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How to Store 3D Printing Filament – A Simple and Cheap Way to Keep Your Filament Dry

Did you know that some of your 3D prints may have partially or completely failed just because of humidity contained in the filament you used? This sort of humidity is invisible to the naked eye, so you probably blamed your print settings, your 3D printer or even doubted your abilities, but all of that may actually not have been the cause of your problem: it was the humid filament.

Some people tried to address this problem by creating more or less elaborate 3D filament storage solutions, like filament driers or special filament containers. The problem is that most are either bulky, energy consuming and/or slow, they come at a certain price or constructing them takes a lot of your time.

Well, we may have just the solution for you: a very simple and cheap way to store your filament without hassle. Your filament will not only stay completely dry, it will be easily accessible, perfectly identifiable (i.e. no need to open every box to find the right kind of filament your are looking for) and it uses humidity absorbents which can be reused indefinitely. If this has peeked your interest, read on.

Failed 3D print

Your failed 3D prints could well be due to humidity contained in your filament

 

If you have your filament spools simply lying around your printer until you use them, without any storage solution in place, you will sooner rather then later witness problems during printing, due to humidity. Your filament has an inherent quality that will make it attract water molecules its surroundings (i.e. the ambient air), known as “hygroscopy“.

As we already briefly explained in this article, nylons will saturate with water (i.e. absorb its maximal capacity in water molecules) in only 18 hours being exposed to ambient air. The situation is even worse with specialty filament like PVA (more about PVA in our materials primer post) which is used to create support structures, which are easily dissolved by putting your print in water. PVA is extremely hygroscopic and needs to be stored in a sealed box or a special container. Otherwise, it will attract so much water from the air that it will render it useless. But not only nylons or PVA are concerned, PLA and ABS also attract water from the air, even if it is to a lesser degree.

The effects of attracting water may result in one or more of the following problems: increased brittleness, diameter augmentation (potential problems with Bowden-tube printers), filament bubbling or hissing steam once reaching the hot-end, filament degradation, breaking filament, etc. which will all lead to increased complications during printing. You also need to factor in the fact that 3D printing filament which has absorbed water will need a higher temperature for extruding correctly.

The level of severity of these problems depends strongly on the type of filament. For instance, PET is nearly not affected by ambient air moisture while Nylon will saturate quite quickly and may pose problems printing (making bubbles for example), if not stored properly.

3D printer filament - various colors

Not the best long term storage solution for 3D printer filament

The Maker community came up with some very innovative ways, in order to find a solution to this recurring problem. Some makers set out to build a filament dryer and storage containers like this “Moisture-free filament spool container“, this “Multiple Filament Dry Holder and Dispenser” or this “Solution for printing with water soluble PVA in Dualstrusion“, but you probably will have to go through different iterations in your designs, before you will be happy with your result. Also, there is always a certain cost involved.

Alternatively, you can check out the solutions elaborated by our good friend Jérémie François. He tried out several systems in his article on printing nylon (a recommended read) and his iteration of a high-tech zero carbon footprint drier box. Unfortunately, not everyone is living in beautiful southern France with accordingly good weather (i.e. lots of sun) in order to use such a drier box. Or you simply don’t want to tinker with such a (quite elaborate) setup.

Home made solar dehydrator

The home-made solar dehydrator by Jérémie François

But don’t worry, we came up with a very simple, yet effective and very cheap solution.

Just get yourself some vacuum bags. Please do pay attention to only buy the type of bags fitted with a vacuum valve, which permit all air to be vacuumed out with a standard household vacuum cleaner. These vacuum bags are normally intended for storing clothes, linen and such in a place-efficient manner. They normally also provide protection against water, odors, mildew, dust and pests.

You need to be careful, as you can also find “vacuum bags” which are normally intended for traveling (i.e. storing clothes in a space-efficient manner in your suitcase). Those use integrated one-way air valves and need to be rolled manually (compressed) in order to let the air out. Sometimes you can find them tagged as compression bags. Pay attention not to buy those as they are not fit for our specific purpose!

Also, only buy vacuum bags with a double zipper line, as they permit to keep the vacuum better then the simple zipper lined ones. The better ones cost about 20 EUR (about 25 $) for 6 bags. One such pack will normally be more than sufficient for your filament storing needs. We strongly urge you to consider buying only the higher quality bags, as their valves are normally better, the plastics used are of higher quality (less prone to cracking over time) and thicker (less danger of a puncture).

