Just like many other things, buying PLA filament in bulk by opting to go for a single, large spool instead of buying smaller spools every time you run out has significant advantages, with consistency, budget-friendliness, and convenience coming to mind.
On the other hand, even though it may not seem like it, PLA filament does degrade over time, which causes the decision to buy it in bulk a slightly challenging one if you aren’t confident that you can go through all the filament in time.
Today, our article will be on the shelf life of PLA filament, where we will explore how long PLA filament lasts in storage before it starts degrading and becoming unfavorable to use.
So, how long does PLA filament last?
Depending on the effects of the environment and the storage conditions on moisture, ambient temperature, and light exposure, PLA filament that you store as optimally as possible can last over ten years.
On the other hand, PLA filament that you expose to factors such as humidity and sunlight may not even last a month, depending on the severity.
In the upcoming sections, we will take a deeper look into the shelf life of PLA filament, analyze the factors that cause PLA filament to deteriorate, discuss the best storage options for PLA filament, and find out what you can do with old spools of PLA.
How Long Does PLA Filament Last (Does It Have a Shelf Life)?
The shelf life of PLA filament is one of the primary factors to consider before committing to a large spool, as wasting the filament can negate everything you stand to gain from this decision.
A spool of PLA filament can have a shelf life of anywhere between a week and over ten years, depending on environmental factors such as moisture, sunlight, and ambient temperature, and how well you negate these factors through proper storage conditions.
Since a range of a week and ten years is quite vague to make any solid calculations on, let’s take a look at a few example storage conditions and shelf life estimations for PLA filament depending on these factors:
- PLA exposed to over 50% humidity regularly – 1 month before it absorbs way too much moisture and needs drying before usage
- PLA exposed to sunlight regularly – 1-2 weeks before it becomes brittle and unusable due to the heat causing damage to its properties of strength and resistance
- PLA stored in a moisture-free, cold, and dark environment – 1 year before signs of moisture start showing up and the spool requires drying
- PLA sealed with dehumidifiers (such as silica) and stored in a cold, dark environment – 10+ years without any issues as long as the dehumidification is optimal
As a rule of thumb, we can say that the more you protect your PLA filament from environmental factors, the longer it will stay in prime condition and avoid degradation.
Which Factors Cause PLA Filament to Go Bad?
As there are a fair few factors that can accelerate the process of the degradation of PLA filament, being knowledgeable about these factors is the best way to ensure that you can provide sufficient storage conditions for your investment.
Exposure to Moisture
Moisture is the primary factor that causes a spool of PLA filament to degrade, but the changes are reversible by drying the filament.
In a nutshell, a spool of PLA filament that has absorbed moisture won’t be suitable to 3D print due to the water in the filament distorting the printing process when it comes into contact with the high temperatures of the extruder.
On the other hand, as water does not degrade the PLA material, drying a spool of PLA filament that has absorbed water should make it as good as new and ready for printing.
Since knowing whether a spool of filament has absorbed water or not is usually not possible until you see the signs during the printing process, it’s still best to avoid the moisture as much as possible.
Exposure to Sunlight
While sunlight isn’t strong enough to melt your PLA filament, it will cause degradation without a doubt.
When you expose PLA to sunlight for prolonged periods, it becomes brittle, loses its strength and resistance, and becomes very prone to breakage due to its weak structural integrity.
As this degradation is not reversible, keeping your PLA filament away from sunlight is paramount to ensure it stays good enough to use.
Exposure to High Temperatures
Similar to sunlight, prolonged exposure to high temperatures can start breaking your filament down and cause it to lose its properties.
When you store PLA in environments where the temperature is higher than room temperature for prolonged periods, it will start degrading and become brittle.
Since you can’t do much to salvage the filament once it degrades due to high temperatures, storing your PLA spools in a cold environment is vital.
How to Store PLA Filament Optimally?
Storing the PLA filament as optimally as possible has a significant impact on its shelf life, which becomes especially important if you are not planning on using the spool for an extended period.
As optimally storing PLA is all about reducing the filament’s exposure to sunlight, moisture, and high temperatures, here is the list of things we recommend doing to prolong your PLA filament’s shelf life:
- Use dry boxes or dry cabinets specially produced for storing filament.
- Seal your spool of PLA filament in airtight containers, vacuum bags, and airtight plastic bags.
- Add dehumidifiers (desiccants) to the containers or bags you seal your PLA in, such as silica gel.
- Add humidity indicators to the containers or bags you store your PLA in to track the humidity status of your filament.
- Store your PLA filament in cold and dark areas.
- Avoid storing your PLA filament in moisture-heavy parts of the house. Rooms close to bathrooms and kitchens are some examples of moisture-heavy areas.
What Do You Do With Old PLA?
In some cases, a spool of PLA filament may become way too old and degraded to yield optimal results in 3D printing, but it doesn’t mean that you can’t do anything with it.
While it’s not possible to recycle PLA alongside other types of regular household plastic (which is why you shouldn’t throw old filament spools into the standard plastic recycle bins) because of its low melting point, PLA is still biodegradable and recyclable.
By contacting the professionals that can recycle PLA, you can contribute to reducing plastic waste through recycling and composting instead of throwing your old PLA filaments into the trash.
Even though you personally won’t gain anything from this process, recycling your old PLA is a quick and easy way of contributing to the environment.
Knowing the shelf life of a spool of PLA filament and the factors that can cause it to degrade is, without a doubt, paramount for deciding the amount of filament you should buy and for picking out an appropriate storage space for it.
To summarize quickly, the shelf life of PLA can fall anywhere between the range of one week to ten years.
As environmental factors, such as sunlight, moisture, and ambient temperature, and how well the storage conditions protect the filament from these factors essentially decide how long your spool of PLA will last, it’s impossible to come up with an exact figure that works for everyone.