Filament drying settings: temperatures, times, and what to use

Wet filament is behind more failed prints than bad slicing ever will be. That crackling noise from the hotend, the rough bubbly surface texture, the stringing that suddenly got worse for no obvious reason — most of the time that is moisture, not a settings problem.

The fix is simple: heat, time, and then proper storage. Here is what works.

How to tell if your filament needs drying

You do not need a moisture meter. Trust what you see and hear:

• Popping or crackling sounds from the hotend during extrusion
• Bubbles or a foamy, pitted texture on the print surface
• Stringing noticeably worse than your last roll of the same material
• Layers that snap cleanly apart when you flex the part — poor interlayer bonding
• Brittle strand that snaps rather than bends when you try to feed it manually
• Faint wisps of steam rising from the nozzle

If you see two or more of those, dry the filament before you touch a single slicer setting.

Drying temperatures and times by material

These are the ranges that work in practice. Aim for the middle rather than the maximum — you want the moisture out, not the spool deformed.

PLA — 45 to 50 °C, 4 to 6 hours. PLA starts to soften around 60 °C, so stay well below that. If your dryer runs hot, set it lower and go longer rather than pushing the temperature up. Coils on an overheated spool can fuse together and make the whole roll unusable.

PETG — 55 to 65 °C, 4 to 6 hours. PETG absorbs moisture faster than PLA. A spool left open on a shelf for a week in a damp room will often show problems. If you print PETG regularly, drying every open spool before a long job is worth making a habit.

ABS and ASA — 60 to 70 °C, 4 to 6 hours. Both handle heat well, so this range is safe. ASA in particular tends to come out better after drying — it is prone to rough surfaces when damp.

TPU and TPE — 45 to 55 °C, 4 to 6 hours. Flexible materials pick up moisture quickly and print gummy and stringy when wet. Always dry TPU before you start fiddling with retraction — nine times out of ten the stringing is moisture, not retraction distance.

Nylon (PA6, PA12, PA-CF) — 70 to 80 °C, 8 to 12 hours. Nylon is extremely hygroscopic. A freshly opened spool can absorb enough moisture in a few hours in a humid room to cause problems. Eight hours is the minimum dry time; twelve is better if the spool has been sitting out for more than a day. If you are printing PA-CF or PA-GF composites, treat them the same way.

Polycarbonate (PC) — 80 to 90 °C, 6 to 8 hours. At these temperatures you need equipment that can actually hold 85 °C accurately and consistently. Many budget dehydrators and filament dryers cannot get there reliably — check your device's actual max temperature before you buy PC.

PVA (dissolvable support) — 45 to 50 °C, 4 to 6 hours. PVA is the most moisture-sensitive material in common use. Store it sealed with fresh desiccant between every session, not just between rolls. Even a short stint on an open printer overnight can ruin it.

What equipment actually works

Purpose-built filament dryers (Sunlu S1 Plus, Bambu filament dryer, Sovol SH01, and similar) are the easiest option. They hold temperature reasonably well, fit a standard 1 kg spool, and some models let you print directly from the dryer while it runs. Expect to pay £25 to £60 for a decent one.

Food dehydrators often outperform budget filament dryers because they circulate warm air more aggressively across the spool. The main thing to check is maximum temperature — many cap at 70 °C, which covers everything except PC. If the tray is large enough you can dry two spools at once. A good Lakeland or Ninja dehydrator that you already own is a perfectly capable filament dryer.

A regular kitchen oven is a last resort, not a first choice. Domestic ovens are often inaccurate by ±15 to 20 °C at low settings, and the fan-assist mode can cycle in ways that spike the temperature unpredictably. If you use one, verify the actual temperature with a separate oven thermometer, leave the door cracked a couple of centimetres so moisture can escape, and only use it for PETG or ABS — the margin for error with PLA is too small. Never walk away from it.

Desiccant boxes and vacuum bags are for storage and prevention, not for rescuing already-wet filament. Silica gel will not pull enough moisture out of a saturated spool. You need heat.

Filament dryer vs food dehydrator: which is better?

For most people, whatever they already own. If you are buying from scratch, a food dehydrator gives you more airflow and often a wider temperature range for a similar price. A dedicated filament dryer is more convenient — easier to load, easier to print-while-drying with, and takes up less bench space. Either works well for PLA, PETG, and ABS. For nylon and PC, check the maximum temperature rating before you buy anything.

How long does drying actually take?

For most materials in a properly set dryer: four to six hours is enough. Nylon is the exception — eight hours minimum, twelve if the spool has been out for a while.

To test mid-dry, heat your hotend to printing temperature and extrude a short length manually. If it still pops and crackles, the spool goes back in. If it extrudes smoothly and quietly, it is ready. That test takes thirty seconds and is more reliable than any timer.

Do not bother weighing spools before and after to calculate moisture loss. The weight change is too small to measure accurately on a kitchen scale.

Does PLA really need drying?

Usually not immediately after opening a fresh sealed bag. PLA absorbs moisture slowly — it typically takes several weeks of open-air storage before problems appear.

But PLA that has been sitting open on a shelf for a month or two in a damp UK winter will show it: brittle strands that snap when you try to feed them, a rough cratered surface on prints, and parts that feel underextruded even with flow dialled up. A quick four-hour dry at 45 °C fixes all of that.

Storing filament after drying

Drying is pointless if the spool goes back to an open shelf. Seal it while it is still warm from the dryer — the residual heat means less condensation forms inside the container as it cools.

Vacuum bags with silica gel desiccant work well and cost very little. Airtight clip-lid boxes designed for filament storage are more convenient if you are loading and unloading spools often. Either way, check the desiccant beads and replace them when they turn pink or clear.

If you run an AMS or multi-material system, any slot left loaded overnight is sitting in open air. Seal whatever is not actively printing. This applies especially to nylon and PVA.

When to get it printed instead

Sorting out a dryer, getting the settings right, and dialling in a difficult material takes time and equipment you may not have. If you need a part in nylon, PC, or a composite material and you do not have a setup capable of drying it properly, it is often faster to hand the job to someone who has the process already sorted.

We dry all filament before use and keep spools sealed between runs. If you have a file ready, upload it for a quote on our printing service — we print in PLA, PETG, ABS, ASA, TPU, and nylon, and we will turn it around within a few working days.