ASTM D3363
Standard Test Method for Film Hardness by Pencil Test
Determines organic coating film hardness by pushing prepared drawing leads of graded hardness across the surface.
What ASTM D3363 specifies
ASTM D3363 ranks cured film resistance using calibrated drawing leads from soft 6B through hard 6H. A prepared pencil is held at a specified angle and pushed across the coating under controlled force. The procedure reports pencil hardness by gouge hardness, scratch hardness, or both, according to the specified evaluation. It is a comparative shop and laboratory method rather than a conversion to indentation hardness such as Vickers or Rockwell. Film thickness, substrate hardness, cure, temperature, humidity, pencil brand, and operator preparation can change results, so reports should identify the procedure and test conditions.
ASTM D3363 types and classes
Every designation the document defines, with the thickness it requires and the tests it imposes.
| Designation | Meaning | Requirement / test |
|---|---|---|
Gouge hardness | Hardest pencil that does not cut or gouge through the film | Pencil sequence from 6B through 6H |
Scratch hardness | Hardest pencil that does not rupture or scratch the film under the specified interpretation | Pencil sequence from 6B through 6H |
Tests and the drawing call-out
Tests the document imposes
- Pencil gouge hardness
- Pencil scratch hardness
How to cite it
Drawing call-out
PENCIL HARDNESS PER ASTM D3363: MINIMUM <GRADE> <GOUGE|SCRATCH>Angle brackets mark the choices the drawing must make; every finish page shows a completed example.
ASTM D3363 — frequently asked
What does 2H pencil hardness mean?
It means the film met the specified gouge or scratch criterion when tested through the pencil sequence up to 2H. The report must say which criterion was used.
Is 6H pencil hardness equal to a Vickers hardness?
No. Pencil hardness is an ordinal coating test and cannot be directly converted to Vickers hardness.
What affects ASTM D3363 results?
Cure, film thickness, substrate support, pencil preparation, environment, and operator technique can all affect the rating.
ASTM D3363 is copyrighted by ASTM International. This page explains the document so a drawing can be read; it does not reproduce the standard. Purchase the current edition from the publisher. Official source ↗