Recently I bought some extra colors of PLA filament for the IKEA ALEX label & handle system and for several other upcoming projects. I enjoy having the option to 3D print in many colors.
The downside of having a lot of filament lying around however, is that the unused filament absorbs moisture from the air. Over time this causes the filament to swell, become brittle, or experience other problems depending on the type of filament material.
Needless to say I wanted to find a way to prevent this from happening, so I designed and built filament storage boxes using 22L IKEA SAMLA boxes and 3D printed parts.
The storage boxes contain a shaft that rotates using bearings. That way I can use the boxes not only to store the filament, but also to directly print from them. The rotating shaft allows for less friction when feeding the filament into the extruder.
Before explaining how to build the filament dry boxes, I would like to give some more information on the relationship between filament and moisture:
How and why does 3D printer filament absorb moisture?
3D printing filaments such PLA, ABS, Nylon and Polycarbonate consist out of polymers. These polymers are hygroscopic, meaning they have a strong affinity to attract moisture. In the case of our spools of filament, this moisture is absorbed from the air.
Why do we need to keep filament dry?
Moist filament can cause a variety of problems. For example, PLA becomes very brittle and can snap when it only gets bent a little. Wet nylon on the other hand can turn opaque instead of transparent.
Some other problems that can occur with wet filament are:
- 3D prints have a rough finish texture.
- Reduced part strength.
- Extruder jams.
- Reduced print bed adhesion.
- A lot of stringing.
How to prevent filament from absorbing moisture?
The best way to keep filament dry is to limit the exposure of the filament to air. This is done by storing the filament in a humidity-controlled environment.
For hobbyists, the most affordable solution is to keep the spools in an air-tight container. Adding desiccant to the container will further help keep the filament dry.
What to do when filament is already moist?
Your filament can still be saved after you notice it has absorbed a lot of moisture. You can do this by exposing the spool of filament to hot (dry) air for a prolonged period of time.
There are several ways to do this:
The drying temperature varies, depending on the type of filament:
- PLA: ~50°C
- ABS: ~65°C
- Nylon: ~70°C
It is recommended to dry the filament for three hours or longer. Both the filament on the outside, and on the inside of the spool need to get enough time to get rid of their moisture.
Read on to learn how to build the IKEA SAMLA dry boxes and keep your filament dry.
Materials (per box)
- A 22L / 6 Gallon IKEA SAMLA box (798.508.75)
- 4 x M4x16mm hex bolt
- 4 x M4x30mm hex bolt
- 8 x M4 washer
- 8 x M4 nut
- 4 x 608 bearing
- A piece of PVC pipe or wooden dowel, ~296 mm long and 18-32 mm in diameter.
- Reusable silica gel desiccant
- 2 x Base
- 2 x Back Plate
- 4 x Bearing Retainer
- 1 x Drill Jig
- 4 x Lid Clip
The included drill jig is for 22L / 6 Gallon SAMLA boxes. With some accurate manual alignment it should be possible to mount the parts on larger SAMLA boxes.
The links to the 3D printable .STL files can be found in the Files & Print Settings section below.
Files & Print Settings
The .STL files for 3D printing are available for download on Thingiverse.
I printed the parts with 2 shells, 25% infill. The printed parts support a lot of weight from the filament spools so I do not recommend using a lower infill percentage.
The bearing retainers need to be printed with support material.
Drilling the holes in the SAMLA box
Assembling the 3D printed components
Cutting the shaft
Inserting the filament spools
I have added reusable silica gel beads to the filament storage boxes to help keep the filament dry.
What does the silica gel do exactly?
The silica gel beads absorb moisture from the air inside the filament box. In turn, the filament has less moisture available to absorb and stays ‘fresh’ for a lot longer.
Reusable? How does that work?
As the reusable silica gel beads absorb moisture, they change color to indicate their level of moisture saturation. The orange silica gel beads turn green over time, and the blue variant turns pink.
When the beads are saturated with moisture and have changed color, they can be reactivated by placing them in an oven or microwave for a while. This removes the absorbed moisture from the beads.
Not at all. Reusable silica gel is very affordable. Especially when factoring in the cost of the saved filament. And because the silica gel is reusable, you can use a single container for a long time.
How much silica gel should I use?
I use about 250 grams (~ 1/2 lb) per filament box. This covers the floor of the 22L IKEA SAMLA boxes with a generous layer. So far this has been working well, so this seems like a good amount.
Does it actually work?
I was curious about this as well, so I decided to log the relative humidity (RH%) in the filament boxes in order to get some actual data.
It took about 10 minutes after inserting the silica gel for the humidity to drop to a minimum level of 10%. Even now, after a couple months, the humidity sensor still indicates 10%.
I should note that the humidity sensor I use only goes down to 10%, so it is possible that the relative humidity in the boxes is lower than that.
Either way, the humidity in the boxes has significantly dropped since adding the silica gel beads.
From a more subjective standpoint, I also seem to have less issues with brittle PLA.
How often does the silica gel need to be dried?
That depends on the circumstances. The main factors that influence it are:
- The humidity of the environment.
- How well the dry box is sealed.
- How often the dry box is opened.
That said, I added silica gel balls in the boxes two months ago and they have only discolored a bit so far.
The environment the boxes are in has about 50% humidity, and I do not open the boxes that often.
I will update this post once I have had to dry the silica gel beads.
The filament dry boxes / storage containers came out great. They look nice, I can easily swap them in and out of the 3D printer and most importantly they prevent exposure of the filament to moist air.
Since using the dry boxes, I haven’t had any issues with the PLA becoming brittle or not printing well. So far the PLA remains flexible, prints without bubbles and with a smooth finish.
If you liked reading this article or have any questions about this project then feel free to leave a comment or check out some of my other projects linked on the all projects page.
Last update on 2019-11-22 / Affiliate links / Images from Amazon Product Advertising API / Affiliate Disclosure