3D Printer Filament Storage

Four filament spools and a moisture absorber packed together tightly in a vacuum bag

 

As for size, the choice is up to you, but in order to keep your stored filament manageable, we prefer bags of 50 x 60cm or so (i.e. 19.6 to 23.6 inches). Normally those bags are transparent, so you can easily recognize what filament you have stored in a specific bag. Clear and comprehensive tagging of your filament will also help a lot in that respect.

Pro tip: Once most of the air has been vacuumed out of the bags, you can easily and place-efficiently stack your spool bags or even store them vertically in a box or cupboard until you need them.

 

3D Printer Filament Storage

Simply vacuum out the air, so to remove all the ambient moisture too

 

The idea behind using those bags is to store your filament spools in an air-free environment (vacuum), so that they cannot absorb any more moisture from the ambient air. As the vacuum in the bag is not absolute, you need a solution to absorb any possible remaining moisture. We recommend to simply add to your bag some silicagel beads, which are very effective moisture absorbents. You can choose to either buy a number of ready-to-use silicagel packs (a.k.a. dry packs), which can be re-used if you dry them in an oven. However, their biggest disadvantage is that you have no way of knowing when the beads are saturated with water, as the (Tyvek) bags they come in are opaque/non-transparent. It is also sometimes difficult to buy them in small numbers at an acceptable price.

 

3D Printer Filament Storage

Once the air has been vacuumed out, you can conveniently store your filament spools completely dry until you need them

 

We actually prefer a much smarter solution, as we use silicagel with moisture saturation indicator. This amorphous, highly porous, synthetically manufactured silicagel uses an ecologically friendly color indicator, so that when the beads absorb moisture, they change their color from yellow/orange to green or blue (depending on ambient moisture level). The beads normally only become blue if they have been soaked in water (i.e. in contact with water) – we use the photos of the blue silica gel for illustration purposes only of this article. Your DIY moisture saturation indicator should only become green, never blue! Used together with some type of slotted box with transparent walls, you can easily determine if the time has come to renew your silica beads.

 

3D Printer Filament Storage

There are a few of these moisture indicator silicagel types out there. Beware and do not buy the cheap one’s which change from dark blue (dry) to pink (saturated), as they usually do contain cobalt chloride, a product which has been linked as being possibly carcinogenic to humans and has been labeled as hazardous material in some countries. We are no chemists, but apparently the color indicator in the orange to green changing silicagel beads is a kind of composite dyeing agent and a lot safer to use then the cobalt chloride one’s.

EDIT: “Since the publication of this article, we have received number of mails, asking us if you can replace the silicagel with rice instead. Rice is cheap and readily available and yes, it does present hygroscopic properties. But we advise against using rice as a desiccant, as its adsorption properties cannot be compared to those of industrially produced silicagel. If you compare rice to silicagel, you can say that rice is maybe a “mild/weak” desiccant. If you would like your filaments to be dried and stored under the most effective conditions, use silicagel.”

The only thing missing now is the appropriate container to put your silicagel beads in. Any transparent vessel with small holes, slots or incisions will do the trick. These are necessary so that the silicagel beads can attract the remaining moisture left in the vacuum bag. As seen before, some ready made solutions do exist, but those dry-packs seem to be only available in the US at the time of this writing. So, as true makers, we decided to 3D print us the vessel we need for our little project. You can use this design of a  desiccant box which you can resize as needed and then 3D print it yourself.

Alternatively, get yourself some plastic containers with a screw lid, like those Polypropylene containers (slightly soft-walled) of 50ml which are frequently used by labs or for storage (coins, screws, etc.), which you can order on eBay or Amazon. Alternatively, search for small plastic jars with cap/lids or coin storage containers. To get a better idea of what I am talking about, just have a look at our photos below. Take out your drill (I used a 2mm drill for wood, as they are  very sharp and perfectly suited for this) and add a good number of holes to the container, so that the beads can easily absorb any remaining moisture. Then you just need to fill in your beads and, voila, you have a moisture absorption system with water saturation indicator.

Once your beads change from orange to green(ish), depending on the moisture level (the vacuum bags and the bead container being transparent, it should be easy for you to check the saturation level), just take them out of your container, put them on a baking tray and let them dry for 3 hours at 120°C in your oven (some types may be also microwaveable, but we do not recommend this). Once they are of a clear orange color again, all moisture has been dried out of the beads and they are ready to be used again.

