Fiberglass/Phenolic Honeycomb (HRP) 4.0
Grade · default condition
also HRP
4.0 = hRP-3/16-4.0
Most common general-purpose HRP density — best balance of weight, shear stiffness and cost.
Values for the 4.0 condition
Other Fiberglass/Phenolic Honeycomb (HRP) grades and fills
Fiberglass/Phenolic Honeycomb (HRP) is listed in 5 conditions; see the grade overview at Fiberglass/Phenolic Honeycomb (HRP).
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
HRP-3/16-3.0 | Lightest HRP grade — non-structural or lightly loaded radome and fairing sandwich panels. | — | 2 | — | — |
4.0DefaultThis page HRP-3/16-4.0 | Most common general-purpose HRP density — best balance of weight, shear stiffness and cost. | — | 4 | — | — |
HRP-3/16-5.5 | Mid-density structural grade for floor panels and moderately loaded fairings. | — | 6 | — | — |
HRP-3/16-8.0 | High-density grade for highly loaded joints, hard points and rotor/engine structures. | — | 12 | — | — |
HRP-3/16-12.0 | Maximum-strength HRP for local reinforcement, ramps and heavily loaded insert areas. | — | 20 | — | — |
What is Fiberglass/Phenolic Honeycomb (HRP) 4.0?
Fiberglass/Phenolic Honeycomb (HRP) 4.0 is Fiberglass/Phenolic Honeycomb (HRP) in the 4.0 grade — most common general-purpose HRP density — best balance of weight, shear stiffness and cost. Fiberglass/Phenolic Honeycomb (HRP) 4.0 has a tensile strength of 4 MPa (0.537 ksi), weaker than 87% of composite grades. The elastic modulus is 0.28 GPa (0.04 Msi). Fiberglass/Phenolic Honeycomb (HRP) 4.0 has a density of 0.06 g/cm³ (0.0023 lb/in³), lighter than 92% of composite grades. Its glass-transition temperature is 180°C (356 °F).
Advantages
- Lightweight — 0.06 g/cm³ (0.0023 lb/in³), better than 92% of composite grades
- Low embodied carbon — 4.5 kg CO₂/kg, better than 79% of composite grades
Limitations
- Low stiffness — 0.28 GPa (0.04 Msi), worse than 88% of composite grades
- Poor heat conductor — 0.06 W/m·K (0.0318 BTU/hr·ft·°F), worse than 83% of composite grades
Fiberglass/Phenolic Honeycomb (HRP) 4.0 properties
Typical room-temperature values for Fiberglass/Phenolic Honeycomb (HRP) 4.0; 12 are specific to this condition. Other listed values are Fiberglass/Phenolic Honeycomb (HRP) reference data and may not represent this condition. Bars are the position among composite grades.
Physical2
Fiberglass/Phenolic Honeycomb (HRP) 4.0 has a density of 0.06 g/cm³ (0.0023 lb/in³), lighter than 92% of composite grades. Its glass-transition temperature is 180°C (356 °F).
Mechanical6
Fiberglass/Phenolic Honeycomb (HRP) 4.0 has a tensile strength of 4 MPa (0.537 ksi), weaker than 87% of composite grades. The elastic modulus is 0.28 GPa (0.04 Msi).
Thermal6
Fiberglass/Phenolic Honeycomb (HRP) 4.0 is rated for continuous service to 177°C (351 °F). It conducts heat at 0.06 W/m·K (0.0318 BTU/hr·ft·°F), worse than 83% of composite grades.
Electrical2
Fiberglass/Phenolic Honeycomb (HRP) 4.0 has an electrical resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), better than 54% of composite grades. UV resistance is fair.
Sustainability3
Producing a kilogram of Fiberglass/Phenolic Honeycomb (HRP) 4.0 takes about 60 MJ of energy and emits 4.5 kg of CO₂ — less than 97% of composite grades. Typical recycled content is 0%.
Manufacturability1
Fiberglass/Phenolic Honeycomb (HRP) 4.0's machinability is fair (40/100, better than 57% of composite grades).
Common Calculations2
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Fiberglass/Phenolic Honeycomb (HRP) 4.0
Is Fiberglass/Phenolic Honeycomb (HRP) easy to machine?
Cut with ultrasonic knife, hot-wire-free abrasive band or crush-grind/diamond-coated tooling with vacuum hold-down and cell filling (wax/ice) for contoured profiles; glass is highly abrasive on carbide.
Can Fiberglass/Phenolic Honeycomb (HRP) be welded?
Not weldable — cores are joined by film adhesive splicing, foaming adhesive, or potting compound at inserts and edges.
Can Fiberglass/Phenolic Honeycomb (HRP) be formed, bent or molded?
Overexpanded (OX) and flexible-core forms allow single-curvature drape; complex double curvature requires heat-forming, kerfing or machined core; co-cure or secondary-bond with 120–180 °C epoxy/phenolic film adhesive under vacuum/autoclave pressure.
What surface finishes work on Fiberglass/Phenolic Honeycomb (HRP)?
Seal all exposed edges and fastener zones with potting epoxy to block moisture ingress; degrease and lightly abrade skins, no plating/anodizing applies to the core itself.
Fiberglass/Phenolic Honeycomb (HRP) 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 |
|---|---|---|
| E-glass fabric (woven, silane finish)bias/plain weave scrim forming the cell walls | 50 – 65 | 58 |
| phenolic resin (resole, cured)multiple dip-and-cure impregnations set final density | ≥ 35 (balance) | — |
Fiberglass/Phenolic Honeycomb (HRP) 4.0 — frequently asked
What is Fiberglass/Phenolic Honeycomb (HRP) 4.0 used for?
Fiberglass/Phenolic Honeycomb (HRP) 4.0 is typically used for fire-rated aircraft panels, marine bulkhead panels, industrial sandwich enclosures and rail interior panels. In short: fire-resistant structural core; cheaper than aramid honeycomb; abrasive to cutting tools.
What is the tensile strength of Fiberglass/Phenolic Honeycomb (HRP) 4.0?
Fiberglass/Phenolic Honeycomb (HRP) 4.0 has a typical tensile strength of 4 MPa (0.537 ksi) — weaker than 87% of composite grades. Strength varies by condition: see the 5 listed tempers.
Is Fiberglass/Phenolic Honeycomb (HRP) 4.0 easy to machine?
Not especially — machinability is rated fair (40/100, better than 57% of composite grades). Cut with ultrasonic knife, hot-wire-free abrasive band or crush-grind/diamond-coated tooling with vacuum hold-down and cell filling (wax/ice) for contoured profiles; glass is highly abrasive on carbide.
Can Fiberglass/Phenolic Honeycomb (HRP) 4.0 be welded?
Not weldable — cores are joined by film adhesive splicing, foaming adhesive, or potting compound at inserts and edges.
What surface finishes work on Fiberglass/Phenolic Honeycomb (HRP) 4.0?
Seal all exposed edges and fastener zones with potting epoxy to block moisture ingress; degrease and lightly abrade skins, no plating/anodizing applies to the core itself.
Can Fiberglass/Phenolic Honeycomb (HRP) 4.0 be formed, bent or molded?
Overexpanded (OX) and flexible-core forms allow single-curvature drape; complex double curvature requires heat-forming, kerfing or machined core; co-cure or secondary-bond with 120–180 °C epoxy/phenolic film adhesive under vacuum/autoclave pressure.
What is the maximum service temperature of Fiberglass/Phenolic Honeycomb (HRP) 4.0?
Fiberglass/Phenolic Honeycomb (HRP) 4.0 is rated for continuous use to about 177°C (351 °F), and briefly to 205°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- HexWeb HRP Glass Fabric/Phenolic Honeycomb Product Data — Hexcel (2020)
- ASTM C365 — Flatwise Compressive Properties of Sandwich Cores — ASTM (2016)
- ASTM C273 — Shear Properties of Sandwich Core Materials — ASTM (2020)
- MIL-C-8073 / AMS-C-8073 Core Material, Plastic Honeycomb — SAE/US DoD (1998)
- MIL-HDBK-23 / CMH-17 Vol.6 Sandwich Structures — SAE International (2013)
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.