3D Printing Info

Filament comparison

PETG-GF vs PLA Silk

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

Glass-fibre polyester (PETG-GF / PET-GF) guideSilk PLA guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PETG-GF comparisonsMore PLA Silk comparisons
PETG-GF vs PLA Silk — documented properties and sources
PropertyGlass-fibre polyester (PETG-GF / PET-GF)PETGSilk PLAPLA
Market snapshot
Listing priceUSD/kg; dated snapshots$27.38/kg median; $18.99–$29.99/kg across 3 dated product listings$19.49/kg median; $9.75–$24.99/kg across 15 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]PLA with a gloss-forming additive package; suppliers publish the composition as polylactic acid only[2]
Densityg/cm³1.43 (Fiberon PET-GF15, ISO 1183)[1]1.27 (ISO 1183)[2]
Typical priceUSD/kg1 kg spools cluster near 25[3][4]Mainstream 1 kg spools cluster near 20[5][6][7]
Price range across brandsUSD/kg19–30 across brands; ELEGOO 19, Polymaker Fiberon 30[3][4]10–25 across brands; CHCKX 10 in a 16-roll bundle, SUNLU 13, LANDU 18, YXPOLYER 20, Polymaker 22, Devil Design 25[8][9][10][11][12]
Market availability1–5Niche, a handful of specialist brands[3][4]Stocked by most mainstream brands[5][8][13]
Spool sizes & diameters1.75 mm; 0.5 and 1 kg spools[4]1.75 mm; 1 and 1.1 kg spools; dual- and tri-colour coextruded variants[14][15]
Typical applicationsStiff, dimensionally stable fixtures; the Fiberon grade is designed to be annealed for heat resistance[1]Decorative prints where surface gloss matters more than strength[2]
Diameter tolerance± mmNot documented±0.03 (Bambu Lab)[16]
Printing Parameters
Nozzle temperature°CNot documented210–240 — 20 °C above the plain PLA window[2]
Bed temperature°CNot documented35–45[2]
Enclosure / chamber requirement1–5Not documentedOpen frame is fine[2][17]
Part cooling fanNot documentedFan on[2]
Bed surface & adhesion aidTextured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[18][19]Cool Plate SuperTack, smooth PEI or textured PEI[2]
Warping tendency1–5Not documentedNone[2]
Bed-adhesion difficulty1–5Needs the right surface or a thin adhesive — the problem is releasing the part, not sticking it[18][19]Sticks to anything[20]
Stringing / oozing tendency1–5Moderate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[19]Not documented
Overall printing difficulty1–5Not documentedEasy — minor profile tuning; hotter nozzle and slower cap of 250 mm/s[2]
Hardware Wear & Reliability
Nozzle hardness required1–4Hardened steel required[1]Brass fine indefinitely[17]
Abrasiveness1–5Highly abrasive — standard GF composite[1]Non-abrasive[21][17]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle; Prusa lists higher risk of nozzle clogging for glass-filled composites[22]Very low[17]
Heat-creep / jam sensitivity1–5Slightly sensitive[23]Moderate — good heatbreak cooling needed; PLA softens below 60 °C[24]
Hotend requirementNo special hot-end required[23]No special hot-end required[20]
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[18]Moderate — 0.40 % saturated at 25 °C / 55 % RH[2]
Equilibrium moisture content at ~50 % RH%Not documented0.40 saturated at 25 °C / 55 % RH (Bambu Lab)[2]
Drying temperature & timeNot documented55 °C for 8 h in a forced-air dryer, or 65–75 °C for 12 h on an X1 heatbed[2][25]
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface[26]Bubbling and popping at the nozzle, stringing, rough surface and weak layers[26]
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[26]Polymaker rates PLA low-sensitivity — the loss shows as poor layer adhesion and brittle layers rather than a published strength figure[26]
Storage requirementSealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[26][19]Sealed with desiccant below 20 % RH; shelf life at ambient is long[27][20]
Mechanical Properties
Tensile strength (XY)MPa59.9 ± 0.8 printed XY, ISO 527 (Fiberon PET-GF15)[1]33 (printed XY, ISO 527); eSun Silk broke 22 % below the 16-brand PLA mean on identical 4×4 mm bars[2][28]
Young's modulusMPa4144 ± 133 printed XY, ISO 527 (Fiberon PET-GF15)[1]2130 (printed XY, ISO 527)[2]
Elongation at break%4.0 ± 0.5 printed XY, ISO 527 (Fiberon PET-GF15)[1]2.8 (printed XY, ISO 527) — a quarter of PLA Basic at 12.2[2][27]
Flexural strengthMPa104.2 ± 2.4 printed XY, ISO 178 (Fiberon PET-GF15)[1]75 (printed XY, ISO 178)[2]
Flexural modulusMPa3705 ± 85 printed XY, ISO 178 (Fiberon PET-GF15)[1]2460 (printed XY, ISO 178)[2]
Charpy impact, notchedkJ/m²8.7 ± 0.6 printed XY, ISO 179, notched (Fiberon PET-GF15)[1]10.3 (printed XY, ISO 179, notched); unnotched 18.5[2]
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]25 (printed Z, ISO 527), and flexural Z collapses to 30 against 75 in XY; eSun Silk broke at 12.3 kg where twelve of the 16 plain PLAs managed 44.6–61.5 kg[2][28][29]
Brittleness1–5Brittle — snaps with little warning; elongation 4.0 % in XY and 2.6 % in Z[1]Brittle — snaps with little warning[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[30][31][32]Poor — no silk-specific creep data published; plain PLA sagged from 12 to 18.7–20.3 mm over 5 days at 1.25 kg[33][34]
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][35]Poor — no grade-specific S-N curve; plain printed PLA ran 38 000–49 000 cycles at 30 % of tensile strength (R = 0.2)[35][24]
Elasticity / flexibility1–5Rigid[1]Rigid[2]
Z strength as % of XY%80 (Fiberon PET-GF15, printed Z against XY tensile)[1]76 by tensile, 40 by flexural (printed, Bambu Lab)[2]
Thermal Properties
HDT at 0.45 MPa°C81.6 as printed, 133.7 after annealing (ISO 75, 0.45 MPa)[1]60 (ISO 75, 0.45 MPa)[2]
HDT at 1.8 MPa°C71.8 as printed, 87.3 after annealing (ISO 75, 1.8 MPa)[1]56 (ISO 75, 1.8 MPa)[2]
Glass transition (Tg)°C59.5 (DSC)[1]57 (DSC)[2]
Melting point / Vicat°C231.6 melting (DSC); Vicat 232.6 (ISO 306)[1]158 peak melt (DSC); Vicat 66 °C[2]
Continuous service temperature°CNot documented50 — a loaded bar begins to move at this temperature (My Tech Fun, eSun eSilk PLA)[29]
Annealing responseAnnealing lifts HDT at 0.45 MPa from 81.6 to 133.7 °C[1]50–55 °C for 6–12 h[2]
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)[36]Not documented
Flammability / UL 94UL 94 HB at 1.5 mm (Fiberon PET-GF15)[1]Flammable; no UL 94 rating published by the major brands[27][37]
Environment & Chemical
UV resistance1–5Not documentedDegrades within weeks outdoors[24][38]
Chemical resistanceWithstands acids, alkalis, oils and UV exposure[19]Good against weak acids, oils and grease; poor against strong acids and alkalis; dissolved by chloroform, THF and hot benzene[37][24]
Water / humidity resistance in service1–5Not documentedGood — insoluble in water[27]
Food contactNot certified for food contact as filament[19]Base resin is food-contact grade, but printed layer grooves harbour bacteria; Prusa advises against food use[24]
Biodegradability / compostabilityNot biodegradable[19]Industrially compostable only — needs sustained 55 °C; not home compostable[39][24]
RecyclabilityNot accepted in household plastic collection[19]Mechanically recyclable; not accepted in household plastic collection[39]
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[40]Low hazard — minimal VOC and particle emission[40]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[40]None needed in a normal room[40]
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[23]Wet sanding — dry sanding heats the surface by friction and smears it[38][24]
Gluing & solvent weldingCyanoacrylate; no common solvent welds PETG cleanly[23]Cyanoacrylate for most joints; some grades partially dissolve and bond with acetone[24][41]
Vapour / chemical smoothingNo practical vapour smoothing[23]No practical vapour smoothing — only chloroform, hot benzene or THF, which are laboratory-only[24]
Support material pairingPrints its own supports; Polymaker rates PolyDissolve S1 for PETG[23]Support for PLA (Bambu Lab)[2]
Dimensional accuracy & detailNot documented55° overhangs and 30 mm bridges; gloss hides fine detail and is destroyed by sanding[2]
Solvents & Solubility
Soluble inNo common workshop solvent; dichloromethane — a carcinogen — dissolves the matrix surface, 1,2-dichloroethane destroys it in a week.[42][43]Chloroform: 10 % w/v in 2–4 h at 23 °C, every grade and morphology; THF and DMF only at 65 °C. Laboratory reagents.[44]
Softened or crazed byAcetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[42]Acetone, ethyl acetate and toluene plasticise it but dissolve <1 % even at 65 °C; submersion in acetone crazes and destroys parts.[44][43]
Solvent welding & smoothing agentDichloromethane reaches only the resin, so the fibre is left standing proud of the surface. Controlled carcinogen.[43]Chloroform vapour smooths and welds PLA at the cost of tensile strength; acetone does not smooth it at all.[45][43]

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. Bambu Filament Technical Data Sheet V1.0 — PLA Silk+ Bambu Lab · 2026-08 · tds
  3. ELEGOO product catalogue ELEGOO · 2026-08 · vendor
  4. Polymaker product catalogue Polymaker · 2026-08 · vendor
  5. Panchroma Silk PLA collection Polymaker Shop · 2026-08 · vendor
  6. Spectrum PLA Silk — product listing 3DJake International · 2026-08 · vendor
  7. 3DJake ecoPLA Silk Black 1.75mm 1000g 3DJake International · 2026-08 · vendor
  8. Sunlu Silk PLA+ 1.75mm 1kg Sunlu Official Store · 2026-08 · vendor
  9. Bambu Lab PLA Silk 1.75mm 1kg 3D Universe · 2026-08 · vendor
  10. CHCKX 16 Pack Silk Dual Color PLA Filament Bundle CHCKX (Amazon US) · 2026-08 · vendor
  11. YXPOLYER Silk PLA Black&Gold product page YXPOLYER · 2026-08 · vendor
  12. LANDU Silk Tri-Color PLA Filament 1.75 mm 1 kg LANDU (Amazon US) · 2026-08 · vendor
  13. Overture Silk PLA 1.75mm Overture3D · 2026-08 · vendor
  14. eSUN PLA-Silk Magic 1.75mm eSUN Official Store · 2026-08 · vendor
  15. JAYO Silk PLA+ 1.75mm 1.1kg JAYO Official Store · 2026-08 · vendor
  16. PLA Basic — product page Bambu Lab US Store · 2026-08 · vendor
  17. Filament Material Guide Prusa Knowledge Base · 2026-08 · doc
  18. Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
  19. PETG — material basics Polymaker Wiki · 2026-08 · doc
  20. PLA — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  21. Prusament PLA — material page Prusa Polymers · 2026-08 · doc
  22. Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
  23. PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  24. PLA — material guide Prusa Knowledge Base · 2026-08 · doc
  25. Filament Drying Recommendations Bambu Lab Wiki · 2026-08 · doc
  26. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  27. Bambu Filament Technical Data Sheet V3.0 — PLA Basic Bambu Lab · 2026-08 · tds
  28. 16 PLA brand comparison test — results spreadsheet My Tech Fun (Igor Gaspar) · 2022-10 · test
  29. Testing eSun PLA filaments: PLA-ST vs PLA+ vs Silk PLA 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. BambuLab PLA Basic vs PLA Tough vs PLA-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  34. PolyTerra PLA vs PLA+ — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  35. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  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. PolyLite PLA Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  38. Prusament PLA Technical Data Sheet v1.0 Prusa Polymers · 2018-09 · tds
  39. Filamentive PLA (recycled) — product page Filamentive · 2026-08 · vendor
  40. 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
  41. Prusament rPLA Corn Pigment 1kg — product page Prusa Research · 2026-08 · vendor
  42. Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
  43. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc
  44. Solubility Study of Ingeo Biopolymer Grades in Common Organic Solvents (NWPD003) NatureWorks · 2019-10 · tds
  45. Effect of vapour smoothing in trichloromethane on 3D printed PLA — surface, mechanical and chemical structure Pitale, Keche & Chopra, Engineering Research Express 6(4) 045579 · 2024-12 · paper