Does 3D Printer Filament Go Bad/Expire? How to Tell


I have my Ender 3 printing a model with the spool of filament in place, and it got me wondering. Does 3D printer filament ever go bad or expire? I had to go out and figure out the answer, so that’s what I’ll be sharing in this article.

Keep on reading through the rest of this article for some interesting information on this topic and some troubleshooting that can definitely help.

Can 3D Printer Filament Actually Expire/Go Bad?

3D printer can expire and does have an expiry date, but it is still possible to restore and successfully 3D print with old filament. You should dry the filament to ensure any moisture is removed from the filament. Your printing quality likely won’t be as good, and the resulting prints more brittle.

You also want to protect your filament from harsh heat, sunlight, and other forces like dropping it or throwing it around without much care.

Like every other item that has a shelf life, 3D printer filament can actually expire. When it comes to the 3D printer filament, the environment of storage is very critical.

In order to make filament last long without going bad, you need to store your 3D printer filament in conditions that are void of moisture. The presence of moisture or humid conditions in an area where you store your 3D printer filament will interfere greatly with its shelf life.

In a nutshell, your 3D printer filament can expire depending on how you store it. This is the main reason why 3D filament manufacturers usually store their filament in very specific conditions, such as a vacuum-sealed bag.

This protects the filament from degradation.

So, how does filament expire/go bad? Basically, the filament will absorb moisture through the air. In most cases, the filament’s outer part is the first to get brittle, following exposure to moisture or humid conditions.

You can sometimes tell that your printer filament is not at its best by the quality of prints, but this is easily overlooked in some cases.

Rather than fine prints that are a characteristic of a filament that is functioning optimally, you will get streaky prints – evidence that something is wrong with your filament.

Consistent exposure to moisture and humid environment may lead to increased fragility, filament degradation, increased diameter, and breaking filaments.

This long list of problems resulting from exposure to humidity will eventually make your filament go bad.

However, a notable fact is that these negative effects that come about as a result of exposure to moisture can be reversed or corrected provided you know what is affecting your filament.

How to Tell If PLA Filament Has Gone Bad?

Moisture absorbed PLA filament will present with certain features that will tell you immediately that something is wrong. 3D printer damage, weaker 3D prints, and poor 3D print quality are the three main features of an expired PLA filament.

  • 3D Printer Damage – when the PLA filament absorbs moisture, it can swell, leading to an increased diameter of the filament. When fed into your printer, the swollen filament will jam your printer extruder and sometimes lead to its replacement. Check the filament diameter for inconsistencies.
  • Weak 3D Prints – The tensile strength of a filament that has absorbed moisture decreases by 6 percent, hence the weak prints. Bend parts of the filament to see if it has little bend to it and snaps easily
  • Poor 3D Print Quality – When heated, the moisture trapped in the filament escapes as steam where you can sometimes hear a popping sound. This steam leads to the interference of the flow of plastic, leading to poor quality 3D prints. Additionally, the layer-to-layer adhesion decreases, resulting in a poor look.

As previously mentioned, you can usually bring your filament back to life by using a good quality filament dryer, or even your oven or food dehydrator. The issue with using something like an oven is how many of them don’t go low enough to what we need.

Many of them also aren’t as well calibrated as you think, where you’d think the heat settings translates closely to the actual temperature, but it doesn’t.

That’s why I’d recommend getting yourself the SUNLU Dry Box for Filament for a great solution to this issue. Tons of people have transformed their 3D printing quality in no time by using this filament dryer.

I’ve seen many stories about people melting their filament spool in the oven, so we can now completely avoid that!

How Long Does PLA, ABS & PETG Filament Last? – Shelf Life

Many people can attest to how they have left their spool of filament, ABS & PETG out in the open for several months, or even years and still 3D print without any noticeable changes in quality.

When people ask how long filament lasts, it really depends on what environment you left your filament in. If you left it by the window in a location that has a beaming hot sun for many hours around the day, and is also humid, it might not last so long.

On the other hand, if you leave it in a cool basement which has a good airflow, low humidity, and doesn’t get pushed around or dropped over the place, you can rest assured you filament will last many years.

I’ve heard people say that when stored in normal settings, filament can last up to 15 years, and how PLA lasts very long when stored away from moisture. While in an adverse environment, PLA is said to last between a few months to two years.

While PLA is not water-soluble, it has a fairly high rate of water absorbency, or in technical terms, is hygroscopic. Exposure to moisture will lead to poor results when put into your 3D printer with the high-temp nozzle.

Luckily, we can remove that moisture with the dry box solution as mentioned above.

ABS filament, on the other hand, is strong, temperature-resistant, and a lot more durable than PLA. It will last longer than PLA when stored in normal conditions because of its good shatter resistance and temperature resistance.

It still is quite sensitive to moisture, so I’d try to store it in a good place. I’d recommend checking out my article Easy Guide to 3D Printer Filament Storage & Humidity – PLA, ABS & More.

ABS is said to last around 10 years, but I’m sure it can last longer when it is stored as normal, then dried before 3D printing.

If the filament absorbs too much moisture from the air, it may degrade, bubble, or simply produce some horrible prints that you won’t be happy with.

Check out my article about How to Fix Bubbles & Popping on Your 3D Printer Filament which has many useful tips you can put to use.

PETG filament is made a co-polyester, which makes it very strong and durable. Because of these properties, PETG filament can last a long time as long as it is stored under normal conditions, away from moisture.

PETG is actually highly hygroscopic, so it absorbs moisture very quickly. Many people have shown the difference between a 3D printed model with “wet” PETG and dry PETG, and the difference is clear.

PETG gets a lot of stringing, and drying it reduces stringing by a lot.

When stored properly, like in vacuumed containers, PETG filament can last several years without issues. The duration of how long it last when used will depend largely on how it is stored.

How Do You Fix Brittle 3D Printer Filament?

Brittleness is a characteristic of a printer filament that has absorbed moisture. A brittle filament will interfere with your productions’ quality; hence, the need to fix the problem.

Usually, a roll of brittle filament results in broken pieces, reduced texture strength, and uneven extrusion during printing. In most cases, it is the outer part of the filament that starts to get brittle due to high exposure to moisture.

You have to remember that filament is storage tightly on the spool for a significant amount of time.

Any attempt to straighten the roll aggravates the situation since it adds mechanical stress to the spool beyond its tolerance. Eventually, it keeps breaking off when you try printing with it.

How then do you fix brittle 3D printer filament?

Below are a few listed suggestions that you can apply in a bid to fix your brittle filament:

  • Heat the Filament roll – In some cases, heating the entire filament roll may reverse its brittleness. This is only applicable when the changes in its physical properties are still reversible.
  • Increase Nozzle temperature – Increasing the temperature of the nozzle ensures that adequate heat is supplied, overtaking the moisture that will absorb a lot of the heat from the nozzle

I wrote an article specific to Why Does PLA Filament Get Brittle & Snap? – Fixes & Solutions which I think you’ll find helpful.

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