 

3 hygroscopic states

The 3 possible states of the silica gel: yellow (dry), green (wet, needs replacement) and blue (saturated with water). It will only become blue if submerged in water – you need to change your beads once they are greenish!

 

If your filament spools have already been exposed to the air over a certain time, they will most likely aready be saturated with moisture. If you wish not to change the silicagel too quickly or too often, you can try drying it in an oven first. But you need to be aware that this may create problems, especially if you are drying at too high temperatures, as the filament may become soft, sticky or may even start fusing single strands together in one big mess. Do not try to shorten the cure time with a higher temperature setting!

There are no specific recommendations we can give you here for “oven curing” your filament, as these settings depend on the nature of the thermoplastic you are trying to dry. As a rule of thumb, use a convection oven (i.e. a fan-assisted oven), where fans distribute the air evenly throughout the oven. Your heat settings should be low to very low. Just consider curing PLA, which has a so-called “glass transition temperature” of 60-65°C. This means that the PLA’s properties will change from “hard and brittle” to “soft, molten or rubber-like” as soon as your ovens temp reaches 60°C! So PLA is not really a good candidate for oven curing, unless you have a very precise (i.e. digital) oven. Also, we never cure our filament for longer than one hour, as the silicagel in the vacuum bag will take care of any remaining moisture.

Please make sure that you always check the glass transistion temperatures on your filaments, as they do vary widely: ABS is around 100°C, Taulman’s T-glase is around 78°C, Polycarbonate around 150°C and so on. Make sure that you research your filaments specifications properly before trying this out. And as usual, all the above is for information purposes only. Should you ruin your oven or loose a spool while trying to dry your filament, don’t blame us, as we warned you properly about this method’s inherent risks and dangers.

One last piece of advice: sometimes the filament, once you have finished printing with it and have pulled it out from the heat chamber (and Bowden-tube, if applicable), can form a spike or be kind of sharp. However, sharp spikes together with thin walled plastic bags do not mix well, as a vacuum bag is quickly pierced by a sharp tip. So we recommend to print some filament clips (many are to be found on Thingiverse), so that unraveling, entanglement and especially spikey ends do not pose any problems. Personally, we prefer this design.

 

Filament Clip

Using a filament clip to keep the filament secured on the spool

 

We hope that this little instruction will help you keep your filament dry in the future. Happy printing!

 

EDIT: We have received a lot of fan-mail from our readers, requesting us to publish an easier method for storing 3D printing filament without involving any do-it-yourself action. So check out our new and revised method for filament storage that gets rid of any DIY-action and that can be implemented in a few, easy-to-follow steps by absolutely everyone

Click Here to Leave a Comment Below 26 comments
3d Printing Mag - January 19, 2015

Thanks for your tips. I found here some useful advices. You are truly know what are you writing about. Keep doing that! It’s a good job.

Reply
    Yves - January 22, 2015

    Thanks for the feedback. Check back regularly, we have more great content coming soon!

    Reply
    William - April 26, 2015

    If you use a non color change desiccant, you can get small litmus strip indicators that change color to indicate the relative humidity in the container. I have been using them for decades with straight Silica Gel in humidity sensitive lab equipment, and they are a lot cheaper than the color changing desiccant.
    My source is http://sorbentsystems.com/hic.html , and you can buy them in 10 packs.
    As for regenerating silica gel, the technique I have used is to spread it evenly in a shallow baking pan and heat it to 250 degrees F for 4 hours, returning it to the storage container while still hot. (I keep mine in Mason Jars)

    Reply
      Mich - April 28, 2015

      Hi William,

      Thanks for this excellent tip. I did not think of the litmus strips in order to indicate humidity, but that has to work well too.
      As for the regeneration of the silica gel in the pan, I had some of the silica beads cracking up from the heat – that’s why I prefer the oven (easier to control for me). But I guess this comes down to personal preferences.

      Anyway, thanks for taking the time to comment and thanks for these excellent suggestions.

      Reply
Diddi - March 30, 2015

Don’t have a 3d printer yet, but having read a few of your articles, I’m finally feeling confident enough about making informed decisions toward that end.

There’s plenty of info out there on 3d printing, but this site definitely boasts the most accessible stuff I’ve seen!

Thanks alot, I’m gonna continue devouring these delicious nuggets of know-how 😉

Reply
    Mich - March 30, 2015

    Hi Diddi,
    Thanks for taking the time to comment. I am very happy to read that we may have helped you make a decision to finally get a 3D printer. There are so many 3D printer models out there right now so that even for us, who are reviewing them, it can sometimes be difficult to choose. Actually, it all comes down to what exactly you are planning to with your 3D printer. Well, if you have any further questions, please do not hesitate to contact us.

    Also, thanks for your kind words on our site and our work. We try our utmost to explain this sometimes dry and/or complicated information in the easiest and most accessible way, so that it can be understood by beginners, but also be used by advanced users. Comments like yours are what keeps us going!
    So thanks to you too! We are happy to count you among our loyal readers.

    Reply
Charles - June 2, 2015

I have the opposite problem, it seems my filament is too dry, it keeps breaking over and over and I can’t complete any printing anymore. Is that possible?

Reply
    Mich - June 2, 2015

    Hi Charles,
    What filament type are you talking about? PLA? ABS?
    When you are working for instance with Laywood (or similar wood-based filaments), Laybrick (chalk-like filament) and carbon-fibre infused filaments, you need to know that those may be quite prone to breaking. But with other types (ABS, PLA, nylon, HIPS, polycarbonate, etc.) that should not happen.
    Please explain whether you bought branded filament or quite cheap filament – quality can make a huge difference. Once I’ve got your answers, I might be able to help you a little further.
    Also, when exactly does it break? When you are trying for feed it into the extruder?

    Reply
      sagar prasad - September 21, 2015

      Hi all..

      Getting an issues with the moisture content in the filaments.. just wanted to store the filaments in a oven to make it dry.. so could you suspect How long should i keep the filaments in any oven to dry and to get better quality.. for both PLA and ABS filament materials..

      Please make it helpful

      Reply
        Mich - September 22, 2015

        Hi Sagar,

        If I understand you well, you do experience issues with moisture in your filaments. And you are not sure how long to dry them in the oven?

        I can’t really tell you how long to “bake” the filaments in your oven, as it first depends on the type of filament your are using for 3D printing. As described in the article, you need to differentiate between PLA and ABS, as both materials have different properties. And it will also depend on your specific brand of filament’s properties. You will need to check your filament manufacturer’s indications for their “glass transistion temperature”.

        PLA normally becomes soft if heated over 60°C, so if you got a very precise fan-assisted oven, set it to no more than 50°C and let if cure for 30 minutes and try it out. Make a test print with your cured filament. If that’s not enough (i.e. you still got hissing or water bubbles forming at your 3D printers hot-end), do cure it for another 30 minutes. And don’t be tempted to put a higher temperature, in order to save time – the filament will melt or at least bake together the individual filament strands, making it unusable.

        For ABS, you should not use temperatures for oven-curing over 90°C, as it normally starts to soften around 100°C. As for time in the oven, I would advise a cautionary 30 minutes and then test it, as for PLA.

        As you see, there is no general formula and you will need to test around a bit for yourself, to find the best temperatures and curing times.

        Reply
Ian Wippell - November 13, 2015

Hi. I have another suggestion. Have you heard of something called food Saver bags and vacuum device. Used for storing food in freezers for long duration. You usually buy the bags in a continuous roll. You cut off enough bag from the roll and use the vacuums heat sealing to seal one end then place what you wish to store in the bag and place the open end of the bag in the vac unit. Turn it on and all air is removed and sealing the open end takes place automatically. Maybe cut enough bag to store 2 spools plus enough extra to make up for each time you wish to remove a spool by cutting the sealed bag at one end. Recommend extra say double the length of the bag I got mine through Dan Ozz but they are now available in most department stores. Buy the bigger size machines and the wider bag rolls. Cheers, Ian

Reply
    Yves - November 14, 2015

    Hi Ian,
    Thanks for sharing your filament storage technique. This sounds like another good way to properly store filament, especially since you get a perfect vacuum. I am just wondering how much you paid for the vacuum device?

