3D Printing Info

Filament comparison

PEI 9085 vs rPETG

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

PEI (ULTEM 9085) guideRecycled PETG (rPETG) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PEI 9085 comparisonsMore rPETG comparisons
PEI 9085 vs rPETG — documented properties and sources
PropertyPEI (ULTEM 9085)HIGHTEMPRecycled PETG (rPETG)PETG
Market snapshot
Listing priceUSD/kg; dated snapshots$309.80/kg median; $220.00–$392.00/kg across 6 dated product listings$28.99/kg median; $17.24–$39.98/kg across 4 dated product listings
Identity & Market
Base polymer / chemistryPolyetherimide, ULTEM 9085 grade — the flame-retardant PEI used for aircraft interiors[1]PETG regranulated from recycled polyester waste; Polymaker's Fiberon PETG-rCF08 adds 8 wt% recycled carbon fibre[2][3][4]
Densityg/cm³1.34 (ISO 1183, 3DXTech) against 1.27 specific gravity on moulded plaques (ASTM D792, Stratasys) — the two suppliers disagree[1][5]1.27 (Prusament) and 1.30 (Fiberon PETG-rCF08), ISO 1183[2][4]
Typical priceUSD/kg1 kg-equivalent spools cluster near 298[6][7][8][9]1 kg spools cluster near 29[6][10][11][12]
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[6][7][8][9][13]17–40 across brands; Filament PM RePETG 17, 3DXTech ECOMAX 26, GreenGate3D 32, Fiberon rCF08 40[6][10][11][12]
Market availability1–5Niche, a handful of specialist brands[6][7][8][9]Available from several mainstream brands[6][10][11]
Spool sizes & diameters1.75 and 2.85 mm; 250 g to 2 kg spools, plus Stratasys canisters[6][9][5]1.75 and 2.85 mm; 0.5, 1 and 3 kg spools[11][10]
Typical applicationsAircraft interior parts and rail rolling stock, where the flame, smoke and toxicity rating is the requirement[1]Not documented
Diameter tolerance± mmNot documented±0.05 (Prusament PETG Recycled), against ±0.02 for virgin Prusament PETG[2][14]
Printing Parameters
Nozzle temperature°CNot documented250 ± 10 (Prusament); 230–255 (Spectrum)[2][3]
Bed temperature°C130–140 (3DXTech)[1]80 ± 10 (Prusament); 60–80 (Spectrum)[2][3]
Enclosure / chamber requirement1–5Actively heated chamber required[15][16]Open frame is fine — Spectrum states a closed chamber is not necessary[3]
Part cooling fanNot documented50 % (Prusament); up to 100 % (Spectrum)[2][3]
Bed surface & adhesion aidNot documentedTextured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[14][17]
Warping tendency1–5Severe — heated chamber needed[15]Not documented
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive — the problem is releasing the part, not sticking it[14][17]
Stringing / oozing tendency1–5Not documentedModerate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[17]
Overall printing difficulty1–5Expert / industrial hardware only[15][16]Easy — minor profile tuning; Spectrum describes printing as similar to standard PETG[3]
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[15]Brass fine indefinitely[2]
Abrasiveness1–5Non-abrasive when unfilled[1]Not documented
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[18]Low — recycled PETG prints on the same hardware as virgin PETG: no special hot-end, no drybox and no hardened nozzle[19][20]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[19]
Hotend requirementNot documentedNo special hot-end required[19]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Not documentedModerate (0.3–0.8 %) — recycled PETG shares the virgin matrix, which reaches 0.40 % saturated at 25 °C / 55 % RH[14]
Equilibrium moisture content at ~50 % RH%Not documented0.07 after 24 h and 0.10 after 7 days at 24 °C / 22 % RH (Prusa Polymers)[2]
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface[21]
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[18]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[21]
Storage requirementNot documentedSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[21][17]
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)[5][1]43 ± 1.8 printed horizontal at yield, ISO 527-1 (Prusament), against 47 ± 2 for virgin Prusament PETG; Spectrum quotes 52 at yield on moulded specimens[2][14][3]
Young's modulusMPa2040-2540 (printed XZ, ASTM D638, Stratasys); 2050 (printed XY, ISO 527, 3DXTech)[5][1]1500 printed horizontal, 1600 printed vertical (Prusament, ISO 527-1) — the same as virgin Prusament PETG[2][14]
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)[5][1]4.5 at yield printed (Prusament); Spectrum quotes 400 at break on moulded specimens[2][3]
Flexural strengthMPa104-116 at break (printed XZ, ASTM D790 Procedure A, Stratasys); 72-98 in ZX; 3DXTech quotes 90 (ISO 178)[5][1]63 ± 1 printed horizontal, ISO 178 (Prusament), against 66 ± 2 for virgin Prusament PETG[2][14]
Flexural modulusMPa2400-2550 (printed XZ, ASTM D790, Stratasys F900 T16 and T16A) against 2120-2130 in ZX; 3DXTech quotes 2170 (ISO 178)[5][1]1800 printed horizontal, ISO 178 (Prusament)[2]
Charpy impact, notchedkJ/m²Not documented12 ± 1 printed horizontal and 15 ± 3 printed vertical, ISO 179-1 notched (Prusament)[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)[5]Charpy unnotched 25 ± 3 printed horizontal and 38 ± 11 printed vertical (Prusament, ISO 179-1)[2]
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[5]15 ± 5 (Prusa Polymers interlayer adhesion test), against 18 ± 4 for virgin Prusament PETG[2][14]
Brittleness1–5Brittle — snaps with little warning[1]Moderate[2]
Hardness (scale-specific)Shore A / Shore D / RockwellRockwell M110 / R126 on extruded PEI stock (ASTM D785)[22]74 Shore D (Prusa Polymers method) — the same as virgin Prusament PETG[2][14]
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[5][22]Below average — no recycled-grade creep test; virgin PETG sagged from 12 to 17.1–20.4 mm over 5 days at 1.25 kg[23][24][25][26]
Fatigue / repeated-flex resistance1–5Not documentedModerate — no recycled-grade S-N curve; virgin printed PETG ran 79 000–193 000 cycles at 30 % of tensile strength[27]
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[5]Not documented
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][5]68 (ISO 75, 0.45 MPa) — the same as virgin Prusament PETG; Spectrum quotes 70[2][14][3]
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[5]68 (ISO 75, 1.8 MPa)[2]
Glass transition (Tg)°C177 (moulded plaque, ASTM D7426 inflection point, Stratasys); 186 (DSC, 3DXTech)[5][1][28]Not documented
Continuous service temperature°C170 long-term service on extruded PEI stock, converted from 338 °F; 200 short term[22]Not documented
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[5]Not documented
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][5]Flammable; no UL 94 rating published for standard grades[29]
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[5]Not documented
Chemical resistanceNot documentedWithstands acids, alkalis, oils and UV exposure[17]
Food contactNot documentedNot certified for food contact as filament[17]
Biodegradability / compostabilityNot documentedNot biodegradable[17]
RecyclabilityNot documentedThe feedstock itself — Spectrum describes collecting, shredding and re-homogenising PETG waste[3]
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[30]Moderate — measurable VOCs and UFPs, ventilation advised[30]
Ventilation / filtration requirement1–5Ventilated room or enclosure recommended[30]Open a window / occasional ventilation[30]
Post-Processing
Sanding & machiningNot documentedSands poorly — the material is tough and gums rather than powders[19]
Gluing & solvent weldingNot documentedCyanoacrylate; no common solvent welds PETG cleanly[19]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[19]
Support material pairingNot documentedPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[19]
Solvents & Solubility
Soluble inChlorinated hydrocarbons — dichloromethane and chloroform — are solvents for polyetherimide. Laboratory reagents.[31][32]No common workshop solvent; 1,2-dichloroethane destroys it inside a week and dichloromethane — a carcinogen — dissolves the surface.[33][34]
Softened or crazed byAcetone, MEK, benzene, toluene and butyl acetate craze or stress-crack it; alcohols, fuels and dilute acids do not.[32][31]Acetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[33]
Solvent welding & smoothing agentDichloromethane is the only welding route, and it is a controlled carcinogen rather than a workshop material.[31][32]Dichloromethane brushed on is the only agent that smooths PETG — a controlled carcinogen, not workshop stock.[34]

