3D Printing Info

Filament comparison

PETG-GF vs TPU soft

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

Glass-fibre polyester (PETG-GF / PET-GF) guideSoft TPU (below 85A) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PETG-GF comparisonsMore TPU soft comparisons
PETG-GF vs TPU soft — documented properties and sources
PropertyGlass-fibre polyester (PETG-GF / PET-GF)PETGSoft TPU (below 85A)FLEX
Market snapshot
Listing priceUSD/kg; dated snapshots$27.38/kg median; $18.99–$29.99/kg across 3 dated product listings$114.04/kg median; $109.80–$122.27/kg across 4 dated product listings
Identity & Market
Base polymer / chemistryGlass-fibre reinforced polyester. Polymaker's Fiberon PET-GF15 uses a PET rather than a PETG matrix and carries 15 wt% glass fibre[1]Very soft thermoplastic elastomers below 85 Shore A. Fiberlogy's FiberFlex 30D measures 81 Shore A, the softest grade with a published datasheet found here[2]
Densityg/cm³1.43 (Fiberon PET-GF15, ISO 1183)[1]1.07 (Fiberlogy FiberFlex 30D, ISO 1183)[2]
Typical priceUSD/kg1 kg spools cluster near 25[3][4]1 kg-equivalent spools cluster near 115[5][6][7]
Price range across brandsUSD/kg19–30 across brands; ELEGOO 19, Polymaker Fiberon 30[3][4]110–122 at 1 kg-equivalent; Recreus 70A 110 and 60A 116 at 500 g, NinjaTek Edge 83A 112, NinjaTek Chinchilla 75A 122; the Recreus 3 kg spools fall to 70–73[5][7][6]
Market availability1–5Niche, a handful of specialist brands[3][4]Niche, a handful of specialist brands[2][8][5]
Spool sizes & diameters1.75 mm; 0.5 and 1 kg spools[4]1.75, 2.85 and 3 mm; 0.5, 0.85, 1, 2 and 3 kg spools[2][5][9][6]
Typical applicationsStiff, dimensionally stable fixtures; the Fiberon grade is designed to be annealed for heat resistance[1]Highly compliant seals, soft grips and prosthetic liners[2]
Printing Parameters
Bed temperature°CNot documented50–70 (Fiberlogy FiberFlex 30D)[2]
Enclosure / chamber requirement1–5Not documentedOpen frame is fine[2]
Bed surface & adhesion aidTextured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[10][11]PEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent[12][13]
Bed-adhesion difficulty1–5Needs the right surface or a thin adhesive — the problem is releasing the part, not sticking it[10][11]Not documented
Stringing / oozing tendency1–5Moderate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[11]Not documented
Overall printing difficulty1–5Not documentedExpert / industrial hardware only — below 85 Shore A the filament buckles in almost any feed path that is not a short, constrained direct drive[9][13]
Extruder requirementNot documentedDirect drive only, with a constrained filament path; Bowden is not viable at this hardness[9][8]
Hardware Wear & Reliability
Nozzle hardness required1–4Hardened steel required[1]Brass fine indefinitely[14]
Abrasiveness1–5Highly abrasive — standard GF composite[1]Non-abrasive[14]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle; Prusa lists higher risk of nozzle clogging for glass-filled composites[15]High — jams from moisture, heat creep or particles; below 85 Shore A the filament buckles and compresses, and Simplify3D warns that raised feed rates most likely end in a jam[12][13][16]
Heat-creep / jam sensitivity1–5Slightly sensitive[17]Very high — softens in the cold zone readily[13]
Hotend requirementNo special hot-end required[17]No special hot-end required, but a direct-drive extruder is (Simplify3D)[12]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate (0.3–0.8 %) — the PETG matrix reaches 0.40 % saturated at 25 °C / 55 % RH; no glass-filled grade publishes its own figure[10]Moderate[16]
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface[16]Bubbling and popping at the nozzle, stringing and a rough surface[16]
Effect of moisture on strengthPolymaker 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]Polymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[16]
Storage requirementSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[16][11]Sealed with desiccant; often kept in a dryer during the print[16]
Mechanical Properties
Tensile strength (XY)MPa59.9 ± 0.8 printed XY, ISO 527 (Fiberon PET-GF15)[1]Not documented
Young's modulusMPa4144 ± 133 printed XY, ISO 527 (Fiberon PET-GF15)[1]Not documented
Elongation at break%4.0 ± 0.5 printed XY, ISO 527 (Fiberon PET-GF15)[1]870 at break (Fiberlogy FiberFlex 30D, ISO 527) — the highest elongation in the dataset[2]
Flexural strengthMPa104.2 ± 2.4 printed XY, ISO 178 (Fiberon PET-GF15)[1]Not documented
Flexural modulusMPa3705 ± 85 printed XY, ISO 178 (Fiberon PET-GF15)[1]Not documented
Charpy impact, notchedkJ/m²8.7 ± 0.6 printed XY, ISO 179, notched (Fiberon PET-GF15)[1]Not documented
Other impact dataCharpy unnotched 27.2 ± 2.0 printed XY (Fiberon PET-GF15, ISO 179)[1]Not documented
Layer adhesion / Z tensileMPa48.2 ± 0.3 printed Z, ISO 527 (Fiberon PET-GF15)[1]Not documented
Brittleness1–5Brittle — snaps with little warning; elongation 4.0 % in XY and 2.6 % in Z[1]Very ductile — bends far before failing[2]
Hardness (scale-specific)Shore A / Shore D / RockwellNot documented81 Shore A and 30 Shore D (Fiberlogy FiberFlex 30D, ISO 7619)[2]
Creep resistance / sustained load1–5Below 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[18][19][20]Poor — no creep test at this hardness; a printed 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[21]
