Surface · Non-metal panels (plastic and fiberglass)
Plastic bumpers: why your paint gauge shows no reading
A magnetic or eddy-current gauge cannot read paint on a plastic bumper. No reading is expected; paint on plastic is measured ultrasonically.
Also listed as plastic bumpers, bumper covers, plastic parts
Short answer
A magnetic or eddy-current paint gauge cannot read paint on a plastic bumper, because there is no metal under the paint. No reading is expected and tells you nothing about the paint. DeFelsko measures coatings on plastic with ultrasonic gauges such as its PosiTector 200, used with a couplant gel. Mirrors can be plastic too.
Key facts
- Material
- Plastic[1]DeFelsko notes recent vehicles can have plastic bumpers and mirrors.
- Gauge mode
- None: Fe and NFe modes need a metal substrate[3]
- What the reading includes
- Total coating thickness; DeFelsko's PosiTector 200 B3 also reports up to three layers[2]Model-specific.
- Published thickness figures
- Not confirmedNo source we checked gives a typical paint thickness on plastic bumpers.
- Polishing note
- Not confirmedNo source we checked gives polishing limits for painted plastic.
Watch out for
- Do not read meaning into a blank screen. Fe and NFe gauges need metal under the coating, so no reading on a plastic bumper is normal.
- Mirrors can be plastic too. DeFelsko lists plastic bumpers and mirrors among the mixed materials on recent vehicles.
- Ultrasonic needs gel. DeFelsko's ultrasonic method needs a couplant gel on the surface, and it intends its affordable ultrasonic models only for non-metal substrates.
For the full explanation, see can a paint gauge measure plastic bumpers.
Questions
Why does my paint gauge show no reading on the bumper?
Magnetic and eddy-current gauges need metal under the coating. UNI-T says the measured object must be metal with a non-conductive coating, and a bumper is usually plastic.[3][1]