3D Printing InfoFilament comparison
Magnetic vs PETG-GF
Compare printing settings, strength, heat resistance, dated prices and sources.
2 selected · all documented properties
| Property | Magnetic filamentSPECIALTY | Glass-fibre polyester (PETG-GF / PET-GF)PETG |
|---|---|---|
| Market snapshot | ||
| Listing priceUSD/kg; dated snapshots | $64.99/kg median; $64.99–$64.99/kg across 1 dated product listings | $27.38/kg median; $18.99–$29.99/kg across 3 dated product listings |
| Identity & Market | ||
| Base polymer / chemistry | PLA loaded with ferromagnetic iron powder, so printed parts respond to magnets[1] | Glass-fibre reinforced polyester. Polymaker's Fiberon PET-GF15 uses a PET rather than a PETG matrix and carries 15 wt% glass fibre[2] |
| Densityg/cm³ | About 1.85 (Proto-pasta manufacturer figure) — 1.5× standard PLA[1] | 1.43 (Fiberon PET-GF15, ISO 1183)[2] |
| Typical priceUSD/kg | 1 kg spools cluster near 65[3] | 1 kg spools cluster near 25[4][5] |
| Price range across brandsUSD/kg | 64–70 across formats; 1 kg spool 65, 500 g 70, 2 kg 70[3] | 19–30 across brands; ELEGOO 19, Polymaker Fiberon 30[4][5] |
| Market availability1–5 | Niche, a handful of specialist brands[3] | Niche, a handful of specialist brands[4][5] |
| Spool sizes & diameters | 1.75 and 2.85 mm; 0.1, 0.5, 1 and 2 kg spools[3] | 1.75 mm; 0.5 and 1 kg spools[5] |
| Typical applications | Sensor targets, magnetic fixtures, and props that need to stick to a magnet or rust deliberately[1] | Stiff, dimensionally stable fixtures; the Fiberon grade is designed to be annealed for heat resistance[2] |
| Printing Parameters | ||
| Nozzle temperature°C | 192 (Proto-pasta)[1] | Not documented |
| Bed temperature°C | 60 (Proto-pasta)[1] | Not documented |
| Enclosure / chamber requirement1–5 | Open frame is fine[1] | Not documented |
| Bed surface & adhesion aid | Not documented | Textured PEI, satin or powder-coated sheets; on smooth PEI a glue stick acts as a release agent[6][7] |
| Maximum volumetric flow (mm³/s; see test conditions)mm³/s | 1.6–2.4 at Proto-pasta's 20–30 mm/s on a 0.4 mm nozzle at 0.2 mm layer[1] | Not documented |
| Bed-adhesion difficulty1–5 | Not documented | Needs the right surface or a thin adhesive — the problem is releasing the part, not sticking it[6][7] |
| Stringing / oozing tendency1–5 | Not documented | Moderate — retraction tuning needed; Polymaker names stringing as PETG's common quirk[7] |
| Overall printing difficulty1–5 | Intermediate — dry filament and a tuned profile; slow, and brittle in filament form[1] | Not documented |
| Extruder requirement | Proto-pasta advises an extrusion width 0.05 mm larger than the nozzle and warns feeding is inconsistent below 0.4 mm and on Bowden machines[1] | Not documented |
| Hardware Wear & Reliability | ||
| Nozzle hardness required1–4 | Brass acceptable; hardened steel for volume work[1] | Hardened steel required[2] |
| Abrasiveness1–5 | Moderately abrasive — metal fill[1] | Highly abrasive — standard GF composite[2] |
| Nozzle clog risk1–5 | Moderate — needs dry filament and a clean nozzle; Prusa lists metal-filled composites as a higher clogging risk and recommends a 0.6 mm nozzle minimum[8] | Moderate — needs dry filament and a clean nozzle; Prusa lists higher risk of nozzle clogging for glass-filled composites[9] |
| Heat-creep / jam sensitivity1–5 | Not documented | Slightly sensitive[10] |
| Hotend requirement | Proto-pasta recommends a wear-resistant or larger nozzle for longer service intervals[1] | No special hot-end required[10] |