Fatigue / repeated-flex resistance1–5Below average — no GF-grade S-N curve; elongation at break falls to 4.0 % in XY against 5.2–9.3 % unfilled[1][22]Excellent — living hinges viable[13]
Elasticity / flexibility1–5Rigid[1]Rubbery / highly elastic[2]
Z strength as % of XY%80 (Fiberon PET-GF15, printed Z against XY tensile)[1]Not documented
Wear resistance & frictionNot documentedTear strength 95 kN/m (Fiberlogy FiberFlex 30D, ISO 34-1)[2]
Thermal Properties
HDT at 0.45 MPa°C81.6 as printed, 133.7 after annealing (ISO 75, 0.45 MPa)[1]Not documented
HDT at 1.8 MPa°C71.8 as printed, 87.3 after annealing (ISO 75, 1.8 MPa)[1]Not documented
Glass transition (Tg)°C59.5 (DSC)[1]Not documented
Melting point / Vicat°C231.6 melting (DSC); Vicat 232.6 (ISO 306)[1]170 melting (Fiberlogy FiberFlex 30D, DSC)[2]
Annealing responseAnnealing lifts HDT at 0.45 MPa from 81.6 to 133.7 °C[1]Not documented
Thermal expansion (CTE)µm/m·K20 along the print bead and 63–74 in the build direction at 30 °C (30 wt% GF, large-format printed, TMA)[23]Not documented
Flammability / UL 94UL 94 HB at 1.5 mm (Fiberon PET-GF15)[1]Not documented
Environment & Chemical
UV resistance1–5Not documentedGood — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[13]
Chemical resistanceWithstands acids, alkalis, oils and UV exposure[11]Withstands industrial solvents and UV exposure (Polymaker)[13]
Food contactNot certified for food contact as filament[11]Not food safe without specific certification (Polymaker)[13]
Biodegradability / compostabilityNot biodegradable[11]Not biodegradable[13]
RecyclabilityNot accepted in household plastic collection[11]Not accepted in household plastic collection[13]
Electrical & ESD propertiesSurface resistivity above 10¹² ohm — insulating (Fiberon PET-GF15, ANSI/ESD S11.11)[1]Not documented
Health & Safety
Fume toxicity1–5Moderate — measurable VOCs and UFPs, ventilation advised[24]Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[24]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[24]Open a window / occasional ventilation[24]
Dust & fibre handling hazardGlass fibre is bound in the matrix; avoid inhaling sanding dust[1]Not documented
Post-Processing
Sanding & machiningSands poorly — the material is tough and gums rather than powders[17]Difficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[13]
Gluing & solvent weldingCyanoacrylate; no common solvent welds PETG cleanly[17]Cyanoacrylate bonds TPU; no common solvent welds it[13]
Vapour / chemical smoothingNo practical vapour smoothing[17]No practical vapour smoothing[13]
Support material pairingPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[17]Polymaker warns TPU supports are often very difficult to remove[13]
Solvents & Solubility
Soluble inNo common workshop solvent; dichloromethane — a carcinogen — dissolves the matrix surface, 1,2-dichloroethane destroys it in a week.[25][26]DMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[27]
Softened or crazed byAcetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[25]Toluene and benzene swell it up to +50 % by weight at 23 °C; esters swell it severely; ethanol and IPA soften it.[27]
Solvent welding & smoothing agentDichloromethane reaches only the resin, so the fibre is left standing proud of the surface. Controlled carcinogen.[26]None practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[27]

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. Fiberon PET-GF15 Technical Data Sheet V1.0 Polymaker · 2026-08 · tds
  2. FiberFlex 30D Technical Data Sheet Fiberlogy · 2026-08 · tds
  3. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  4. Polymaker product catalogue Polymaker · 2026-08 · vendor
  5. Recreus product catalogue Recreus · 2026-08 · vendor
  6. Chinchilla product page — print guidelines, spool sizes and price NinjaTek · 2026-08 · vendor
  7. NinjaFlex Edge product page — durometer, print guidelines and price NinjaTek · 2026-08 · vendor
  8. Filaflex 82A product page (Shore hardness and elongation) Recreus · 2026-08 · vendor
  9. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  10. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  11. PETG — material basics Polymaker Wiki · 2026-08 · doc
  12. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  13. TPU — material basics Polymaker Wiki · 2026-08 · doc
  14. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  15. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  16. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  17. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  18. Extrudr PETG vs PCTG vs XPETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  19. Prusament PETG-CF vs PETG V0 vs PETG — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  20. BambuLab PETG Basic vs Translucent vs PETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  21. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  22. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  23. 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
  24. 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
  25. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  26. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc
  27. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds