Key Takeaways
- Moisture and dust: Filaments can absorb water and dust from the air, causing swelling, brittleness, poor adhesion, and rough surface. Airtight containers and desiccants can help prevent this.
- Heat and UV light: Filaments can degrade from exposure to high temperatures and UV rays, causing fading, melting, and cracking. Keep filaments away from direct sunlight and heat sources.
- Shelf life and signs: Filaments have different shelf lives depending on their type and storage conditions. Signs of worn filaments include holes, sizzling, steam, snapping, and warping. Measure the filament diameter and check the color regularly.
- Storage options: Filaments can be stored in various ways, such as vacuum bags, dry boxes, racks, shelves, or cabinets. Some storage options have features like temperature control, vacuum sealing, or humidity monitoring. Choose the option that suits your budget, space, and filament type.
Proper 3D printer filament storage is essential to prevent hygroscopic filaments from absorbing moisture.
Poor filament storage has a range of consequences, from warped and brittle prints to damaging even the best 3D printers.
The shelf life and signs of wear differ between different filaments, so in this guide, I’m going to explain how to identify and protect yourself from problems with all of the popular filaments.
Then, I’ll share the strategies I use to prolong my filament’s lifespan – so you can keep your prints in top condition for longer.
Filament Storage for 3D Printing
What Makes 3D Printer Filament Wear Down?
Most 3D printer filaments are hygroscopic, meaning they absorb atmospheric moisture over time. This moisture affects the usability of the filaments as the absorbed moisture causes the filament to swell in ways that may not be immediately visible to the naked eye.
While this may not seem like a big deal on paper, the exact size that filaments and extruders are designed is no accident. Even a human hair’s width difference can affect filament performance.
While the hygroscopic nature of 3D printer filaments is its most damaging trait, keep in mind that other environmental factors will play a role in how quickly a filament expires. Filament storage is needed to also avoid prolonged exposure to harsh heat, UV light, and sunlight which can fade the colors as well as damage the material.
While UV light damage is far less likely to be a concern in the average home, it should be known that is one of the most damaging things for filaments, and being left in the sun for long periods of time will cause irreversible damage to some filaments including ABS and PETG.
While humid, hot, or generally wet surroundings are very bad for 3D printer filaments, this doesn’t mean that simply keeping them dry will make them last forever. Atmospheric moisture is all around us, and filament will absorb it over time regardless of how careful you are.
In order to maximize the shelf life, we’ve picked out some of the best 3D printer filament storage options depending on the kind of filament you use and how susceptible it is to these outside factors.
Filament damage is most common in PLA, nylon, PETG, and TPU, with each filament absorbing moisture at different rates. In as little as 24 hours, these thermoplastics can soak in water from the air and swell up if they’re not kept in closed storage.
How Do I Tell if a Filament Has Become Worn Down?
Most filaments will show the same telltale signs of age and degradation. If you’re careful, you’ll be able to spot this age before you attempt to print with worn down filament, lessening the risk to your printer and projects.
Hygroscopic filament that has absorbed too much moisture won’t be obviously larger on a simple observation, but you can tell if it has expanded too much by looking for holes in the filament thread. These holes are a sign of stretching and will indicate that the filament has expanded too much.
If you don’t manage to catch these problems but are still a little doubtful as to how long you’ve had your filament, then you should listen out for a particularly off sizzling noise when feeding your filament into a heated nozzle.
If this noise isn’t present, you’ll be able to tell if your filament is too wet by observing its bed adhesion. Wet filament will have poor bed adhesion and be very prone to warping, you’ll also notice that your prints come out with holes and misshapen parts.
The long-term effects of using worn or expired filament can be dangerous and expensive. Frequent clogs and extensive nozzle damage will occur if left unchecked.
Identifying Wet Filament
The first giveaway sign of wet filament is the popping/crackling sound it makes during extrusion. This is an indication that the moisture in the filament is heating up, evaporating, and forming air bubbles that pop inside the hot end. In really bad cases, you’ll see some steam coming out of the extruder, a sign of filament that has absorbed too much water.
So what happens to filament that has soaked up moisture from the air?
Moisture and Swelling
Filament that has absorbed moisture tends to swell. It may not be noticeable to the eye, but when you measure it, you’ll realize an increase in its diameter. A quick way to know if your filament has become bloated is by measuring it with calipers and noticing any increase in its factory diameter.
Brittle Filament
Wet filament also loses its flexibility and becomes brittle. When you try to bend the filament on the spool, it may snap quickly as a sign of excess moisture.
This is more common in PLA than in other materials and usually happens when the filament is left uncovered during months of printing inactivity.
Layer Adhesion and Print Surface Quality
Due to the extra water, wet filament has a more fluid consistency when it melts. On top of that, the moisture leaves behind air bubbles in the extruded material after it evaporates. As a result, printed layers do not bond well and you may see splitting or layer separation in your prints.
