Without using a PTG..

[Bullitt AK]

here is something from another forum as an approximation...is it a good guideline to use?

Using a medium abrasive polish and a rotary polisher will remove approximately 0. 1 Mil (3µ ) Range 0.8 – 1.1 Mil (20 – 28 µ) from the paint surface (typically 4 passes at 1500-1800 RPM)

A paint thickness reading of 4 Mil < ( 100 µ (Microns) is reasonably safe for polishing. 3 – 3.5 Mil ( 80-90 µ) I wouldn't use anything stronger than > 2000 grit polish, 2.75 – 3.0 Mil (70-80 µ) > 2500 grit polish and under 2.75 Mil (70 µ) use a glaze.

[Mindflux]

200 mils would be insanely thick! Cutting through .5 mils of clear is usually considered risky and can lead to clear failure. Are you sure you are reading that PTG right?

[Bullitt AK]

lol pretty sure he means microns not mils..and im pretty sure they have ones that can read multi layer on composites so maybe for corvettes, viper gts or other high ends that arent metal....
and judging by the approximation that i posted how can you tell what grit a polish is?

[Mindflux]

lol pretty sure he means microns not mils

I hope so.