How to Check Coating Thickness Before Polishing
Before you start polishing a ceramic coated car, it’s critical to know exactly what you’re working with. Polishing removes material — and on a coated car, that means you risk thinning or removing both the coating and clear coat if you don’t know the surface depth. In this guide, you’ll learn how to check coating and paint thickness safely before you begin polishing, so you never go too far.
Estimated Reading Time: ~13 minutes
Why Checking Thickness Matters
Every time you polish a surface, you’re removing some material — whether it’s the top of a ceramic coating or part of the clear coat beneath it. Because coatings are extremely thin (typically 1–3 microns thick), even light polishing can compromise protection. Checking thickness ensures you don’t over-correct or damage the finish.
- → Prevents over-polishing and permanent damage to clear coat.
- → Helps you decide if correction or recoating is the smarter move.
- → Establishes a baseline for future maintenance or detailing records.
Understanding Paint and Coating Layers
Modern automotive finishes typically consist of three main layers:
- Base coat: Provides color — typically 10–20 microns thick.
- Clear coat: Provides gloss and protection — around 30–50 microns thick.
- Ceramic coating: Adds chemical and UV resistance — around 1–3 microns thick.
When polishing, your goal is to remove minimal material — ideally just enough to refine the surface, not to cut through protective layers. This is why using Picture Perfect Polish matters: it corrects and finishes clean without unnecessary cut.
Tools You’ll Need
- Paint Thickness Gauge (PTG): A handheld meter that measures total paint film thickness in microns or mils.
- Lighting: Proper inspection lighting helps identify inconsistencies or repair spots.
- Notebook or app: Log readings for each panel to identify thin or repainted areas.
Step-by-Step: How to Check Coating Thickness
1. Clean the Surface
Before measuring, wash the area with The Super Soaper to remove dust, debris, or residues that could affect readings. Dry with a Massive Drying Towel before placing your gauge on the paint.
2. Calibrate Your Paint Gauge
Most gauges come with calibration plates. Use them before starting to ensure accurate results, especially if you’re switching between steel and aluminum panels.
3. Take Readings Across Each Panel
Measure in at least 5–6 spots per panel — top, center, and edges. The average factory finish thickness is 80–160 microns. Anything below 90 means you should polish conservatively.
4. Compare Left and Right Panels
If one side measures significantly thicker, that area may have been repainted. Approach with caution — repainted sections are often softer and more prone to burn-through.
5. Note Variations and Plan Your Approach
Areas near edges, door handles, and hood lines are typically thinner. Adjust your pressure, pad, and polish choice accordingly.
Typical Paint Thickness Reference Chart
| Surface Type | Average Thickness (Microns) | Recommended Polishing Approach |
|---|---|---|
| Factory Paint | 100–150 | Safe for light correction |
| Repainted Surface | 150–250 | Harder to cut, use moderate pressure |
| Thin Factory Clear | Below 90 | Use only finishing polish (Picture Perfect Polish) |
Polish Smarter, Not Harder
Picture Perfect Polish is pad-dependent and residue-free, giving you complete control over correction without over-cutting or removing your coating.
Shop Picture Perfect Polish Buy on AmazonWhen You Should Avoid Polishing Altogether
If your readings show 80 microns or less, it’s best to avoid any mechanical polishing. Instead, use a chemical decontaminant and top with Tough As Shell for extra gloss and protection without abrasion. Remember — once clear coat is gone, it can’t be replaced without repainting.
Pro Tips for Measuring Like a Pro
- → Always measure before and after polishing to know exactly how much you’ve removed.
- → Keep your gauge perpendicular to the surface for consistent readings.
- → Avoid measuring over decals or body lines — they can skew results.
- → Track results in a log for customer reports or maintenance planning.
Recommended Polishing Workflow Based on Readings
- 100+ microns: Safe for light-to-medium polishing with Picture Perfect Polish.
- 90–100 microns: Limit to finishing passes with soft pads.
- Under 90 microns: Skip polishing and recoat with The Gloss Boss or Tough As Shell.
Related Reading
- Why Paint Correction Is Harder on Ceramic Coatings
- Common Mistakes When Polishing Ceramic Coated Cars
- Recoating After Using Picture Perfect Polish
- Why Picture Perfect Polish Finishes So Clean
- Can You Polish Over Tough As Shell?
FAQs
Can I measure ceramic coating thickness directly?
Most consumer paint gauges measure total paint system thickness, not just the coating layer. Still, comparing before-and-after readings helps estimate removal.
What’s a safe polishing range for coated cars?
Anything above 100 microns total thickness is safe for mild correction with Picture Perfect Polish.
What if my paint reads below 80 microns?
It’s too thin for mechanical correction — skip polishing and use a ceramic spray for gloss.
Do all cars have the same paint thickness?
No. European cars typically have thicker finishes, while Japanese and American cars can vary widely.
Does polishing once or twice remove too much material?
Not with a finishing polish like Picture Perfect Polish. It removes minimal microns and finishes clean every time.
