How to store and dry filament

All filament takes in moisture from the air. Damp filament gives stringing, bubbles and weak prints. Storing it sealed – and drying it when needed – fixes most of that.

By GRP 3D, Aberbeeg · Updated 7 November 2026 · Facts from Bambu Lab, sources below

Why damp filament prints badly

Water in the filament turns to steam inside the hot nozzle. The plastic bubbles and comes out unevenly, which gives stringing, oozing, holes, rough surfaces and weaker parts. The damper the air and the longer a roll is left out, the worse it gets.

How quickly filament gets damp

Indoor air is usually 45–65% relative humidity, and higher in wet weather.
Bambu Lab says freshly dried filament left out at about 55% humidity can take in enough moisture to affect print quality within 2 to 12 hours, depending on the type.
Stored below 20% humidity, most filaments stay dry for roughly 2 to 7 days. The drier the air, the longer they last.

How to store filament

Keep opened rolls in a sealed box or bag with desiccant (silica gel). A cheap hygrometer inside shows the humidity.
Put a roll away as soon as you've finished printing with it.
An AMS 2 Pro or AMS HT keeps spools sealed and can dry them. The first-generation AMS is sealed with desiccant but has no heater; the AMS lite is open.

Ways to dry filament

In an AMS 2 Pro or AMS HT. Load the spool, choose the filament type and start drying. The AMS 2 Pro reaches 65 °C, the AMS HT 85 °C.
On the heated bed of an enclosed printer (H series, P2S, P1S). Unload the filament, lower the bed, put the spool on the plate and cover it with the filament's cardboard box or a printed high-temperature cover. Turn the spool over half way. The P1S has no drying mode, so you set the bed temperature and time it yourself.
In a forced-air (fan) oven with the spool well away from the heating elements.

Bambu Lab says don't dry filament in a microwave or a kitchen oven: the heat is uneven and can melt the spool or the filament. The open-frame A1 mini, A1 and A2L can't be used to dry filament.

Drying settings by filament

Bambu Lab's recommended drying temperatures and times for its own filaments. Bed drying is for enclosed H series, P2S and P1S printers.
Filament	Dry before use?	AMS 2 Pro	AMS HT	Printer bed	Fan oven
PLA Basic, PLA Matte	Recommended	45 °C, 12 h	45 °C, 12 h	60–70 °C, 12 h	50 °C, 8 h
PLA Silk	Recommended	45 °C, 12 h	45 °C, 12 h	65–75 °C, 12 h	55 °C, 8 h
PLA Wood	Required	45 °C, 12 h	45 °C, 12 h	70–75 °C, 12 h	55–65 °C, 8 h
PETG, PETG-CF	Recommended	65 °C, 12 h	65 °C, 12 h	75–85 °C, 12 h	60–65 °C, 8 h
ABS, ASA	Recommended	Not compatible	80 °C, 8 h	90–100 °C, 12 h	75–85 °C, 8 h
TPU for AMS	Required	65 °C, 12 h (may not dry fully)	75 °C, 18 h	80–90 °C, 12 h	70 °C, 8 h
Support for PLA/PETG	Recommended	60 °C, 12 h	60 °C, 12 h	65–75 °C, 12 h	75 °C, 8 h
PVA	Required	Not compatible	85 °C, 18 h	90–100 °C, 12 h	75–85 °C, 8–12 h
PC	Required	Not compatible	80 °C, 8 h	90–100 °C, 12 h	75–85 °C, 8 h

Good to know

Fit a refill onto a reusable spool before drying it.
When drying a high-temperature filament in an AMS 2 Pro, take any PLA out of that AMS first.
Bambu Lab says not to use the AMS "static" drying mode for PLA, PVA, Support for PLA/PETG or TPU – the layers can stick together. Use the rotating mode.
Once printing starts, the AMS lowers its drying temperature to protect the filament (45 °C with PLA, 55 °C with PETG).
Wear gloves when turning a hot spool on the bed, and let it cool before you take it off.
After drying, store the filament sealed with desiccant straight away.

Questions we get asked

Does PLA need drying?

Bambu Lab recommends drying PLA Basic and PLA Matte before use if you're not sure how they've been stored, and says PLA Wood must be dried. PLA takes in moisture more slowly than PETG, TPU or nylon.

Can I dry filament in my kitchen oven?

Bambu Lab advises against it. Kitchen ovens and microwaves heat unevenly and can damage the spool or filament. Use an AMS 2 Pro, AMS HT, an enclosed printer's heated bed or a forced-air (fan) oven.

How long does dried filament stay dry?

In normal indoor air (about 55% humidity) Bambu Lab says it can take in enough moisture to affect print quality within 2 to 12 hours. Stored sealed with desiccant below 20% humidity, most filaments stay dry for around 2 to 7 days.

Can I dry filament on an A1 or A1 mini?

No. Bambu Lab says the open-frame A1 mini, A1 and A2L can't be used to dry filament. Use an AMS 2 Pro or AMS HT connected to the printer, or a fan oven.

Can the AMS 2 Pro dry ABS and ASA?

No. Bambu Lab lists ABS, ASA, PC and PVA as not compatible with AMS 2 Pro drying. The AMS HT dries ABS and ASA at 80 °C for 8 hours.

Still not sure?

Call us on 01495 820215 (Monday to Friday, 9am to 5pm), email hello@grp3d.shop, or visit our shop in Aberbeeg.

Sources

Specifications are Bambu Lab's own figures. Prices and stock come live from our shop and can change.