In addition, moist filament leads to a poor surface finish. In such cases, your prints tend to have a rough surface in places that should be smooth. This all comes back to poor layer adhesion and air gaps in the material, creating a bumpy, uneven finish.
What is the Best 3D Printer Filament Storage Method?
Your choice of 3D printer filament storage will depend on a few things. Mainly how naturally susceptible the filament is and when you plan on using it.
If you’ve just got a new 3D printer and have a dozen and one things in mind, then filament storage won’t be at the front of your mind because you’ll likely use all – or at least most – of it within a few days anyway.
If you’re the kind to bulk-buy, or just like to make sure you have filament on hand for when inspiration or necessity strikes, then you’re going to need to consider 3D printer filament storage carefully to ensure reliability and reduce the risk of damaging your prints and your printer.
Here are some of the various 3D printer filaments, their shelf lives, and how best to store them for longer-lasting materials. Though it is worth noting that no filament should be stored in open air.
You must always keep your filament in an airtight container to prevent degradation. Keeping your filament covered protects it from collecting dust particles and moisture.
If you’re going to take a long break from 3D printing, you can store your filament spool in a vacuum airbag. Simply place the filament into the bag and suck out the air from inside, ensuring no chance of getting your filament wet or contaminated with dust.
PLA
- Lifespan without filament storage: ~3 months
- Lifespan with filament storage: ~2 years
- Best filament storage option: Airtight box out of direct sunlight
- Best corrective measure: Air purifier
Ideal humidity level for PLA filament is below 50%.
ABS
- Lifespan without filament storage: ~3 months
- Lifespan with filament storage: 5+ years
- Best filament storage option: Airtight container out of direct sunlight and away from any UV light
- Best corrective measure: Blower dryer (if problems are caught on time) or air purifier
PETG*
- Lifespan without filament storage: Up to 6 months
- Lifespan with filament storage: 3+ years
- Best filament storage option: Vacuum sealed box or bag
- Best corrective measure: None, but can be somewhat salvaged if carefully blow dried
*It is worth noting that PETG is less sensitive to UV light than ABS and PLA, but is far more susceptible to moisture absorption, so vacuum-sealed containers are the most reliable standard filament storage method.
Storage Inspection
You need to monitor the condition of the filament regularly because no storage unit is perfect.
How often you monitor your filament storage depends on your environment. Hot, humid areas have plenty of atmospheric moisture that can quickly soak into your filament. This is why it’s important to check on your filament size every couple of months to be sure it’s good to print.
Cold, dry places may be less brutal on your filament, keeping it intact for months or even years without any chemical reaction with the filament.
Best Options for Filament Storage
While airtight boxes may help make your materials last longer, there are some specialty filament storage options that provide solutions to common degradation problems like temperature control and vacuum sealing.
If you’re using an airtight box, you can expect to keep most filaments for about a year before they age too much, but with specialty filament storage, you can make anything from PLA to Nylon last far longer.
Here are some of the best specialty filament storage options available today.
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Matterhackers PrintDry Filament Drying System & Storage System
- Drying System Price: $179 — Available at Matterhackers here
- Storage System Price: $99 — Available at Matterhackers here
If you’ve ever worked in a bar or grew up in a household that rationed soft drinks, you may know of the concept of a fizz-keeper. Essentially, they’re small air pumps that render soda bottles airtight, which makes them stay carbonated for longer.
Matterhackers’ PrintDry system works in very much the same way. At a glance, they look like simple plastic containers, but their pump system vacuum seals your filaments away.
The best thing about the PrintDry system is that it doesn’t need to be used right away. If you’re worried that your filament has already absorbed moisture and want to minimize the risks of that, you can use the PrintDry system to dry your filament before use.
Essentially, this means that the Matterhackers’ PrintDry system not only works as a filament storage device, but also as a preparation method to ensure the filament is ready for printing without worries, provided they aren’t too far gone.
Sunlu Dry Box
- Price: $49 — Available on Amazon here
The Sunlu Dry Box is similar to many viable filament storage containers with a key difference in that its internal temperature can be monitored and controlled.
This is good news for people who live in particularly cold areas or simply want to ensure that their filament is kept in optimal condition.
Much like the PrintDry system, the Sunlu Dry Box can also act as a dehydrator, helping to dry out from filaments that have already been exposed to atmospheric moisture.
The Dry Box, however, isn’t financially viable for those of you who want to store a lot of filament spools at once. At $49.99 each, they can only hold 1kg of filament at a time, making them a very costly choice if you’re storing more than a couple of filament spools at a time.
RepBox
The RepBox is a professional filament storage option that can hold six 1 kg spools (or 12 half kg spools) in a sealed acrylic case. Each spool gets its own hole so it can feed through to your printer for direct printing.
It contains a hygrometer and thermometer for measuring humidity and temperature within the box. It comes in two versions: Standard and Premium.
The standard version is technically not a filament dry box. But in the words of manufacturer, Repkord, “it reasonably adequate protection from moisture when desiccant cartridges or packets are placed inside.”
The premium version offers complete moisture control, with rechargeable alumina desiccant cartridges and seal gaskets.
