Fibreglass (GRP)
Density of fibreglass (GRP)
1,900 kg/m³ (1,500–2,100)
1.90 g/cm³ · 118.6 lb/ft³
Glass fibre is about a third the stiffness of carbon at a fifth of the price, which is why boats are fibreglass and only racing yachts are carbon. The strength range here is mostly lay-up, not chemistry: chopped strand mat lands near 100 MPa and woven roving near 300. Its long-term enemy is water — polyester laminates absorb it slowly and blister, which is what osmosis in old boat hulls is, and epoxy laminates resist it far better.
Properties
- Density
- 1,900 kg/m³ (1,500–2,100) — 1.90 g/cm³
- Tensile strength
- 100–300 MPa
- Young's modulus
- 20 GPa
- Thermal conductivity
- 0.35 W/(m·K)
- Floats in water
- No
- Magnetic
- No
What it is used for
- Boat hulls and decks
- Corrugated roof sheeting and tanks
- Vehicle body panels and truck bodies
- Printed circuit board substrate (FR-4)
How it compares
Water is 1,000 kg/m³. Anything with a shorter bar than water floats in it.
air 1.2 kg/m³
expanded polystyrene foam 20 kg/m³
rigid polyurethane foam 40 kg/m³
Water — the float line 1,000 kg/m³
fibreglass (GRP) 1,900 kg/m³
tungsten 19,250 kg/m³
gold 19,300 kg/m³
platinum 21,450 kg/m³
| Material | Density | Relative to water |
|---|---|---|
| rigid polyurethane foam | 40 kg/m³ | 0.04× |
| expanded polystyrene foam | 20 kg/m³ | 0.02× |
| air | 1.2 kg/m³ | 0.00× |
| fibreglass (GRP) ← | 1,900 kg/m³ | 1.90× |
| platinum | 21,450 kg/m³ | 21.45× |
| gold | 19,300 kg/m³ | 19.30× |
| tungsten | 19,250 kg/m³ | 19.25× |
Does it rust?
Fibreglass (GRP) contains no iron, so it cannot rust. Whether it degrades depends on the material, not on oxidation.
Is it magnetic?
Fibreglass (GRP) is not a metal and has no ferromagnetic response.
Common questions
- What is the density of fibreglass (GRP)?
- 1,900 kg/m³ (1,500–2,100), or 1.90 g/cm³.
- Does fibreglass (GRP) float?
- No. At 1,900 kg/m³ it is denser than water.
- Is fibreglass (GRP) magnetic?
- Fibreglass (GRP) is not a metal and has no ferromagnetic response.
Related pages
- Does fibreglass (GRP) float? No
- Unidirectional carbon fibre composite 1,600 kg/m³
- Woven carbon fibre composite 1,550 kg/m³
- Asphalt (hot-mix) 2,350 kg/m³
Sources
- Typical range compiled from manufacturer specifications — At One Place