CPVC vs HDPE
Polymer · grade comparison
CPVC and HDPE are both polymer grades, both corrosion resistant plastic. CPVC is the stronger of the two: yield strength 52 MPa (7.54 ksi) against 26 MPa (3.77 ksi) for HDPE, about 100% more; tensile strength follows at 55 MPa (7.98 ksi) vs 28 MPa (4.06 ksi). In exchange, HDPE is the more ductile: elongation 600% versus 25% for CPVC, and CPVC is harder (82 Shore D vs 65 Shore D). HDPE is lighter (0.96 g/cm³ vs 1.54 g/cm³ for CPVC) and CPVC is stiffer (3 GPa vs 1.1 GPa). On the shop floor, HDPE welds better (excellent vs good) and HDPE sits in a lower cost tier (budget, $) than CPVC (standard, $$).
CPVCChoose it when strength drives the design, or when the part sees heat.
HDPEChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
CPVC vs HDPE: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Hardness, Shore D
Hardness, Rockwell R
Bulk Modulus
Fracture Toughness (K_IC)
Same in both: Izod Impact, Notched 90 J/m1.7 ft·lbf/in
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Refractive Index
Melting Temperature (Tm)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Limiting Oxygen Index
Max Service Temperature (short-term)
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
Surface Resistivity
Same in both: Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Melt Flow Rate
Same in both: Machinability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Same in both: Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | CPVC | HDPE |
|---|---|---|
| Default condition | Unfilled | FDA Compliant |
| Relative cost | $$ Standard | $ Budget |
| Min. machined wall | 0.5 mm | 0.5 mm |
| Best machined surface | Ra 0.8 µm | Ra 0.8 µm |
Both are offered for CNC machining, Sheet metal and Injection molding. Both take the same 6 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Painting, Soft Touch Coating, Spray Painting, UV Coating.
CPVC vs HDPE — frequently asked
Is CPVC stronger than HDPE?
Yes. CPVC has a typical yield strength of 52 MPa (7.54 ksi) against 26 MPa (3.77 ksi) for HDPE — about 100% more. Tensile strength is 55 MPa (7.98 ksi) vs 28 MPa (4.06 ksi).
Which is cheaper, CPVC or HDPE?
HDPE is the lower-cost material: it sits in the budget tier ($) while CPVC is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which welds better, CPVC or HDPE?
HDPE. Its weldability rates excellent (95/100) against good (65/100) for CPVC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in CPVC and HDPE side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.