3D Printing Info

Filament comparison

PA6/66 vs PETG-GF

Compare printing settings, strength, heat resistance, dated prices and sources.

PA66 (Nylon 66) guideGlass-fibre polyester (PETG-GF / PET-GF) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PA6/66 comparisonsMore PETG-GF comparisons
PA6/66 vs PETG-GF — documented properties and sources
PropertyPA66 (Nylon 66)PAGlass-fibre polyester (PETG-GF / PET-GF)PETG
Market snapshot
Listing priceUSD/kg; dated snapshotsNot documented$27.38/kg median; $18.99–$29.99/kg across 3 dated product listings
Identity & Market
Base polymer / chemistryPolyamide 66, condensed from hexamethylenediamine and adipic acid; melts around 40 °C above PA6[1]Glass-fibre reinforced polyester. Polymaker's Fiberon PET-GF15 uses a PET rather than a PETG matrix and carries 15 wt% glass fibre[2]
Densityg/cm³1.14 (extruded unfilled PA66 stock)[3]1.43 (Fiberon PET-GF15, ISO 1183)[2]
Typical priceUSD/kgNot documented1 kg spools cluster near 25[4][5]
Price range across brandsUSD/kgNot documented19–30 across brands; ELEGOO 19, Polymaker Fiberon 30[4][5]
Market availability1–5Special order, 1–2 makers worldwide — no unfilled PA66 filament appeared in any catalogue searched, and the 3DXTech nylon range offers PA6, PA12 and a 6/66 copolymer but no straight PA66[6][5]Niche, a handful of specialist brands[4][5]
Spool sizes & diametersNot documented1.75 mm; 0.5 and 1 kg spools[5]
Typical applicationsNot documentedStiff, dimensionally stable fixtures; the Fiberon grade is designed to be annealed for heat resistance[2]
Printing Parameters
Enclosure / chamber requirement1–5Enclosure required (passive)[1]Not documented
Bed surface & adhesion aidNot documentedTextured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[7][8]
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive — the problem is releasing the part, not sticking it[7][8]
Stringing / oozing tendency1–5Not documentedModerate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[8]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning[1]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Not documentedHardened steel required[2]
Abrasiveness1–5Not documentedHighly abrasive — standard GF composite[2]
Nozzle clog risk1–5Very high — frequent jams without careful setup[9][10]Moderate — needs dry filament and a clean nozzle; Prusa lists higher risk of nozzle clogging for glass-filled composites[11]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[12]
Hotend requirementNot documentedNo special hot-end required[12]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Very high (>2 %)[10]Moderate (0.3–0.8 %) — the PETG matrix reaches 0.40 % saturated at 25 °C / 55 % RH; no glass-filled grade publishes its own figure[7]
Equilibrium moisture content at ~50 % RH%8.5 at saturation on extruded PA66 stock (ASTM D570) — the highest uptake of any polymer in this dataset[3]Not documented
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface[10]
Effect of moisture on strengthMeasured dry against wet on printed specimens at 6.16 % moisture (Polymaker CoPA): tensile 78.0 → 34.3 MPa, Young's modulus 2703 → 724 MPa, flexural strength 109.8 → 22.6 MPa, while notched Charpy rises 6.9 → 27.7 kJ/m² and elongation 12.7 → 13.2 %[13][9]Polymaker groups PETG with nylon, PVA and TPU as highly hygroscopic; no dry-versus-conditioned strength figures are published for this grade and the loss shows as bubbling and poor layer adhesion[10]
Storage requirementNot documentedSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[10][8]
Mechanical Properties
Tensile strength (XY)MPa82.7 at yield and 84.8 at break on extruded PA66 stock (ASTM D638; converted from 12,000 and 12,300 psi) — no printed figure exists because no unfilled PA66 filament was found[3]59.9 ± 0.8 printed XY, ISO 527 (Fiberon PET-GF15)[2]
Young's modulusMPa2413 on extruded PA66 stock (ASTM D638; converted from 350,000 psi)[3]4144 ± 133 printed XY, ISO 527 (Fiberon PET-GF15)[2]
Elongation at break%50 at break on extruded PA66 stock (ASTM D638)[3]4.0 ± 0.5 printed XY, ISO 527 (Fiberon PET-GF15)[2]
Flexural strengthMPa113.8 on extruded PA66 stock (ASTM D790; converted from 16,500 psi)[3]104.2 ± 2.4 printed XY, ISO 178 (Fiberon PET-GF15)[2]
Flexural modulusMPa3034 on extruded PA66 stock (ASTM D790; converted from 440,000 psi)[3]3705 ± 85 printed XY, ISO 178 (Fiberon PET-GF15)[2]
Charpy impact, notchedkJ/m²Not documented8.7 ± 0.6 printed XY, ISO 179, notched (Fiberon PET-GF15)[2]
Other impact dataIzod 53 J/m on extruded PA66 stock, converted from 1.0 ft-lb/in (ASTM D256)[3]Charpy unnotched 27.2 ± 2.0 printed XY (Fiberon PET-GF15, ISO 179)[2]
