Clear all

How not to store filament  

How not to store filament

I am posting this as a cautionary reminder so that others do not make the same mistake as I did. Indeed lack of knowledge can be dangerous especially as one tries to make a better installation for the printer and accessories. 

A couple of years ago when I started 3d printing and design I purchased the mk3s kit building it was such a thrill, then to see it print following the first calibration was great. 

I purchased an Mmu2s along with the printer and that of course is quite a different story. My unit works well now but there were several growing pains as I had to make some modifications so that it operates correctly. I've posted other things related to the mmu2s but that's not the reason for this post. 

As most people printing with filament learn, keeping the filament dry is not an option. Dry filament eliminates many esthetic printing problems stringing and bubbles are a couple of problems that dry filaments avoid. With the mmu2s the stringy ends are culprit to loading errors. I ventured to resolve this issue with dry boxes with dessicant in the box. 

Jumping to Amazon I bought three hermetic boxes and a couple of pounds of dessicant. This is where I committed a grave error, one that I'd not realize until months later. Not all dessicants are equal and one should verify the chemical properties prior to using the product. 

The dessicant that I purchased was calcium chloride,  a quite grave error on my part. This stuff is messy as well as an efficient oxidant when exposed to metals. That's the worst thing to use with a printer having metal parts. I ended up replacing rails, extruder gears and bearngs from the three  axis' and the mmu2s. 

This stuff is horrible when it becomes liquid or in powder form it releases gets on any surface. 

As I ventured along with my error, the dessicant hadn't absorbed too much water yet.  So I went and purchased the Sunlu S1 dryers. Using  these I soon realized that something had gone wrong. Drops of a gooey liquid started to reach the build plate, the filament dryers had liquid inside them, and I had a mess to clean up. 

Calcium chloride when it absorbs too much water turns into a liquid form. This liquid can also evaporate as if it was water; however, the vapor carries the calcium chloride mixture with it. Thus traveling wherever the filament passes leaving a gooey mess wherever it passes. The result for me involved the replacement of several parts and a major cleaning up of the mess left behind. 

I've replaced the following:

  1. All the smooth rods and bearings. 
  2. The extruder gears
  3. The bearings in the mmu2s 
  4. The wood top of the enclosure 
  5. All of the ptfe tubes

I've repaired the following:

  1. The mmu2s 
  2. The enclosure
  3. The filament dryers (4)
  4. Any other metals that came in contact with the liquid calcium chloride. 

Until yesterday I'd  gotten what I thought was everything corrected but yesterday I found another box that had been contaminated with the dessicant. There were three reels of filament therein, I'll have to leave them out to see if they leak. If that's the case I will have to toss them out rather than risk another oxidation of my equipment. 

To sum it up, never use a dessicant that turns into liquid once its saturated with water. Especially calcium chloride which is a highly efficient oxidant that shouldn't be exposed to a 3d printer. 


Stay safe and healthy, Phil

Posted : 06/02/2023 9:38 am
Honorable Member
RE: How not to store filament

Ouch, that’s a painful lesson.

Thanks for sharing; I hope your experience will save someone else from such a dilemma.


Posted : 07/02/2023 4:49 am