# ASTM D2240

Source: https://coatmentor.com/standards/astm-d2240/ · Updated 2026-10-14

Durometer hardness (Shore A and Shore D).

**Publisher**: ASTM International

**Area**: Adhesion, cure and holidays

ASTM D2240 measures indentation hardness with a durometer. Coating inspectors use it on thick, chemically resistant films and elastomeric linings: Type A for soft materials, Type D for hard ones.

## The procedure

- The specimen should be at least 6 mm thick, unless thinner material is known to give the same result. On a thin film the hard substrate below falsifies the reading.
- Keep each reading at least 12 mm from an edge and the readings apart from each other.
- Read the dial within one second of firm contact, unless the specification gives another time.
- Take five readings and report their mean or median.

A hardness value on its own says little. The specification or the product data sheet gives the hardness a cured film should reach.

**1** practice item in the members area mentions ASTM D2240 (CIP 2: 1).

## Related

- **Concepts:** [Drying, curing and recoat windows](https://coatmentor.com/learn/cure-and-recoat/)
- **Standards:** [ASTM D4752](https://coatmentor.com/standards/astm-d4752/)
- **Defects:** [Undercure](https://coatmentor.com/defects/undercure/)

## About this page

This page describes the subject of ASTM D2240 in our own words; it does not reproduce the standard. For the full text, buy the current edition from ASTM International. Checked on 2026-10-14; errors go in the [corrections log](https://coatmentor.com/method/). CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.