PEI filament

Polyetherimide, sold as ULTEM. A high-temperature aerospace polymer with an inherent amber cast that shows through any pigment.

• Enclosure recommended — Shrinks enough while cooling that draughts cause warping and split layers. An enclosure, or simply a still room, makes the difference.
• Keep dry — Absorbs moisture from the air, which prints as stringing, popping and weak layers. Filament that has sat out usually needs drying before use.

Engineering materials · 23 color variants from 10 brands · 5 with a retailer link.