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 Recycled Technical Datasheet Prusa Polymers · 2026-08 · tds
  3. Spectrum r-PETG Technical Data Sheet Spectrum Filaments · 2026-08 · tds
  4. Fiberon PETG-rCF08 Technical Data Sheet V1.0 Polymaker · 2026-08 · tds
  5. ULTEM 9085 Resin — FDM Material Data Sheet Stratasys · 2026-04 · tds
  6. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  7. Kimya PEI-9085 Natural 2.85 mm 500 g igo3d · 2026-08 · vendor
  8. Fiberlogy PEI 9085 Natural, 1.75 mm / 500 g 3DJAKE · 2026-08 · vendor
  9. 3D4Makers product catalogue 3D4Makers · 2026-08 · vendor
  10. GreenGate3D Recycled PET-G — product data GreenGate3D · 2026-08 · vendor
  11. Polymaker product catalogue Polymaker · 2026-08 · vendor
  12. Filament PM RePETG technical data sheet Filament PM (Plasty Mladec) · 2026-08 · tds
  13. IEMAI 3D PEI 9085 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  14. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  15. Prusament PEI 1010 Technical Datasheet v1.0 Prusa Polymers · 2024-09 · tds
  16. Prusament PEI 1010 — material page Prusa Polymers · 2026-08 · doc
  17. PETG — material basics Polymaker Wiki · 2026-08 · doc
  18. THERMAX PEI 9085 — product page (print recommendations) 3DXTech · 2026-08 · doc
  19. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. Filament Material Guide Prusa Knowledge Base · 2026-08 · doc
  21. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  22. TECAPEI natural (PEI) — stock shape properties Ensinger · 2026-08 · tds
  23. PCTG vs PETG comparison — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  24. Extrudr PETG vs PCTG vs XPETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  25. Prusament PETG-CF vs PETG V0 vs PETG — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  26. BambuLab PETG Basic vs Translucent vs PETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  27. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  28. ThermaX PEI 1010 Technical Data Sheet v4 3DXTech · 2026-08 · tds
  29. Prusament PETG V0 Technical Datasheet Prusa Polymers · 2026-08 · tds
  30. 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
  31. Radel PPSU, Veradel PESU, Acudel modified PPSU Design Guide — environmental stress cracking tables Solvay Specialty Polymers · 2026-08 · tds
  32. Chemical resistance — resistance of Ensinger plastics to chemicals (DIN 50 014, 23/50) Ensinger · 2026-08 · tds
  33. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  34. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc