If you’re using a filament printer, it’s very likely that you don’t use reels of filament immediately. That means you’ll have to store them somewhere.
While beginners often keep filament spooled on the printer in between use, that can be a bad idea. For example, unless your print room is low-humidity and dust free, it could result in brittle prints and clogged print nozzles.
There’s no one best way to store 3D printer filament. However, keeping the filament storage humidity level as low as possible is always a good idea. In addition, you’ll want to reduce dust and possible contamination as much as possible.
Considerations For Filament Storage
A 3D print filament is normally vulnerable to contamination from moisture, dust, and chemicals in the air. In most cases, 3D print filament should be stored in an airtight or sealed container.
While some filaments need it more than others, every filament will benefit from this type of storage.
Humidity
Popular print filaments like PETG, ABS, and PLA are hygroscopic. This means that the material absorbs moisture from the air – resulting in changes to the material.
For example, PLA is not very hygroscopic. However, over time, it will become brittle if exposed to moisture. ABS and PETG can both become very brittle and can bubble if not stored in a dry container.
In addition, some materials, like PVA, will literally slowly dissolve if left in the open.
In most cases, the lower the humidity for your filament storage, the better. However, it’s unnecessary to keep your filament in heated boxes – unless the local temperature fluctuates a great deal or you don’t keep your filament in a heated building.
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Temperature
Good temperature regulation is not necessary to keep your filament in good condition. However, it is important to keep your filament relatively cool.
For example, storing filament in a closed container in the sun could result in the filament overheating and annealing or even melting. That’s important, because even if it’s 80 degrees outside, a box in the sun could more than double that temperature over the course of a day.
Because most 3D print filament starts to anneal or crystallize at about half its melting point, that could prove disastrous to PLA and other low-heat filaments.
You’ll also want to ensure that storage solutions are kept away from high-heat areas, like radiators or hot water pipes, water heaters, and very warm electronics.
Duration of Storage
The longer your filament is stored, the more you want to consider practicality and ease of storage rather than ease of access.
For example, if you’re using filament frequently, a box with a rack for airflow might be the best solution. On the other hand, if you won’t be using filament for several months, a vacuum bag that prevents airflow and moisture would be a safer solution.
Dust
Dust collects on the filament and can be extremely difficult to get off without unspooling and wiping down the entire roll.
If left on the filament, it can clog the nozzle, eventually causing problems with the print. The easiest way to prevent dust is to use an airtight container or a vacuum.
Airflow
If you’re using a storage container, you normally want to allow airflow around the filament. For this reason, spool racks, normally composed of rods or bars that you can rack the spools on, are extremely popular.
They’re also essential if you’re using a heated dry box because they prevent heat from building up on one part of the spool and overheating the filament.
How To Store Filament Properly
Storing 3D print filament is always a matter of using an airtight container to keep it dry and clean.
Otherwise, there are very few things you should worry about.
1. Keep Cool
A 3D print filament is thermoplastic, which means that it can degrade and crystallize even in low heat conditions. In most cases, problems start to occur at just under 50% of the melting point of the filament.
So, if your filament starts to melt at 90°C, it would start to anneal at around 45°C. Luckily, most filament requires much more heat than that – unless you’re using a very low-heat filament.
However, it’s usually best to maintain a temperature between about 65 and 80° Fahrenheit. Going a little over or under won’t hurt anything, but trying to keep the temperature stable is a good idea.
The good news is that this means you can store your filament at an average house temperature, away from doors and windows where that temperature might fluctuate.
2. Keep Dry
All 3D print filaments are at least somewhat hygroscopic, meaning that they absorb moisture from the environment. In almost every case, it’s important to keep filament as dry as possible.
Normally, that means storing your filament between 30 and 50 percent humidity. You can normally easily achieve this in a sealed box or bag.
For example, a vacuum bag is a great way to keep humidity out. However, if your filament is already damp, a vacuum bag will simply trap the humidity in.
Here, people in high-humidity environments often get around this problem by installing a heat mat and a fan in a box and running them for the first 6 hours of storage. Afterwards, you can normally assume moisture is evaporated and can turn the heat and fan off.
This is a good workaround to ensure that your dry box stays dry – without racking up the expense of leaving the heat on all the time. However, you will have to ensure that the box is airtight.
3. Store in the Dark
UV light can break down thermoplastics just like it does with other plastics. This means that storing thermoplastics in daylight is bad for them.
The easiest solution is to choose a storage box that doesn’t allow light to pass through. However, if you live in a dry area, simply racking your filament in a closet may be enough.
4. Protect from Dust
Dust builds up on filament and can go on to clog your nozzles and cause problems with your printer and your prints.
While many people make a habit of unspooling and wiping filament down after it’s been stored for a while, it’s a good idea to try to store your filament in an airtight space. This will prevent dust contamination, so you don’t have to clean the filament before using it.
5. Provide Airflow
Good airflow is important for ensuring that moisture doesn’t build up in any one place on your filament reel. That’s especially important if you’re using a heated dry box, where a lack of airflow could cause moisture buildup.
Here, most people use a racking system to hang their filament reels. Inside a box, the best way is to insert rods through the side of the box. You can then hang the reels on that rod by pushing the rod through the holes.
However, you can achieve the same thing by hanging reels in the open air, provided your space is dark, clean, and dry enough.
Storage Ideas For Each Filament
ABS
ABS is a moderately hygroscopic filament that absorbs moisture from the air and becomes brittle over time.
While not heavily hygroscopic like PETG, it should still be kept as dry as possible, especially if you’re storing it for longer periods.
- Store in the dark.
- Keep at 65-75°F.
- Keep as close to 30% humidity as you can.
- Seal it in a container rather than keeping it in the open air.
- Dry the material if you leave it out for more than a few days.
PLA
PLA is a low hygroscopic material, but it will still absorb moisture over time. This means that PLA can be stored in the open air, provided you’re not keeping it for very long.
However, like other filaments, PLA still greatly benefits from being stored in an airtight container.
- Store in the dark.
- Keep under 75°F.
- Store under 50% humidity.
- Seal in a container if storing it for longer than a few weeks.
- Dry the material if you leave it out for more than a week.
PETG
PETG is a hygroscopic filament and will easily absorb moisture from the air.
This means you should keep it in an airtight container and potentially reduce the humidity of that storage container if your normal humidity is over about 50%.
- Store in the dark.
- Keep under 75°F.
- Store as close to 30% humidity as possible.
- Seal in a container immediately after use.
- Use a hygrometer and either heat the storage container to reduce humidity or store it with desiccants such as silica.
In most cases, any 3D print filament should be stored cool, dry, and in an airtight container.
Desiccants are always a good idea. In addition, for some materials, like PVA, it’s actually necessary to do so immediately to prevent the filament from degrading.
Frequently Asked Questions
If you still have questions about storing 3D printer filament, these answers may help.
Can a dehumidifier dry filament?
It is unlikely that a dehumidifier will dry the filament. However, it will help to maintain low humidity in your air, which will prevent PLA from getting too damp in the first place.
On the other hand, if your filament is already damp, you’ll have to use heat or a vacuum dryer to remove the moisture. Here, a dehydrator is a great choice. You can also use your oven, so long as you keep both below about 60°C.
Does filament need a dry box?
A filament does not need a dry box. However, a dry box can be a great storage option.
On the other hand, many people prefer reusable vacuum bags. These allow you to remove all of the air from around the filament with your household vacuum – and then leave the filament safe in a cupboard until you’re ready to use it again.
However, vacuum bags are time-consuming if you frequently use and put the filament away. Therefore, dry boxes offer easier access.
In addition, a dry box allows you to install a heat source, which means you can also dry filament out when you put it away.
That’s a great option if you live in an area with high normal humidity – because it prevents you from trapping a lot of moisture in the box with your filament.
Final Thoughts
Storing 3D printer filament is generally very straightforward. While some filaments are more sensitive than others, all 3D print filaments want to be kept cool and dry and stored in a dark place. You’ll also have to consider dust and airflow. Otherwise, there won’t be many differences between different types of filament. As a result, vacuum bags and airtight boxes are two of the most popular solutions for storing 3D printer filaments.