| Moisture Behaviour | ||
| Moisture absorption (hygroscopicity)1–5 | Not documented | Moderate (0.3–0.8 %) — the PETG matrix reaches 0.40 % saturated at 25 °C / 55 % RH; no glass-filled grade publishes its own figure[6] |
| Symptoms when wet | Not documented | Bubbling and popping at the nozzle, stringing and a rough surface[11] |
| Effect of moisture on strength | Polymaker rates PLA low-sensitivity and publishes no dry-versus-conditioned figures; absorbed water flashes to steam and shows as bubbling and poor layer adhesion[11] | 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[11] |
| Storage requirement | Not documented | Sealed with desiccant; Polymaker groups PETG with the highly hygroscopic materials[11][7] |
| Mechanical Properties | ||
| Tensile strength (XY)MPa | Not documented | 59.9 ± 0.8 printed XY, ISO 527 (Fiberon PET-GF15)[2] |
| Young's modulusMPa | Not documented | 4144 ± 133 printed XY, ISO 527 (Fiberon PET-GF15)[2] |
| Elongation at break% | Not documented | 4.0 ± 0.5 printed XY, ISO 527 (Fiberon PET-GF15)[2] |
| Flexural strengthMPa | Not documented | 104.2 ± 2.4 printed XY, ISO 178 (Fiberon PET-GF15)[2] |
| Flexural modulusMPa | Not documented | 3705 ± 85 printed XY, ISO 178 (Fiberon PET-GF15)[2] |
| Charpy impact, notchedkJ/m² | Not documented | 8.7 ± 0.6 printed XY, ISO 179, notched (Fiberon PET-GF15)[2] |
| Other impact data | Not documented | Charpy unnotched 27.2 ± 2.0 printed XY (Fiberon PET-GF15, ISO 179)[2] |
| Layer adhesion / Z tensileMPa | Not documented | 48.2 ± 0.3 printed Z, ISO 527 (Fiberon PET-GF15)[2] |
| Brittleness1–5 | Brittle — Proto-pasta describes the filament as more brittle than standard PLA and needing extra care in handling[1] | Brittle — snaps with little warning; elongation 4.0 % in XY and 2.6 % in Z[2] |
| Creep resistance / sustained load1–5 | Not documented | Below 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[12][13][14] |
| Fatigue / repeated-flex resistance1–5 | Not documented | Below average — no GF-grade S-N curve; elongation at break falls to 4.0 % in XY against 5.2–9.3 % unfilled[2][15] |
| Elasticity / flexibility1–5 | Rigid[1] | Rigid[2] |
| Z strength as % of XY% | Not documented | 80 (Fiberon PET-GF15, printed Z against XY tensile)[2] |
| Thermal Properties | ||
| HDT at 0.45 MPa°C | Not documented | 81.6 as printed, 133.7 after annealing (ISO 75, 0.45 MPa)[2] |
| HDT at 1.8 MPa°C | Not documented | 71.8 as printed, 87.3 after annealing (ISO 75, 1.8 MPa)[2] |
| Glass transition (Tg)°C | Not documented | 59.5 (DSC)[2] |
| Melting point / Vicat°C | Not documented | 231.6 melting (DSC); Vicat 232.6 (ISO 306)[2] |
| Annealing response | Not documented | Annealing lifts HDT at 0.45 MPa from 81.6 to 133.7 °C[2] |
| Thermal expansion (CTE)µm/m·K | Not documented | 20 along the print bead and 63–74 in the build direction at 30 °C (30 wt% GF, large-format printed, TMA)[16] |
| Flammability / UL 94 | Not documented | UL 94 HB at 1.5 mm (Fiberon PET-GF15)[2] |
| Environment & Chemical | ||
| Outdoor durability | Deliberately rustable — Proto-pasta markets the iron content as oxidising when exposed to moisture[1] | Not documented |
| Chemical resistance | Not documented | Withstands acids, alkalis, oils and UV exposure[7] |
| Food contact | Not documented | Not certified for food contact as filament[7] |
| Biodegradability / compostability | Not documented | Not biodegradable[7] |
| Recyclability | Not documented | Not accepted in household plastic collection[7] |
| Electrical & ESD properties | Ferromagnetic: Proto-pasta states it responds to magnets and behaves similarly to pure iron[1] | Surface resistivity above 10¹² ohm — insulating (Fiberon PET-GF15, ANSI/ESD S11.11)[2] |
| Health & Safety | ||
| Fume toxicity1–5 | Low hazard — minimal VOC and particle emission; none of these materials was in the chamber study[17] | Moderate — measurable VOCs and UFPs, ventilation advised[17] |
| Ventilation / filtration requirement1–5 | Open a window / occasional ventilation[17] | Open a window / occasional ventilation[17] |
| Dust & fibre handling hazard | Not documented | Glass fibre is bound in the matrix; avoid inhaling sanding dust[2] |
| Post-Processing | ||
| Sanding & machining | Polishing and deliberate rusting are the intended finishes[1] | Sands poorly — the material is tough and gums rather than powders[10] |
| Gluing & solvent welding | Not documented | Cyanoacrylate; no common solvent welds PETG cleanly[10] |
| Vapour / chemical smoothing | Not documented | No practical vapour smoothing[10] |
| Support material pairing | Not documented | Prints its own supports; Polymaker rates PolyDissolve S1 for PETG[10] |
| Solvents & Solubility | ||
| Soluble in | Chloroform dissolves the PLA matrix and leaves the iron powder behind; laboratory reagent, not workshop stock.[18][1] | No common workshop solvent; dichloromethane — a carcinogen — dissolves the matrix surface, 1,2-dichloroethane destroys it in a week.[19][20] |
| Softened or crazed by | Acetone and ethyl acetate plasticise the matrix rather than dissolving it; water attacks the exposed iron.[18][1] | Acetone (+16 % weight over 1 year at 23 °C), ethyl acetate, toluene and DMF swell and soften it; methanol crazes it.[19] |
| Solvent welding & smoothing agent | None — PLA has no workshop-safe solvent, and the iron loading blocks the surface flow smoothing needs.[18] | Dichloromethane reaches only the resin, so the fibre is left standing proud of the surface. Controlled carcinogen.[20] |
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
- Magnetic Iron PLA — product page and technical data Proto-pasta · 2026-08 · tds
- Fiberon PET-GF15 Technical Data Sheet V1.0 Polymaker · 2026-08 · tds
- Proto-pasta product catalogue Proto-pasta · 2026-08 · vendor
- ELEGOO product catalogue ELEGOO · 2026-08 · vendor
- Polymaker product catalogue Polymaker · 2026-08 · vendor
- Prusament PETG Technical Datasheet v1.1 Prusa Polymers · 2022-02 · tds
- PETG — material basics Polymaker Wiki · 2026-08 · doc
- Composite materials with metal or wood particles Prusa Knowledge Base · 2026-08 · doc
- Composite materials filled with carbon, kevlar or glass Prusa Knowledge Base · 2026-08 · doc
- PET and PETG — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
- Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
- Extrudr PETG vs PCTG vs XPETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
- Prusament PETG-CF vs PETG V0 vs PETG — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
- BambuLab PETG Basic vs Translucent vs PETG-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
- Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
- 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
- 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
- Solubility Study of Ingeo Biopolymer Grades in Common Organic Solvents (NWPD003) NatureWorks · 2019-10 · tds
- Eastman Spectar copolyester — Chemical resistance (unstressed bars, 1 year at 23 °C) Eastman Chemical Company · 2026-08 · tds
- Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc