Nylon

TL;DR

For nylon, control moisture and cooling: dry the spool, keep it sealed (ideally print from a dry box), and print in a warm, draft-free setup (often an enclosure). Listen for nozzle popping and watch for lifted corners or mid-print cracks—those are your early warnings.

What nylon is good for (and when not to use it)

Nylon (PA) is a tough, abrasion-resistant engineering plastic that shines for functional parts like gears, bushings, hinges, clips, cable guides, and shop fixtures. It tends to survive impacts and repeated flexing better than many common filaments. The tradeoffs are that nylon absorbs water from air quickly and it shrinks as it cools, so it is less “set-and-forget” than PLA/PETG and often less dimensionally stable than stiffer materials.

Common nylon filament variants (what changes)

Material decision points (nylon)

Moisture control

Assume drying is required. Store sealed with desiccant; for consistent results, print directly from a dry box.

Temperature capability

Confirm hotend/bed can reach the filament’s recommended range. Nylon typically needs higher nozzle and bed temps than PLA/PETG.

Enclosure / drafts

Many nylons benefit from an enclosure to prevent rapid cooling that causes warping and layer splitting.

Bed adhesion plan

Pick a surface + adhesive method before starting. If the first layer lets go, nylon’s shrink stress will amplify the failure.

Wear and friction needs

Choose nylon for toughness and sliding wear. Avoid it when you need maximum stiffness or tight dimensional stability.

Proof test

Before long jobs, print a small functional coupon (hole fit, snap arm, gear segment) to validate dryness and settings.

Moisture: what is physically happening

Nylon absorbs water into the filament. In the hotend that water flashes into steam, which expands and disrupts the extrusion. You’ll see or hear signs (popping/sizzling), and the printed plastic can become bubbly/foamy with tiny voids. Those voids reduce layer-to-layer contact and can make parts snap along layer lines even when the print looks “fine” at a glance.

Moisture signs to check during the first minutes of a print

• Audible popping/sizzling at the nozzle
• Stringing that seems excessive even with reasonable retraction
• Surface looks rough, pitted, or slightly foamy
• Extrusion looks inconsistent (micro-surging) despite stable temps

Drying and storage habits that actually move the needle

• Dry the spool using the filament maker’s temperature/time guidance (avoid guessing high heat—spools can deform).
• After drying, move it immediately to a sealed bag or container with desiccant; don’t leave it on the printer between sessions.
• If quality degrades over a day or two, switch to printing directly from a dry box or re-dry before the next job.
• Treat “new in box” nylon as potentially wet; confirm with a small test print or by listening for nozzle popping.

Shrink stress: why nylon warps and cracks

Nylon shrinks as it cools. If the outside of the part cools faster than the inside, internal stress builds. On the bed that stress pulls corners upward (warping) and can peel the first layer free. Higher up, the same stress can open cracks between layers (layer splitting), especially on tall parts, thin walls, or long straight runs that cool quickly between passes. An enclosure helps by reducing drafts and keeping the whole print warmer so it cools more evenly.

Nylon troubleshooting: symptom → likely cause → first fix