PU Cast · hardness band
PU Cast Shore A 70
Properties of the Shore A 70 condition, compared with the other PU Cast grades.
General-purpose workhorse hardness for rollers, drive wheels, wiper blades and dynamic seals combining resilience with good abrasion resistance.
What is PU Cast Shore A 70?
PU Cast Shore A 70 is PU Cast heat treated to Shore A 70 — general-purpose workhorse hardness for rollers, drive wheels, wiper blades and dynamic seals combining resilience with good abrasion resistance. PU Cast Shore A 70 has a tensile strength of 30 MPa (4.35 ksi), weaker than 62% of polymer grades. Elongation at break is 600% and the elastic modulus is 0.01 GPa (0.001 Msi). PU Cast Shore A 70 has a density of 1.1 g/cm³ (0.0397 lb/in³), lighter than 65% of polymer grades. Its glass-transition temperature is -50°C (-58 °F). Shore A 40 is the default condition FabDigit quotes; Shore A 70 is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 600%, better than 93% of polymer grades
Limitations
- Hard to polish — 25/100, worse than 90% of polymer grades
- Low stiffness — 0.01 GPa (0.001 Msi), worse than 85% of polymer grades
- Difficult to machine — 38/100, worse than 82% of polymer grades
PU Cast Shore A 70 properties
Typical room-temperature values for PU Cast Shore A 70 — 8 properties are specific to this condition; the rest are grade-level values shared by every PU Cast grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical5
PU Cast Shore A 70 has a density of 1.1 g/cm³ (0.0397 lb/in³), lighter than 65% of polymer grades. Its glass-transition temperature is -50°C (-58 °F).
Mechanical9
PU Cast Shore A 70 has a tensile strength of 30 MPa (4.35 ksi), weaker than 62% of polymer grades. Elongation at break is 600% and the elastic modulus is 0.01 GPa (0.001 Msi).
Thermal8
PU Cast Shore A 70 is rated for continuous service to 90°C (194 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 56% of polymer grades. Thermal expansion is 200 µm/m·K (111.1 µin/in·°F).
Electrical5
PU Cast Shore A 70 is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), worse than 55% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PU Cast Shore A 70 takes about 102 MJ of energy and emits 5 kg of CO₂ — less than 55% of polymer grades. Typical recycled content is 0%.
Manufacturability5
PU Cast Shore A 70's machinability is fair (38/100, worse than 82% of polymer grades).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other PU Cast grades and fills
PU Cast is also supplied in 13 other conditions. The full side-by-side table is on the PU Cast overview.
- Shore A 40DefaultPick for soft pads, vibration isolators, gaskets, flexible tooling and skin-friendly grip parts where high elongation matters more than load capacity.12 MPa tensile
- Shore D 75Pick for rigid urethane tooling boards, jigs, master models and hard structural castings replacing filled epoxy.60 MPa tensile
- Shore D 60Pick for structural cast parts, tooling blocks, gears, dies and impact-resistant machine components where a rigid but non-brittle thermoset is wanted.50 MPa tensile
- Shore A 95Pick where near-plastic stiffness plus impact toughness is required: scraper blades, cyclone liners, sheet-metal forming punches.45 MPa tensile
- Shore A 90Pick for heavy-duty wheels, mill liners, press pads and abrasion-critical wear parts at high unit loads.42 MPa tensile
- Shore A 80Pick for load-bearing wheels, chute liners, forming pads and stripper plates where higher stiffness is needed but some flex remains.36 MPa tensile
- Shore A 70General-purpose workhorse hardness for rollers, drive wheels, wiper blades and dynamic seals combining resilience with good abrasion resistance.30 MPa tensile
- Shore A 60Pick for seals, bumpers, printing/feed rollers and low-load wheels needing a compliant but tougher rubber.22 MPa tensile
Working with PU Cast Shore A 70
Is PU Cast easy to machine?
Machinable by turning/grinding with very sharp, high-rake carbide tools, high surface speed and low feed; soft grades (<70A) need chilling, mandrel support or wet grinding to stop smearing and deflection, Shore D grades cut like a tough plastic.
