3D Printing Info

Filament comparison

PEI 9085 vs PETG

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

PEI (ULTEM 9085) guidePETG guide

2 selected · all documented properties

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PEI 9085 vs PETG — documented properties and sources
PropertyPEI (ULTEM 9085)HIGHTEMPPETGPETG
Market snapshot
Listing priceUSD/kg; dated snapshots$309.80/kg median; $220.00–$392.00/kg across 6 dated product listings$19.99/kg median; $8.99–$69.99/kg across 21 dated product listings
Identity & Market
Base polymer / chemistryPolyetherimide, ULTEM 9085 grade — the flame-retardant PEI used for aircraft interiors[1]Polyethylene terephthalate glycol copolymer — PET with a glycol comonomer that suppresses crystallisation[2][3]
Densityg/cm³1.34 (ISO 1183, 3DXTech) against 1.27 specific gravity on moulded plaques (ASTM D792, Stratasys) — the two suppliers disagree[1][4]1.24–1.30 (ISO 1183)[2][3][5][6]
Typical priceUSD/kg1 kg-equivalent spools cluster near 298[7][8][9][10]1 kg spools cluster near 20[11][12][13]
Price range across brandsUSD/kg220-392 across brands and formats; 3DXTech ThermaX PEI 9085 220 at 2 kg, 3D4Makers 270 at 2 kg, Fiberlogy 298 at 500 g, Kimya 321 at 500 g, IEMAI 3D 385 at 1 kg, 3DXTech CarbonX PEI 9085+CF 392[7][8][9][10][14]12–70 across brands; IEMAI 12, ELEGOO 14, CHCKX 14, Bambu Lab 18–20, Hatchbox 26, Prusament 38, Prusament PETG V0 70[11][12][15][13][16][17]
Market availability1–5Niche, a handful of specialist brands[7][8][9][10]Ubiquitous, every brand and retailer[11][12][18][13]
Spool sizes & diameters1.75 and 2.85 mm; 250 g to 2 kg spools, plus Stratasys canisters[7][10][4]1.75 and 2.85 mm; 0.75, 0.8 and 1 kg spools plus spool-less refills[12][13]
Typical applicationsAircraft interior parts and rail rolling stock, where the flame, smoke and toxicity rating is the requirement[1]Functional parts, enclosures and outdoor fittings that need more toughness and heat tolerance than PLA[2][3]
Diameter tolerance± mmNot documented±0.02 (Prusament)[2]
Printing Parameters
Nozzle temperature°CNot documented230–260 across brands; Prusament 250 ± 10, Polymaker 240–260[2][3][6]
Bed temperature°C130–140 (3DXTech)[1]60–90; Prusament 80 ± 10, Polymaker 60–70[2][6]
Enclosure / chamber requirement1–5Actively heated chamber required[19][20]Open frame is fine[6]
Part cooling fanNot documentedAround 50 %; Polymaker specifies 20–60 %, less than PLA to protect layer bonding[2][6]
Bed surface & adhesion aidNot documentedTextured PEI, satin or powder-coated sheets. On smooth PEI a glue stick is used as a release agent, not an adhesive — PETG bonds to bare PEI hard enough to tear the sheet[2][6]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sNot documented8–15 (PrusaSlicer guidance); My Tech Fun ran Bambu Lab PETG Basic at 13 mm³/s[21][22]
Warping tendency1–5Severe — heated chamber needed[19]Slight — corner lift on large flat parts[2][6]
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive — the problem is releasing the part, not sticking it[2]
Stringing / oozing tendency1–5Not documentedModerate — retraction tuning needed[2][6]
Overall printing difficulty1–5Expert / industrial hardware only[19][20]Easy — minor profile tuning[6]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely for unfilled grades, but brass softens near these nozzle temperatures — hardened or plated hot ends are the norm[19]Brass fine indefinitely[21]
Abrasiveness1–5Non-abrasive when unfilled[1]Non-abrasive[6]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle; 3DXTech lists no special nozzle concerns but a mandatory 120 °C pre-dry before every print[23]Low — no special hot-end required and clogging is not among the listed drawbacks; Prusa lists no drybox and no hardened nozzle[24][25]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[24]
Hotend requirementNot documentedNo special hot-end required[24]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Not documentedModerate (0.3–0.8 %) — Bambu Lab reports 0.40 % saturated at 25 °C / 55 % RH; Prusa measures only 0.07 % in 24 h and 0.10 % in 7 days at the drier 22 % RH[2][26]
