3D Printing Info

Filament comparison

e-TPU vs rPETG

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

Foaming / expanded TPU (TPU Aero / TPU Air) guideRecycled PETG (rPETG) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore rPETG comparisons
e-TPU vs rPETG — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXRecycled PETG (rPETG)PETG
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$28.99/kg median; $17.24–$39.98/kg across 4 dated product listings
Identity & Market
Base polymer / chemistryFoaming thermoplastic polyurethane — a blowing agent expands the extrudate so the printed Shore hardness can be tuned by flow rate[1]PETG regranulated from recycled polyester waste; Polymaker's Fiberon PETG-rCF08 adds 8 wt% recycled carbon fibre[2][3][4]
Densityg/cm³1.15 filament (Siraya Tech Flex TPU Air) and 1.05 (Roamr TPU Air HR), ISO 1183; the printed part falls to 0.51–0.93 depending on nozzle temperature (ISO 845)[5][6]1.27 (Prusament) and 1.30 (Fiberon PETG-rCF08), ISO 1183[2][4]
Typical priceUSD/kg1 kg-equivalent spools span 42–85; the middle of the market is about 52[7][8][9][10][11][12]1 kg spools cluster near 29[13][14][15][16]
Price range across brandsUSD/kg42–85 across brands; QIDI TPU-Aero 42, Siraya Tech Flex TPU Air 45, Phaetus aeFlex TPU-Aero 49 direct and 40 at West3D, Roamr TPU Air HR 80A 55 at 800 g, Recreus Filaflex Foamy 73 at 750 g, colorFabb varioShore 85 at 700 g[7][8][9][10][11][12][17]17–40 across brands; Filament PM RePETG 17, 3DXTech ECOMAX 26, GreenGate3D 32, Fiberon rCF08 40[13][14][15][16]
Market availability1–5Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[1][7][8][9][11][12]Available from several mainstream brands[13][14][15]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][7][9][10][12]1.75 and 2.85 mm; 0.5, 1 and 3 kg spools[15][14]
Typical applicationsCushioning, midsoles, insoles and soft-touch parts where the softness needs to vary within one print; Siraya Tech's Roamr line is aimed specifically at printed footwear[1][10]Not documented
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[5][6]±0.05 (Prusament PETG Recycled), against ±0.02 for virgin Prusament PETG[2][18]
Printing Parameters
Nozzle temperature°C230–270 (QIDI and Siraya Tech), 220–260 (Roamr); foaming activates near 230 °C and is strongest at the top of the range[1][5][6][11]250 ± 10 (Prusament); 230–255 (Spectrum)[2][3]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[5][6][11]80 ± 10 (Prusament); 60–80 (Spectrum)[2][3]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][6]Open frame is fine — Spectrum states a closed chamber is not necessary[3]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[5][6]50 % (Prusament); up to 100 % (Spectrum)[2][3]
Bed surface & adhesion aidPEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent, and Siraya Tech recommends PVP glue or Magigoo as a release agent on PEI[19][20][5]Textured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[18][21]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[9]Not documented
Bed-adhesion difficulty1–5Not documentedNeeds the right surface or a thin adhesive — the problem is releasing the part, not sticking it[18][21]
Stringing / oozing tendency1–5Severe — the material expands inside the hot end, so it oozes on travel moves; QIDI states retraction tuning cannot fix it and Siraya Tech advises setting retraction distance and speed to zero[5][11]Moderate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[21]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Easy — minor profile tuning; Spectrum describes printing as similar to standard PETG[3]
Extruder requirementDirect drive; the base material is a 92A TPU[1][22]Not documented
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[23][6]Brass fine indefinitely[2]
Abrasiveness1–5Non-abrasive[23]Not documented
Nozzle clog risk1–5Not documentedLow — recycled PETG prints on the same hardware as virgin PETG: no special hot-end, no drybox and no hardened nozzle[24][25]
Heat-creep / jam sensitivity1–5Not documentedSlightly sensitive[24]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[19]No special hot-end required[24]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[26]Moderate (0.3–0.8 %) — recycled PETG shares the virgin matrix, which reaches 0.40 % saturated at 25 °C / 55 % RH[18]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[11]0.07 after 24 h and 0.10 after 7 days at 24 °C / 22 % RH (Prusa Polymers)[2]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[5][6][11]Not documented
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface; Siraya Tech adds that moisture wrecks the foaming itself, not only the surface[26][5]Bubbling and popping at the nozzle, stringing and a rough surface[26]
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[26]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[26]
Storage requirementSealed with desiccant; often kept in a dryer during the print[26]Sealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[26][21]
Mechanical Properties
Tensile strength (XY)MPaFalls with foaming: colorFabb 24 unfoamed and 12 foamed (ISO 527-1A); Siraya Tech 10.3 at break printed at 240 °C down to 3.8 at 270 °C; QIDI 6.81 at break (ISO 527, XY)[1][5][11]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][18][3]
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]1500 printed horizontal, 1600 printed vertical (Prusament, ISO 527-1) — the same as virgin Prusament PETG[2][18]
Elongation at break%465 unfoamed and 450 foamed (colorFabb, ISO 527-1A); Siraya Tech 629 at 240 °C down to 475 at 270 °C; Roamr 760 down to 540; QIDI 576 (ISO 527, XY)[1][5][6][11]4.5 at yield printed (Prusament); Spectrum quotes 400 at break on moulded specimens[2][3]
Flexural strengthMPaNot documented63 ± 1 printed horizontal, ISO 178 (Prusament), against 66 ± 2 for virgin Prusament PETG[2][18]
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[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 dataNot documentedCharpy unnotched 25 ± 3 printed horizontal and 38 ± 11 printed vertical (Prusament, ISO 179-1)[2]
