Filiment Storage

For those who have reels of filament, how are you storing yours to keep from moisture and breaking? Though we have them in storage bags with desiccant and have tried to “bake” a reel in a oven, still came out brittle. Looking for cost effective ways, I know there are special boxes you can buy but are somewhat expensive.

Thanks in advance!


What temperature did you set the oven to, and how long did you dry it for? This is for ABS, right? Apparently the best temp is just below the glass transition temp, which for ABS can be around 100-115°C. Some people dry their filament for 10-15 hours at a time, some people leave it for way longer. Like a lot of other 3D printing topics, there are a lot of conflicting opinions about filament drying.

Maybe we could get some drying experiments rolling in FabLab. We do have several spools of old, brittle ABS sitting around that might work as test subjects. Perhaps we can invest in a filament dryer to try it out and do some before/after tests.

Definitely a subject to discuss as the next Fab Lab meeting.


I followed off a website - ALL3DP.COM info for ABS, 80-90 C for 4 to 6 hours with a oven my wife bought used. May have not held temp or need to up the temp and longer timeframe. Since we keep it in a ziplock bag and a bag of desiccant, I’m wondering if there is not enough desiccant in the bag to dry up moisture.

1 Like

If you keep it in a fairly dry environment, it should be okay. Definitely recommend upping the temp of the oven for ABS.


I would have guessed that once the filament has absorbed any moisture that it cannot be restored.

And that heating would only be useful to reactivate the desiccant.

But, I must be wrong if there are people successfully restoring filament that had been damaged by improper storage.

Time to fire up the electron microscope and see what’s happening physically.


I have much experience with drying plastic in many forms. For many purposes. Including 3D printing.
I will try to come to the next meeting.

I will offer again to help build a dry storage that is constantly purged.

Yes you can dry it quickly near to Tg temp.
But if you have an old roll and lots of time… just putting it in an ultra dry box with a slow flow thru, it will slowly dry it back out. The dryer the box is the better. The higher the flow the better. But honestly, microflows are good enuf if you arent opening it a hundred times a day. Even then, you can deal with it, using stages.
Yes ABS is a hundred times harder to dry out compared to PLA, polycarbonate or Nylon.

1 Like

There are a lot of filament dryers on the market now, plus lots of home-drying techniques. It’s big business. But…I haven’t seen any quantitative studies on the effectiveness of drying or comparative drying techniques and I’d be fascinated to see what you and @teya find out about this. SCIENCE!!!


What night are meetings for 3d printing? Waa it Tues or Wedn?

2nd Wednesday of the month, but we can always put together a discussion group for another day if that doesn’t work for you.


We have vacuum bags for our filament and desiccant packs in those and an attempt is made to keep filament in them.

Also have a special filament oven that serves as a spooler, just put the whole spool in there and feed the line out through a whole and it keeps the spool at whatever temp the whole time you’re printing.

1 Like

Thanks for the information. Will look into that.


John Madden, IV

1 Like

Dessicant bags. This is what works for us. Dessicant packs in bags. Occassional Oven visits. These remove first layer water. But not deeper chemisorbed water. Which is harder to release.
Dryboxes are [mostly] a step beyond what we need. Still… sometimes there is doubt.

We have [i think] occassional exposures of folks failing at keeping filament “dry enuf” for the project they are printing… [or who just wonder if trace water is a furtive problem] [yes, it often is] and if so, they are missing the confidence of the ultra drying benefit from “DRY FLOW THROUGH” in a DRY storage cabinet.
And let me reiterate this. Low level water Problems… ARE furtive when at low levels… i used to write them up as “occult” sort of problems in my reports. [I had the equipment to PROVE trace water was a culprit]. Trace water will often bedevil and aggravate in performance without asserting reliably and for sure, that the problem is in fact trace water. Thats part of why I cant get off the drybox horse. And am willing to pitch in on the dessicant tube[s]. Without spectrometers and 6 place balances, we are unlikely to measure the levels, to show correlations.
There is another part - that was long perspective: and one way to see it was “problem count” … trace water was the most frequent problem i was called out on, everywhere all over the plant in many different processes. Painting, bonding, composite laminates, fillers, liquid shims etc. Trace water problems were followed closely by silicone contamination, followed by oil and fingerprint contamination. [These are the problems they couldnt figure out on their own, and called in the chemist problem solver]. These rankings applied every year for 23 years. All over the shops using organic materials to build and coat airplane parts. Those investigation results likely overlap here somewhat.

So… Water is a sneaky problem. So I like to recommend removing it from the list of potential concerns. With a flow thru drybox. Gold plating not required. [Climbs down offa soapbox]

1 Like

The person who said they put their ABS in an oven, believed that just getting to temp releases much of the moisture. That was first and second level release of absorbed h2o.
But without flow thru dry air… the filament does the same thing as the dessicant pack does. Pulls it right back in and quickly too.
And keep in mind, I did not see their process. And shouldnt project my interpretation of what they did. I am guessing. I try to help, not judge. We work together here, and as humbly as needed to want to try again tomorrow on this great team.

In industrial settings, dry-gas-flow-thru is the only kind of drybox i know of used on the production floor, like for creel houses [the box that holds the spools that are feeding the hot end or the laminating machines or injection molding extruders]. These ALL need flow through dryboxes. Designed to leak a little all day. This setup DRAGS molecular water OUT better, and much quicker and it cannot reabsorb.

And in a few cases, like my lab, for dry box storage, we just fixed this with compressed air tube [pin valve as regulator] with a CaSO4 [drierite] dessicator on the feed tube. Cheap confidence. The box is most of the cost. Pin valves are hard to find but old pressure regulators have one.

Flow thrru Drybox seems like serious overkill for us.
It is.
But at work, we do it coz pesky problems crop up almost every day. And just removing one of the most COMMON causes of plastic and prepreg problems was SO CHEAP… there wasnt a good reason to NOT do it. The confidence is worth it. The price is low for any single machine or instance. Is it different here? Yes. But not so different, that a drybox isnt recommended by me. I know we are mostly good with dessicant bags. And I defer to local experience. And im willing to put some scratch in to match funds to help relieve sticker shock.
Can we do a small demo version in another room… before going to the trouble to pipe in compressed air to fablab? I think so. I regard that piping as THE most likely obstacle to getting a flow thru drybox in fablab. [I have a cheap compressor at home. And HATE the noise level of a hundred dollar unit.]

This was part of my job for 23 years all over the plant. Analyze, measure trace water [or oil], show correlation with detrimental affect on finishes or bond quality, etc etc. I wish i had access to the analyzers again. NIAR can test for us, but at $375+ per analysis, its expensive, and we might need quite a few of these tests to prove what the level bedeviling us is. Or isnt.

And if we set fablab up to do one machine for ABS or PC printing… you may as well keep all the spools dry too. Etc, etc. The scope creep sounds awful. Until you check the “per item” divvied up cost. Its amazingly cost effective. Once you have a drybox setup. And are covering all spools and printers.

Yes, we CAN get by on dessicant bags. We are unlikely to be visited by a small mob of members demanding we do this. Just to match industry. Im not in that mob, but still, I recommend this, just for the confidence. And because we dont yet know how to identify when we are being affected by trace water. Should i plan to do some “waterlogged filament prints”? A wet rag in a filament bag for a week would do it. Print a benchy on a slow print. Then do one fast? Or better yet, do vase mode with and without waterlog to help show “affected surface”.

How can I help hang the bell on the cat?

I will.

Right now, i just wish to help guide. Thats my persistent assignment, wherever I go. I wont lead you astray out of pride or profit. But im no savior either. Problems will still happen. Even with dry filament. Dry material and process will likely reduce just a few problems.

But we dont know for sure… and likely never really will- know for sure, when or if to graduate to dry box storage and creel houses. We just know that mostly we are ok, as we are. With dessicant bags.

We wont know how many times a [filament feed] problem, or first layer failure, or surface blowouts is coming from trace water. Until afterwards and then see a reduction in problems. Maybe we will see it. Maybe we are ok.