Dry Cabinet
The dry cabinet wasn’t designed with specifically filament storage in mind, but its marketability towards photography equipment and the general protection of devices and materials that are prone to moisture absorption. Naturally, this makes it the perfect choice for 3D printer filament storage.
The main draw of the dry cabinet as filament printer storage is its size. The larger model can hold at least ten rolls of filament depending on their size. While not the most sophisticated of storage options, the dry cabinet is a good choice if you want to store a lot of filament at once in an environment suitable for hygroscopic materials.
If you’re looking for something smaller, try storing your filaments in a repurposed wine cooler, especially one with a digital thermostat. These are specifically designed to regulate temperature and humidity levels so they make a great storage place for printing filament.
DIY Desiccant Solutions
If you’re big on DIY, you can skip the part where you buy a commercial drybox and make your own. You can take an extra step to keep your DIY box dry by adding desiccant to it. A desiccant is a hygroscopic substance that absorbs the moisture from the air before your filament does.
You can buy desiccant in the form of beads or small packets.
The packets are inexpensive and come in sizes of 0.5 to 500 grams, making them convenient for both small and large-scale users. Most retailers can give you a discount if you buy in bulk, allowing you to spend $1 on each 50 g packet and use it at your convenience since desiccant doesn’t expire.
Desiccant beads are what you find inside the packets, and you can buy and use them on their own. They are the better option if you have a large storage space requiring plenty of absorption. The beads are about 3 mm in diameter and are sold by weight at about $30 for 5 lbs.
So how do you know how much desiccant you need for your filaments?
Luckily, there’s a simple formula you can follow: 1.2 units of desiccant per 1 cubic foot of storage space, where each unit is considered one ounce of desiccant.
The beauty of desiccants is that they can be reused after a while. All you have to do is recharge the beads and packets by baking at a low temperature to remove excess moisture.
To reactivate, silica gel desiccant:
- Place a foil-lined baking sheet in your oven
- Preheat the oven to 135 °C (275°F)
- Place the desiccant packets flat onto the foil. If you’re heating beads, keep them in a layer of about 2 inches thick.
- Heat for about 4 hours
- Take out the desiccant and store it in an airtight container.
You’ll typically need to recharge your desiccant after every 2-3 years, depending on how much moisture it’s dealing with on a daily basis. Color-indicating desiccants give you a more defined answer on when to reactivate them because they visibly change color when full of moisture.
For example, indicating silica gel is laced with cobalt chloride, which turns from deep blue to pink as it gets wetter over time.
Once you have your desiccant packets/beads, simply place them into the DIY storage of your choice, such as a gasketed Rubbermaid container. Add an extra layer of humidity control by including a temperature/humidity sensor and reptile heater mat in the container.
Vacuum Seal Bags
A low-tech solution that’s great if you’re low on pace is a simple pack of vacuum seal bags.
The ultimate in airtight containers, and very cheap at that, they are an ideal 3D printer storage option if you want to keep your filament protected without spending a lot of money or having to clear out a new space at your workstation.
Standard vacuum bags have a valve that lets you suck the air out of the bag using a vacuum cleaner or hand pump. To empty the vacuum bag of air, place the hose of the vacuum cleaner or hand pump completely around the valve and pump the air out.
Be sure to get vacuum bags with a double zipper seal to completely block air from entering the bag. You may also throw in a color-changing desiccant packet to absorb any stubborn moisture, but this is not necessary in most cases.
Vacuum seal bags come in a variety of sizes, ranging from 16 to 30 inches wide, allowing you to fit single or multiple 1-kg spools in one place.
Filament clips are also an important addition to your homemade filament storage system. These attach to the end of your filament spool to prevent it from unraveling and poking holes into the storage bag, especially during transit.
Filament Drying Times
Here are the drying times for common filaments. Try to stay within these temperature ranges as going beyond will cause the filament to melt and soften instead.
| Filament | Drying temperature | Dry time |
|---|---|---|
| PLA, PETG, ABS | 50-55 ºC | >3 hours |
| TPU, ASA | 55 ºC | >4 hours |
| Nylon | 75 ºC | 12 |
Organisation Storage / Options for Filament:
The easiest way to store your filament is by keeping it on a rack or shelf. It gives you easy access to your filament spools since you only need to identify what you need and pick it out. It also makes it easy for you to see where each filament is, how much of it is left, and its present condition.
The downside of racks and shelves is that they’re open and therefore expose your filament to degrading elements. Naturally, the filament collects dust and gives in to humidity if it’s left standing on a shelf or rack without any covers.
Racks come in all shapes and sizes and can be purchased or homemade.
Homemade options, such as this filament rack and spool holder, are usually 3D printed by the users themselves. This allows you to create the perfect, custom-made storage option for your spool collection and physical space.
You can also purchase an already-made filament holder such as this RepRack wall mount from Repkord. If you want to get the best of both worlds, you can convert a bookshelf into a storage unit by installing a spool holder in it.
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