    Reply
      Ian Wippell - November 16, 2015

      Hi William. Cant remember what I paid. The first one I had to throw out due to a mouse plague. I couldn’t even look at it anymore. I just purchased a Sunbeam Fully automatic for $349au after reading your article, but I did a google on them and found them as low as $129. There are 2 sizes 28cm and 22 cm machines. I opted for the 28 cm machine. My new 3d printer arrived today – A Creatbot DX2 300 x 250 x 300 mm volume. Good solid build. Thank you so much for taking the time to publish this article, keep up the good work, cheers, Ian

      Reply
        Ian Wippell - November 16, 2015

        PS. I would still reccomend using some sort of silica gell pellets in a container you described in the vac bag. Cheers

        Reply
Mcc - November 15, 2015

ganz interessanten Artikel, lo huet e bei geleiert. Thanks

Reply
    Mich - November 16, 2015

    Merci vir deen ënnerstetzenden Kommentar, daat ass appréciéiert! Ech fannen et gudd, dat och mol méi Lëtzebuerger am 3D printing Domain aktiv sin! Sidd Dir schons méi laang mat derbai?

    Reply
      Mcc - November 16, 2015

      3Wochen , de Plang an den Obbau sin am Kapp, en Rumba Board leit schon hei, an ech sin amgangen mech do eran ze schaffen.
      Virun 5Joer hun ech emol schon’s eng CnC Portal-Fräs gebaut, mee ed ass hei e bessi anescht……mee ed misst klappen .

      https://picasaweb.google.com/101339907319724020179/CnCPortalfrase?noredirect=1

      P.S. iwregens eng flott Seit…och wann ech muss heiansdo alles 5 mol liesen….zu menger Zeit haat ech leider ken englesch an der Schoul…mee ed klappt.

      Reply
        Mich - November 16, 2015

        Hu mer déi Photo’en mol ugekuckt, ech sin impressionnéiert. Also, wann Dir déi CNC-Fräs do färdeg brengt, dann dierf 3D printing weider kee Problem sin.
        Et ass manner komplizéiert an d’Prinzipien sin basesch gesin déi selwecht. Waat vir e Printer baut Dir do?

        Merci vir de Luew. Mir stinn Iech awer och gären mat Root an Doot zur Verfügung, och wann daat Englescht e bessen schwéier dierft sin…
        Schreift einfach op “mich[at]onsen Domainnumm”, do léisst et sech och besser diskutéieren wéi um öffentlechen Deel hei vum Site.

        Reply
Garry - November 26, 2015

Will ABS, PLA, Nylon, etc. filaments be damaged by freezing? I need to find a new home for my filament and the best location other than my house is in our attached garage which may reach -10 to -15C (14 to 5F) in winter. Obviously they would be brittle when frozen but after they were thawed would they be the same as prior to freezing? I have a feeling they will all be fine but don’t want to risk more than $1,000 worth of plastic without having input on the idea. Thanks.

Reply
    Mich - December 4, 2015

    Hi Garry,
    I must admit, that is one question that I have neither asked myself. Also, I have never tested the hypothesis of frozen filament.
    I would avise you to write directly to your filament manufacturer who can certainly help you better than I could.

    Although, now that you have asked the question, I am putting it onto my to-do list, as I am quite intrigued by the question myself.
    And if I test it, I’ll write up about it.

    Reply
    Eiac - March 28, 2016

    Condensation on removal would be the issue. If you stored them in vacuum bags (foodsaver, not clothes ones) at room temp, stored them, they would be fine as long as you let them come up to room temp before opening the bags.

    Make sure they are fully warmed up before opening the bags, or moisture from the air will condense directly onto the surface of the filament.

    As to the physical properties of PLA/ABS itself changing on temp shifts, no idea. Try it out and tell us the results!

    Reply
Ian Wippell - December 11, 2015

Well, I have been tearing my hair out over my new CreatBot 3D printer with models not sticking to print bed. The general concensus was the bed temp for ABS is 45c. Read the CreatBot pdf manual and it stated 90c bed temp and fully enclosed. Performed a new bed leveling with feeler guage and upped the bed temp to 90c and “Wallah” Perfect print out. I had the same problem with PETG plastic. Recomended temps 215c – 220c nozzle and 65c bed temp. Does anyone have other temps I should try for PET plastic filament?

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Troy - June 7, 2016

A reusable dehumidifier is loads better then getting the beads on there own.
Once it shows color that means the beads are full you plug in to a power point and it heats up and brings the beads back to new.
This is the one i use in my filament box and gun safe.
http://www.ebay.com.au/itm/121795278556?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Reply
Kyle - June 10, 2016

Worth noting you can put the silica packs in the oven and they’ll return to like-new status for reuse.

The YouTube channel AppliedScience has a video on doing this.

Reply
    Yves - June 11, 2016

    You are right Kyle, silica gel packs can be dried in the oven to make them fit for re-use. Thanks for pointing that out.

    Reply

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