Wow, this thread got out of control quick. I am sure all this crap in here is going to be really helpful to myself an others looking for a paint thickness gauge.
Makes common sense... here's the perspective of someone fairly new (at least compared to most of these guys who have 20+ years in) who does not and has not worked with a PTG:
First, I rather have it, than not have it. Its NOT the be all and end all of mistakes. First you need to be able to properly choose compounds, pads, and accurately work a DA or Rotary or your sunk anyway.
Secondly if I had one this is how I would use it. I would first do a visual inspection. Working in a body shop at one time it is possible to tell when something has been repainted. There is always some sort of indicator. Generally, the factory does not include fish eyes anywhere in the paint. A top dollar job is nearly perfect but there is always some sort of indicator suggesting a repaint. I would also visually inspect each panel for more or less orange peel, and all the moldings and trim (especially the hidden ones) for overspray. If that didn't yield any results I would move to the PTG. Generally, and I think most of us will agree, the hood, roof, and trunk lid are the first to get hammered are are not a good indicator of paint thickness. However if I went over all the panels with the PTG and found that they were all within +or- 15% reading of each other i would have a good indicator that either A. I have a fairly decent amount to work with, or B. panels are all the same... indicating no repaint. It is very unlikely IMO that a repaint by hand would have the same paint thickness as paint from the factory... so I would AT MINIMUM know if I found a panel with much more or much less paint thickness that it was likely compounded to death or repainted.
Coming from someone "inexperienced" there is no replacement for experience.
I am an Automotive Technician by trade. I hated my job so I left to persue other ventures. I found I am more comfortable behind a desk. From time to time people tell me how great my work is and how I am wasting talents. I have no desire to do the job. Once in a while I would take a walk though the shop,... there would ways be some kid from Lincoln Tech struggling with something. I have only a few years on these kids (or at least that's what you guys are going to believe :rofl ) and yet so much more experience has helped me help them.
One more thing... for any of you who have worked with a GM Tech II scan tool or a Snap-on RedBrick... you know that reading codes only points you in the direction of the problem (and sometimes it doesn't even do that). It takes experience and knowledge of the product to really pinpoint the main issues. You will always know the technician that is experienced from the one that is not. They both solve the problem in the end, but the experienced guy has thrown less parts at the car....
Now can we please get back on track?
DG