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 quick, 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.
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.
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 one, or 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.
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).
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.