How Long to Dry Each Filament Type: PLA, PETG, Nylon, TPU Guide

Why Moisture Ruins Prints

Water molecules bond to polymer chains in hygroscopic filaments. When that filament reaches your hot end — for PA, typically 260–290°C across the 113 nylon materials in our database — the water instantly vaporizes. The result: popping sounds, stringing, bubbles in the extrusion, and dramatically weakened layer adhesion. Moisture-damaged PA prints can lose over 50% of their tensile strength versus dried material.

Not all filaments absorb moisture at the same rate. The key variable is the polymer's chemical polarity — how strongly water molecules are attracted to the chain. Polyamide (nylon) has highly polar amide groups, making it extremely hygroscopic. PLA's ester bonds are less polar, giving it much lower moisture sensitivity. PVA (polyvinyl alcohol) is so hygroscopic it can become unprintable within hours in a humid environment.

Drying Parameters by Material

The table below covers the 10 main polymer families tracked in our database. Drying temperature should be below the material's heat deflection temperature (HDT) to avoid deforming spools. Print temperature ranges come directly from manufacturer TDS data in the Filabase database.

Nylon (PA): The Most Critical Material to Dry

Of the 113 nylon materials in our database, print temperatures range from 220°C to 320°C (average minimum: 262°C, average maximum: 280°C). At these temperatures, any absorbed water vaporizes explosively. Nylon absorbs moisture faster than any other common FDM filament — an open spool can reach saturation in as little as 12 hours in humid conditions.

Drying PA at 80–100°C is necessary because moisture binds deeply into the polyamide backbone. Lower temperatures (e.g., 60°C) will remove surface moisture but not the embedded water. Key examples from our database:

• Bambu Lab PA6-CF: print temp 260–290°C, bed 80–100°C, HDT 164°C — drying at 80–100°C for 8–12h is safe given the high HDT
• Polymaker PolyMide CoPA: print temp 250°C, HDT 110.5°C, tensile strength 66.2 MPa — moisture loss is essential to achieve that tensile figure
• Prusament PA11-CF: print temp 285°C, HDT 192°C, tensile 42 MPa — bed temp 110°C requires thorough pre-drying
• eSUN PA: print temp 250–290°C, bed 70–90°C, HDT 99.6°C, tensile 43.64 MPa

Keep PA sealed with desiccant when not printing. If a spool has been open for more than 8 hours in a room above 50% relative humidity, dry it before printing regardless of visible symptoms.

PVA: Dry Immediately, Print Immediately

PVA (polyvinyl alcohol) is used as a water-soluble support material. The 15 PVA materials in our database have print temperatures from 180–230°C and are used at bed temperatures as low as 23°C (3DXTech AquaTek PVA) to as high as 100°C (BASF Ultrafuse BVOH). The same solubility that makes PVA useful as a support also makes it the fastest moisture absorber in common use.

Dry PVA at 45–55°C for 4–6 hours. Do not exceed 55°C — PVA begins to degrade above 60°C. Print as soon as it comes out of the dryer. PVA left in an open bowden tube or humidity above 40% for 30 minutes can develop surface tackiness that causes jamming. Many users run PVA directly from a closed drybox during printing, not from a pre-dried spool on a spool holder.

TPU: Hygroscopic and Tricky to Dry

Of the 109 TPU materials in our database, print temperatures average 212–234°C. TPU absorbs moisture through its urethane groups, and moisture degrades both surface finish and mechanical properties. Wet TPU shows stringing and rough extrusion; the shore hardness of the printed part can also be affected.

Dry TPU at 60–70°C for 4–8 hours. Don't use excessively high temperatures — TPU can stick to itself or deform inside the dryer above 75°C. Representative examples:

• Bambu Lab TPU 85A: print 200–250°C, bed 30–35°C, tensile 12 MPa — softer grades are more sensitive to moisture
• Polymaker PolyFlex TPU95-HF: print 200°C, bed 25–50°C, tensile 23.11 MPa
• Prusament TPU95A: print 230°C, bed 65°C, tensile 41 MPa
• 3DJAKE TPU A95: print 200–230°C, bed 60–90°C, tensile 55 MPa

Softer TPU grades (85A and below) absorb moisture more readily than harder grades (95A) due to their higher soft-segment content. If printing 85A, dry for the full 8 hours; for 95A, 4–6 hours is usually sufficient.

PC (Polycarbonate): High Temperature Drying Required

Polycarbonate is both highly hygroscopic and printed at very high temperatures. The 62 PC materials in our database have average print temperatures of 266–273°C, and some CF-reinforced grades run as high as 300°C. The HDT for Polymaker PolyCore PC is 139°C, Bambu Lab PC is 117°C, and Prusament PC Blend is 113°C.