Layer adhesion / Z tensileMPaNot documented48.2 ± 0.3 printed Z, ISO 527 (Fiberon PET-GF15)[2]
Brittleness1–5Not documentedBrittle — snaps with little warning; elongation 4.0 % in XY and 2.6 % in Z[2]
Hardness (scale-specific)Shore A / Shore D / RockwellShore D 86 and Rockwell 85 (108) — the source does not name the scales on extruded PA66 stock (ASTM D2240, D785)[3]Not documented
Creep resistance / sustained load1–5Not documentedBelow average — no GF-grade creep test; the CF grades sagged to 14.8–16.7 mm over 5 days at 1.25 kg against 17.1–20.4 mm unfilled[14][15][16]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[1]Below average — no GF-grade S-N curve; elongation at break falls to 4.0 % in XY against 5.2–9.3 % unfilled[2][17]
Elasticity / flexibility1–5Semi-flexible[9]Rigid[2]
Z strength as % of XY%Not documented80 (Fiberon PET-GF15, printed Z against XY tensile)[2]
Wear resistance & frictionWear factor 200e-10 in3*min/(ft*lb*h) on extruded PA66 stock (ASTM D3702); Ensinger lists very good slide and wear properties[3]Not documented
Thermal Properties
HDT at 0.45 MPa°C232 on extruded PA66 stock (ASTM D648 at 66 psi; converted from 450 °F)[3]81.6 as printed, 133.7 after annealing (ISO 75, 0.45 MPa)[2]
HDT at 1.8 MPa°C90 on extruded PA66 stock (ASTM D648 at 264 psi; converted from 194 °F) — the gap to the 0.45 MPa figure is the widest in the dataset[3]71.8 as printed, 87.3 after annealing (ISO 75, 1.8 MPa)[2]
Glass transition (Tg)°CNot documented59.5 (DSC)[2]
Melting point / Vicat°C255 melting on extruded PA66 stock (ASTM D2133; converted from 491 °F)[3]231.6 melting (DSC); Vicat 232.6 (ISO 306)[2]
Continuous service temperature°C85 long term and 149 short term on extruded PA66 stock (converted from 185 °F and 300 °F)[3]Not documented
Annealing responseNot documentedAnnealing lifts HDT at 0.45 MPa from 81.6 to 133.7 °C[2]
Thermal expansion (CTE)µm/m·K81.0 (extruded PA66 stock, ASTM D696; source states 4.5e-5 in/in/°F)[3]20 along the print bead and 63–74 in the build direction at 30 °C (30 wt% GF, large-format printed, TMA)[18]
Flammability / UL 94UL 94 V-2 on extruded PA66 stock[3]UL 94 HB at 1.5 mm (Fiberon PET-GF15)[2]
Environment & Chemical
Chemical resistanceNot documentedWithstands acids, alkalis, oils and UV exposure[8]
Food contactNot documentedNot certified for food contact as filament[8]
Biodegradability / compostabilityNot documentedNot biodegradable[8]
RecyclabilityNot documentedNot accepted in household plastic collection[8]
Electrical & ESD propertiesVolume resistance 1e15 ohm-cm and dielectric constant 4 on extruded PA66 stock (ASTM D257, D150)[3]Surface resistivity above 10¹² ohm — insulating (Fiberon PET-GF15, ANSI/ESD S11.11)[2]
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised[19]Moderate — measurable VOCs and UFPs, ventilation advised[19]
VOC emission rateµg/minUp to 180 caprolactam, the dominant VOC from nylon; total VOC reached nearly 200 µg/min, the highest of the nine filaments tested[19]Not documented
Ultrafine-particle emission rateparticles/min≈2 × 10⁸ median — low for ultrafine particles despite the highest VOC mass of any filament tested[19]Not documented
Hazardous species emittedCaprolactam, at up to 180 µg/min from nylon filament — the largest single-VOC emission rate measured in the study[19]Not documented
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[19]Open a window / occasional ventilation[19]
Dust & fibre handling hazardNot documentedGlass fibre is bound in the matrix; avoid inhaling sanding dust[2]
Post-Processing
Sanding & machiningNot documentedSands poorly — the material is tough and gums rather than powders[12]
Gluing & solvent weldingNot documentedCyanoacrylate; no common solvent welds PETG cleanly[12]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[12]
Support material pairingNot documentedPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[12]
Solvents & Solubility
Soluble inDissolved at 23 °C by formic acid above ~80 %, phenol, m-cresol, 96 % sulphuric acid or hexafluoroisopropanol — laboratory reagents.[20]No common workshop solvent; dichloromethane — a carcinogen — dissolves the matrix surface, 1,2-dichloroethane destroys it in a week.[21][22]
Softened or crazed byZinc chloride solutions stress-crack it — 10 % marginal, 37 % not resistant; alcoholic calcium chloride dissolves it.[20]Acetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[21]
Solvent welding & smoothing agentNone — nylon's only solvents are formic acid, phenol and HFIP, all of which degrade the part they wet.[20]Dichloromethane reaches only the resin, so the fibre is left standing proud of the surface. Controlled carcinogen.[22]

