Drying Nylon: The Single Most Important Step

If you take one thing from any nylon guide, take this: nylon must be bone-dry, and it does not stay that way on its own. More failed nylon prints come from moisture than from every other cause combined.

Nylon is intensely hygroscopic — it pulls water vapour straight out of the air. When that moisture reaches the melt zone it flashes to steam, blowing bubbles in the extrudate. The result is popping and hissing while printing, a rough foamy surface, stringing, and — worst of all — badly weakened layers. A spool that felt fine yesterday can be too wet to print today after a humid night.

Dry nylon hot and long:

• Temperature: 70–80°C in a filament dryer or oven.
• Time: 6–12 hours for a normal spool; longer if it has been exposed.
• After drying: store sealed with fresh desiccant immediately — it re-absorbs within hours of being out.

A cheap filament dryer that only reaches 50°C is not enough to fully dry nylon; it can maintain a dry spool but struggles to rescue a soaked one. An oven or a dryer rated to 70°C+ does the real work.

Because nylon re-absorbs moisture so fast, the professional habit is not to “dry it once” but to print directly from a heated dry box — an enclosed container with a dryer or desiccant that feeds the printer through a PTFE tube. On a long nylon print, a spool left in open air can pick up enough moisture partway through to ruin the top of the part. Keeping it in a dry box the whole time is the reliable fix.

Reviewed 2026-08-18. Starting points and general guidance — always calibrate for your filament brand and machine.