3D Printing Info

Filament comparison

PA6/66 vs PCTG

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

PA66 (Nylon 66) guidePCTG guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PA6/66 comparisonsMore PCTG comparisons
PA6/66 vs PCTG — documented properties and sources
PropertyPA66 (Nylon 66)PAPCTGPETG
Market snapshot
Listing priceUSD/kg; dated snapshotsNot documented$34.99/kg median; $14.00–$50.67/kg across 5 dated product listings
Identity & Market
Base polymer / chemistryPolyamide 66, condensed from hexamethylenediamine and adipic acid; melts around 40 °C above PA6[1]Poly(cyclohexylenedimethylene terephthalate) glycol — a copolyester with a higher cyclohexanedimethanol content than PETG[2][3]
Densityg/cm³1.14 (extruded unfilled PA66 stock)[4]1.23 (Extrudr, ASTM D792; 3DXTech, ISO 1183)[3][5]
Typical priceUSD/kgNot documented1 kg spools cluster near 34[6][5][7]
Price range across brandsUSD/kgNot documented14–51 across brands; CHCKX 14 in a 10-roll bundle, Push Plastic 30, Proto-pasta 35 at 1 kg, 3DXTech 51[6][5][8]
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[9][10]Available from several mainstream brands[6][5][7][11]
Spool sizes & diametersNot documented1.75 and 2.85 mm; 0.5, 0.75, 1, 3 and 5 kg spools[6][7][5]
Typical applicationsNot documentedTransparent covers, guards and impact-loaded parts where PETG cracks[2][3]
Printing Parameters
Nozzle temperature°CNot documented250–270 (Spectrum, Extrudr)[2][3]
Bed temperature°CNot documented60–100 (Spectrum)[2]
Enclosure / chamber requirement1–5Enclosure required (passive)[1]Open frame is fine — Spectrum and Extrudr both say a closed chamber is not necessary, Extrudr adds it helps on larger parts[2][3]
Part cooling fanNot documentedUp to 100 % (Spectrum); 20–50 % (Extrudr)[2][3]
Bed surface & adhesion aidNot documentedTextured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[12][13]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sNot documented1.6–16 at the 20–200 mm/s Extrudr rates the material for, on a 0.4 mm nozzle at 0.2 mm layer[3][14]
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive — the problem is releasing the part, not sticking it[12][13]
Stringing / oozing tendency1–5Not documentedModerate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[13]
Shrinkage%Not documented0.2–0.5 (Extrudr, ASTM D955)[3]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning[1]Easy — minor profile tuning[2][3]
Hardware Wear & Reliability
Nozzle hardness required1–4Not documentedBrass fine indefinitely — Extrudr explicitly states no hardened nozzle is needed[3]
Abrasiveness1–5Not documentedNon-abrasive[3]
Nozzle clog risk1–5Very high — frequent jams without careful setup[15][16]Low — 3DXTech lists no special nozzle concerns and no minimum layer height for PCTG, only a 65 °C pre-dry[17]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[18]
Hotend requirementNot documentedNo special hot-end required[18]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Very high (>2 %)[16]Moderate (0.3–0.8 %) — the copolyester matrix reaches 0.40 % saturated at 25 °C / 55 % RH and 3DXTech specifies a 65 °C, 4 h pre-dry[12][17]
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[4]Not documented
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface[16]
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 %[19][15]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[16]
Storage requirementNot documentedSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[16][13]
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[4]43–44 at yield and 45–46 at break (ISO 527, injection-moulded resin data from Spectrum and Extrudr); 48 on My Tech Fun printed bars[2][3][20]
Young's modulusMPa2413 on extruded PA66 stock (ASTM D638; converted from 350,000 psi)[4]Not documented
Elongation at break%50 at break on extruded PA66 stock (ASTM D638)[4]215–220 at break on moulded specimens (ISO 527); 4.3–4.4 at yield[2][3]
Flexural strengthMPa113.8 on extruded PA66 stock (ASTM D790; converted from 16,500 psi)[4]Not documented
Flexural modulusMPa3034 on extruded PA66 stock (ASTM D790; converted from 440,000 psi)[4]Not documented
Charpy impact, notchedkJ/m²Not documented93–94 notched Izod at 23 °C on moulded specimens (ISO 180); 3DXTech quotes 8 by ISO 180/A[2][3][5]
Other impact dataIzod 53 J/m on extruded PA66 stock, converted from 1.0 ft-lb/in (ASTM D256)[4]Izod 4.14 kJ/m² on My Tech Fun printed bars, against 3.37 for PETG on the same rig[20]
Layer adhesion / Z tensileMPaNot documented21.6 on My Tech Fun 4×4 mm printed bars, against 32.9 for PETG[20]
Brittleness1–5Not documentedTough — absorbs impact, yields before breaking[2][3]
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)[4]69 Shore D measured by My Tech Fun, against 72 for PETG[20]
Creep resistance / sustained load1–5Not documentedBelow average — a 12 mm bar sagged to 19.4 mm over 5 days at 1.25 kg, slightly worse than PETG's 18.2[20]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[1]Good — 215 % elongation at break and 94 kJ/m² notched Izod on moulded specimens (Extrudr, Spectrum)[2][3]
Elasticity / flexibility1–5Semi-flexible[15]Slightly flexible in thin sections[20]
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[4]Not documented
Thermal Properties
HDT at 0.45 MPa°C232 on extruded PA66 stock (ASTM D648 at 66 psi; converted from 450 °F)[4]Not documented
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[4]Not documented
Glass transition (Tg)°CNot documented78 (3DXTech, DSC)[5]
Melting point / Vicat°C255 melting on extruded PA66 stock (ASTM D2133; converted from 491 °F)[4]Amorphous — no melting point; Vicat 88 (Spectrum, Extrudr)[2][3]
Continuous service temperature°C85 long term and 149 short term on extruded PA66 stock (converted from 185 °F and 300 °F)[4]68 — loaded bars begin to move at this temperature, against 65 for PETG[20]
Thermal expansion (CTE)µm/m·K81.0 (extruded PA66 stock, ASTM D696; source states 4.5e-5 in/in/°F)[4]Not documented
Flammability / UL 94UL 94 V-2 on extruded PA66 stock[4]Flammable; no UL 94 rating published for standard grades[21]
Environment & Chemical
Chemical resistanceNot documentedWithstands acids, alkalis, oils and UV exposure[13]
Water / humidity resistance in service1–5Not documentedGood — minor absorption; Spectrum describes the polymer as hydrophobic[2]
Food contactNot documentedNot certified for food contact as filament[13]
Biodegradability / compostabilityNot documentedNot biodegradable[13]
RecyclabilityNot documentedNot accepted in household plastic collection[13]
Electrical & ESD propertiesVolume resistance 1e15 ohm-cm and dielectric constant 4 on extruded PA66 stock (ASTM D257, D150)[4]Surface resistance above 10¹³ ohm/sq — insulating (3DXTech, ASTM D257)[5]
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised[22]Moderate — measurable VOCs and UFPs, ventilation advised[22]
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[22]Not documented
Ultrafine-particle emission rateparticles/min≈2 × 10⁸ median — low for ultrafine particles despite the highest VOC mass of any filament tested[22]Not documented
Hazardous species emittedCaprolactam, at up to 180 µg/min from nylon filament — the largest single-VOC emission rate measured in the study[22]Not documented
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[22]Open a window / occasional ventilation[22]
Post-Processing
Sanding & machiningNot documentedSands poorly — the material is tough and gums rather than powders[18]
Gluing & solvent weldingNot documentedCyanoacrylate; no common solvent welds PETG cleanly[18]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[18]
Support material pairingNot documentedPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[18]
Dimensional accuracy & detailNot documentedOptical clarity is the selling point; Extrudr recommends a layer height at most 50 % of nozzle diameter[3]
Solvents & Solubility
Soluble inDissolved at 23 °C by formic acid above ~80 %, phenol, m-cresol, 96 % sulphuric acid or hexafluoroisopropanol — laboratory reagents.[23]No common workshop solvent; Eastman's CHDM copolyester data shows 1,2-dichloroethane destroying it within a week.[24]
Softened or crazed byZinc chloride solutions stress-crack it — 10 % marginal, 37 % not resistant; alcoholic calcium chloride dissolves it.[23]Acetone, ethyl acetate, toluene and DMF swell and soften the copolyester; methanol crazes it (Eastman, 1 y at 23 °C).[24]
Solvent welding & smoothing agentNone — nylon's only solvents are formic acid, phenol and HFIP, all of which degrade the part they wet.[23]Dichloromethane brushed on is the only agent that smooths PETG — a controlled carcinogen, not workshop stock.[25]