Can PU Cast be welded?
Thermoset — cannot be melt-welded; join by two-part urethane or polyurethane-compatible adhesive, or by casting fresh material against a cleaned, primed cured surface for a chemical bond.
Can PU Cast be formed, bent or molded?
Open or closed-mould gravity casting of a hot (70–90 °C) degassed prepolymer/curative mix into 100–110 °C moulds, demould in 0.5–2 h and post-cure 16 h at 100 °C; centrifugal casting for rollers and metal-insert bonding with primed, grit-blasted cores.
What surface finishes work on PU Cast?
Surface quality replicates the mould, so use polished or lacquered tools and mould release; PU can be ground, sanded and flash-trimmed, and painted or printed only with flexible urethane-based coatings after solvent wipe or plasma/primer treatment.
PU Cast chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| diisocyanate (MDI/TDI/NDI/H12MDI)prepolymer hard segment; aromatic MDI/TDI standard, aliphatic for light stability | 15 – 35 | 25 |
| chain extender / curative (1,4-BDO, HQEEsets hardness and hot strength; MOCA restricted in many markets | 3 – 12 | 7 |
| catalyst, antioxidant, hydrolysis stabil | 0.1 – 3 | 1 |
| filler (talc/silica/ATH/FR) — filled graused in rigid tooling and FR formulations | 0 – 30 | 0 |
| polyol (polyether PTMEG/PPG or polyestersoft segment; determines hydrolysis vs abrasion balance | ≥ 50 (balance) | — |
PU Cast Shore A 70 — frequently asked
What is PU Cast Shore A 70 used for?
PU Cast Shore A 70 is typically used for drive and conveyor rollers, forklift and caster wheels, wear pads and scraper blades, suspension bushings and spring elements, vacuum-cast prototype housings and die-cushion and press pads. In short: vacuum-cast urethane prototype.
What is the tensile strength of PU Cast Shore A 70?
PU Cast Shore A 70 has a typical tensile strength of 30 MPa (4.35 ksi) — weaker than 62% of polymer grades. Strength varies by condition: see the 14 listed tempers.
Is PU Cast Shore A 70 easy to machine?
Not especially — machinability is rated fair (38/100, worse than 82% of polymer grades). Machinable by turning/grinding with very sharp, high-rake carbide tools, high surface speed and low feed; soft grades (<70A) need chilling, mandrel support or wet grinding to stop smearing and deflection, Shore D grades cut like a tough plastic.
Can PU Cast Shore A 70 be welded?
Thermoset — cannot be melt-welded; join by two-part urethane or polyurethane-compatible adhesive, or by casting fresh material against a cleaned, primed cured surface for a chemical bond.
What surface finishes work on PU Cast Shore A 70?
Surface quality replicates the mould, so use polished or lacquered tools and mould release; PU can be ground, sanded and flash-trimmed, and painted or printed only with flexible urethane-based coatings after solvent wipe or plasma/primer treatment.
Can PU Cast Shore A 70 be formed, bent or molded?
Open or closed-mould gravity casting of a hot (70–90 °C) degassed prepolymer/curative mix into 100–110 °C moulds, demould in 0.5–2 h and post-cure 16 h at 100 °C; centrifugal casting for rollers and metal-insert bonding with primed, grit-blasted cores.
What is the maximum service temperature of PU Cast Shore A 70?
PU Cast Shore A 70 is rated for continuous use to about 90°C (194 °F), and briefly to 120°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PU Cast Shore A 70?
Yes — PU Cast Shore A 70 is available for CNC machining, sheet metal and injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Adiprene / Vibrathane cast urethane prepolymer datasheets — LANXESS (formerly Chemtura) (2022)
- Cast polyurethane elastomer property charts (rollers, wheels, wear parts) — Gallagher Corporation (2023)
- VytaFlex / Task urethane casting resin technical bulletins — Smooth-On (2023)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- ASTM D412 / D624 / D2240 / D395 rubber test methods — ASTM (2021)
- GB/T 531.1 / GB/T 528 (2009)
- CES/Granta EduPack polymer & eco property records (PU elastomer) — Ansys Granta (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.