Thirty-five filament materials, grouped into eight families. Every page carries the same spec card — density, nozzle and bed temperatures, shrinkage and whether it is isotropic, tensile strength, heat deflection temperature, outdoor suitability, difficulty, typical price and a drying schedule — followed by what that material is genuinely bad at.
That last field is deliberate. Manufacturer marketing tells you what a filament is for. It rarely tells you where it fails, and the failure is usually the thing that decides whether it is right for your part.
How the families are organised
- PLA and PLA blends — the default first spool, and the family with the widest spread of hidden density differences. A matte or glow-filled PLA is meaningfully heavier than the plain version.
- ABS, ASA and styrenics — higher temperature resistance, solvent smoothing, and warping that requires an enclosure to control.
- PETG and copolyesters — the middle ground, and the usual right answer for a functional outdoor part.
- Nylon — tough and abrasion-resistant, and the most moisture-hungry material on the site by a wide margin.
- Flexible filaments — sold by Shore hardness, printed slowly, and with a failure mode set of their own.
- Fibre and particle filled — a base polymer plus chopped carbon, glass or metal. Stiffer, more dimensionally stable, and abrasive enough to destroy a brass nozzle in tens of hours.
- Engineering and high-temperature — polycarbonate and above, chosen for a specific requirement rather than convenience.
- Support and specialty — soluble supports, foaming filaments and the low-temperature niche materials.
Density is the field to get right
Density drives both the cost calculator and the length-to-weight converter, so it is stored as a range with its basis recorded rather than as a single confident number. The spread is real: polypropylene is around 0.90 g/cm³ and floats in water, PLA sits near 1.24, PETG near 1.27, and metal-filled PLA can reach 4.0. A 1 kg spool of one of those holds several times the length of another.
If a weight estimate came out light, the density figure in your slicer's filament profile is the first thing to check, and filled or blended grades are where it is most often wrong.
Reading the shrinkage figure
Shrinkage is stored as a percentage range together with a note on whether it is isotropic. For most materials it is not: the build plate holds the base while the upper layers contract freely, so X and Y move more than Z. That asymmetry is why a part can be dimensionally fine in height and out of tolerance across its width, and it is why the shrinkage calculator asks which axis you are compensating.