Voron Filament Drying Guide — Dry Your Filament for Perfect Prints

Materials Printing Guide

Wet filament is the number one cause of print quality problems that Voron owners blame on their hardware. Stringing, popping, bubbles, matte finishes, and poor layer adhesion are often the result of moisture-saturated filament rather than a mechanical issue. This guide covers how filament absorbs moisture, how to dry it, and how to keep it dry in a Voron environment.

Why Filament Absorbs Moisture

Most 3D printing filaments are hygroscopic — they absorb water from the air. The rate of absorption depends on the material chemistry and the ambient humidity.

• ABS and ASA: Absorb moisture slowly. It takes approximately 24 hours of exposure to saturate a spool in 60% humidity. ABS is less hygroscopic than nylon but still benefits from drying.
• Nylon and Polycarbonate (PC): Extremely hygroscopic. A fresh spool can absorb enough moisture to cause print defects within hours of opening. Drying before every print session is recommended.
• PETG: Moderately hygroscopic. PETG absorbs moisture faster than PLA but slower than nylon. A few hours in humid air can cause noticeable stringing.
• PLA: Absorbs moisture slowly, but it does absorb. PLA can go brittle and snap in the extruder if stored in humid conditions.
• PEEK and PEKK: Highly hygroscopic and require rigorous drying. These high-temperature materials must be dried to exacting standards before printing.

Wet Filament Symptoms

Recognizing wet filament is the first step. Common symptoms include:

• Popping and clicking at the nozzle: Water trapped in the filament flashes to steam as it exits the nozzle. The steam creates bubbles that burst audibly. You will hear a distinct popping sound.
• Excessive stringing: Moisture causes the molten plastic to be more fluid, leading to more oozing and stringing between travel moves.
• Bubbles and voids in the print surface: Steam bubbles burst on the surface leaving small craters or voids. These are visible on the top layers and side walls.
• Matte or dull surface finish: Wet ABS and PETG often print with a matte finish instead of the usual gloss. This is a reliable indicator of moisture.
• Reduced layer adhesion: Steam between layers prevents proper bonding. Prints may delaminate or feel weaker than expected.
• Filament snapping during feeding: Some materials (especially PLA and nylon) become brittle when wet. The filament may snap inside the PTFE tube or extruder.

If you see any of these symptoms, stop printing and dry your filament before continuing. Printing with wet filament wastes time and material, and the results will not improve by tuning hardware settings.

Drying Temperatures by Material

Drying filament requires maintaining a specific temperature for a specific duration. Too hot and the spool deforms. Too cool and the moisture does not release. Use these guidelines:

Important: These are material-specific guidelines. Always check the filament manufacturer's recommended drying temperature, as formulations vary. Drying at too high a temperature can permanently damage the filament by altering its polymer structure.

Drying Methods

Food Dehydrator (Best Option)

A food dehydrator with adjustable temperature control is the most recommended drying solution in the Voron community. It is safe, effective, and inexpensive.

• Cost: $30 to $50 on Amazon. Brands like Nesco, Magic Mill, and Cosori work well.
• Setup: Remove the dehydrator trays and place the spool directly on the mesh base. Some dehydrators require removing the center hub to fit a spool.
• Modification: Many Voron users 3D print a spacer ring to hold the spool centered in the dehydrator. STL files are available on Printables and Thingiverse.
• Advantages: Even airflow, consistent temperature, safe for unattended operation. The mesh base allows moisture to escape from all sides.

Oven Drying

A kitchen oven can work, but it has significant caveats:

• Temperature accuracy: Most home ovens fluctuate by 10-20 C. Set the oven 5-10 C below your target temperature and measure the actual temperature with a reliable thermometer.
• Gas ovens produce moisture: Gas combustion creates water vapor as a byproduct. A gas oven can make filament wetter rather than drier. Use an electric oven only.
• Risk of melting: Spools deform at temperatures above 70-80 C depending on the plastic. Never leave a spool in an oven unattended.
• Food safety: Filament outgassing can leave residues in your oven. Do not use your primary cooking oven for filament drying unless you are willing to deep-clean it afterward.

