3D Printing InfoFilament comparison
Magnetic vs PP
Compare printing settings, strength, heat resistance, dated prices and sources.
2 selected · all documented properties
| Property | Magnetic filamentSPECIALTY | Polypropylene (PP)POLYOLEFIN |
|---|---|---|
| Market snapshot | ||
| Listing priceUSD/kg; dated snapshots | $64.99/kg median; $64.99–$64.99/kg across 1 dated product listings | $46.56/kg median; $31.99–$53.00/kg across 4 dated product listings |
| Identity & Market | ||
| Base polymer / chemistry | PLA loaded with ferromagnetic iron powder, so printed parts respond to magnets[1] | Polypropylene — a semi-crystalline polyolefin with no polar groups, so it neither absorbs water nor bonds to most bed surfaces[2][3] |
| Densityg/cm³ | About 1.85 (Proto-pasta manufacturer figure) — 1.5× standard PLA[1] | 0.91 (Prusa PP composite, ISO 1183) — the lightest common filament[4] |
| Typical priceUSD/kg | 1 kg spools cluster near 65[5] | 1 kg-equivalent spools span 27–53; the middle of the market is about 44[6][7][8][9] |
| Price range across brandsUSD/kg | 64–70 across formats; 1 kg spool 65, 500 g 70, 2 kg 70[5] | 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[6][10][7][8][9] |
| Market availability1–5 | Niche, a handful of specialist brands[5] | Available from several mainstream brands[10][7][6] |
| Spool sizes & diameters | 1.75 and 2.85 mm; 0.1, 0.5, 1 and 2 kg spools[5] | 1.75 and 2.85 mm; 0.75 kg spools are common[7] |
| Typical applications | Sensor targets, magnetic fixtures, and props that need to stick to a magnet or rust deliberately[1] | Living hinges, chemical-resistant containers, automotive clips and packaging prototypes[2] |
| Printing Parameters | ||
| Nozzle temperature°C | 192 (Proto-pasta)[1] | 210–230 (Braskem-type PE/PP window); Formfutura's Centaur PP melts at 205 ± 15 °C[2] |
| Bed temperature°C | 60 (Proto-pasta)[1] | Not documented |
| Enclosure / chamber requirement1–5 | Open frame is fine[1] | Enclosure recommended — Simplify3D lists an enclosure as a hardware requirement and Polymaker advises one below 70 °C ambient to stop warping and cracking[11][3] |
| Part cooling fan | Not documented | Part cooling fan required (Simplify3D)[11] |
| Bed surface & adhesion aid | Not documented | Packing tape, a polypropylene sheet, or a PP-specific adhesive such as Magigoo PP — ordinary PLA and ABS adhesives do not hold it[11][3] |
| 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 |
| Warping tendency1–5 | Not documented | High — enclosure needed for reliable large parts; PP's crystallinity drives shrinkage and Prusa recommends a brim on its PP grades[4][12] |
| Bed-adhesion difficulty1–5 | Not documented | 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 tendency1–5 | Not documented | Slight — Polymaker advises 1–2 mm retraction at 20–30 mm/s[3] |
| Overall printing difficulty1–5 | Intermediate — dry filament and a tuned profile; slow, and brittle in filament form[1] | Advanced — enclosure, hardware upgrades, tuning; bed adhesion is the whole problem[3][4] |
| 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] | Brass fine indefinitely for unfilled grades — Simplify3D states no special hotend is required[11] |
| Abrasiveness1–5 | Moderately abrasive — metal fill[1] | Non-abrasive when unfilled[11] |
| 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[13] | Low — Simplify3D lists no special hotend requirement for PP and clogging is not among its listed drawbacks[14][11] |
| Heat-creep / jam sensitivity1–5 | Not documented | Slightly sensitive[11] |
| Hotend requirement | Proto-pasta recommends a wear-resistant or larger nozzle for longer service intervals[1] | No special hot-end required (Simplify3D)[11] |
| Moisture Behaviour | ||
| Moisture absorption (hygroscopicity)1–5 | Not documented | 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 documented | 0.03 after 24 h and 0.04 after 7 days at 24 °C / 22 % RH (Prusa Polymers, measured on its PP composite)[4] |
| Drying temperature & time | Not documented | No drying step is published for PP; uptake is below the level that affects printing[4] |
| Symptoms when wet | Not documented | 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 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[14] | 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][14] |
| Storage requirement | Not documented | No special storage needed[4] |
| Mechanical Properties | ||
| Tensile strength (XY)MPa | Not documented | 12 at yield (Formfutura Centaur PP, ASTM D638)[2] |
| Young's modulusMPa | Not documented | 724 on extruded PP stock (ASTM D638; converted from 105,000 psi)[15] |
| Elongation at break% | Not documented | Above 600 at break (Formfutura Centaur PP, ASTM D638)[2] |
| Flexural strengthMPa | Not documented | 31.0 on extruded PP stock (ASTM D790; converted from 4500 psi)[15] |
| Flexural modulusMPa | Not documented | 402 flexural modulus (Formfutura Centaur PP, ASTM D790) — an order of magnitude below any rigid filament[2] |
| Other impact data | Not documented | Izod notched 112 J/m on extruded PP stock, converted from 2.1 ft-lb/in (ASTM D256)[15] |
| Brittleness1–5 | Brittle — Proto-pasta describes the filament as more brittle than standard PLA and needing extra care in handling[1] | Very ductile — bends far before failing[2] |
