3D Printing Info

Filament comparison

e-TPU vs PVA

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

Foaming / expanded TPU (TPU Aero / TPU Air) guidePVA (soluble support) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore e-TPU comparisonsMore PVA comparisons
e-TPU vs PVA — documented properties and sources
PropertyFoaming / expanded TPU (TPU Aero / TPU Air)FLEXPVA (soluble support)SUPPORT
Market snapshot
Listing priceUSD/kg; dated snapshots$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings$65.98/kg median; $42.00–$96.00/kg across 5 dated product listings
Identity & Market
Base polymer / chemistryFoaming thermoplastic polyurethane — a blowing agent expands the extrudate so the printed Shore hardness can be tuned by flow rate[1]Polyvinyl alcohol — a water-soluble support polymer[2][3]
Densityg/cm³1.15 filament (Siraya Tech Flex TPU Air) and 1.05 (Roamr TPU Air HR), ISO 1183; the printed part falls to 0.51–0.93 depending on nozzle temperature (ISO 845)[4][5]0.6–0.9 (3DXTech AquaTek, ISO 1183) and 1.13 (Polymaker PolyDissolve S1)[2][3]
Typical priceUSD/kg1 kg-equivalent spools span 42–85; the middle of the market is about 52[6][7][8][9][10][11]1 kg-equivalent spools span 42–96; the middle of the market is about 66[12][13][14][15]
Price range across brandsUSD/kg42–85 across brands; QIDI TPU-Aero 42, Siraya Tech Flex TPU Air 45, Phaetus aeFlex TPU-Aero 49 direct and 40 at West3D, Roamr TPU Air HR 80A 55 at 800 g, Recreus Filaflex Foamy 73 at 750 g, colorFabb varioShore 85 at 700 g[6][7][8][9][10][11][16]42–96 across brands; IEMAI 3D E-WATER 42, YXPOLYER 55, Reli3D 66 at 500 g, Polymaker PolyDissolve S1 67 at 750 g, 3DXTech AquaTek 96 at 750 g in 1.75 mm[12][13][14][17][15]
Market availability1–5Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[1][6][7][8][10][11]Stocked by most mainstream brands[12][13][14][17][15]
Spool sizes & diameters1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[1][6][8][9][11]1.75 and 2.85 mm; 0.5 and 0.75 kg spools[12][13]
Typical applicationsCushioning, midsoles, insoles and soft-touch parts where the softness needs to vary within one print; Siraya Tech's Roamr line is aimed specifically at printed footwear[1][9]Dissolvable support for PLA, TPU, PVB and PETG — Polymaker names those four for PolyDissolve S1[3]
Diameter tolerance± mm0.03 (Siraya Tech and Roamr, 1.75 mm)[4][5]Not documented
Printing Parameters
Nozzle temperature°C230–270 (QIDI and Siraya Tech), 220–260 (Roamr); foaming activates near 230 °C and is strongest at the top of the range[1][4][5][10]215–225 (Polymaker PolyDissolve S1)[3]
Bed temperature°C30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[4][5][10]25–60 (Polymaker PolyDissolve S1)[3]
Enclosure / chamber requirement1–5Open frame is fine — Roamr states no enclosure is required[1][5]Open frame is fine[3]
Part cooling fan100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[4][5]Part cooling fan required (Simplify3D)[18]
Bed surface & adhesion aidPEI sheet or painter's tape; Polymaker warns TPU can over-stick and advises a glue stick as a release agent, and Siraya Tech recommends PVP glue or Magigoo as a release agent on PEI[19][20][4]PEI sheet or painter's tape[18]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sUp to 12 (Siraya Tech, Flex TPU Air)[8]4–12 at Polymaker's 50–150 mm/s on a 0.4 mm nozzle at 0.2 mm layer[3]
Bed-adhesion difficulty1–5Not documentedSticks to most surfaces[18]
Stringing / oozing tendency1–5Severe — the material expands inside the hot end, so it oozes on travel moves; QIDI states retraction tuning cannot fix it and Siraya Tech advises setting retraction distance and speed to zero[4][10]Moderate — retraction tuning needed[18]
Overall printing difficulty1–5Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[1]Intermediate — dry filament and a tuned profile; PVA is unusable once it has taken up moisture[21][3]
Extruder requirementDirect drive; the base material is a 92A TPU[1][22]A second extruder or a tool changer; PVA is a support material, not a model material[3]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[23][5]Brass fine indefinitely[3]
Abrasiveness1–5Non-abrasive[23]Non-abrasive[3]
Nozzle clog risk1–5Not documentedVery high — frequent jams without careful setup; wet PVA foams and carbonises in the nozzle[21]
Heat-creep / jam sensitivity1–5Not documentedHigh — all-metal hotend and strong cooling needed; Simplify3D warns PVA clogs if the nozzle is left hot while not extruding[18]
Hotend requirementNo special hot-end required, but a direct-drive extruder is (Simplify3D)[19]No special hot-end required, but the nozzle must not be parked hot[18]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Moderate[21]Very high (>2 %) — Polymaker measures 10.21 % equilibrium water absorption, by far the highest in the dataset[3]
Equilibrium moisture content at ~50 % RH%1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[10]10.21 equilibrium water absorption (Polymaker PolyDissolve S1)[3]
Drying temperature & time70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[4][5][10]Not documented
Symptoms when wetBubbling and popping at the nozzle, stringing and a rough surface; Siraya Tech adds that moisture wrecks the foaming itself, not only the surface[21][4]Bubbling and popping at the nozzle, stringing and a rough surface; with PVA this progresses to clogging[21]
Effect of moisture on strengthPolymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[21]Polymaker groups PVA with nylon as the most moisture-prone class and says it often has to stay in a dryer while printing; there is no published dry-versus-conditioned strength comparison because PVA is not a structural material[21]
Storage requirementSealed with desiccant; often kept in a dryer during the print[21]Sealed with desiccant at all times; PVA takes up water faster than any other filament here[21][3]
Mechanical Properties
Tensile strength (XY)MPaFalls with foaming: colorFabb 24 unfoamed and 12 foamed (ISO 527-1A); Siraya Tech 10.3 at break printed at 240 °C down to 3.8 at 270 °C; QIDI 6.81 at break (ISO 527, XY)[1][4][10]Not documented
Young's modulusMPa50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[1]Not documented
Elongation at break%465 unfoamed and 450 foamed (colorFabb, ISO 527-1A); Siraya Tech 629 at 240 °C down to 475 at 270 °C; Roamr 760 down to 540; QIDI 576 (ISO 527, XY)[1][4][5][10]Not documented
Flexural modulusMPa50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[1]Not documented
Brittleness1–5Very ductile — bends far before failing[1]Not documented
Hardness (scale-specific)Shore A / Shore D / RockwellTunable by nozzle temperature: colorFabb 92 Shore A unfoamed; Siraya Tech 78 A printed at 240 °C falling to 63 A at 270 °C, Roamr TPU Air HR 80A 80 A down to 66 A and HR 85A 83 A down to 70 A (ISO 7619)[1][4][5][24]Not documented
Creep resistance / sustained load1–5Poor — no foamed-grade creep test; a printed 95A TPU bar crept from 74.5 to 82.7 mm over 5 days at 1.25 kg[25]Poor — deforms under load at room temperature; PVA is not used structurally[2]
Fatigue / repeated-flex resistance1–5Excellent — living hinges viable[20]Poor — fails after a few cycles[2]
Elasticity / flexibility1–5Rubbery / highly elastic[1]Not documented
Wear resistance & frictionNot documented3DXTech marks tensile strength, modulus and elongation as not applicable for its PVA support grade — it is not characterised as a structural material[2]
Thermal Properties
Glass transition (Tg)°CNot documented60 (3DXTech AquaTek, DSC)[2]
Melting point / Vicat°CVicat softening drops as the foam expands: 83 printed at 240 °C to 53 at 270 °C (Siraya Tech, ISO 306); QIDI 70.4[4][10]Not documented
Continuous service temperature°CNot documentedBounded by a glass transition of 60 °C[2]
Annealing responseFoaming activates near 230 °C and expands the extrudate about 1.6×; colorFabb advises dropping flow to 60–70 % to realise the weight saving, and Siraya Tech publishes a flow schedule from 85–90 % at 230 °C down to 50–55 % at 270 °C[1][4]Not documented
Flammability / UL 94Not documentedFlammable; no UL 94 rating published[2]
Environment & Chemical
UV resistance1–5Good — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[20]Degrades within weeks outdoors, and dissolves in rain long before UV matters[3]
Chemical resistanceWithstands industrial solvents and UV exposure (Polymaker)[20]Dissolves in water; unusable in any wet or humid service environment[3][18]
Water / humidity resistance in service1–5Not documentedDissolves or disintegrates — by design[3][2]
Food contactNot food safe without specific certification (Polymaker)[20]Not offered as a food-contact material[2]
Biodegradability / compostabilityNot biodegradable[20]PVA is water-soluble and biodegrades in wastewater treatment, but Simplify3D notes disposal should follow local guidance[18]
RecyclabilityNot accepted in household plastic collection[20]Dissolved PVA goes to drain rather than to recycling[18]
Electrical & ESD propertiesNot documentedSurface resistance above 10^13 ohm/sq (ASTM D257, 3DXTech AquaTek PVA)[2]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[26]Low hazard — minimal VOC and particle emission; none of these materials was in the chamber study[26]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[26]Open a window / occasional ventilation[26]
Post-Processing
Sanding & machiningDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[20]Not sanded — it is dissolved away rather than finished[18]
Gluing & solvent weldingCyanoacrylate bonds TPU; no common solvent welds it[20]Not applicable — PVA is a sacrificial support[18]
Vapour / chemical smoothingNo practical vapour smoothing[20]Water is the solvent; no vapour smoothing is used[3]
Support material pairingPolymaker warns TPU supports are often very difficult to remove[20]This is the support material; Polymaker pairs PolyDissolve S1 with PLA, TPU, PVB and PETG[3]
Dimensional accuracy & detailFoamed surfaces are matte and textured; holding a consistent hardness means holding the nozzle temperature steady, and the printed density moves by nearly a factor of two across the 230–270 °C window[1][4]Not documented
Solvents & Solubility
Soluble inDMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[27]Water — tap water works cold, warm moving water is faster; 6–12 h typical, changing the water every few hours.[28][29]
Softened or crazed byToluene and benzene swell it up to +50 % by weight at 23 °C; the foamed wall soaks up esters and alcohols faster still.[27]Nothing else: polyvinyl alcohol resists organic solvents, so an IPA or acetone rinse leaves the support intact.[30]
Solvent welding & smoothing agentNone practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[27]None — water dissolves PVA rather than welding it, and no solvent gives it a smoothed surface.[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. varioShore TPU Technical Data Sheet colorFabb · 2026-08 · tds
  2. AquaTek PVA Water Soluble Support Technical Data Sheet v1.0 3DXTech · 2026-08 · tds
  3. PolyDissolve S1 Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  4. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  5. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · tds
  6. Recreus product catalogue Recreus · 2026-08 · vendor
  7. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  8. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  9. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  10. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  11. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  12. 3DXTech product catalogue 3DXTech · 2026-08 · vendor
  13. Polymaker product catalogue Polymaker · 2026-08 · vendor
  14. YXPOLYER PVA 1 kg — product page YXPOLYER · 2026-08 · vendor
  15. IEMAI 3D E-WATER water-soluble support filament — store page IEMAI 3D · 2026-08 · vendor
  16. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  17. Reli3D PVA Filament 1.75 mm 500 g Natural — Amazon listing Amazon.com · 2026-08 · vendor
  18. PVA — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  19. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  20. TPU — material basics Polymaker Wiki · 2026-08 · doc
  21. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  22. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  23. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  24. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  25. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  26. 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
  27. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  28. PolyDissolve S1 — Polymaker Wiki Polymaker · 2026-08 · doc
  29. 3DXTech AquaTek PVA product page 3DXTech · 2026-08 · vendor
  30. Polyvinyl alcohol — KURARAY POVAL application guide Kuraray · 2026-08 · tds