filament, it's best to adhere to the following safety precautions:

• Monitor filament dryer temperatures to prevent filament from melting.

• Dry the filament in a place with adequate ventilation to prevent the accumulation of harmful gases.

• Keep the filament away from open flames.

• Periodically check in on the drying process for signs of danger.

• Allow your filament to cool completely before you store it.

Conclusion

In conclusion, knowing how to dry filament is a necessary skill for any 3D printing lovers. Whether you use a filament dryer, oven, or food dehydrator, ensure you follow the recommended temperature and time settings for each filament type. Regularly drying and storing your filament in airtight containers with desiccants will maintain its condition, ensuring reliable prints and reducing material waste. By adopting these practices, you can consistently achieve optimal results in your 3D printing projects.

FAQ

Can you microwave filament to dry it?

Microwaving filament is not recommended as it can cause uneven heating and potentially damage the filament or your microwave. Filament contains polymers that may deform or even melt when exposed to intense, uncontrolled heat. Instead, use a filament dryer, oven, or food dehydrator to safely remove moisture.

Does drying filament damage it?

Properly drying 3D printing filament will not cause damage. However, if the drying temperature is too high or the drying time is too long, the filament may become deformed or brittle. These guidelines can help when you're drying your filament:

• Do not attempt to dry your filament past its melting point.

• Most filaments will only need 4-6 hours of dry time.

• After drying, seal filament in an airtight container and store properly.