Hello, Maker!

Today we’re going to talk about a topic that is important yet easily neglected (and will surely bring you problems someday if so): Filament storage and drying. Ten minutes taken for reading this article, and troubles in the future saved!

Why Serious About Filament Storage

Have you ever bought many filaments at one time when there's actually not much need? Do you always tear their packings and try them all in the first place? And do you seldom use up a spool of filament before you start with a new one?
If the answers are yes, I guess that most of the filaments you've purchased are left unused in some corner now, and some of them might have been “killed” by the moisture if you haven't paid any attention to the environment and methods for their storage and let them stay exposed to the open air.

Almost all kinds of 3D Printing filament are hygroscopic, which means they can absorb the water from the air and end up wet sooner or later.

"Being wetted" seems no big deal since it happens so commonly in our daily life, but things go different for 3D printing filaments in that it can bring about irreversible changes and lead to severe consequences in at least three ways as follows.

• Quality degradation
  The physical properties of the filament change as it becomes wet. For example, the filament will swell in diameter, not easy to notice with your naked eyes though. At the same time, it will also turn harder and more brittle, which makes them easier to break, thereby increasing the difficulty of use and maintenance.
  
• Bad print
  When the wet filament is heated in the nozzle, the moisture contained in it will boil and produce many tiny bubbles. This gives rise to an unstable flow of the extruded filament, and therefore a rough and uneven surface of the print. What's more, after the printer has given the order for the nozzle to stop extruding, the filament is very likely to continue to run out of the nozzle since the moisture in it will be boiling for a while, which causes strings on the print, a real headache for many makers.
  
  
• Printer damage
  Not joking, printing with wet filaments can bring damage to your machine. As we just mentioned, wet filaments are more prone to be stringy during the printing, and that will likely clog or even damage the nozzle. Additionally, the melting point of the filament will become higher when it is wetted. Thus, the filament will not be melt so well at the original temperature, which possibly causes the nozzle jam too. Beyond that, if the filaments are left unused in the machine for a long time, they will swell in diameter, as said before, and get stuck in the nozzle.

Some may wonder: wet quilts can be easily dried if put under the sun, then how about the wet filament? Can we restore its quality by drying it?
Research shows that drying helps, but the quality of the filament will still decrease by 33% even after it is perfectly redried, since its physical property has been changed more or less, which cannot be recovered simply by drying the moisture contained in it.

So, how exactly does its physical property change?
When the filament absorbs water, they react with each other. The filaments are polymer — until water molecules break up all the secondary molecular bonds and change them into monomers, and this is also the reason why wet filaments are harder and more brittle.

If you have been long confused by problems like filament quality degradation, bad prints, or clogged nozzles without any clues, it's time to think about the storage of your filament.

Appropriate Storage Conditions

The temperature and the humidity are the two of the most key factors to consider here.
Generally speaking, you should store your filament away from direct sunlight and where the temperature is not too hot or cold. Data show that filaments such as PLA, TPU, PC, Nylon, etc. are better stored between -20 ℃/-4 ℉ and 30 ℃/86 ℉. The humidity is better kept between 10% to 20%. If it goes higher than 50%, your filament is very likely to be wetted. Nevertheless, the most suitable conditions differ from filament to filament, and that's why most professional filament manufacturers generally include instructions or guides inside the packaging, describing in detail the properties and storage conditions of their filaments. Just remember not to throw them away at first!

Ways to Store Filament

Several things need to be clear before we talk about the storage methods:

• Even if the filament can be stored for up to two years in an ideal environment, it's recommended that you buy just as much as you need
• Try to use up the filament in a month after it starts to be exposed to the air;
• If you have to leave it unused for the moment, don't keep it waiting for more than one year.

Now, let me introduce the moisture-proof storage methods for filaments that are more popular (and economic) among makers.

1. Put your filament in a sealed bag or box with enough desiccant packets inside or a whole layer of silica gel beads on the bottom. You can also put inside a cheap electronic thermometer that tells both the temperature and the humidity, which enables you to monitor the storage from time to time.
   You don’t need to buy the desiccant packets in particular—just collect them from the snack bags. Silica gel beads are also a good choice because they can be heated and dried for reuse at regular intervals. In addition, some makers said that it would be better to wrap the silica gel beads in cloth bags, because the cloth helps absorb water too.
   Although the household sealed storage box can meet the demand, many makers designed special containers for storing filaments. You can download the file and print one out directly, or make some adjustments and create the most suitable filament container for yourself!
   
   Filament dry box for 3-4 spools of filament
   Filament Storage Solution
   Build your own DIY filament box
   
   
   
   
2. Try a vacuum bag, put inside again desiccant packets or silica gel beads, and force the air out of the bag with a pump. It's more suited to store the filament that will not be used very frequently.
3. If you happen to have a cat and use the crystal cat litter, you can borrow some to store your filament. The crystal cat litter is made of silica gel, so it can work as the desiccant too. Just look out for one thing: don't let the cat mistake that you've got it a new toilet...
   
4. Again if you have a pet, you can use the pet food container to store the filament. Generally speaking, such containers are made satisfactory in being airtight, for the pet food absorbs moisture easily too.
5. Choose professional filament storage equipment. Several filament manufacturers have developed specially-designed containers for makers to best store their filaments. Although it might be a little more expensive than other methods, it saves you time and effort in the long run.

How to Judge Whether Filament Is Wet

Now, you have been clear about the importance and specific methods of filament storage. But before putting them into practice, probably you should first judge whether your filament has been wetted.
Check the following ten descriptions carefully. If you get 5 or 6 hits, you'd better dry the filaments before storing them.

1. The filament becomes harder, and easier to break.
2. Abnormal spots or bubbles on the surface of the filament.
3. The melting point of the filament becomes higher.
4. There is steam coming out of the nozzle during printing.
5. There are crackling and popping sounds when the filament is extruded out (the moisture is boiling and evaporating).
6. Poorer adhesion of the first layer with the printing parameters unchanged.
7. The printed lines are not continuous.
8. Severe stringing or oozing.
9. Fuzzy or complex textures or small bubbles on the surface of the print.
10. The nozzle is often clogged.

Ways to Dry Filament

If you have found that the filament has been wetted, then it's time to dry them. As for the drying methods, makers have shown their strange yet effective wisdom.

1. Use an oven that can heat at low temperatures (e.g., below 50 ℃/122 ℉). Since the actual temperature is not always the same as set, you can put a thermometer inside the oven to measure the heat difference before drying.
   If the filament is heated at temperatures that are higher than recommended, the result could be counterproductive. Therefore, frequent monitoring is also required.
   What's worth noting is that this method cannot be used to dry the filament that might produce toxic substances when heated, which will pollute the interior of the oven. The steps are as follows.
   
   1. Set the target temperature.
   2. After the preheating, put the filament inside the oven.
   3. Heat the filament for four to six hours (for reference only; depending on the filament types, the quantity, and other factors).
   
   
2. Use a food dehydrator or fruit dryer. The recommended temperature settings are similar to the case of the oven.
3. Use a pet hair dryer that can heat above 40 ℃/104 ℉. Considering the health of your pet, this method is not suitable for drying filaments that may produce toxic substances, either.
4. Put the filament on the Heated Bed of your 3D printer, cover it with a box, then set the desired temperature, and leave it heated for about six to eight hours.
5. Use professional drying equipment, which is safer and more efficient.

For reference only, here are some recommended drying temperatures for common 3D printing filaments:
PLA: 40 °C–48 °C (104 ℉–118.4 ℉)
TPU: 45 °C–55 °C (113 ℉–131 ℉)
ABS, Nylon: 60 °C–80 ℃ (140 ℉–176 ℉)
PETG: 60 °C–70 °C (140 ℉–158 ℉)
PC: 120 °C–130 °C (248 ℉–266 ℉)

Generally speaking, it is necessary to dry the filament as soon as you find it wetted. The longer it is being wet, the more difficult for you to dry it.

Besides the moisture, filaments are also susceptible to dust if not stored properly, which is another cause of nozzle jam. Therefore, you should also dedust the filament before printing, like blowing (instead of collecting, because some dust hidden in the filament coil is difficult to be collected up but easy to blow away) it with a dust cleaner, or install a dust-cleaning clip on your 3D printer, ensuring that the filament is dust-free before loaded into the extruder. The following are some cleaning clips designed by makers in TG, go print one and say Bye to the dust!

Universal Filament Filter and Lubricator
Snap-on Filament Filter/Oiler
Universal Filament filter or dust filter

We hope this article could be useful for you.
In the future, Snapmaker Academy will bring you more exciting topics, so STAY TUNED!
If you are interested in other topics of 3D printing, feel free to contact us at support@snapmaker.com, or leave your message in the community.

Disclaimer

All the data and methods in this article are for reference only.

Snapmaker does not assume responsibility for loss, injuries, damage, or expense arising from or in any way connected with the data or methods in this article.