Dedicated Filament Dryers

Purpose-built filament dryers are increasingly popular. They are safer and more convenient than ovens:

• eSun eBox: Single-spool dryer with analog temperature control. Reliable and inexpensive ($40-50).
• Sunlu S2 / S4: Digital temperature control, built-in timer, and fan-assisted drying. The S4 holds four spools simultaneously.
• Creality Space Pi: Newer dryer with good temperature range and a viewing window. Holds two spools.
• Sovol SH01 / SH02: Budget-friendly option with digital controls. Good for occasional drying.
• PrintDry Pro: More expensive but includes a circulating fan and precise temperature control. Can also act as a dry box during printing.

Using the Voron Enclosure as a Dryer

One of the advantages of a Voron is the heated enclosure. You can use the printer itself to dry filament:

• Set the bed temperature to the desired drying temperature (e.g., 65 C for ABS).
• Place the spool on the bed or on a printed spool holder inside the enclosure.
• Close the enclosure and let it heat-soak for the required duration.
• This method works well for ABS and PETG but may not reach high enough temperatures for nylon (80 C) or PC (80 C+).
• Do not run the print head during drying. The hotend can overheat if sitting idle at chamber temperature.

Dry Box Build

For long-term storage and printing directly from a dry environment, build a dry box. A simple dry box keeps filament at consistent low humidity for weeks.

Materials Needed

• Airtight container: A clear plastic storage box with a gasket seal. Sterilite, Iris, or Really Useful Boxes are common choices. Size for at least one spool plus desiccant.
• Desiccant: Silica gel beads or molecular sieve.
• PTFE feedthrough: A Bowden coupler with a short piece of PTFE tube to route filament out of the box without letting air in.
• Hygrometer: A digital humidity sensor to monitor internal conditions.

Building Instructions

1. Drill a hole in the side or top of the container for the PTFE feedthrough. Use a step bit for clean holes in plastic.
2. Install the Bowden coupler and PTFE tube. The tube should be just long enough to reach the extruder without binding.
3. Place desiccant in a mesh bag or printed container inside the box. Do not let desiccant directly contact the filament.
4. Install the hygrometer and seal the box. The humidity inside should stabilize below 20% within a few hours.
5. Place the spool inside, route the filament through the PTFE tube, and seal the lid.

Desiccant Types

• Silica gel (rechargeable): The most common desiccant. Absorbs moisture from the air and can be recharged by heating in an oven at 120 C for 2 hours. Color-changing silica gel (orange to green) lets you know when it is saturated.
• Molecular sieve (3A type): More aggressive moisture absorption than silica gel. Better for deep drying of nylon and PC. Molecular sieve can also be recharged by heating, but requires higher temperatures (250-300 C) for full regeneration. Not all desiccants are created equal — 3A molecular sieve is the gold standard for filament storage.
• Indicating desiccant: Changes color when saturated. This is very helpful for knowing when to recharge without guessing.

Storage Solutions

• Vacuum bags: Seal each spool in a vacuum bag with a small packet of silica gel. This is the most space-efficient long-term storage method. Reusable vacuum bags are available for around $1 each.
• Dry boxes: As described above, for active use during printing.
• Ziploc bags with silica: The simplest method. Squeeze the air out before sealing. Not as effective as vacuum bags but far better than open storage.
• Filament cabinets: A converted cabinet or bookshelf with sealed doors and desiccant. Good for large filament collections.

Moisture Meters and Testing

A digital moisture meter (pin type) can measure the moisture content of filament directly. This is useful for:

• Confirming that a drying cycle was effective.
• Testing filament from an unknown source or questionable storage.
• Comparing different brands or batches of the same material.

A simple hygrometer inside your dry box is sufficient for most users. Pin-type moisture meters are more of a diagnostic tool for troubleshooting. If you print mostly ABS and PETG, a hygrometer and good silica gel are all you need.

Wet filament is a solvable problem. With a $40 food dehydrator or a $50 dedicated dryer, you can eliminate moisture-related print defects and get the consistent, high-quality prints your Voron is capable of producing. Dry your filament before every print session with hygroscopic materials, and store everything in low-humidity conditions. Your print quality will improve immediately.