How Moisture Affects 3D Printing

Filament is hygroscopic — it absorbs moisture from the air.
Even small amounts of water inside the polymer cause major print issues, from surface defects to structural weakness.

Traditional filament absorbs moisture during:

manufacturing
cooling
handling
shipping
storage
even while sitting on the printer

This page explains exactly what moisture does to filament and why UltraDry™ Filament eliminates these problems at the source.

1. Bubbling and Popping During Extrusion

Moisture inside the filament flashes into steam when heated.
This creates micro‑explosions that disrupt extrusion flow.

2. Stringing and Oozing

Wet filament becomes less viscous and more unpredictable, causing uncontrolled extrusion between travel moves.

3. Weak Layer Adhesion

Moisture interferes with polymer bonding, reducing mechanical strength and making parts brittle.

4. Surface Pitting and Roughness

Steam pockets create pits, bumps, and inconsistent surface texture.

5. Dimensional Inaccuracy

Moisture‑induced bubbling changes flow rate, causing over‑extrusion or under‑extrusion in different areas.

6. Nozzle Clogs and Inconsistent Flow

Steam pressure disrupts melt flow, increasing the risk of partial clogs and extrusion gaps.

Common Signs of Moisture in Filament:

• Popping or crackling sounds during printing
• Excessive stringing or wispy hairs
• Blobs, zits, or random surface artifacts
• Pitted or rough surface finish
• Brittle parts that snap easily
• Inconsistent extrusion or under‑extrusion
• Poor bridging and sagging overhangs
• Dimensional inaccuracies or warped geometry

Traditional filament is exposed to humidity during:

open‑air cooling
handling and spooling
packaging
shipping containers
warehouses
retail storage
your home or print farm

Even vacuum‑sealed bags with commodity desiccant cannot always prevent moisture uptake during manufacturing and cooling.

This is why so many users rely on dryers, ovens, and dry boxes — and why results vary so widely.

UltraDry™ Filament is engineered using PETGUSA’s DryFusion™ dual‑drying process and sealed to meet the UltraDry™ Certification Standard.

UltraDry™ solves moisture problems by:

removing bound moisture before extrusion
stabilizing the polymer after extrusion
spooling in a controlled, low‑humidity environment
sealing with industrial‑grade barrier film
using engineered UltraDry™ desiccant
batch moisture testing
batch test printing

This ensures the filament arrives pre‑dried, moisture‑stable, and ready to print.

Home Drying:
- Removes some surface moisture
- Results vary by dryer, time, and humidity
- Moisture reabsorbs quickly after drying

UltraDry™:
- Removes bound moisture at the polymer level
- Stabilizes the filament during manufacturing
- Maintains ultra‑low moisture through packaging
- Certified through testing and test printing

Print farms needing consistent output

Engineering teams requiring dimensional accuracy

High‑speed printers (Bambu, K1, Prusa XL)

Large‑format printers

Makers who want perfect prints without drying

Industrial users needing repeatable mechanical performance

• What is UltraDry™ Filament?
• UltraDry™ Certification Standard
• Is Wet Filament Ruining Your Prints?
• PETG Troubleshooting Guide
• UltraDry™ Filament Collection