Layer adhesion / Z tensileMPaNot documented15 ± 5 (Prusa Polymers interlayer adhesion test), against 18 ± 4 for virgin Prusament PETG[2][18]
Brittleness1–5Very ductile — bends far before failing[1]Moderate[2]
Hardness (scale-specific)Shore A / Shore D / RockwellTunable by nozzle temperature: colorFabb 92 Shore A unfoamed; Siraya Tech 78 A printed at 240 °C falling to 63 A at 270 °C, Roamr TPU Air HR 80A 80 A down to 66 A and HR 85A 83 A down to 70 A (ISO 7619)[1][5][6][27]74 Shore D (Prusa Polymers method) — the same as virgin Prusament PETG[2][18]
Creep resistance / sustained load1–5Poor — no foamed-grade creep test; a printed 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[28]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[29][30][31][32]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[20]Moderate — no recycled-grade S-N curve; virgin printed PETG ran 79 000–193 000 cycles at 30 % of tensile strength[33]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Slightly flexible in thin sections[2]
Thermal Properties
HDT at 0.45 MPa°CNot documented68 (ISO 75, 0.45 MPa) — the same as virgin Prusament PETG; Spectrum quotes 70[2][18][3]
HDT at 1.8 MPa°CNot documented68 (ISO 75, 1.8 MPa)[2]
Melting point / Vicat°CVicat softening drops as the foam expands: 83 printed at 240 °C to 53 at 270 °C (Siraya Tech, ISO 306); QIDI 70.4[5][11]Not documented
Annealing responseFoaming activates near 230 °C and expands the extrudate about 1.6×; colorFabb advises dropping flow to 60–70 % to realise the weight saving, and Siraya Tech publishes a flow schedule from 85–90 % at 230 °C down to 50–55 % at 270 °C[1][5]Not documented
Flammability / UL 94Not documentedFlammable; no UL 94 rating published for standard grades[34]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[20]Not documented
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[20]Withstands acids, alkalis, oils and UV exposure[21]
Food contactNot food safe without specific certification (Polymaker)[20]Not certified for food contact as filament[21]
Biodegradability / compostabilityNot biodegradable[20]Not biodegradable[21]
RecyclabilityNot accepted in household plastic collection[20]The feedstock itself — Spectrum describes collecting, shredding and re-homogenising PETG waste[3]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[35]Moderate — measurable VOCs and UFPs, ventilation advised[35]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[35]Open a window / occasional ventilation[35]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[20]Sands poorly — the material is tough and gums rather than powders[24]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[20]Cyanoacrylate; no common solvent welds PETG cleanly[24]
Vapour / chemical smoothingNo practical vapour smoothing[20]No practical vapour smoothing[24]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[20]Prints its own supports; Polymaker rates PolyDissolve S1 for PETG[24]
Dimensional accuracy & detailFoamed surfaces are matte and textured; holding a consistent hardness means holding the nozzle temperature steady, and the printed density moves by nearly a factor of two across the 230–270 °C window[1][5]Not documented
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[36]No common workshop solvent; 1,2-dichloroethane destroys it inside a week and dichloromethane — a carcinogen — dissolves the surface.[37][38]
Softened or crazed byToluene and benzene swell it up to +50 % by weight at 23 °C; the foamed wall soaks up esters and alcohols faster still.[36]Acetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[37]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[36]Dichloromethane brushed on is the only agent that smooths PETG — a controlled carcinogen, not workshop stock.[38]

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. varioShore TPU Technical Data Sheet colorFabb · 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. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  6. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · tds
  7. Recreus product catalogue Recreus · 2026-08 · vendor
  8. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  9. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  10. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  11. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  12. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  13. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  14. GreenGate3D Recycled PET-G — product data GreenGate3D · 2026-08 · vendor
  15. Polymaker product catalogue Polymaker · 2026-08 · vendor
  16. Filament PM RePETG technical data sheet Filament PM (Plasty Mladec) · 2026-08 · tds
  17. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  18. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  19. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. TPU — material basics Polymaker Wiki · 2026-08 · doc
  21. PETG — material basics Polymaker Wiki · 2026-08 · doc
  22. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  23. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  24. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  25. Filament Material Guide Prusa Knowledge Base · 2026-08 · doc
  26. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  27. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  28. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  29. PCTG vs PETG comparison — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  30. Extrudr PETG vs PCTG vs XPETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  31. Prusament PETG-CF vs PETG V0 vs PETG — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  32. BambuLab PETG Basic vs Translucent vs PETG-CF — 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. Prusament PETG V0 Technical Datasheet Prusa Polymers · 2026-08 · tds
  35. 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
  36. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  37. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  38. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc