How does one measure the paint depth?

[IntrstlarOvrdrv]

I have seen people say make sure not to go too much on the paint with certain products, but how does one know how thin the paint is getting? How do you measure it? Thanks.

[Eliot Ness]

Some of the pro`s use an ETG (electronic thickness gauge) as shown in this link:



http://www.meguiarsonline.com/forums/showthread.php?threadid=4013

[C. Charles Hahn]

I`ve got a (cheap, probably inaccurate) thickness guage that uses a magnet; just pull it away from the surface until the magnet is about to pop off, and it gives you a reading. Picked it up at a local paint supply store for like $10

[togwt]

Paint Film Thickness:

Most modern vehicle paint film systems (paint build) comprise a primer coat of 2 Mil, a colour coat of 1-2 Mil, and clear coat of 2-3 Mil, an unprotected paint surface will lose approximately 8-10% or 0.4 Mil (0.0004-inch) to environmental exposure in a twelve month period (dependant upon geographic location), as a point of reference a sheet of copy paper is 3.5Mil (0.0035") removing more that 0.3 Mil (0.0003") of clear coat will cause premature paint film failure.



The clear coat provides protection from a hostile environment and an excellent brilliance, but is easily scratched; once it is compromised repairs involve re-painting, as the base colour has no brilliance, shine or depth, start with the least abrasive product to accomplish desired results, and only if necessary move up to the next grade of abrasive.



Q: What is the "right" paint thickness for a vehicle?

A: There is no "right" paint thickness for any vehicle. Automobile manufacturers paint thousands of vehicles each day with a wide variety of paint formulations; their specification has a range of thicknesses.

For some models this can be as low as 3 Mil and, in the case of the rocker panels of Sports Utility Vehicles (SUVs), as high as 17 Mils.



Q: If there is no "right thickness", what am I looking for?

A: Paint thickness consistency; for example, when you are reading between 3.5 and 5.0 Mils and a reading shows a sudden reduction in thickness, you know there is a cause for concern in that particular area of the bodywork.



Paint Thickness Gauge:

An electronic paint thickness gauge can be an invaluable tool, before buffing itâ€â„¢s always a good idea to check the paint film thickness to see how much of the paint film thickness is available, check periodically during the process and on completion to see how much was removed. Take measurements with a paint and coating thickness gauge (Check-Line Model DEF-900)



All the major car manufacturers specify that measurements should be taken before, during and after these steps. This is primarily because removal of too much clear coat can cause paint failure over time due to the fact that UVR absorption is the job of the clear coat. Too little clear and the colour coat won`t be protected from UV radiation. For this reason, itâ€â„¢s also recommended that paint be measured when buffing since you canâ€â„¢t see how much paint is being removed during the buffing process. If too much clear is removed, either on the original OEM finish or the refinished areas, a warranty issue may develop down the road

How much paint are you removing (http://meguiarsonline.com/forums/showthread.php?s=&threadid=4013&highlight=removing+clear+coat)



Itâ€â„¢s interesting to note that painters must now demonstrate proficiency with an electronic paint thickness gauge in order to become certified to perform refinish warranty work for General Motors Corp. (GM) vehicles.

JonM