How do you store unused PLA filaments?

Quick Answers

Here are some quick answers to common questions about storing unused PLA filaments:

What is PLA filament?

PLA (polylactic acid) is a biodegradable thermoplastic made from renewable resources like corn starch or sugar cane. It is commonly used for 3D printing.

Why should you store unused PLA properly?

Proper storage keeps PLA dry and free from dust/debris which can clog the 3D printer nozzle. It also prevents the filament from becoming brittle over time.

What happens if PLA absorbs moisture?

Moisture makes PLA brittle and causes popping/crackling during printing. This leads to weak prints and clogged nozzles.

How should you store unused PLA?

Store PLA filament in an airtight container with desiccant packs. Use storage containers made specifically for filament. Keep it in a cool, dry place away from sunlight.

3D printing is an exciting hobby that allows you to turn digital designs into physical objects. It involves melting and extruding thermoplastic filament, like PLA, through a heated nozzle to build up an object layer by layer.

PLA (polylactic acid) is one of the most popular filaments for desktop FDM/FFF 3D printers. It’s low-cost, easy to print with, and produces decent quality prints. When shopping for PLA filament, you’ll often find good deals on multi-pack rolls.

However, most home filament storage systems aren’t designed to keep a whole Duplicator Spool Box or other large supply protected indefinitely. So what’s the best way to store all that extra PLA without ruining it?

Proper storage is crucial because PLA can degrade surprisingly fast once it’s exposed to moisture in the air. And degraded filament leads to poor print quality and clogged nozzles. In this guide, you’ll learn everything you need to know about keeping unused PLA in good condition for future prints.

The Problem With Exposed PLA Filament

PLA filament is hygroscopic, which means it absorbs moisture from the surrounding air. Many plastics behave this way, but PLA is especially sensitive compared to more printing-friendly filaments like PETG and nylon.

Absorbed moisture causes major issues during printing. As the filament enters the hot end, the trapped water turns to steam. This causes the filament to bubble and sputter instead of melting smoothly. Filament with too much moisture will not extrude properly or bond to the previous layer.

Printing with wet filament usually leads to:

  • Stringing
  • Weak layer adhesion
  • Oozing
  • “Popping” sounds
  • Clogged nozzle

Moisture also makes PLA brittle. The plastic becomes easier to snap and crack either inside the printer or when you try to unload it.

Exposure to sunlight can also degrade PLA over time. The ultraviolet radiation breaks down the polymer chains, causing the material to become discolored and brittle.

How Quickly Does PLA Absorb Moisture?

You may be surprised by how fast PLA can go bad when left in the open. Filament that’s exposed to ambient humidity can absorb enough water to cause major print quality issues in just a day or two.

PLA is very sensitive because it’s hygroscopic and also has a low glass transition temperature. The glass transition temperature (Tg) is the point where the filament begins to soften and become malleable. PLA’s Tg is only around 60°C.

Compare this to PETG filament, which has a Tg of 80°C and is far less absorbent. Because of its low Tg, PLA filament starts degrading quickly at room temperature.

So don’t accidentally leave PLA spools out for too long. Those attractive open acrylic filament holders may look nice, but they won’t protect material over the long term.

Proper PLA Storage

To prevent degradation, unused PLA filament must be stored carefully. The main storage guidelines are:

  • Use an airtight container – This prevents ambient humidity from reaching the filament.
  • Include desiccant – Desiccant packs actively absorb moisture from the air inside the container.
  • Keep cool and away from light – Heat and sunlight also degrade PLA over time.

Here are some good storage solutions that meet these criteria:

PLA Storage Containers

Specialty containers designed for filament storage are the best option. They seal completely to keep out moisture and often include integrated desiccant packs.

Popular versions include:

  • PrintDry Filament Box
  • HATCHBOX 3D Printer Filament Dry Box
  • COMGROW Filament Dry Box
  • Winsinn 3D Printer Filament Storage Container

These systems have gasket-sealed transparent lids allowing you to see your spools while protecting them. With multiple compartments, they can house several different filament types in neatly organized fashion.

Filament Storage Container Highlights
PrintDry Filament Box Holds 6 spools, gasket seal, reusable desiccant
HATCHBOX 3D Printer Filament Dry Box Holds 8 spools, digital humidity display
COMGROW Filament Dry Box Holds 10 spools, calcium chloride desiccant

With containers like these, you can keep multiple PLA, PETG, ABS, and other spools protected in a single organizer. The best ones remove moisture while conveniently letting you find and retrieve filament.

Airtight Storage Bags/Canisters

Another option is to seal spools in airtight bags or plastic canisters along with desiccant packs. This prevents air exchange while actively drying the contents.

Look for bags and canisters designed for long term filament storage. Generic plastic bags may not have a robust enough seal or be sized appropriately. Products like Polymaker’s filament canisters are optimized for handling full size spools.

The downside to bags and canisters is that you cannot see your filament. You need to remove the spool if you want to inspect color, material type, etc. An enclosed container with transparent lid is often more convenient.

Vacuum Sealing

For maximum protection, you can vacuum seal filament spools in plastic pouches. This removes nearly all air to prevent moisture absorption. Just make sure to include several desiccant packs before vacuum sealing.

Vacuum sealing works great but is more labor intensive. The plastic pouches can also be punctured more easily than a hard case. Casual users may prefer the simplicity of a storage box or canister.

Desiccants

No matter which storage method you use, desiccant packs are essential. Look for containers that include desiccants optimized for moisture absorption. Common types include:

  • Silica gel – The tiny beads adsorb vapor effectively.
  • Calcium chloride – Very moisture-avid and long lasting.
  • Montmorillonite clay – Swells as it adsorbs water molecules.

Packs containing calcium chloride or clay tend to be reusable. You can dry them out in the oven periodically to remove absorbed moisture. Just make sure to use desiccants rated as safe for plastics.

For containers without integrated desiccants, include multiple spare packs. Replace them periodically or when you see moisture buildup inside the container.

Filament Drying

If your PLA filament has already absorbed excess moisture, don’t despair. You can often dry it out again before use.

Baking wet filament at low heat for several hours will drive out absorbed water. Use your oven’s “Warm” setting or a temperature of 50-60°C. It’s best to spool the filament onto something like a pasta machine so air can circulate.

After baking, quickly move the dry filament into an airtight container with desiccant before it reabsorbs moisture. Now it will be ready for printing again.

Note that severely degraded filament may not be salvageable. If the material is discolored or brittle, it’s probably too far gone. For mildly wet filament, though, baking can often restore printability.

Ideal Storage Conditions

To summarize, here are the ideal conditions for storing PLA filament:

  • Inside an airtight sealed container or bag
  • With desiccant packs to actively absorb moisture
  • Kept at room temperature or cooler
  • Away from direct sunlight
  • Use printable storage lengths of 1 kg or less

Follow those guidelines, and your PLA filament should stay dry and print-ready for a year or more, even if a spool is only partially used. Proper storage lets you get the most value from multi-pack filament deals.

For other filament types like ABS and nylon, the principles are similar but drying requirements vary. PETG is less sensitive to moisture but still benefits from sealed storage.

Signs of Degraded Filament

With poor storage, PLA will develop visible signs of degradation. Here’s what to inspect your filament for periodically:

  • Bubbles, cracking, or discoloration – Indicates moisture damage.
  • Brittleness – Filament snaps instead of bending.
  • Poor spooling – Badly wound filament jams the printer.
  • Specks or particles – Attracted dust and debris.

Any filament showing those flaws should be baked to regain printability. Severely degraded PLA may need to be discarded.

Preventing Filament Dust

Particles and dust on stored filament can also lead to clogged nozzles. Here are some tips to avoid loose filament dust:

  • Avoid filament abrasion – Don’t let spools grind on each other.
  • Use filament filters – Install inline filters to catch particles.
  • Clean extruder gear – Clear out accumulated grime on the hobbed bolt.
  • Swab the nozzle – Lint-free swabs clean nozzle holes.

With good filament handling practices, particles won’t become an issue. Any accumulation is easy to clear from key printer parts.

Vacuum Storage

Storing filament spools in vacuum bags provides the ultimate protection by removing nearly all air and moisture. Vacuum sealing works great but has some limitations:

  • Sealed bags are prone to punctures.
  • Takes more effort to access filament.
  • You’ll need a nonzero-colossal-sized vacuum sealer.
  • Spools don’t stack efficiently.

For casual users, a normal airtight box with desiccant provides sufficient drying at lower hassle. But vacuum sealing is a smart approach for long term archival storage or shipping filament through very humid regions.

Vacuum Sealing Procedure

To vacuum pack filament, you will need:

  • Vacuum sealer system
  • Vacuum chamber and bags (or a vacuum hose adapter)
  • Desiccant packs

Steps for packaging spools:

  1. Cut a section of vacuum bag to fit the spool.
  2. Add 3-4 desiccant packs around the spool.
  3. Carefully seal one end only.
  4. Load the open bag into the vacuum chamber.
  5. Turn on vacuum pump to remove air.
  6. Quickly seal the open end once vacuum achieved.

Store the vacuum packed spool in a cool, dry place. Make sure to open the bag and use the filament within 6-12 months.

Conclusion

Caring for your PLA filament is just as important as maintaining the 3D printer itself. With proper storage, you can keep large multi-packs of filament fresh for the long term.

The keys are using an airtight container, desiccant, and keeping PLA away from moisture, sunlight, and dust. Check spools periodically for degradation issues.

A bit of filament care goes a long way to improving print quality and avoiding failed prints. So invest in some good storage boxes or canisters to get the most out of your material.

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