Okay, first things first, do you need to dry filament? The short answer is yes, you should dry filament whenever it’s hygroscopic or already showing signs of moisture. With that being said, knowing when and how to dry filament can make a world of difference to print quality. In the guide, we’ll explore why moisture causes trouble, which materials are most at risk, when you should intervene, and more. Whether you’re experimenting with flexible TPU or turning out production parts each week, a solid grasp of filament care belongs next to bed-levelling and
slicer profiles in every 3D printing checklist.
Why Does Filament Need to Be Dried?
Put simply, filament needs to be dried because wet plastic prints badly. Many 3D printer filaments act like little sponges, soaking up water from the air—a property called hygroscopy. When that damp strand reaches the printer’s nozzle (also called the hot end), sitting around 200 °C, the trapped water flashes into steam and blasts tiny bubbles through the softened plastic. You’ll hear the effect as popping sounds and hisses, and you’ll see it as uneven, wiggly extrusion with fine stringing between travel moves.
Because steam disrupts flow, each new line of plastic (the ‘bead’ or ‘road’ coming out of the nozzle) can’t grip the build plate (print bed) or previous layers, causing poor adhesion. Expanding bubbles also push those lines off track, so holes can shrink, walls can bulge, and the whole part may suffer dimensional inaccuracy. In short, drying 3D filament helps keep the plastic solid and strong.
What Happens When Filament Absorbs Moisture?
You should be able to spot moisture issues early on: The nozzle may crackle or hiss, and the fresh plastic bead can puff up with tiny bubbles. Surfaces that should be shiny appear chalky or fuzzy, and parts meant to bend might just snap. Flexible materials like TPU even turn tacky in the feeder gears and slip. In bad cases, steam travels back up the PTFE or Bowden tube (the hollow guide that feeds filament to the nozzle), condenses, and drips onto the print. Every wet-then-dry cycle shortens the plastic’s molecular chains, so each new layer is a little weaker than the last.
How Moisture Affects Print Quality and Performance
Moisture affects print quality by filling the softened filament with countless tiny air pockets. These pockets swell during printing, so each layer puffs up and leaves small gaps that weaken the part. Moisture also affects printer performance because the foamy, rough plastic drags along the inside of the nozzle, which can lead to clogs or uneven flow (under-extrusion). On the outside of the model, trapped steam escapes as zits, pits and thin strings of plastic that spoil the finish.
Precision may take a bit of a hit too, with expanding bubbles shoving the molten roads of plastic sideways, making one wall thicker while the opposite wall ends up thinner. When that happens, peg-and-hole joints don’t fit, and gears can jam. Even the nozzle opening can wear faster as steam scours the metal. If you keep your filament dry, then you should be able to avoid all of these issues, with prints coming off the bed smoother and the right size.
What Filaments Need to Be Dried?
The temperatures and times in the above table are solid starting points, but think of them as averages rather than hard rules. Because each manufacturer tweaks its polymer recipe by adding colourants, impact modifiers or recycled content, the ideal drying temperature for your specific spool can vary by a few degrees. To avoid warping the filament or under-drying it, always check the brand’s packaging before drying 3D filament, and adjust the settings if their guidance varies from the figures shown here.
When Do You Need to Dry Filament?
You should dry filament whenever you notice (or expect) excess moisture, for example:
- You’ve just opened a new spool. Sometimes, even factory-sealed filament can absorb moisture during storage or shipping.
- It has been stored in open air where the relative humidity (the percentage of water vapour in the air) reading is above 40%
- The spool has sat unused for weeks, and prints have started to hiss or string.
- You can hear popping inside the nozzle as the filament melts.
- Printed layer lines look swollen or fuzzy instead of crisp and smooth.
- You plan to print moisture-loving plastics such as nylon, PC or TPU during a particularly humid spell.
How to Dry 3D Filament Properly
When drying 3D filament, follow these steps:
- Preheat your appliance, whether that be a purpose-built dryer or a conventional oven, to the lowest recommended temperature for your material.
- Verify temperature with an oven thermometer, keeping in mind that kitchen ovens often overshoot.
- Remove cardboard labels, tape and silica packs that could scorch.
- Position the spool on a rack or dryer hub for full airflow.
- Set a timer at the low end of the time band; extend in 30-minute blocks until hissing stops.
- Cool and store the reel immediately in a bag or dry box so it doesn’t re-absorb moisture.
Filament Dryer vs. Oven: What’s Better?
Filament dryers are purpose-built boxes that keep heat within ± 2 °C of the set point—only two degrees above or below—so the plastic can’t over-cook. Inside is a desiccant chamber, a slot for moisture-absorbing packets that pulls humidity near zero while the spool warms. Most units also double as holders, letting you feed filament straight to the printer for overnight jobs.
Meanwhile, a household oven is free to use, but its food-grade thermostat can swing 10 °C or more. Those spikes may soften the thin PLA flanges (the side rims) of a spool or any printed adapters, causing warping and jams. You’ll need an accurate oven thermometer and a raised rack for airflow to keep temperatures steady. Both methods dry filament, yet the dryer’s tight control and built-in humidity trapping mean it is likely to be the safer long-term option.
How Long to Dry Filament Before Printing?
Here’s a quick-fire guide to how long, and at what temperature, you should dry each popular filament type:
- Does PLA filament need to be dried? The answer is yes, but only after the spool has met humidity. Dry PLA for 4-6 hours at 40-45 °C to clear any absorbed water.
- Does ABS filament need to be dried? Absolutely—run it for 4-6 hours at 80 °C to stop popping and warping.
- Do I need to dry PETG filament? PETG loves to hide moisture, so play it safe with 4-6 hours at 65 °C.
- Does TPU filament need to be dried? Yes – sticky extrusion is the giveaway. Give TPU 4-6 hours at 45–50 °C to restore smooth flow.
- Does ASA filament need to be dried? Definitely, otherwise it can crack. Dry for 4-6 hours at 80 °C.
- Does nylon need to be dried? Without question, yes. Nylon is highly hygroscopic. Dry for 6-12 hours at 70-80 °C.
- Does polycarbonate (PC) need to be dried? Yes, moisture causes bubbles and weak layers. Dry PC for 6-8 hours at 80-90 °C.
Drying times can still vary with material brand, how the spool was stored, and the accuracy of your dryer or oven, so treat these numbers as a general guide and adjust as needed.
Is It Necessary to Dry Filament Every Time?
No, most filaments don’t need to be dried before every single print. If you store PLA in a sealed box with fresh desiccant and use it frequently, it can stay moisture-free for months. By contrast, highly hygroscopic materials such as nylon, PC, ASA or ABS do benefit from a quick dry whenever they’ve been left out in humid air, even if that’s only overnight. As a rule of thumb, let storage quality (sealed vs. open air) and how often you print (daily vs. once a fortnight) determine whether a spool needs another pass through the dryer.
Ready to Print? Keep Your Filament Dry and Your Printer Happy
Control moisture and you control print quality. Dry filament means cleaner layers, stronger parts and fewer surprises. When you need reliable spools, dryers or other essentials, shop Ink Station’s full range of 3D printing supplies, including filaments, and enjoy worry-free printing from the first layer to the last.