3D Printing Info

Filament comparison

PLA Metal vs TPU soft

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

Metal-filled PLA guideSoft TPU (below 85A) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore PLA Metal comparisonsMore TPU soft comparisons
PLA Metal vs TPU soft — documented properties and sources
PropertyMetal-filled PLAPLASoft TPU (below 85A)FLEX
Market snapshot
Listing priceUSD/kg; dated snapshots$79.69/kg median; $24.99–$94.99/kg across 6 dated product listings$114.04/kg median; $109.80–$122.27/kg across 4 dated product listings
Identity & Market
Base polymer / chemistryPLA loaded with real metal powder — bronze, copper, steel or iron. Bambu Lab's PLA Sparkle TDS states it has "metal particles included in its composition"; its separately sold PLA Metal does not, and the store page says so explicitly[1][2][3][4][5][6]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[7]
Densityg/cm³1.26 (Bambu Lab Sparkle, a trace-metal glitter grade) up to 3.9–4.0 for colorFabb bronze and copper and 2.3 for Proto-pasta steel, ISO 1183[4][1][2][8]1.07 (Fiberlogy FiberFlex 30D, ISO 1183)[7]
Typical priceUSD/kg1 kg spools cluster near 78[9][10][3]1 kg-equivalent spools cluster near 115[11][12][13]
Price range across brandsUSD/kg25–95 across brands; Bambu Lab Sparkle 25, Proto-pasta iron 65, colorFabb bronze and copper 84, Proto-pasta steel 95[9][3][10][8]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[11][13][12]
Market availability1–5Available from several mainstream brands[10][3][8][9]Niche, a handful of specialist brands[7][14][11]
Spool sizes & diameters1.75 and 2.85 mm; 0.1, 0.5, 0.75, 1 and 1.5 kg spools[15][10]1.75, 2.85 and 3 mm; 0.5, 0.85, 1, 2 and 3 kg spools[7][11][16][12]
Typical applicationsDecorative castings and props that are polished or left to patinate; the density gives prints a metallic heft[1][3]Highly compliant seals, soft grips and prosthetic liners[7]
Printing Parameters
Nozzle temperature°C195–220 (colorFabb bronze and copper); 192 (Proto-pasta iron); 198 (Proto-pasta steel); 190–230 (Bambu Lab Sparkle)[1][3][8][4]Not documented
Bed temperature°C50–60 (colorFabb, Proto-pasta); 35–45 (Bambu Lab)[1][3][4]50–70 (Fiberlogy FiberFlex 30D)[7]
Enclosure / chamber requirement1–5Open frame is fine[1]Open frame is fine[7]
Part cooling fanOn (colorFabb copper); 0–100 % (colorFabb bronze)[1][2]Not documented
Bed surface & adhesion aidGlass plate with glue stick or tape (colorFabb)[1][2]PEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent[17][18]
Maximum volumetric flow (mm³/s; see test conditions)mm³/s1.6–2.4 at Proto-pasta's 20–30 mm/s for iron and steel, 3.2–8 at colorFabb's 40–100 mm/s, on a 0.4 mm nozzle at 0.2 mm layer[3][8][1][19]Not documented
Overall printing difficulty1–5Intermediate — dry filament and a tuned profile; brittle in filament form and slow to print[3][8]Expert / industrial hardware only — below 85 Shore A the filament buckles in almost any feed path that is not a short, constrained direct drive[16][18]
Extruder requirementProto-pasta advises an extrusion width 0.05 mm larger than the nozzle and warns that feeding is inconsistent below 0.4 mm and on Bowden machines[3][8]Direct drive only, with a constrained filament path; Bowden is not viable at this hardness[16][14]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass acceptable; hardened steel for volume work[3][8]Brass fine indefinitely[20]
Abrasiveness1–5Moderately abrasive — metal fill[3][8]Non-abrasive[20]
Nozzle clog risk1–5Moderate — needs dry filament and a clean nozzle[8]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[17][18][21]
Heat-creep / jam sensitivity1–5Not documentedVery high — softens in the cold zone readily[18]
Hotend requirementProto-pasta recommends a wear-resistant or larger nozzle for longer service intervals[3][8]No special hot-end required, but a direct-drive extruder is (Simplify3D)[17]
Other hardware wearProto-pasta warns of more frequent nozzle replacement and first-layer adjustment[3][8]Not documented
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate — the PLA matrix takes up 0.40–0.51 % saturated; the metal powder itself does not absorb water[22][23]Moderate[21]
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface[21]
Effect of moisture on strengthPolymaker rates PLA low-sensitivity and publishes no dry-versus-conditioned figures for this grade; absorbed water flashes to steam and shows as bubbling and poor layer adhesion[21]Polymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[21]
Storage requirementNot documentedSealed with desiccant; often kept in a dryer during the print[21]
Mechanical Properties
Tensile strength (XY)MPa25 (colorFabb copper) and 30 (colorFabb bronze), ISO 527-1A; Bambu Lab Sparkle 39 ± 3 printed XY, ISO 527[1][2][4]Not documented
Young's modulusMPa1940 ± 230 printed XY, ISO 527 (Bambu Lab Sparkle)[4]Not documented
Elongation at break%3–10 (colorFabb copper) and 5–10 (colorFabb bronze), ISO 527-1A; 11.7 for Bambu Lab Sparkle printed XY[1][2][4]870 at break (Fiberlogy FiberFlex 30D, ISO 527) — the highest elongation in the dataset[7]
Flexural strengthMPa75 ± 4 printed XY, ISO 178 (Bambu Lab Sparkle)[4]Not documented
Flexural modulusMPa2350 ± 140 printed XY, ISO 178 (Bambu Lab Sparkle)[4]Not documented
Charpy impact, notchedkJ/m²23.2 ± 2.4 printed XY, ISO 179, notched (Bambu Lab Sparkle)[4]Not documented
Other impact dataIzod notched 4.5 kJ/m² for colorFabb bronzeFill and 10 kJ/m² for copperFill (ISO 180); Charpy unnotched 66.5 kJ/m² for Bambu Lab Sparkle[1][2][4]Not documented
Layer adhesion / Z tensileMPa32 ± 2 printed Z, ISO 527 (Bambu Lab Sparkle)[4]Not documented
Brittleness1–5Brittle — Proto-pasta describes both its iron and steel grades as more brittle than standard PLA in filament form[3][8]Very ductile — bends far before failing[7]
Hardness (scale-specific)Shore A / Shore D / RockwellNot documented81 Shore A and 30 Shore D (Fiberlogy FiberFlex 30D, ISO 7619)[7]
Creep resistance / sustained load1–5Poor — no metal-filled creep test; plain printed PLA sagged from 12 to 16.2–21.8 mm over 5 days at 1.25 kg[24][25][26]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[27]
Fatigue / repeated-flex resistance1–5Poor — no grade-specific S-N curve; plain printed PLA ran 38 000–49 000 cycles at 30 % of tensile strength and Proto-pasta describes its iron and steel grades as more brittle than standard PLA[28][3][8]Excellent — living hinges viable[18]
Elasticity / flexibility1–5Rigid[4]Rubbery / highly elastic[7]
Z strength as % of XY%82 by tensile (printed, Bambu Lab Sparkle)[4]Not documented
Wear resistance & frictionNot documentedTear strength 95 kN/m (Fiberlogy FiberFlex 30D, ISO 34-1)[7]
Thermal Properties
HDT at 0.45 MPa°C55 (ISO 75, 0.45 MPa, Bambu Lab Sparkle)[4]Not documented
HDT at 1.8 MPa°C53 (ISO 75, 1.8 MPa, Bambu Lab Sparkle)[4]Not documented
Glass transition (Tg)°C56 (DSC, Bambu Lab Sparkle)[4]Not documented
Melting point / Vicat°C156 peak melt (DSC, Bambu Lab Sparkle)[4]170 melting (Fiberlogy FiberFlex 30D, DSC)[7]
Environment & Chemical
UV resistance1–5Degrades within weeks outdoors[29]Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[18]
Outdoor durabilityProto-pasta markets its iron grade as rustable — the iron oxidises deliberately when exposed to moisture[3]Not documented
Chemical resistanceNot documentedWithstands industrial solvents and UV exposure (Polymaker)[18]
Food contactNot documentedNot food safe without specific certification (Polymaker)[18]
Biodegradability / compostabilityNot documentedNot biodegradable[18]
RecyclabilityNot documentedNot accepted in household plastic collection[18]
Electrical & ESD propertiesProto-pasta magnetic iron PLA is ferromagnetic and responds to magnets[3]Not documented
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission[30]Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[30]
Ventilation / filtration requirement1–5None needed in a normal room[30]Open a window / occasional ventilation[30]
Post-Processing
Sanding & machiningPolishing is the intended finish — colorFabb and Proto-pasta both sell these grades to be sanded and buffed to a metallic shine[1][2][8]Difficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[18]
Gluing & solvent weldingNot documentedCyanoacrylate bonds TPU; no common solvent welds it[18]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[18]
Support material pairingNot documentedPolymaker warns TPU supports are often very difficult to remove[18]
Dimensional accuracy & detailcolorFabb notes the metal fill increases die swell, so flow needs raising above plain PLA[2]Not documented
Solvents & Solubility
Soluble inChloroform dissolves the PLA matrix (10 % w/v, 2–4 h at 23 °C) and leaves the filler as loose sludge; laboratory reagent.[31]DMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[32]
Softened or crazed byAcetone, ethyl acetate and toluene plasticise the matrix but dissolve <1 % even at 65 °C; acetone submersion crazes parts.[31][33]Toluene and benzene swell it up to +50 % by weight at 23 °C; esters swell it severely; ethanol and IPA soften it.[32]
Solvent welding & smoothing agentChloroform vapour attacks only the resin fraction, so the filler is left standing proud; no workshop-safe agent exists.[34][33]None practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[32]

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. bronzeFill technical data sheet colorFabb · 2026-08 · tds
  2. copperFill technical data sheet colorFabb · 2026-08 · tds
  3. Magnetic Iron PLA — product page and technical data Proto-pasta · 2026-08 · tds
  4. Bambu Filament Technical Data Sheet — PLA Sparkle Bambu Lab · 2026-08 · tds
  5. PLA Metal — product page Bambu Lab US Store · 2026-08 · vendor
  6. Bambu Filament Technical Data Sheet V3.0 — PLA Metal Bambu Lab · 2026-08 · tds
  7. FiberFlex 30D Technical Data Sheet Fiberlogy · 2026-08 · tds
  8. Stainless Steel PLA — product page and technical data Proto-pasta · 2026-08 · tds
  9. PLA Sparkle — product page Bambu Lab US Store · 2026-08 · vendor
  10. bronzeFill — product page colorFabb US · 2026-08 · vendor
  11. Recreus product catalogue Recreus · 2026-08 · vendor
  12. Chinchilla product page — print guidelines, spool sizes and price NinjaTek · 2026-08 · vendor
  13. NinjaFlex Edge product page — durometer, print guidelines and price NinjaTek · 2026-08 · vendor
  14. Filaflex 82A product page (Shore hardness and elongation) Recreus · 2026-08 · vendor
  15. Proto-pasta product catalogue Proto-pasta · 2026-08 · vendor
  16. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  17. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  18. TPU — material basics Polymaker Wiki · 2026-08 · doc
  19. Max volumetric speed Prusa Knowledge Base · 2026-08 · doc
  20. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  21. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  22. Bambu Filament Technical Data Sheet V3.0 — PLA Basic Bambu Lab · 2026-08 · tds
  23. PolyLite PLA Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  24. BambuLab PLA Basic vs PLA Tough vs PLA-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  25. Polymaker PLA Pro vs PLA-CF — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  26. Carbon Fiber PLA vs META-PLA vs PLA+ vs PLA by Sunlu — results spreadsheet My Tech Fun (Igor Gaspar) · 2026-08 · test
  27. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  28. Mechanical Properties of Additively Manufactured Polymeric Materials — PLA and PETG — For Biomechanical Applications Polymers 16(13):1868 · 2024-06 · paper
  29. PLA — material guide Prusa Knowledge Base · 2026-08 · doc
  30. 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
  31. Solubility Study of Ingeo Biopolymer Grades in Common Organic Solvents (NWPD003) NatureWorks · 2019-10 · tds
  32. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  33. Improve your 3D prints with chemical smoothing Prusa Research · 2026-08 · doc
  34. 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