Equilibrium moisture content at ~50 % RH%Not documented0.10 after 7 days at 24 °C / 22 % RH (Prusa Polymers); 0.40 saturated at 25 °C / 55 % RH (Bambu Lab)[2][26]
Drying temperature & timeNot documented60–65 °C for 6–8 h[6][26]
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface[2]
Effect of moisture on strengthNo dry-versus-conditioned figures are published; 3DXTech mandates a 120 °C, 4 h pre-dry before every print because trapped water flashes to steam at these nozzle temperatures[23]Polymaker groups PETG with nylon, PVA and TPU as highly hygroscopic and shows a before-and-after-drying comparison; the loss appears as poor layer adhesion and weak, brittle layers rather than a published dry-versus-conditioned figure[27]
Storage requirementNot documentedSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[27][28]
Mechanical Properties
Tensile strength (XY)MPa63-77 at break (printed XZ, ASTM D638, Stratasys F900/F3300/Fortus 450mc, three tips and two colours); 54 (printed XY, ISO 527, 3DXTech)[4][1]38–51 (printed XY, ISO 527); Prusament 47 ± 2 at yield; 62 on My Tech Fun 4×4 mm bars[2][3][5][29]
Young's modulusMPa2040-2540 (printed XZ, ASTM D638, Stratasys); 2050 (printed XY, ISO 527, 3DXTech)[4][1]1500–2311 (printed XY, ISO 527)[2][3][5][6]
Elongation at break%5.4-9.1 at break (printed XZ, ASTM D638, Stratasys); 1.9-4.3 in ZX; 3DXTech quotes 3 (ISO 527)[4][1]5.2–9.3 at break (printed XY, ISO 527); Prusament 5.1 at yield[3][5][6][2]
Flexural strengthMPa104-116 at break (printed XZ, ASTM D790 Procedure A, Stratasys); 72-98 in ZX; 3DXTech quotes 90 (ISO 178)[4][1]58–80 (printed XY, ISO 178); Prusament 66 ± 2[2][3][5][6]
Flexural modulusMPa2400-2550 (printed XZ, ASTM D790, Stratasys F900 T16 and T16A) against 2120-2130 in ZX; 3DXTech quotes 2170 (ISO 178)[4][1]1068–2277 (printed XY, ISO 178)[2][3][5][6]
Charpy impact, notchedkJ/m²Not documented2.6 (PolyLite) to 11.6 (PolyMax) printed XY, ISO 179, notched; Prusament 6 ± 1[3][5][2]
Other impact dataIzod notched 88.5-140 J/m XZ against 37-80 J/m ZX; unnotched 647-2260 J/m XZ against 169-633 J/m ZX (printed, ASTM D256/D4812, Stratasys, across three printers and three tips)[4]Charpy unnotched does not break on Prusa's 4 J pendulum (ISO 179-1); Izod 3.37 kJ/m² on My Tech Fun printed bars[2][29]
Layer adhesion / Z tensileMPa39-63 at break (printed ZX, ASTM D638, Stratasys); the low end is the F900 T16 baseline, the high end the F3300 N500 hot end[4]18 ± 4 (Prusa interlayer adhesion test); 42.8 printed Z for PolyLite PETG; 33 on My Tech Fun bars[2][3][29]
Brittleness1–5Brittle — snaps with little warning[1]Moderate[2][3]
Hardness (scale-specific)Shore A / Shore D / RockwellRockwell M110 / R126 on extruded PEI stock (ASTM D785)[30]74 Shore D (Prusa Polymers method); measured on printed bars at 68.2 for Extrudr PETG, 72 for Fiberlogy PETG and 72.8 for Prusament PETG[2][29][31][32]
Creep resistance / sustained load1–5Excellent — holds load for years. Printed ZX coupons keep 87 % of room-temperature tensile strength at 104 °C and 70 % at 132 °C (ASTM D638); extruded PEI stock is rated 170 °C long-term service[4][30]Below average — a 12 mm bar sagged to 18.2 mm (Fiberlogy) and 19.4 mm (Bambu Lab Basic) over 5 days at 1.25 kg[29][22]
Fatigue / repeated-flex resistance1–5Not documentedModerate — 79 000–193 000 cycles at 30 % of tensile strength, about three times printed PLA (R = 0.2, 7 Hz)[33]
Elasticity / flexibility1–5Rigid[1]Slightly flexible in thin sections[2]
Z strength as % of XY%56-86 (Stratasys ZX against XZ tensile at break, ASTM D638, across F900/F3300/Fortus 450mc and T16/T20/T40A tips); 58 on the F900 T16 baseline[4]84 (PolyLite, printed Z against XY tensile)[3]
Thermal Properties
HDT at 0.45 MPa°C158 (printed XY, ISO 75 at 0.45 MPa, 3DXTech) to 178 (printed XY 178.2 and ZX 178.4, ASTM D648 Method B at 66 psi, Stratasys); moulded 176.9[1][4]68 (Prusament) to 78 (PolyLite), ISO 75 at 0.45 MPa[2][3][6]
HDT at 1.8 MPa°C170-173 (printed XY 170.2 and ZX 172.6, ASTM D648 Method B at 264 psi); moulded 172.9[4]65 (Polymaker) to 75 (PolyLite), ISO 75 at 1.8 MPa; Prusament 68[2][3][6]
Glass transition (Tg)°C177 (moulded plaque, ASTM D7426 inflection point, Stratasys); 186 (DSC, 3DXTech)[4][1][34]71–81 (DSC)[3][5][6]
Melting point / Vicat°CNot documentedAmorphous — no melting point; Vicat 75–84 (ISO 306)[3][5][6]
Continuous service temperature°C170 long-term service on extruded PEI stock, converted from 338 °F; 200 short term[30]61–66 — loaded bars begin to move at this temperature across six grades from four brands; Prusa publishes 68 for Prusament PETG[29][31][32][22][35]
Thermal expansion (CTE)µm/m·K44.9 (printed XY, -50 to 80 °C, ASTM E831), falling to 31.4 over 80-160 °C; ZX gives 44.5 over -50 to 60 °C. Black pigment raises it to 51.9[4]65 at 30 °C (neat PETG, large-format printed bead, TMA)[36]
Flammability / UL 94UL 94 V-0 at 1.5 mm on the base resin. Printed parts are tested to 14 CFR 25.853, BSS 7238 and 7239 and AITM 2.0007B and 3.0005 covering 60 s and 12 s vertical burn, 15 s horizontal burn, smoke density, toxic gas emission and OSU heat release[1][4]Flammable; no UL 94 rating published for standard PETG, though flame-retardant V0 grades exist[37][28]
Environment & Chemical
UV resistance1–5Good — years with some colour shift. 1000 h of QUV cycling to ASTM G154 left printed ZX coupons at 55.5 MPa yield against 56.0 unexposed, with elongation and modulus unchanged[4]Moderate — a season or two[2]
Chemical resistanceNot documentedWithstands acids, alkalis, oils and UV exposure — Polymaker names outdoor use as a result[28]
Water / humidity resistance in service1–5Not documentedGood — minor absorption[2]
Food contactNot documentedPET is the polymer of drinks bottles, but printed layer grooves harbour bacteria and no filament here carries a food-contact certification[28]
Biodegradability / compostabilityNot documentedNot biodegradable[28]
RecyclabilityNot documentedPET is widely recycled as bottle stock, but printed PETG waste is not accepted in household collection[28]
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised. None of these polymers was in the chamber study, and all are processed far above the temperatures it covered[38]Moderate — measurable VOCs and UFPs, ventilation advised[38]
Ultrafine-particle emission rateparticles/minNot documented≈5 × 10⁹ median for the PET-based T-Glase filament in the same chamber study, against ≈1 × 10⁸ for PLA[38]
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[38]Open a window / occasional ventilation[38]
Post-Processing
Sanding & machiningNot documentedSands poorly — the material is tough and gums rather than powders[24]
Painting & finishingNot documentedPaint adheres poorly without abrasion and a primer[2]
Gluing & solvent weldingNot documentedCyanoacrylate; no common solvent welds PETG cleanly[24]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[2]
Support material pairingNot documentedPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[24]
Dimensional accuracy & detailNot documentedStringing and blobbing are the usual accuracy limits, not shrinkage[2][6]
Solvents & Solubility
Soluble inChlorinated hydrocarbons — dichloromethane and chloroform — are solvents for polyetherimide. Laboratory reagents.[39][40]No common workshop solvent; 1,2-dichloroethane destroys it inside a week and dichloromethane — a carcinogen — dissolves the surface.[41][42]
Softened or crazed byAcetone, MEK, benzene, toluene and butyl acetate craze or stress-crack it; alcohols, fuels and dilute acids do not.[40][39]Acetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[41]
Solvent welding & smoothing agentDichloromethane is the only welding route, and it is a controlled carcinogen rather than a workshop material.[39][40]Dichloromethane brushed on is the only agent that smooths PETG — a controlled carcinogen, not workshop stock.[42]

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. ThermaX PEI 9085 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  2. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  3. PolyLite PETG Technical Data Sheet Polymaker Wiki · 2026-08 · tds
  4. ULTEM 9085 Resin — FDM Material Data Sheet Stratasys · 2026-04 · tds
  5. PolyMax PETG Technical Data Sheet Polymaker Wiki · 2026-08 · tds
  6. Polymaker PETG Technical Data Sheet Polymaker Wiki · 2026-08 · tds
  7. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  8. Kimya PEI-9085 Natural 2.85 mm 500 g igo3d · 2026-08 · vendor
  9. Fiberlogy PEI 9085 Natural, 1.75 mm / 500 g 3DJAKE · 2026-08 · vendor
  10. 3D4Makers product catalogue 3D4Makers · 2026-08 · vendor
  11. PETG Basic — product page Bambu Lab US Store · 2026-08 · vendor
  12. Polymaker product catalogue Polymaker · 2026-08 · vendor
  13. Printed Solid product catalogue Printed Solid · 2026-08 · vendor
  14. IEMAI 3D PEI 9085 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  15. Black PETG Filament 1.75 mm 1 kg — product data Hatchbox · 2026-08 · vendor
  16. IEMAI PETG 3D Printing Filament product page IEMAI 3D · 2026-08 · vendor
  17. CHCKX PETG 3D Printer Filament 1.75 mm 1 kg, Black CHCKX (Amazon US) · 2026-08 · vendor
  18. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  19. Prusament PEI 1010 Technical Datasheet v1.0 Prusa Polymers · 2024-09 · tds
  20. Prusament PEI 1010 — material page Prusa Polymers · 2026-08 · doc
  21. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  22. BambuLab PETG Basic vs Translucent vs PETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  23. THERMAX PEI 9085 — product page (print recommendations) 3DXTech · 2026-08 · doc
  24. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  25. Filament Material Guide Prusa Knowledge Base · 2026-08 · doc
  26. Bambu Filament Technical Data Sheet — PETG HF Bambu Lab · 2026-08 · tds
  27. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  28. PETG — material basics Polymaker Wiki · 2026-08 · doc
  29. PCTG vs PETG comparison — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  30. TECAPEI natural (PEI) — stock shape properties Ensinger · 2026-08 · tds
  31. Extrudr PETG vs PCTG vs XPETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  32. Prusament PETG-CF vs PETG V0 vs PETG — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  33. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  34. ThermaX PEI 1010 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  35. Prusament PETG — material page Prusa Polymers · 2026-08 · doc
  36. 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
  37. Prusament PETG V0 Technical Datasheet Prusa Polymers · 2026-08 · tds
  38. 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
  39. Radel PPSU, Veradel PESU, Acudel modified PPSU Design Guide — environmental stress cracking tables Solvay Specialty Polymers · 2026-08 · tds
  40. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds
  41. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  42. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc