How to Dry 3D Printing Filament After Storage

Nothing frustrates 3D printing hobbyists more than opening a spool of filament after storage only to find it's absorbed moisture from the air, leading to poor print quality like stringing, popping noises, or brittle parts. Hygroscopic materials like Nylon, PETG, and even PLA can ruin hours of printing time if not dried properly.

In this guide, you'll learn proven methods to dry filament effectively using affordable tools or household items. We'll cover assessment, preparation, drying techniques, testing, and storage to keep your filament print-ready. Expect 4-24 hours total time depending on the method and material—perfect for intermediate makers looking to save filament and time.

By the end, you'll achieve crisp, bubble-free prints and extend your filament's lifespan significantly.

▸What You'll Need

• •Filament dryer box (recommended) or food dehydrator or convection oven
• •Digital hygrometer/thermometer (required for oven/dehydrator methods)
• •Oven-safe filament spool holder or cardboard tube (optional for ovens)
• •Vacuum-sealed bags or airtight container with desiccant for storage
• •Resealable ziplock bags (optional for small tests)

Estimated Time: 4-24 hours (drying time varies by material; prep and testing: 30 minutes) Difficulty: intermediate

▸Step-by-Step Instructions

Step 1: Assess Filament Moisture Level

Before drying, confirm your filament is moist. Signs include hissing/popping during extrusion, stringy prints, or brittle snapped strands. Extrude a small amount through your printer's hotend at normal temp—if bubbles form or it sputters, it's wet.

Why it matters: Drying dry filament wastes time and energy. Use a hygrometer inside your storage bag for precise reading (>20% RH indicates moisture).

Success: You'll know exactly how wet it is, guiding drying time.

💡 Tips:

• •Test extrude on scrap; saves filament.

⚠️ Warnings:

• •Don't print wet filament—it clogs nozzles.

Step 2: Choose Your Drying Method

Select based on tools: Filament dryer (fastest, precise), food dehydrator (affordable alternative), or convection oven (household option). Avoid microwaves—they melt filament unevenly.

Match temps/times to material: PLA (40-50°C, 4-6 hrs), PETG/ABS (60-70°C, 6-12 hrs), Nylon (70-80°C, 12-24 hrs). Why? Each absorbs moisture differently; over-drying cracks filament.

Success: Method selected with temp/time noted.

💡 Tips:

• •Filament dryers auto-regulate humidity—ideal for intermediates.

Step 3: Prepare the Filament Spool

Remove filament from packaging. For partial spools, loosely wind to expose inner layers. Place on a spool holder or mandrel to allow airflow.

Optional: Weigh the spool before/after to measure moisture loss (5-10% common).

Why it matters: Tight windings trap moisture. Success: Spool ready, fully exposed.

⚠️ Warnings:

• •Avoid bending filament sharply—risks kinks.

Step 4: Set Up Your Drying Equipment

For dryers: Load spool, set temp/humidity. Dehydrators/ovens: Use middle rack, prop door slightly for airflow, insert hygrometer probe.

Preheat to target temp (use thermometer for accuracy).

Success: Equipment stable at set temp (<5°C variance), spool centered.

💡 Tips:

• •Add desiccant packs inside dryer for extra humidity pull.

Step 5: Dry the Filament

Monitor every 2-4 hours. Rotate spool halfway for even drying. Check hygrometer—stop when RH <15% or no weight loss.

Don't exceed max times; PLA brittles after 8 hrs.

Why it matters: Proper drying removes 90%+ moisture without damage. Success: Filament feels dry, extrudes smoothly in a test.

⚠️ Warnings:

• •High heat melts PLA (>60°C)—use low fan settings.

Step 6: Cool and Test the Filament

Remove and let cool to room temp in a dry environment (use silica gel). Test: Extrude 1m or print a small calibration cube.

Look for: Smooth flow, no pops, strong layers.

Success: Perfect test print—no defects.

💡 Tips:

• •Print a temp tower to verify.

Step 7: Store Properly to Prevent Re-Absorption

Seal in vacuum bag with desiccant or airtight box. Label with dry date/material.

Why it matters: Maintains dryness for months. Success: Filament ready for future use.

⚠️ Warnings:

• •Avoid garages/basements—high humidity.

▸Pro Tips

• •Dry in batches overnight for efficiency.
• •Use PTFE tube to guide filament during drying tests.
• •For multi-material setups, dedicate dryers per type.
• •Track drying logs in a spreadsheet for each spool.
• •Pre-dry new filament upon arrival—prevents issues.
• •Combine with enclosure printing for ongoing dryness.
• •Reuse oven mitts as spool handles for hot removal.

▸Common Mistakes to Avoid

• •Drying at wrong temps: Melts low-temp filaments like PLA—always check material specs.
• •Skipping airflow: Traps steam—use fans or prop doors.
• •Not testing post-dry: Re-wets during print—always extrude first.
• •Over-drying: Causes brittleness—time strictly by material.
• •Poor storage post-dry: Moisture returns fast—seal immediately.

▸Troubleshooting

Problem: Filament still popping after drying

Solution: Extend time by 2-4 hrs or check inner layers; deeply saturated needs 24+ hrs.

Problem: Filament warped or melted

Solution: Temp too high—lower by 10°C and use convection mode.

Problem: No equipment available

Solution: DIY with PC case fans + heater, but buy a dryer for consistency.

Problem: Prints weak despite dry filament

Solution: Check printer calibration; moisture might be in bowden tube—dry it too.

SUNLU S4 Filament Dryer

Dries up to 4 spools simultaneously with precise temp (35-70°C) and humidity control.

Best for: Ideal for intermediate users with multiple filaments; fastest method.

Price Range: $69.99

Creality Filament Dryer Box

Compact, affordable single-spool dryer with LCD and auto-humidistat.

Best for: Budget option for occasional drying of PLA/PETG.

Price Range: $49.99

eSUN eBox Filament Dryer

Heats to 70°C with built-in hygrometer; dries while printing.

Best for: For active printing sessions with hygroscopic Nylon/TPU.

Price Range: $89.99

ThermoPro TP50 Digital Hygrometer

Accurate RH/temp monitoring essential for oven/dehydrator methods.

Best for: Verify drying success without guesswork.

Price Range: $9.99

FoodSaver Vacuum Seal Bags

Keeps dried filament dry long-term with reusable desiccant compatibility.

Best for: Post-drying storage for all spools.

Price Range: $19.99 (50-pack)