---
title: "POM (acetal / Delrin) — density, melting point and properties"
description: "POM (acetal / Delrin) has a density of 1,410 kg/m³ (1,400–1,420). Melting point, strength, conductivity, what it is used for, and whether it floats, rusts or is magn"
url: https://atoneplace.net/material/pom/
site: "At One Place"
---

# POM (acetal / Delrin)

**Density of POM (acetal / Delrin): 1,410 kg/m³ (1,400–1,420)**

1.41 g/cm³ · 88.0 lb/ft³

The plastic engineers reach for when a part must be machined to size and stay there: unlike nylon it barely absorbs water, so a POM gear cut in a dry workshop still fits in a damp one. It is stiff, slippery and fatigue-resistant, which is why plastic gear trains default to it. Two catches: it cannot be glued reliably by any common adhesive, and it depolymerizes if overheated, releasing formaldehyde — machine it cool and never leave it sitting in a hot barrel.

## Properties

- **Density:** 1,410 kg/m³ (1,400–1,420) — 1.41 g/cm³
- **Melting range:** 165–175 °C
- **Tensile strength:** 60–75 MPa
- **Young's modulus:** 3 GPa
- **Thermal conductivity:** 0.31 W/(m·K)
- **Thermal expansion:** 110 µm/(m·K)
- **Floats in water:** No
- **Magnetic:** No

## What it is used for

- Gears, cams and bushings
- Zip fastener sliders and buckles
- Fuel system and pump components
- Machined precision 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
- POM (acetal / Delrin): 1,410 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× |
| POM (acetal / Delrin) ← | 1,410 kg/m³ | 1.41× |
| platinum | 21,450 kg/m³ | 21.45× |
| gold | 19,300 kg/m³ | 19.30× |
| tungsten | 19,250 kg/m³ | 19.25× |

## Does it rust?

POM (acetal / Delrin) contains no iron, so it cannot rust. Whether it degrades depends on the material, not on oxidation.

## Is it magnetic?

POM (acetal / Delrin) is not a metal and has no ferromagnetic response.

## Common questions

### What is the density of POM (acetal / Delrin)?

1,410 kg/m³ (1,400–1,420), or 1.41 g/cm³.

### Does POM (acetal / Delrin) float?

No. At 1,410 kg/m³ it is denser than water.

### Is POM (acetal / Delrin) magnetic?

POM (acetal / Delrin) is not a metal and has no ferromagnetic response.

## Related pages

- [Does POM (acetal / Delrin) float?](https://atoneplace.net/does-it-float/pom/)
- [PLA](https://atoneplace.net/material/pla/)
- [ABS](https://atoneplace.net/material/abs/)
- [Acrylic (PMMA)](https://atoneplace.net/material/acrylic/)
- [Polycarbonate](https://atoneplace.net/material/polycarbonate/)
- [Polypropylene](https://atoneplace.net/material/polypropylene/)
- [PTFE](https://atoneplace.net/material/ptfe/)
- [Rigid PVC](https://atoneplace.net/material/pvc-rigid/)
- [HDPE](https://atoneplace.net/material/hdpe/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)