Written by Danielle Arnold
Quick answer: Keep opened filament sealed with desiccant, ideally below 20% relative humidity, and store it somewhere cool and out of the sun. If prints start stringing, popping or looking rough, dry the spool at the temperature on its product page before printing. Nylon, PVA and TPU need the most care. PLA is the most forgiving.
A roll that printed cleanly when you opened it can string and bubble after a week on the printer in a humid room, and a spool left in a hot car can soften before it reaches the printer. This guide covers why filament takes on water, how our climate changes the problem, how to tell when a roll is wet, the drying settings we publish for OzFDM filaments, and storage setups that work.
Why filament absorbs moisture
Most 3D printing plastics are hygroscopic: they pull water vapour out of the air and hold it inside the polymer. Nylon and PVA have strongly water-attracting molecular structures and soak up moisture quickly. PLA and ABS absorb much less, but still enough to show up in prints after long exposure.
The problem appears in the hotend. Water trapped in the filament turns to steam as the plastic melts, which leaves tiny voids in the extruded line, disrupts flow and weakens the bond between layers. Bambu Lab's drying guide lists the results as stringing, lack of material, holes, rough surfaces and reduced strength. Slicer settings cannot fully fix them, because the cause is in the material.
Every OzFDM roll is vacuum sealed with a desiccant pack, so it arrives dry. The clock starts once you open the bag.
How the Australian climate changes the problem
Australia is not one climate, and the right storage routine in Darwin is overkill in Alice Springs. The table below uses long-term averages from the Bureau of Meteorology for four stations. Relative humidity (RH) is usually highest in the morning and lowest in mid-afternoon, so the 9am and 3pm figures show the range a typical day moves through.
| Location (BOM station) | Most humid month (mean 9am RH) | Driest month (mean 3pm RH) | What it means for filament |
|---|---|---|---|
| Darwin Airport | February, 83% | July, 37% | The wet season is the hardest test in the country. Keep every open roll sealed. |
| Brisbane Aero | June, 70% | July and August, 50% | Humid all year. Seal rolls between prints, not just over summer. |
| Perth Metro | July, 80% | February, 38% | Winter mornings are damp. Summer afternoons are dry but hot. |
| Alice Springs Airport | June, 64% | October and November, 19% | Moisture matters less. Heat is the bigger risk, with a December mean maximum of 35.6°C. |
These are outdoor readings. Air-conditioning brings indoor humidity down, but a garage, shed or spare room without it will follow the weather.
Humid coast and the tropics
Along the Queensland and northern New South Wales coast and across the Top End, humid air is the normal state of affairs. Bambu Lab's sealed box guidance recommends keeping moisture-sensitive filaments below 20% RH, and notes that freshly dried filament in a normal indoor room at about 55% RH can become damp enough to affect print quality within 2 to 12 hours. In these regions, a roll left on the printer overnight should be treated as exposed.
Dry inland and southern summers
Inland areas and southern capitals are drier for much of the year, so PLA and PETG can sit out longer without trouble. Do not skip storage altogether: Perth's 9am humidity climbs to 80% in July, and a few damp weeks will affect nylon, TPU or PVA.
Heat in sheds, garages and cars
Sealed bags stop moisture, not heat. Sheds and garages can run hotter than the air outside on sunny days, and the Victorian Government's Better Health Channel states that the temperature inside a parked car can be 20 to 30 degrees hotter than outside. Our PLA+ data sheet lists a heat deflection temperature of 53°C, so on a warm day a spool on the back seat can soften and deform, or its outer wraps can stick together. Keep filament indoors, out of direct sun, and collect orders on the way home rather than leaving them in the car. For the heat limits of each material, see our heat deflection temperature chart.
Signs your filament is wet
- Popping, crackling or hissing from the nozzle as trapped water turns to steam.
- Bubbles, pits or a rough, fuzzy surface on walls that should be smooth.
