Filament drying and storage

23. 05. 2023

How does wet filament form and how to recognize it?

All material used for 3D printing is hygroscopic, meaning it can absorb and retain moisture from the air. However, this feature can cause considerable problems when printing. That's why it's a good idea to learn how to store filament properly to avoid complications in the future. In the article, you will find instructions on how to recognize that the filament is wet, how to store it properly and, if necessary, how to dry it.

Each type of filament can absorb moisture at a different rate. But there are a few signs that will tell you that you have a wet filament:

cracking sounds are heard when it is extruded
visibly lower strength of prints and adhesion of layers
uneven material extrusion
lumps and bumps on the press string
non-standard textured surfaces on prints
the print does not stick to the mat
"foam" comes out of the nozzle

If you've noticed any of these symptoms with your filament, it's time to dry it. Some materials are more susceptible to wetting. For example, we are talking about nylon, PETG or PVA, which can show moisture the very next day after being left in the air.

To dry the filament you can use:

1) Filament dryer / filament dehumidifier

Filament dryers are specially made to remove moisture from the printing material. So they can be your first choice for filament drying. There are different types of filament dryers on the market that use different drying methods, but all of them are relatively simple to operate. Basically, it works by putting a spool of filament inside, choosing the right setting, and letting the dryer do its job.

There are dryers where the filament can be connected directly to the printer and this will make your work easier. Dryers designed directly for drying the filament are a reliable and simple choice, thanks to which you can eliminate a lot of worries and you can fully focus on printing.

2) Classic oven

We all probably have one at home, so this is the easiest and most common way to dry filament. All you have to do is set the temperature just below the glass transition temperature, put the filament in the oven and leave it there for four to six hours so that it has enough time to evaporate the moisture. The longer you leave it there, the drier it will be. For PLA, ABS and nylon, the ideal drying temperatures are:

PLA: 40-45°C

ABS: approx. 80 °C

Nylon: approx. 80 °C

It is important to make sure that your oven can maintain the set temperature for a long time. Because if the temperature is exceeded, the filament and the entire coil could melt. Keep in mind that it is a good idea to put the coil in the oven after some time has reached the target temperature, as some ovens can exceed the set temperature when heating.

3) Food dehydrator

Another option you have to choose from is a food dryer. These dryers reach lower temperatures than conventional ovens. Therefore, for material such as ABS and nylon, where the desired drying temperature is around 80 °C, you can simply set the highest possible temperature on the food dehydrator (in case they cannot reach this temperature).

Food dehydrators are available and usually allow you to remove some of the inner layers so that you can fit the filament spool there.

How to properly store the filament?

Now that you've dried your fiber properly, it's your job to keep it that way for as long as possible. For this, you can use an airtight box, desiccant bags or specially designed vacuum bags with a membrane to extract air. These methods ensure the preservation of the filament and prolong its life.

The bags and vacuum pump are available separately (you can find the bags here and you can view the pump here ) or in a set together with the vacuum pump (you can view it here ).

You don't have to worry that the stored filament could dry out excessively. The problem arises when improperly stored printing material becomes wet, after which it is necessary to follow the drying process according to the advice mentioned in the article above.