<HTML>Hi Phil, no we dont measure the paint as of right now, although I'd like to be, its on my "to buy " list.
It is my understanding that the paint on the vehicle that has not been re-painted , only has about a 1.0 to 1.5 mm of clearcoat on it. We got in to wet sanding for a while but have stopped doing it now. The main reason was that we were never given any formal training in it, we could get some of the scratches out , but we didnt really know what we were doing. The second reason was that after doing some research we learnt that the clear coat contains UV blockers in the top .5 mm of the clear..most OEM's recommend that you do not buff any deeper than .3 mm otherwise it will lead to early clear coat failure. So while you may remove the scratch , you may well end up sending the customer to the body shop anyway in a few months. We decided that it if the scratch was that deep anyway it would be better for the customer ( and ultimatly for us) to have it re clearcoated to start with.
While I think the paint gague is an important tool, as was pointed out earlier , it does not measure the indivdual coats, it only gives you a total depth.
Right now we dont use one, we should as I think its an important tool, so we do as you do, use what we believe to be an experienced eye. We get it wrong sometimes too .
I think it would be useful to buy a paint gague , simply measure the total thickness of the paint, and then take care to buff no deeper than .3 mm if thats possible.
I might go ahead and buy one of these for myself anyway, just be intresting to see how much clear we do remove when we buff cars with different compounds.
Hope this helps.
Jim.</HTML>