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. Spectrum Premium PCTG Technical Data Sheet Spectrum Filaments · 2026-08 · tds
  3. Extrudr PCTG technical data Extrudr · 2026-08 · tds
  4. TECAMID 66 natural (PA66) — stock shape properties Ensinger · 2026-08 · tds
  5. MAX-G PCTG Technical Data Sheet 3DXTech · 2026-08 · tds
  6. Push Plastic product catalogue Push Plastic · 2026-08 · vendor
  7. Proto-pasta product catalogue Proto-pasta · 2026-08 · vendor
  8. CHCKX 10KG Multicolor PCTG Filament bundle CHCKX (Amazon US) · 2026-08 · vendor
  9. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  10. Polymaker product catalogue Polymaker · 2026-08 · vendor
  11. Atomic Filament product catalogue Atomic Filament · 2026-08 · vendor
  12. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  13. PETG — material basics Polymaker Wiki · 2026-08 · doc
  14. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  15. Moisture Conditioning — effect on printed nylon properties Polymaker Wiki · 2026-08 · doc
  16. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  17. MAX-G PCTG — product page (print recommendations) 3DXTech · 2026-08 · doc
  18. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  19. PolyMide CoPA Technical Data Sheet V5.4 (dry and wet status blocks) Polymaker · 2024-11 · tds
  20. PCTG vs PETG comparison — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  21. Prusament PETG V0 Technical Datasheet Prusa Polymers · 2026-08 · tds
  22. 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
  23. Ultramid Nylon Chemical Resistance guide (unmodified PA6 B27E and PA66 A27E) BASF · 2026-08 · tds
  24. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  25. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc