3D Printing Info

Filament comparison

BVOH vs e-TPU

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

BVOH (soluble support) guideFoaming / expanded TPU (TPU Aero / TPU Air) guide

2 selected · all documented properties

Open these two in the interactive comparisonMore BVOH comparisonsMore e-TPU comparisons
BVOH vs e-TPU — documented properties and sources
PropertyBVOH (soluble support)SUPPORTFoaming / expanded TPU (TPU Aero / TPU Air)FLEX
Market snapshot
Listing priceUSD/kg; dated snapshots$165.72/kg median; $165.72–$165.72/kg across 1 dated product listings$52.05/kg median; $41.99–$85.29/kg across 6 dated product listings
Identity & Market
Base polymer / chemistryButenediol vinyl alcohol copolymer — a vinyl alcohol copolymer that dissolves faster and in cooler water than straight PVA[1]Foaming thermoplastic polyurethane — a blowing agent expands the extrudate so the printed Shore hardness can be tuned by flow rate[2]
Densityg/cm³Not documented1.15 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)[3][4]
Typical priceUSD/kg1 kg-equivalent spools cluster near 166[1]1 kg-equivalent spools span 42–85; the middle of the market is about 52[5][6][7][8][9][10]
Price range across brandsUSD/kg166 at Fiberlogy's 500 g pricing on 3DJake[1]42–85 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[5][6][7][8][9][10][11]
Market availability1–5Niche, a handful of specialist brands[1]Available from several mainstream brands — colorFabb, Recreus, QIDI, Phaetus, Siraya Tech and FusRock all sell an active-foaming TPU[2][5][6][7][9][10]
Spool sizes & diameters1.75 and 2.85 mm; 0.5 kg spools[1]1.75 mm; 0.7, 0.75, 0.8, 1 and 3 kg spools[2][5][7][8][10]
Typical applicationsDissolvable support where PVA dissolves too slowly, and for materials PVA bonds to poorly[1]Cushioning, 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[2][8]
Diameter tolerance± mmNot documented0.03 (Siraya Tech and Roamr, 1.75 mm)[3][4]
Printing Parameters
Nozzle temperature°CNot documented230–270 (QIDI and Siraya Tech), 220–260 (Roamr); foaming activates near 230 °C and is strongest at the top of the range[2][3][4][9]
Bed temperature°CNot documented30–45 (QIDI and Siraya Tech), 35–50 (Roamr) — a hot bed makes the foamed part over-stick[3][4][9]
Enclosure / chamber requirement1–5Open frame is fine[12]Open frame is fine — Roamr states no enclosure is required[2][4]
Part cooling fanNot documented100 % — cooling sets the foamed structure quickly (Siraya Tech and Roamr)[3][4]
Bed surface & adhesion aidNot documentedPEI 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[13][14][3]
Maximum volumetric flow (mm³/s; see test conditions)mm³/sNot documentedUp to 12 (Siraya Tech, Flex TPU Air)[7]
Stringing / oozing tendency1–5Not documentedSevere — 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[3][9]
Overall printing difficulty1–5Intermediate — dry filament and a tuned profile[15]Advanced — enclosure, hardware upgrades, tuning; both density and hardness follow nozzle temperature and flow[2]
Extruder requirementA second extruder or a tool changer[12]Direct drive; the base material is a 92A TPU[2][16]
Hardware Wear & Reliability
Nozzle hardness required1–4Brass fine indefinitely[12]Brass fine indefinitely — Roamr states plainly that no hardened nozzle is needed[17][4]
Abrasiveness1–5Non-abrasive[12]Non-abrasive[17]
Nozzle clog risk1–5Very high — frequent jams without careful setup[15]Not documented
Hotend requirementNot documentedNo special hot-end required, but a direct-drive extruder is (Simplify3D)[13]
Moisture Behaviour
Moisture absorption (hygroscopicity)1–5Very high (>2 %) — the vinyl alcohol backbone is what makes it soluble[15][12]Moderate[15]
Equilibrium moisture content at ~50 % RH%Not documented1.09 water absorption (QIDI TPU-Aero; the standard is not stated)[9]
Drying temperature & timeNot documented70–80 °C for 4–6 h; keep below 15 % RH while printing (Siraya Tech, Roamr and QIDI)[3][4][9]
Symptoms when wetNot documentedBubbling and popping at the nozzle, stringing and a rough surface; Siraya Tech adds that moisture wrecks the foaming itself, not only the surface[15][3]
Effect of moisture on strengthNot a structural material; no dry-versus-conditioned data is published[15]Polymaker groups TPU with the highly hygroscopic materials; no dry-versus-conditioned figures are published[15]
Storage requirementSealed with desiccant at all times[15]Sealed with desiccant; often kept in a dryer during the print[15]
Mechanical Properties
Tensile strength (XY)MPaNot documentedFalls 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)[2][3][9]
Young's modulusMPaNot documented50 unfoamed and 40 foamed (colorFabb, ISO 527-1A)[2]
Elongation at break%Not documented465 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)[2][3][4][9]
Flexural modulusMPaNot documented50 unfoamed and 40 foamed flexural modulus (colorFabb, ISO 178)[2]
Brittleness1–5Not documentedVery ductile — bends far before failing[2]
Hardness (scale-specific)Shore A / Shore D / RockwellNot documentedTunable 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)[2][3][4][18]
Creep resistance / sustained load1–5Not documentedPoor — 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[19]
Fatigue / repeated-flex resistance1–5Not documentedExcellent — living hinges viable[14]
Elasticity / flexibility1–5Not documentedRubbery / highly elastic[2]
Thermal Properties
Melting point / Vicat°CNot documentedVicat softening drops as the foam expands: 83 printed at 240 °C to 53 at 270 °C (Siraya Tech, ISO 306); QIDI 70.4[3][9]
Annealing responseNot documentedFoaming 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[2][3]
Environment & Chemical
UV resistance1–5Not documentedGood — years with some colour shift; Polymaker lists UV exposure among the conditions TPU withstands[14]
Chemical resistanceNot documentedWithstands industrial solvents and UV exposure (Polymaker)[14]
Water / humidity resistance in service1–5Dissolves or disintegrates — by design[1]Not documented
Food contactNot documentedNot food safe without specific certification (Polymaker)[14]
Biodegradability / compostabilityNot documentedNot biodegradable[14]
RecyclabilityNot documentedNot accepted in household plastic collection[14]
Health & Safety
Fume toxicity1–5Low hazard — minimal VOC and particle emission; none of these materials was in the chamber study[20]Low hazard — minimal VOC and particle emission; TPU was not among the nine filaments in the chamber study[20]
Ventilation / filtration requirement1–5Open a window / occasional ventilation[20]Open a window / occasional ventilation[20]
Post-Processing
Sanding & machiningNot documentedDifficult to sand or smooth; Polymaker limits post-processing to trimming or tumbling[14]
Gluing & solvent weldingNot documentedCyanoacrylate bonds TPU; no common solvent welds it[14]
Vapour / chemical smoothingNot documentedNo practical vapour smoothing[14]
Support material pairingThis is the support material[1]Polymaker warns TPU supports are often very difficult to remove[14]
Dimensional accuracy & detailNot documentedFoamed 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[2][3]
Solvents & Solubility
Soluble inWater: about 1 g of BVOH per 20 g of water, several hours; warmer water is faster but must not be too hot.[21][1]DMF, DMSO, NMP and THF dissolve TPU; acetone, MEK and cyclohexanone are partial solvents. All laboratory reagents.[22]
Softened or crazed byNothing else — a vinyl alcohol copolymer resists organic solvents, so IPA or acetone will not touch it.[23]Toluene and benzene swell it up to +50 % by weight at 23 °C; the foamed wall soaks up esters and alcohols faster still.[22]
Solvent welding & smoothing agentNone — water is a removal solvent, not a welding one.[21]None practical — the true solvents (DMF, THF, NMP) are laboratory reagents and leave the joint swollen and weak.[22]

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. Fiberlogy BVOH Natural — product page 3DJake International · 2026-08 · vendor
  2. varioShore TPU Technical Data Sheet colorFabb · 2026-08 · tds
  3. Siraya Tech Flex TPU Air Technical Data Sheet Siraya Tech · 2026-08 · tds
  4. Roamr TPU Air HR 80A Technical Data Sheet Siraya Tech · 2026-08 · tds
  5. Recreus product catalogue Recreus · 2026-08 · vendor
  6. varioShore TPU Natural — product page colorFabb US · 2026-08 · vendor
  7. Siraya Tech Flex TPU Air Black Filament — lightweight foaming flexible, product page Siraya Tech · 2026-08 · vendor
  8. Roamr TPU Air HR 80A Filament — product page Siraya Tech · 2026-08 · vendor
  9. TPU-Aero Lightweight TPU Filament — product page with specification tables QIDI Tech · 2026-08 · vendor
  10. aeFlex TPU-Aero — active foaming low weight TPU, product page Phaetus · 2026-08 · vendor
  11. Phaetus aeWorthy TPU-Aero — reseller listing West3D · 2026-08 · vendor
  12. PolyDissolve S1 Technical Data Sheet V5.4 Polymaker · 2024-11 · tds
  13. Flexible (TPE/TPU) — Ultimate 3D Printing Materials Guide Simplify3D · 2026-08 · doc
  14. TPU — material basics Polymaker Wiki · 2026-08 · doc
  15. Wet Filament — signs, causes and drying Polymaker Wiki · 2026-08 · doc
  16. NinjaFlex 85A Technical Specifications NinjaTek · 2026-08 · tds
  17. Extrudr Product Catalogue (DURAPRO PA12 data block) Extrudr · 2025-03 · tds
  18. Roamr TPU Air HR 85A Technical Data Sheet Siraya Tech · 2026-08 · tds
  19. BambuLab TPU 95A HF vs Qidi TPU 95A HF — results spreadsheet My Tech Fun (Igor Gaspar) · 2024-02 · test
  20. 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
  21. Water soluble (BVOH/PVA) — Knowledge Base Prusa Research · 2026-08 · doc
  22. Elastollan — Chemical properties: swelling and chemical resistance BASF · 2026-08 · tds
  23. Polyvinyl alcohol — KURARAY POVAL application guide Kuraray · 2026-08 · tds