Dry PC at 80–100°C for 6–8 hours. Even brief moisture absorption causes surface bubbles, hydrolytic degradation, and weakened interlayer bonding. At PC printing temperatures, moisture damage is severe. Key examples:

• Polymaker PolyCore PC-7413: print 280°C, bed 100–120°C, HDT 139°C, tensile 74.6 MPa
• Bambu Lab PC: print 260–280°C, bed 90–110°C, HDT 117°C, tensile 55 MPa
• Prusament PC Blend: print 275°C, bed 110°C, HDT 113°C, tensile 63 MPa

PETG: Often Overlooked, Definitely Hygroscopic

PETG is the second-largest polymer family in our database at 185 materials, with print temperatures averaging 232–246°C across the dataset. PETG's ester groups absorb moisture, but it's less aggressive than PA or PC. However, wet PETG shows visible stringing and poor layer adhesion that frustrates many users who never realize drying was the fix.

Dry PETG at 65–70°C for 4–6 hours. The HDT for PETG varies considerably — Polymaker PolyCore PETG-1113 has an HDT of 78°C, while Bambu Lab PETG HF is 62°C and Prusament PETG Tungsten is 94°C. Keep your drying temperature below the specific material's HDT to avoid spool deformation.

• eSUN PETG: print 230–260°C, bed 75–90°C, HDT 64°C, tensile 34.77 MPa
• Bambu Lab PETG HF: print 230–260°C, bed 65–75°C, HDT 62°C, tensile 34 MPa
• Polymaker PolyCore PETG-1113: print 210–230°C, bed 70°C, HDT 78°C, tensile 100.3 MPa

ABS and ASA: Dry If Stored Openly

ABS and ASA are moderate moisture absorbers. The 95 ABS materials in our database print at an average 235–259°C; the 67 ASA materials average 239–259°C. Both have higher bed temperatures (ABS: 80–130°C; ASA: 35–120°C across the dataset) and are typically printed in enclosed printers where the chamber itself can help drive off some surface moisture.

Dry ABS/ASA at 70–80°C for 3–4 hours if the spool has been open for more than a week. In low-humidity environments (<40% RH), freshly opened ABS may print fine without drying. Representative examples from the database:

• Bambu Lab ABS: print 240–270°C, bed 80–100°C, HDT 84°C, tensile 33 MPa
• Bambu Lab ASA: print 240–270°C, bed 80–100°C, HDT 92°C, tensile 37 MPa
• eSUN ABS-CF: print 230–270°C, bed 95–110°C, HDT 78°C, tensile 43 MPa
• Prusament ASA: print 260°C, bed 110°C, HDT 93°C, tensile 42 MPa

PLA: Low Priority, But Still Worth Drying

PLA is the largest polymer family in our database — 533 materials — and the least hygroscopic of common FDM filaments. Most PLA prints at 190–230°C (average minimum: 196°C, maximum: 225°C). The HDT of standard PLA is low: Polymaker PolyTerra PLA has an HDT of 57.8°C, Bambu Lab PLA Silk+ is 56°C.

Dry PLA at 45–55°C for 4–6 hours if it's been open for weeks or if you see stringing. Because the HDT of PLA spools is close to the drying temperature, monitor the spool and don't exceed 55°C. A lower-temperature food dehydrator works well here.

HT-PLA: Same Risk as PLA, Higher Drying Tolerance

The 23 HT-PLA materials in our database print at 210–260°C. HT-PLA (like Polymaker HT-PLA at 210–230°C, HDT 61.4°C) benefits from drying at 55–65°C for 4–6 hours. Its higher glass transition temperature versus standard PLA means you have a bit more drying headroom without deforming the spool, but treat it similarly to PLA for moisture sensitivity.

Signs Your Filament Needs Drying

These symptoms apply across materials regardless of family:

• Popping or crackling sounds during extrusion — water vaporizing in the hot end. Most audible with PA and PC.
• Excessive stringing — wet filament has lower viscosity and strings between features. Common symptom with PETG and TPU.
• Rough or bubbly surface finish — steam creates micro-bubbles in the extrusion. All materials affected.
• Inconsistent extrusion diameter — wet filament varies in flow rate. Causes under/over-extrusion artifacts.
• White residue or fumes — particularly with PA and PC at high temperatures, moisture causes visible degradation.
• Reduced mechanical properties — the most important but invisible symptom. Wet PA loses significant tensile strength vs. dried PA.

How Long Before Drying Is Needed

The timeline depends on relative humidity and the specific material:

Dryer vs. Oven vs. Food Dehydrator

A dedicated filament dryer (Sunlu S1, eSUN eBox, Bambu AMS) is the best option because it maintains consistent temperature while allowing active printing from the dryer. A conventional oven works for pre-drying but temperatures are less precise and there's no active drying during printing. A food dehydrator works well for PLA and PETG (which need lower temperatures) but typically can't reach 80–100°C needed for PA and PC.

For PA and PC, use a dryer or oven that can sustain 80–100°C. Monitor with a separate thermometer — oven thermostats are notoriously inaccurate at low settings. The 62 PC materials in our database average HDT values well above 110°C, so drying PC at 80–100°C won't damage spools. But always verify your specific material's HDT before setting dryer temperature.

Storage After Drying

Drying is only effective if you store the filament sealed afterward. Immediately after drying, place the spool in an airtight bag or container with fresh silica gel desiccant. Colored indicator desiccant (blue when dry, pink when saturated) makes it easy to monitor effectiveness. For PA and PVA, consider printing directly from a sealed drybox to avoid re-absorption between sessions.