- Stringing and oozing that retraction tuning does not fix.
- Weak layer bonding, so parts split along layer lines.
- Inconsistent extrusion, with thin or gappy lines.
- Brittle filament that snaps in the feed path, especially PLA that has been left out for months.
If a roll that has been open for a while shows several of these, dry it before changing slicer settings. This short OzFDM video shows the difference between wet and dry PA6 nylon.
Which materials are most sensitive
- Most sensitive: PVA support, nylons (PA6, PA12 and their carbon or glass fibre versions) and TPU95A. Store these sealed at all times and plan to dry before printing. Bambu Lab's guidance names the PA family as prone to absorbing more water and getting damp more quickly.
- Sensitive: polycarbonate, PC-ABS and PETG, including PETG-CF and PETG-GF. Seal between prints and dry after a roll has sat open.
- Moderate: ABS, ASA and HIPS. Dry when symptoms appear or after long storage.
- Least sensitive: PLA in all its forms, and polypropylene, which our product page notes absorbs very little moisture. Dry storage still keeps the surface finish at its best.
Drying temperatures and times
These settings come from the drying recommendation on each OzFDM product page. Treat the times as a starting point and add more for a roll that has been open for weeks. Do not go above the listed temperature, as that can soften filament on the spool.
| Material | Temperature | Time | Notes |
|---|---|---|---|
| PLA Basic | 50°C | 5 hours | Only needed if symptoms appear |
| PLA+, High Speed PLA, Matte, Silk and Wood PLA | 40–45°C | 4–6 hours | Low sensitivity |
| PLA-CF | 60°C | 5 hours | |
| PETG Basic, PETG+, Metallic PETG-HS, PETG-CF, PETG-GF | 70°C | 5 hours | Seal between prints |
| TPU95A | 70°C | 5 hours | Store sealed at all times |
| ABS Basic, ABS+, ABS-HS, ABS-FR, ABS-GF, ASA, ASA-CF, ASA-GF, HIPS | 80°C | 5 hours | ABS-ESD is 70°C for 5 hours |
| Polycarbonate, PC-CF, PC-ABS | 80°C | 12 hours | Store well to avoid repeated drying |
| PA6 Nylon, PA6-CF, PA12 Nylon, PA12-CF, PA12-GF | 80°C | 12 hours | Our PA6 page suggests 24 hours if it still strings after 12 |
| PET-CF | 100°C | 5 hours | Check your dryer reaches this |
| PPA-CF, PPS-CF | 120°C | 8 hours | Needs a dryer or oven that holds 120°C |
| PVA | 50°C | 3 hours | Keep sealed at all times |
| Polypropylene (PP) | 50°C | 4–6 hours | Rarely needed, only if stored open |
For any material not listed, use the drying recommendation on its product page or the PDF technical data sheet linked there.
Filament dryer, food dehydrator or oven?
A dedicated filament dryer is the simplest option, and models with a feed port let you print straight from the dryer. Our filament dryer review covers what to look for, including temperature accuracy and airflow. A food dehydrator can also work if it fits a 1 kg spool and genuinely holds temperature, so check it with a separate thermometer before trusting the dial.
Before buying either, compare its maximum temperature with the table. A unit that tops out below 80°C cannot reach the settings we list for ABS, ASA, PC or nylon, and the 100°C and 120°C materials need equipment built for those temperatures.
Avoid the kitchen oven and microwave. Bambu Lab's drying guide explains that heat inside a kitchen oven is highly uneven, with areas near the heating elements reaching very high temperatures that can damage both spools and filament.
Getting the most from a drying cycle
- Move the spool straight into a vacuum bag or dry box when the cycle ends. Our product pages recommend drying filament before sealing it for long-term storage.
- For long nylon or TPU prints in humid weather, feed from the dryer or a sealed dry box rather than leaving the spool in open air.
- Do not rely on repeated drying. Bambu Lab notes that PC can become brittle after many drying and cooling cycles, so good storage is better than drying the same roll again and again.
Storage options that work
Vacuum bags with desiccant
For rolls you are not using this week, a vacuum bag is the most reliable option and takes up little space. Our Filament Roll Vacuum Seal Bag is made from tough polypropylene, measures 340 x 300 mm and suits standard 1 kg rolls. Add a desiccant bag, seal it and pump out the air.
The bags need a pump. The Filament Storage Starter Kit includes five bags, a hand pump, five humidity indicator cards and five desiccant bags. If you seal several rolls after each session, the Electric USB Vacuum Pump does the job at the press of a button and recharges over USB. When you need more bags, the Filament Storage Refill Pack adds ten bags and ten desiccant bags that work with the same pump.
Dry boxes and airtight tubs
Rolls in regular rotation are easier to keep in an airtight container with a rubber gasket seal. Add desiccant, fit a hygrometer you can read without opening the lid, and keep it closed except when swapping spools. Several smaller boxes are easier to keep dry than one large one, because opening a small box lets in less humid air.
Desiccant
Desiccant absorbs the moisture left in a bag or box after sealing. Our Silica Gel Desiccant Bags hold 5 g of silica gel in a non-woven fabric bag and come in packs of 5, 50 and 100. Use one per vacuum bag and several in a dry box, and add more if the humidity reading will not come down.
Hygrometers
Our Mini Hygrometer (round) and Mini Hygrometer (rectangular) both show temperature and humidity and are small enough for a dry box. The round version has a 45 mm face with a narrower 41.5 mm body behind it, which suits mounting in a hole in a box lid. Both are rated at ±5% humidity accuracy, so use the reading to spot trends and rising humidity rather than as an exact figure.
A simple routine
- Leave new rolls in their sealed bag until you need them.
- After printing, bag the roll with fresh desiccant and pump out the air, or return it to a dry box.
- Store bags and boxes indoors, somewhere cool and dark, never in a car or hot shed.
- Check the hygrometer weekly and replace desiccant when humidity rises.
- Dry before printing if a roll has sat open, and always before long nylon, TPU or PVA jobs.
- Write the drying date on the bag so you know when a roll was last refreshed.
Shop the materials in this guide
- Filament Storage Starter Kit: five vacuum bags, a hand pump, humidity indicator cards and desiccant in one box.
- Filament Roll Vacuum Seal Bag: extra bags sized for standard 1 kg rolls.
- Electric USB Vacuum Pump with USB Cable: faster sealing when you store several rolls at once.
- Silica Gel Desiccant Bags 5 Gram: one per bag, or several per dry box.
- Mini Hygrometer (round): shows temperature and humidity inside a dry box.
- Mini Hygrometer (rectangular): the same readings in a slimmer format.
Frequently asked questions
Does new OzFDM filament need drying?
Most OzFDM rolls ship vacuum sealed with desiccant, so PLA and PETG usually print well straight from the bag. For nylon, PC, PVA and the fibre-filled grades, drying before the first print is worth the time, and several product pages recommend it. Dry any roll whose bag has lost its vacuum.
How long does dried filament stay dry?
It depends on the room. Bambu Lab's guidance is that freshly dried filament can become damp enough to affect print quality within 2 to 12 hours at about 55% RH, and stays dry for about 2 to 7 days at 20% RH. Sealed in a vacuum bag with desiccant, it keeps far longer.
Can I dry filament in my kitchen oven?
It is not recommended. Kitchen ovens heat unevenly, and hot spots near the elements can soften filament or warp the spool. The 120°C materials such as PPA-CF and PPS-CF need a dryer or oven built to hold that temperature accurately.
Will a vacuum bag protect filament in a hot shed?
It protects against moisture, not heat. PLA in particular can soften at temperatures a closed shed or car can reach in summer, so store sealed rolls indoors and out of direct sun.
