How to Store Filament in Australia's Humidity

Danielle A.

Fighting the Moisture Monster

If there's one piece of advice that will save Australian 3D printing enthusiasts more grief than anything else, it's this: store your filament properly. Australia's climate — particularly in coastal, tropical, and subtropical regions — creates moisture conditions that can ruin a spool of filament in as little as a few hours. Wet filament produces print quality issues that no amount of tuning will fix, because the root cause is in the material itself, not the machine settings.

When thermoplastic filament absorbs atmospheric moisture, the water molecules become embedded within the polymer. When this filament reaches the hotend, the water flash-boils into steam. The result is micro-bubbles in the extrudate — visible as a rough, grainy surface texture; audible as a popping or hissing sound from the hotend, and measurable as dramatically reduced layer adhesion. In severe cases, the steam bubbles disrupt the extrusion so severely that layers separate entirely or the print fails completely.

Which Filaments Are Most At Risk?

Not all filaments absorb moisture at the same rate. The most hygroscopic (moisture-absorbing) filaments, in rough order of urgency: Nylon (PA) is the worst — it can absorb enough moisture to cause visible print quality degradation within 2 hours in coastal QLD conditions. TPU (flexible filaments) is a close second — it absorbs moisture rapidly and produces a particularly bad surface finish when wet. PVA (water-soluble support material) absorbs moisture so quickly it's essentially unusable if left open in humid conditions. PETG is moderately hygroscopic and should be sealed between uses. PLA is the least sensitive but still benefits from dry storage for optimal results.

OzFDM filaments are vacuum-sealed at dispatch with a desiccant pack included. But once you open a new spool, the protection is gone — it's up to you to maintain dry conditions from that point forward.

The DIY Dry Box Solution

You don't need expensive commercial equipment to store filament properly. The classic Australian DIY solution is an airtight storage container with indicating silica gel desiccant. Purchase a large airtight storage tub with a rubber gasket seal from Bunnings, Kmart, or Target. Pour a thick layer of silica gel bags in the bottom — the type that turn from blue (or orange, depending on brand) to pink/clear when saturated. Place your filament spools on top, clamp the lid shut, and you're done. The silica gel actively pulls moisture from the enclosed air, maintaining relative humidity well below 20% — safe for all filament types.

Check the silica gel colour monthly. When saturated, refresh it by spreading it on a baking tray and heating it in the oven at 120°C for 2–3 hours. The colour will return as the moisture is driven out. A single kilogram of silica gel can be refreshed and reused indefinitely, making this an extremely cost-effective long-term solution.

Active Drying: Rescuing Wet Filament

If a spool has already absorbed moisture, passive storage won't fix it — you need active heat to drive the water out. Dedicated filament dryers are the gold standard, as they maintain a precise temperature over many hours whilst the spool rotates (or feeds directly to the printer). For PLA, 45°C for 4–6 hours removes most absorbed moisture. PETG needs 65°C for 6 hours. Nylon requires 80°C for 8–12 hours. TPU dries at 55–60°C for 4–6 hours.

If you don't have a dedicated dryer, a food dehydrator works excellently — they're widely available at kitchen shops for $30–60 and hold temperature well. Never use a kitchen oven unless you've verified its thermostat accuracy with an independent thermometer — many domestic ovens swing 10–20°C from their set point, which can cause higher-temperature filaments to reach their glass transition temperature and sag or deform on the spool.

Printing in Humid Conditions

Even with a good dry box, opening it and printing immediately in a humid room means the exposed filament on the way to the printer is absorbing moisture as you print. For long prints with sensitive materials like Nylon (PA) or TPU, consider a print-through-dryer setup where the filament feeds from the dryer directly to the printer without ever touching ambient air. This is standard practice for anyone regularly printing hygroscopic engineering materials in coastal Australian locations.