just to add to this thread
POLISHING = cutting into clearcoat (NOT PAINT) to remove uneven surfaces, troughs and peaks (light bounces of these especially sunlight on swirls etc)
Polish as LITTLE as possible = clear coat is finite, don't cut too much or too regularly or you either BURN through and /or need a respray.
Paint Thickness Gauge (PTG) = beg borrow or steal, if you're attempting machine polishing, to see how much clearcoat you have to play with.
Determine Clearcoat Thickness = usually paint is sprayed everywhere on said vehicle however, in the interest of costs, under the hood/bonnet clearcoat is not usually applied.
use this to determine clearcoat thickness
e.g. take multiple readings at different points on the bonnet surface with it shut.. get an average reading,
open the lid, take multiple readings from under the bonnet ( you should see the paint difference ) = subtract average underneath reading from average surface reading et voila you are left with CC thickness
