3D Printing Info

Filament comparison

PETG-GF vs PP

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

Glass-fibre polyester (PETG-GF / PET-GF) guidePolypropylene (PP) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PETG-GF comparisonsMore PP comparisons
PETG-GF vs PP — documented properties and sources
PropertyGlass-fibre polyester (PETG-GF / PET-GF)PETGPolypropylene (PP)POLYOLEFIN
Market snapshot
Listing priceUSD/kg; dated snapshots$27.38/kg median; $18.99–$29.99/kg across 3 dated product listings$46.56/kg median; $31.99–$53.00/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]Polypropylene — a semi-crystalline polyolefin with no polar groups, so it neither absorbs water nor bonds to most bed surfaces[2][3]
Densityg/cm³1.43 (Fiberon PET-GF15, ISO 1183)[1]0.91 (Prusa PP composite, ISO 1183) — the lightest common filament[4]
Typical priceUSD/kg1 kg spools cluster near 25[5][6]1 kg-equivalent spools span 27–53; the middle of the market is about 44[7][8][9][10]
Price range across brandsUSD/kg19–30 across brands; ELEGOO 19, Polymaker Fiberon 30[5][6]27–53 across brands; Reli3D 32 on Amazon, SUNLU 44 at 0.8 kg, Fiberlogy 49 at 750 g, IEMAI 3D 53, and the 3DJake PP listing spans 27–49[7][11][8][9][10]
Market availability1–5Niche, a handful of specialist brands[5][6]Available from several mainstream brands[11][8][7]
Spool sizes & diameters1.75 mm; 0.5 and 1 kg spools[6]1.75 and 2.85 mm; 0.75 kg spools are common[8]
Typical applicationsStiff, dimensionally stable fixtures; the Fiberon grade is designed to be annealed for heat resistance[1]Living hinges, chemical-resistant containers, automotive clips and packaging prototypes[2]
Printing Parameters
Nozzle temperature°CNot documented210–230 (Braskem-type PE/PP window); Formfutura's Centaur PP melts at 205 ± 15 °C[2]
Enclosure / chamber requirement1–5Not documentedEnclosure recommended — Simplify3D lists an enclosure as a hardware requirement and Polymaker advises one below 70 °C ambient to stop warping and cracking[12][3]
Part cooling fanNot documentedPart cooling fan required (Simplify3D)[12]
Bed surface & adhesion aidTextured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[13][14]Packing tape, a polypropylene sheet, or a PP-specific adhesive such as Magigoo PP — ordinary PLA and ABS adhesives do not hold it[12][3]
Warping tendency1–5Not documentedHigh — enclosure needed for reliable large parts; PP's crystallinity drives shrinkage and Prusa recommends a brim on its PP grades[4][15]
Bed-adhesion difficulty1–5Needs the right surface or a thin adhesive — the problem is releasing the part, not sticking it[13][14]Very difficult — special plates or slurry required. PP bonds to almost nothing; a polypropylene-specific tape or adhesive is the normal answer[4][3]
Stringing / oozing tendency1–5Moderate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[14]Slight — Polymaker advises 1–2 mm retraction at 20–30 mm/s[3]
Overall printing difficulty1–5Not documentedAdvanced — enclosure, hardware upgrades, tuning; bed adhesion is the whole problem[3][4]
Hardware Wear & Reliability
Nozzle hardness required1–4Hardened steel required[1]Brass fine indefinitely for unfilled grades — Simplify3D states no special hotend is required[12]
Abrasiveness1–5Highly abrasive — standard GF composite[1]Non-abrasive when unfilled[12]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle; Prusa lists higher risk of nozzle clogging for glass-filled composites[16]Low — Simplify3D lists no special hotend requirement for PP and clogging is not among its listed drawbacks[17][12]
Heat-creep / jam sensitivity1–5Slightly sensitive[18]Slightly sensitive[12]
Hotend requirementNo special hot-end required[18]No special hot-end required (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[13]Negligible (<0.1 % EMC) — Prusa measures 0.03 % in 24 h and 0.04 % in 7 days on its PP composite, the lowest figures it publishes for any filament[4]
Equilibrium moisture content at ~50 % RH%Not documented0.03 after 24 h and 0.04 after 7 days at 24 °C / 22 % RH (Prusa Polymers, measured on its PP composite)[4]
Drying temperature & timeNot documentedNo drying step is published for PP; uptake is below the level that affects printing[4]
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface[17]Bubbling and popping at the nozzle; Polymaker still advises a 70 °C dry for 4–6 h despite the low uptake[3]
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[17]Not applicable in practice — with equilibrium uptake at 0.04 %, there is no moisture-driven strength loss to measure. Polymaker's sensitivity tiers put polyolefins below even PLA[4][17]
Storage requirementSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[17][14]No special storage needed[4]
Mechanical Properties
Tensile strength (XY)MPa59.9 ± 0.8 printed XY, ISO 527 (Fiberon PET-GF15)[1]12 at yield (Formfutura Centaur PP, ASTM D638)[2]
Young's modulusMPa4144 ± 133 printed XY, ISO 527 (Fiberon PET-GF15)[1]724 on extruded PP stock (ASTM D638; converted from 105,000 psi)[19]
Elongation at break%4.0 ± 0.5 printed XY, ISO 527 (Fiberon PET-GF15)[1]Above 600 at break (Formfutura Centaur PP, ASTM D638)[2]
Flexural strengthMPa104.2 ± 2.4 printed XY, ISO 178 (Fiberon PET-GF15)[1]31.0 on extruded PP stock (ASTM D790; converted from 4500 psi)[19]
Flexural modulusMPa3705 ± 85 printed XY, ISO 178 (Fiberon PET-GF15)[1]402 flexural modulus (Formfutura Centaur PP, ASTM D790) — an order of magnitude below any rigid filament[2]
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]Izod notched 112 J/m on extruded PP stock, converted from 2.1 ft-lb/in (ASTM D256)[19]
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 documentedRockwell R102 (and M95) on extruded PP stock (ASTM D785)[19]
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[20][21][22]Below average[2]
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][23]Excellent — living hinges viable, the classic polypropylene application[2]
Elasticity / flexibility1–5Rigid[1]Semi-flexible[2]
Z strength as % of XY%80 (Fiberon PET-GF15, printed Z against XY tensile)[1]Not documented
Thermal Properties
HDT at 0.45 MPa°C81.6 as printed, 133.7 after annealing (ISO 75, 0.45 MPa)[1]74 on extruded PP stock (ASTM D648 at 66 psi; converted from 165 °F)[19]
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]205 ± 15 melting (Formfutura Centaur PP)[2]
Continuous service temperature°CNot documentedBounded by a melting point of 205 ± 15 °C and by the 158 °C heat deflection of the carbon-filled grade; no loaded-bar service figure is published for unfilled PP[2][4]
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)[24]Not documented
Flammability / UL 94UL 94 HB at 1.5 mm (Fiberon PET-GF15)[1]Flammable; no UL 94 rating published for the grades surveyed[4]
Environment & Chemical
UV resistance1–5Not documentedMonths outdoors before embrittlement — unstabilised polypropylene chalks under UV[3]
Chemical resistanceWithstands acids, alkalis, oils and UV exposure[14]Excellent against acids, alkalis and most solvents — the usual reason to choose PP[3]
Water / humidity resistance in service1–5Not documentedExcellent — essentially unaffected[4]
Food contactNot certified for food contact as filament[14]Polypropylene is a common food-packaging polymer, but no filament here carries a food-contact certification[3]
Biodegradability / compostabilityNot biodegradable[14]Not biodegradable[3]
RecyclabilityNot accepted in household plastic collection[14]Mechanically recyclable as resin code 5, but printed waste is not accepted in household collection[3]
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[25]Low hazard — minimal VOC and particle emission. Inferred: no polyolefin was among the nine filaments in the Azimi chamber study, so this is a family-level judgement rather than a measurement[25]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[25]Open a window / occasional ventilation. Inferred — no polyolefin was measured in the chamber study[25]
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[18]Sands poorly — the waxy surface loads abrasive paper[12]
Painting & finishingNot documentedPaint and adhesives do not key to untreated PP; flame or plasma treatment is normally needed first[3]
Gluing & solvent weldingCyanoacrylate; no common solvent welds PETG cleanly[18]Nothing common bonds untreated PP; flame or plasma treatment is needed before adhesives key[3]
Vapour / chemical smoothingNo practical vapour smoothing[18]No practical vapour smoothing[12]
Support material pairingPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[18]Prints its own supports; no soluble support is rated for PP[12]
Dimensional accuracy & detailNot documentedShrinkage and warping dominate; the low modulus means parts flex rather than hold tolerance[4]
Solvents & Solubility
Soluble inNo common workshop solvent; dichloromethane — a carcinogen — dissolves the matrix surface, 1,2-dichloroethane destroys it in a week.[26][27]None at room temperature; chloroform dissolves it at 60 °C and xylene at about 118 °C — the xylene-solubles route.[28][29]
Softened or crazed byAcetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[26]Xylene, decalin, CCl4 and chlorobenzene are heavily absorbed at 20 °C; oleum, chlorosulphonic acid and bromine destroy it.[28]
Solvent welding & smoothing agentDichloromethane reaches only the resin, so the fibre is left standing proud of the surface. Controlled carcinogen.[27]None — nothing softens PP at room temperature, so joints have to be welded thermally rather than chemically.[28]