Material entries describe families or representative grades, not an interchangeable specification for every spool. Test methods, orientations and conditions may differ. Unknown values are marked “Not documented”. Prices and source dates remain historical snapshots; check the linked guide for product details. Differences highlight text, not a universal winner.

Sources for this comparison

  1. PA (Nylon) — material basics Polymaker Wiki · 2026-08 · doc
  2. Fiberon PET-GF15 Technical Data Sheet V1.0 Polymaker · 2026-08 · tds
  3. TECAMID 66 natural (PA66) — stock shape properties Ensinger · 2026-08 · tds
  4. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  5. Polymaker product catalogue Polymaker · 2026-08 · vendor
  6. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  7. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  8. PETG — material basics Polymaker Wiki · 2026-08 · doc
  9. Moisture Conditioning — effect on printed nylon properties Polymaker Wiki · 2026-08 · doc
  10. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  11. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  12. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  13. PolyMide CoPA Technical Data Sheet V5.4 (dry and wet status blocks) Polymaker · 2024-11 · tds
  14. Extrudr PETG vs PCTG vs XPETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  15. Prusament PETG-CF vs PETG V0 vs PETG — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  16. BambuLab PETG Basic vs Translucent vs PETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  17. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  18. Effects of Fiber Orientation on the Coefficient of Thermal Expansion of Fiber-Filled Polymer Systems in Large Format Polymer Extrusion-Based Additive Manufacturing Materials 15(8):2764 · 2022-04 · paper
  19. Emissions of Ultrafine Particles and Volatile Organic Compounds from Commercially Available Desktop Three-Dimensional Printers with Multiple Filaments (Azimi et al.) Environmental Science & Technology 50(3) 1260-1268 · 2016-01 · paper
  20. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds
  21. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  22. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc