Surface
Clear coat: what a paint gauge can and can't tell you
Fe/NFe gauges cannot isolate clear coat. DeFelsko's 35-50 µm typical figure and 8 µm removal statement, and why they are not OEM specs.
Also listed as clearcoat, clear, top coat
Short answer
A magnetic or eddy-current gauge cannot isolate clear coat: it reads the whole stack to the metal. DeFelsko gives typical clear coat as 35-50 µm and says most automakers recommend removing at most about 8 µm, but it names no automaker document, so treat both as DeFelsko's figures, not specifications. Polishing removes clear coat, and Milwaukee warns that pressure, angle or motion errors may cause swirl marks or burning.
Key facts
- Material
- Clear top layer over the base color[1]
- Gauge method
- No Fe/NFe method isolates it; some ultrasonic gauges report layers on non-metal substrates[1]DeFelsko's PosiTector 200 B3 reports up to three layers; DeFelsko intends its affordable ultrasonic models for non-metals only.
- Gauge mode
- Not separable in Fe or NFe mode[1]
- What the reading includes
- On metal panels, clear coat is only part of the total reading[1]
- Published thickness figures
- DeFelsko: typically 35-50 µm (1.5-2.0 mils)[1]DeFelsko's rough figure, not an automaker specification.
- Polishing note
- DeFelsko: most automakers recommend removing at most about 8 µm (0.3 mil)[1]DeFelsko's statement; it names no automaker document.
- Inspection tip
- A Fe/NFe reading cannot tell you how much clear coat is left[1]
Watch out for
- The 8 µm figure is DeFelsko's, not an OEM document. DeFelsko attributes it to most auto manufacturers without naming one.
- A total reading is not clear-coat thickness. A Fe/NFe gauge includes primer, color, clear and any repaint in one number.
- A dual-action polisher can still burn paint. Milwaukee's polisher manual warns that too much pressure, the wrong angle or improper motion may cause swirl marks or burning.
How the polisher moves matters: compare free-spinning dual-action, forced-rotation and rotary machines.
Questions
How thick is clear coat on a car?
DeFelsko gives typical clear coat as 35-50 µm (1.5-2.0 mils). That is DeFelsko's rough figure, not an automaker specification, and it will vary by vehicle.[1]
How much clear coat can I safely polish off?
DeFelsko states that most auto manufacturers recommend removing at most about 8 µm (0.3 mil), but it does not name an automaker document. No source we checked gives a model-specific limit.[1]
Can a paint thickness gauge measure clear coat alone?
Not a magnetic or eddy-current one. DeFelsko says those gauges measure the full distance to the metal with no distinction between layers. Its PosiTector 200 B3 ultrasonic gauge reports layers, but only on non-metal substrates.[1]