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. Centaur PP Technical Data Sheet Formfutura · 2026-08 · tds
  3. PP — material basics Polymaker Wiki · 2026-08 · doc
  4. Prusament PP Carbon Fiber Technical Datasheet v1.0 Prusa Polymers · 2024-11 · tds
  5. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  6. Polymaker product catalogue Polymaker · 2026-08 · vendor
  7. SUNLU product catalogue SUNLU · 2026-08 · vendor
  8. Fiberlogy PP Natural — product page 3DJake International · 2026-08 · vendor
  9. Reli3D Low Warp PP Filament 1.75 mm 1 kg Black — Amazon listing Amazon.com · 2026-08 · vendor
  10. IEMAI 3D PP 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
  11. PP filament listing 3DJake International · 2026-08 · vendor
  12. Polypropylene — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  13. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  14. PETG — material basics Polymaker Wiki · 2026-08 · doc
  15. Prusament PP Glass Fiber Technical Datasheet v1.0 Prusa Polymers · 2024-11 · tds
  16. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  17. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  18. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  19. TECAFINE PP natural — stock shape properties Ensinger · 2026-08 · tds
  20. Extrudr PETG vs PCTG vs XPETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  21. Prusament PETG-CF vs PETG V0 vs PETG — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  22. BambuLab PETG Basic vs Translucent vs PETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  23. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  24. 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
  25. 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
  26. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  27. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc
  28. Pro-fax and Moplen polypropylene — Chemical Resistance Guide (20, 60 and 100 °C) LyondellBasell · 2026-08 · tds
  29. US 5,278,282 Polymer recycling by selective dissolution — xylene dissolution temperatures Nauman & Lynch, Rensselaer Polytechnic Institute · 1994-01 · paper