How to dry 3D printer filament: heat the spool gently at the right temperature for the material, for several hours, in a space where the moisture can escape. For PLA that is roughly 45–55°C for 4–6 hours. For PETG, around 60–65°C. For nylon and nylon carbon fibre, 70–80°C for 8–12 hours or more. Always follow the label on your specific roll, because brands differ.
The rest of this guide shows how to tell whether your filament is actually wet, how to dry it safely at home, and the mistakes that ruin a spool.
How do you know if filament is wet?
Wet filament leaves clear fingerprints in your prints and your printer’s behaviour:
- Popping, hissing or crackling sounds from the nozzle.
- Tiny bubbles or steam visible where plastic leaves the nozzle.
- Stringing and oozing that was not there before.
- Rough, fuzzy or matte-looking surfaces that should be smooth.
- Weak parts that snap easily along layer lines.
- Inconsistent extrusion and the odd blob or void.
If you see two or more of these on a roll that has been open for a while, dry it before you blame your slicer. The same symptoms cause most “mystery” stringing, so if that is your problem, read why your PLA is stringing alongside this guide.
Why does filament absorb moisture?
Most filament plastics are hygroscopic, meaning they pull water vapour out of the air. Nylon is the worst, PETG and TPU are moderate, and PLA is the mildest but still affected over weeks. When wet plastic hits a 200°C nozzle, the water flashes to steam inside the melt, which causes the bubbles, popping and weak layers you see.
South African conditions make this a real problem. Summer afternoons on the Highveld bring humid storms, coastal areas stay damp year-round, and a roll left on the printer for weeks in an unsealed room slowly takes on water. Prevention is easier than drying, and we cover it in our storage guide.
What temperature should you dry each filament at?
These are common starting ranges. Your roll’s label or the supplier’s data sheet always wins.
| Material | Drying temperature | Typical time |
|---|---|---|
| PLA | 45–55°C | 4–6 hours |
| PETG | 60–65°C | 4–6 hours |
| TPU | 50–55°C | 4–6 hours |
| ABS / ASA | 80°C | 4–6 hours |
| Nylon (PA12), nylon CF | 70–80°C | 8–12 hours or more |
Do not exceed the limit for PLA. PLA starts to soften around 55–60°C, and a spool dried too hot can warp, fuse layers on the spool or tangle when it cools.
How to dry 3D printer filament at home: what are the options?
You have four realistic options, from best to worst.
- A dedicated filament dryer. Holds a stable temperature, often lets you print straight from the box, and is the best choice if you print nylon or use filament regularly.
- A food dehydrator. It works well for PLA, PETG and TPU if the temperature is adjustable and accurate. Remove trays to fit the spool.
- A kitchen oven. Only use it if you have verified the temperature with a separate thermometer. Many ovens run well above or below their dial setting at low temperatures, and a spool that melts or warps is an expensive lesson.
- A sealed box with desiccant. This keeps dry filament dry, but it is slow at pulling moisture out of a properly wet roll. Use it for storage, not as a rescue.
Do not use a hairdryer, heat gun or microwave. Heat is uneven, and you will damage the spool.
How do you dry a spool step by step?
- Take the spool off the printer and remove it from any holder or box.
- Set the dryer to the right temperature for the material.
- Place the spool inside with the lid slightly open or vented, so moist air can leave.
- Dry for the full time. Short drying removes surface moisture only.
- Let the spool cool to room temperature before sealing it.
- Print soon, or store it in an airtight container with fresh desiccant.
If you have an open-vented dryer, you can feed filament directly from it while printing, which is the easiest way to keep nylon healthy through a long job.
How long does dried filament stay dry?
Not long, especially nylon. A dried nylon roll can reabsorb enough moisture to cause problems in a matter of hours in humid air. PLA is much slower, but even PLA is happiest in a sealed container. If a job matters, dry the roll before starting and keep it in a sealed box during the print.
Which filaments need drying most?
Nylon and nylon carbon fibre need drying almost every time. Our ERYONE Nylon CF (PA12-CF) is a good example: it is stiff and strong, but it will not print cleanly if wet. PETG and TPU need drying more often than people expect, especially if they have been sitting open. PLA usually only needs it after weeks in damp air or if you see symptoms.
How to dry 3D printer filament: common mistakes to avoid
- Drying PLA at PETG temperatures and warping the spool.
- Drying for 30 minutes and expecting a miracle.
- Sealing the spool while it is still warm, which traps moisture and condensation.
- Storing dried filament in a loose bag instead of an airtight container.
- Blaming the printer for stringing without checking the filament first.
When should you replace a roll instead of drying it?
If a roll is brittle, snaps when you bend it, or still prints badly after a proper dry, replace it. Some damage is permanent, especially on very old or heat-stressed spool.
Can you print straight from a dryer?
Yes, and for moisture-sensitive materials it is the best habit. Many filament dryers have a small hole or feed port, so the spool stays warm and dry while it feeds the printer. Keep the Bowden tube or feed path short and smooth, so the filament does not pick up moisture on the way, and make sure the dryer sits where the filament can travel without a sharp bend.
For PLA and most PETG, you can usually skip this and dry before the job. For nylon and nylon carbon fibre, printing from the dryer is worth the effort.
How do you check that drying worked?
Do not just trust the timer. Check with a quick test:
- Listen. A dry roll prints quietly. Popping and crackling mean there is still moisture.
- Watch the nozzle. Visible steam or bubbles at the tip mean the roll is still wet.
- Print a small stringing test. A good test tower shows clean surfaces and little stringing.
- Weigh the spool (optional). Weigh before and after drying. A small drop in grams shows moisture left the roll.
If the test still fails after a full cycle, dry for longer, or accept that the roll may be too far gone.
How do you keep dried filament dry?
Use an airtight container with desiccant. A box with a rubber seal, a vacuum bag or a purpose-made storage bin all work. Add silica gel desiccant, and replace or recharge it when it saturates. Many silica gel packs change colour when full, and indicator beads can often be recharged by gentle heating, following the instructions on the pack.
A cheap hygrometer inside the container shows you what is actually happening. As a rule of thumb, lower is better: a reading in the low teens as a percentage of relative humidity is comfortable for most filaments, and nylon prefers even lower. Our storage guide covers storage in more detail.
What does a simple drying routine look like?
- New, sealed roll: open it only when you are ready to print.
- Roll open for a few days: store it sealed, and print without drying unless you see symptoms.
- Roll open for weeks: dry it for the full time, then print.
- Nylon and nylon CF: dry before every important print, and print from a dry box if you can.
- Roll that has soaked in humid air for a long time: dry for longer than the table suggests, and check at the end.
Does drying fix every print problem?
No. Moisture is one cause of stringing, bubbling and weak layers, but not the only one. Wrong temperature, retraction settings, a worn nozzle and over-cooling cause similar symptoms. If a dried roll still strings, work through the slicer settings next, and our PLA stringing guide shows the order to check them in.
Frequently asked questions
Can you dry filament in an oven? Yes, if you verify the temperature with an independent thermometer and keep PLA well below its softening point.
How long should you dry PLA? About 4–6 hours at 45–55°C is a common starting point.
Does vacuum-sealed filament need drying? Usually not when new, but it will once opened and left out.
Why does my filament pop? Trapped water turning to steam inside the nozzle.
If you want a quick reference next to your printer, our Troubleshooting Cheat Sheet (Excel) covers 27 common FDM print problems and fixes for R99.