At One Place

Acrylic (PMMA)

Density of acrylic (PMMA)
1,180 kg/m³
1.18 g/cm³ · 73.7 lb/ft³

Clearer than glass — it transmits about 92% of visible light against glass's 90% — and it holds that clarity outdoors for decades, which is why signs are acrylic rather than polycarbonate. It is also brittle: it cracks around drilled holes and chips at edges, so holes are drilled oversize with a bit reground to zero rake. It laser-cuts to a flame-polished edge, which polycarbonate does not, and that alone decides most hobby projects.

Properties

Density
1,180 kg/m³ — 1.18 g/cm³
Tensile strength
50–75 MPa
Young's modulus
3 GPa
Thermal conductivity
0.19 W/(m·K)
Thermal expansion
70 µm/(m·K)
Floats in water
No
Magnetic
No

What it is used for

  • Illuminated signs and display cases
  • Aquarium panels
  • Light diffusers and lenses
  • Laser-cut craft and model parts

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
acrylic (PMMA) 1,180 kg/m³
tungsten 19,250 kg/m³
gold 19,300 kg/m³
platinum 21,450 kg/m³
Water is 1,000 kg/m³. Anything below that floats.
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×
acrylic (PMMA) ← 1,180 kg/m³ 1.18×
platinum 21,450 kg/m³ 21.45×
gold 19,300 kg/m³ 19.30×
tungsten 19,250 kg/m³ 19.25×

Does it rust?

Acrylic (PMMA) contains no iron, so it cannot rust. Whether it degrades depends on the material, not on oxidation.

Is it magnetic?

Acrylic (PMMA) is not a metal and has no ferromagnetic response.

Common questions

What is the density of acrylic (PMMA)?
1,180 kg/m³, or 1.18 g/cm³.
Does acrylic (PMMA) float?
No. At 1,180 kg/m³ it is denser than water.
Is acrylic (PMMA) magnetic?
Acrylic (PMMA) is not a metal and has no ferromagnetic response.

Related pages

Sources

  1. Typical range compiled from manufacturer specifications — At One Place

How these figures are compiled and checked