Filament is one of those things you can never have too much of. With so many colors, finishes, and materials to experiment with, spools rack up until you have a whole stack of them. However, allowing your stash to get too large can result in expired filaments, which may interfere with the quality of your 3D prints.
3D printer filament has a shelf life. Depending on the type of filament you are using, 3D printer filament will last from 12 months to 3 years once open and exposed to moisture in the air.
Since the life expectancy of a filament varies, I’ll break down the different types of filaments and their shelf life. Read on to learn more about how long your filament will last, what happens if you use an expired filament, and how to keep yours in the best condition possible.
The Shelf Life of Different 3D Printer Filaments
Thermoplastics are filaments for 3D printers which melt under hot temperatures instead of burning. The plastic used to create 3D printer filament is virtually everlasting in its natural form – thermoplastics take over 450 years to break down or biodegrade.
So ultimately, we would think filament would last that long. Unfortunately, some of these filaments are finicky and expire once they’re open for a while. There are many different types of filaments, but I’ll focus on the top four for this article.
PLA (Polylactic Acid)
Polylactic acid is a thermoplastic with a low melting point at 180-230℃ (356-446℉). That may seem high, but it is relatively low when melting and molding plastics. PLA will retain its composition for 2-3 years if stored properly. If used after the expiration, PLA becomes challenging to use in a 3D printer.
Old PLA will usually still thread through the printer nozzle, but the result will be frail. The filament will harden and crack, leaving your printed piece brittle and stringy.
ABS (Acrylonitrile Butadiene Styrene)
Acrylonitrile butadiene styrene is one of the most common thermoplastics in 3D printing. ABS has a high melting point of 210-250℃ (410-482℉).
Like PLA, ABS has a shelf life of 2-3 years. ABS absorbs moisture rather rapidly, which causes it to lose its strength and durability.
A popular filament for 3D printing is nylon. Nylon was first crafted in the DuPont research labs in the 1920s and became a household name for many items such as pantyhose, blouses, and toothbrushes. Nylon is a synthetic polymer thermoplastic with a high melting point of 240℃ (464℉).
3D printer enthusiasts flock to this filament due to its flexibility and ability to withstand high temperatures.
The shelf life of nylon is a maximum of 12 months. Due to its ability to attract, absorb, and retain moisture, I don’t advise you to continue using this filament after its one-year expiration date.
In its natural state, nylon could pretty much last forever. However, as a printer filament, using it after 12 months will leave you with brittle and unstable printed pieces – if the nylon makes it through the nozzle. With the high moisture content, Nylon will swell and can clog the nozzle.
PETG (Polyethylene Terephthalate Glycol)
PETG is a thermoplastic (PET, polyethylene terephthalate) and glycol. This combination allows the plastic to melt at a higher heat, about 230-250℃ (446-482℉), and it is more flexible and durable than PLA.
PETG filament has a shelf life of 2 years. PETG thermoplastics are popular for outdoor projects because of their UV resistance. The built-in UV protection means your project will last longer in the sun without deteriorating from the sun’s rays.
What Happens if You Use Expired or Bad 3D Printer Filament?
You might be thinking, “Hey, this filament still looks good. I’ll try it out.” Trying a piece of filament for a small project is generally not going to cause an issue, and it is a great way to test the durability of a part of the filament. However, if your filament does produce a print, it will likely be brittle, have streaks, and possibly holes.
If you use expired or bad 3D printer filament, you may see success. However, it is more likely that your print will be brittle, include artifacts and stringing, and have poor layer and bed adhesion. Moist expired filament may also damage or clog your printer’s hotend.
Even if you are successful with a small part of the filament, it does not mean the entire roll is intact. Keep that in mind, and pay close attention to the printer and filament as it creates your 3D object. If you notice an issue, stop the printing process immediately to ensure minimal or no damage comes to your printer.
Additionally, if you use a filament, like Nylon, that quickly absorbs moisture, the thread may swell and will not thread through the nozzle. Using a filament in this state will cause the filament to clog the nozzle or hotend, which could be costly to replace.
Other filaments like PLA will break because they will be too fragile. This breakage could also cause clogging in the nozzle.
How To Properly Store 3D Printer Filament
The best way to keep your 3D printer filament from going bad or expiring before its shelf life date is to ensure it is properly stored. Keep your filament in a sealed container to prevent moisture from the air from altering the plastic.
Silica gel packets also reduce moisture content in the containers to add an extra layer of protection. Try these Aquapapa Silica Gel Desiccant from Amazon.com as a quick and inexpensive way to preserve your filaments to keep them from going bad before their expiration date.
Thermoplastics in their natural state will last almost forever. However, they have a shorter shelf life when used as a 3D printer filament. Depending on the filament you are using, the shelf life is 12 months to 3 years.
You can reduce the risk of your 3D printer filament going bad before its expiration date by sealing the filament in an airtight container and adding a silica gel packet to reduce moisture.
Use expired 3D printer filament at your own risk as it could damage your printer. I hope this information helps you with your 3D projects.