Inspecting multilayer paint: dry film thickness with a P.I.G.
For many paint systems, an electronic DFT reading gives total thickness rather than each individual layer. A Paint Inspection Gauge, or P.I.G., opens the system with a defined cut. Suitable layer boundaries can then be evaluated under a microscope. The method is destructive and can also be used on suitable non-metal substrates.
Products and methods at a glance
| Method / parameter | Meaning / application | Practical decision |
|---|---|---|
| 45° | t = b | Geometric principle at this angle. |
| About 26.6° | t ≈ 0.5 × b | Wider cut for the same thickness. |
| About 5.7° | t ≈ 0.1 × b | Suitable for thinner layers; consider the viewing window. |
Settings and assessment framework
Choose the cutter for expected thickness and field of view. Table angles explain the geometry; instrument instructions and cutter identification take priority. Do not claim reliable evaluation where layer boundaries are unclear.
Professional workflow
- Agree the inspection task and permitted damage location.
- Check and fit a suitable cutter.
- Apply a contrast mark following instructions.
- Make a defined cut across the mark to the substrate.
- Examine the cut and convert layer widths using the factor.
- Record layers, location and result; repair the damaged area appropriately.
Troubleshooting
Cut too wide
Choose another cutter angle; check range.
Unclear layer boundaries
Improve contrast and lighting; consider alternative analysis.
Ragged cut
Check cutter condition; select a new representative location.
Incorrect thickness
Check scale factor; check units.
Maintenance and quality assurance
- Store cutters safely.
- Inspect cutting edges.
- Keep optics clean.
- Check the measurement scale.
- Remove residues following instructions.
FAQ
Is P.I.G. non-destructive?
No, the cut damages the coating.
Can it measure on plastic?
It can be used with a suitable system and evaluable cut.
Why different cutters?
They adapt cut width and measurement range to thickness.
Are all layers visible?
Only sufficiently distinguishable boundaries can be evaluated.
Must the location be repaired?
Yes, according to component and coating requirements.
Conclusion
P.I.G. complements total thickness readings with a view into the coating system. Beschicht.com helps you choose suitable inspection gauges and cutters.
Explore inspection equipment at Beschicht.comSources and sections used
German - Elcometer Guide to Dry Film Thickness_corrected (2).docx
- Destructive dry film thickness
- Paint Inspection Gauge (P.I.G.)