| Hardness (scale-specific)Shore A / Shore D / Rockwell | Not documented | Rockwell R102 (and M95) on extruded PP stock (ASTM D785)[15] |
| Creep resistance / sustained load1–5 | Not documented | Below average[2] |
| Fatigue / repeated-flex resistance1–5 | Not documented | Excellent — living hinges viable, the classic polypropylene application[2] |
| Elasticity / flexibility1–5 | Rigid[1] | Semi-flexible[2] |
| Thermal Properties | ||
| HDT at 0.45 MPa°C | Not documented | 74 on extruded PP stock (ASTM D648 at 66 psi; converted from 165 °F)[15] |
| Melting point / Vicat°C | Not documented | 205 ± 15 melting (Formfutura Centaur PP)[2] |
| Continuous service temperature°C | Not documented | Bounded 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] |
| Flammability / UL 94 | Not documented | Flammable; no UL 94 rating published for the grades surveyed[4] |
| Environment & Chemical | ||
| UV resistance1–5 | Not documented | Months outdoors before embrittlement — unstabilised polypropylene chalks under UV[3] |
| Outdoor durability | Deliberately rustable — Proto-pasta markets the iron content as oxidising when exposed to moisture[1] | Not documented |
| Chemical resistance | Not documented | Excellent against acids, alkalis and most solvents — the usual reason to choose PP[3] |
| Water / humidity resistance in service1–5 | Not documented | Excellent — essentially unaffected[4] |
| Food contact | Not documented | Polypropylene is a common food-packaging polymer, but no filament here carries a food-contact certification[3] |
| Biodegradability / compostability | Not documented | Not biodegradable[3] |
| Recyclability | Not documented | Mechanically recyclable as resin code 5, but printed waste is not accepted in household collection[3] |
| Electrical & ESD properties | Ferromagnetic: Proto-pasta states it responds to magnets and behaves similarly to pure iron[1] | Not documented |
| Health & Safety | ||
| Fume toxicity1–5 | Low hazard — minimal VOC and particle emission; none of these materials was in the chamber study[16] | 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[16] |
| Ventilation / filtration requirement1–5 | Open a window / occasional ventilation[16] | Open a window / occasional ventilation. Inferred — no polyolefin was measured in the chamber study[16] |
| Post-Processing | ||
| Sanding & machining | Polishing and deliberate rusting are the intended finishes[1] | Sands poorly — the waxy surface loads abrasive paper[11] |
| Painting & finishing | Not documented | Paint and adhesives do not key to untreated PP; flame or plasma treatment is normally needed first[3] |
| Gluing & solvent welding | Not documented | Nothing common bonds untreated PP; flame or plasma treatment is needed before adhesives key[3] |
| Vapour / chemical smoothing | Not documented | No practical vapour smoothing[11] |
| Support material pairing | Not documented | Prints its own supports; no soluble support is rated for PP[11] |
| Dimensional accuracy & detail | Not documented | Shrinkage and warping dominate; the low modulus means parts flex rather than hold tolerance[4] |
| Solvents & Solubility | ||
| Soluble in | Chloroform dissolves the PLA matrix and leaves the iron powder behind; laboratory reagent, not workshop stock.[17][1] | None at room temperature; chloroform dissolves it at 60 °C and xylene at about 118 °C — the xylene-solubles route.[18][19] |
| Softened or crazed by | Acetone and ethyl acetate plasticise the matrix rather than dissolving it; water attacks the exposed iron.[17][1] | Xylene, decalin, CCl4 and chlorobenzene are heavily absorbed at 20 °C; oleum, chlorosulphonic acid and bromine destroy it.[18] |
| Solvent welding & smoothing agent | None — PLA has no workshop-safe solvent, and the iron loading blocks the surface flow smoothing needs.[17] | None — nothing softens PP at room temperature, so joints have to be welded thermally rather than chemically.[18] |
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
- Centaur PP Technical Data Sheet Formfutura · 2026-08 · tds
- PP — material basics Polymaker Wiki · 2026-08 · doc
- Prusament PP Carbon Fiber Technical Datasheet v1.0 Prusa Polymers · 2024-11 · tds
- Proto-pasta product catalogue Proto-pasta · 2026-08 · vendor
- SUNLU product catalogue SUNLU · 2026-08 · vendor
- Fiberlogy PP Natural — product page 3DJake International · 2026-08 · vendor
- Reli3D Low Warp PP Filament 1.75 mm 1 kg Black — Amazon listing Amazon.com · 2026-08 · vendor
- IEMAI 3D PP 3D Printing Filament — store page IEMAI 3D · 2026-08 · vendor
- PP filament listing 3DJake International · 2026-08 · vendor
- Polypropylene — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
- Prusament PP Glass Fiber Technical Datasheet v1.0 Prusa Polymers · 2024-11 · tds
- Composite materials with metal or wood particles Prusa Knowledge Base · 2026-08 · doc
- Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
- TECAFINE PP natural — stock shape properties Ensinger · 2026-08 · tds
- 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
- Pro-fax and Moplen polypropylene — Chemical Resistance Guide (20, 60 and 100 °C) LyondellBasell · 2026-08 · tds
- US 5,278,282 Polymer recycling by selective dissolution — xylene dissolution temperatures Nauman & Lynch, Rensselaer Polytechnic Institute · 1994-01 · paper