Paint Thickness Gauges

How a paint thickness gauge works

The gauge touches the panel and measures the distance from the paint surface down to the metal underneath. On steel it uses magnetic induction; on aluminium it uses the eddy current method. A reading takes about a second and appears on the screen in microns. The measurement is non-destructive and leaves no mark.

Fe and nFe — what is the difference

Fe stands for steel, nFe for non-ferrous metals, primarily aluminium. A cheaper Fe-only model will read zero on an aluminium bonnet or wing because it simply cannot measure that surface.

Most modern cars use aluminium panels — bonnet, boot lid, wings. For inspecting a used car you therefore need a dual-sensor (Fe/nFe) model; otherwise the very panels that are replaced most often are the ones you cannot check.

What thickness is normal

A factory paint layer is usually 80–150 μm. A reading above 200 μm suggests the panel has been resprayed. Above 300 μm often indicates body filler, meaning the panel has been repaired.

Do not read too much into the absolute number. Some factory finishes — metallics and pearlescents in particular — are thicker from new and can reach 180 μm. German cars generally leave the factory with a thicker layer than Japanese ones. What matters is the difference between panels, not the figure itself: if every panel reads 120–140 μm and one reads 260, that single panel is the resprayed one.

How to inspect a car step by step

Measure every panel separately: bonnet, both front wings, all four doors, boot lid and roof. Take three or four readings on each — near the top, in the middle and close to the edge.

Write the figures down, then compare them. Symmetrical panels — left and right wing, left and right doors — should read almost the same. A large gap means one of them has been worked on.

Which model to choose

The right choice depends on how often you will use the tool.

For occasional use — buying a single car, for example — a basic model is enough. The Paint Thickness Gauge RD-TC100 costs under 200 GEL and handles the core task well.

For regular use — a dealership, a car importer, an appraiser — a faster and more durable model makes sense: the R&D TC-200 or the Paint Thickness Tester ET-360.

For professional accuracy — expert inspection, insurance assessment — the ETARI ET-700 Max is the top model in this range.

Measuring body filler is a separate task: once you already know a panel has been repaired, you may need to know how thick the filler layer is. The putty thickness gauge is designed for that.

Exact measuring range, accuracy and contents are listed on each product page. For other inspection equipment see the diagnostic tools section.