Paint gauge measuring

Jmbrown415

Jmbrown415

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Sorry another dumb question. I

just ordered a new paint gauge. Which measures in um ( micrometres )

as as a rule of thumb how much clear coat generally do you have to work with?

for example I have a 2015 solid black Audi, has had a bit of correction, so some cutting.

also do paint gauges just measure the clear coat or everything including primer etc??

thanks
justin
 
No such thing as a dumb question....

As a normal rule, the clear layer from the factory MUST be around 2 mils in order for their to be enough "material" to keep the entire paint job from failing.

I spoke with Dr. David Ghodoussi about this a few years ago when writing my first how-to book,

The Art of Detailing


Any thinner than that and the clear layer will fail prematurely and thus the entire paint job will fail.


Somewhere on this forum I think I have an article on this, it may be on page 2 of this article.

Beginning Clearcoat Failure




And yes, most entry level paint thickness gauges read the entire film build.

I have a very in-depth article on how to use the

All about the Defelsko Paint Thickness Gauge by Mike Phillips

watermark.php


Hope that helps...



:)
 
Another note to consider, the less expensive gauges read on metal only. So any fiberglass or plastic parts, like many bumper covers, will not give a reading.
 
Typical audi thickness is 120-150 microns including primer, color and clear. That is my personal rule based on measuring a lot of audis, it is a generalization and generalizations can be dangerous. 30 microns of variance on a car is not uncommon. It's important to understand that a PTG is helpful in understanding how much paint you are removing, but provides minimal information as to what has been done previously and if it is safe to work on; that takes experience and some risk.

PTGs that measure individual layers are a bit more useful, but no meter can tell you how much paint has been previously removed from a specific vehicle.

If your audi measured 100 microns or 200 microns, id investigate more as to why it varies from 'typical'. If it measures 100 microns, perhaps it's been worked on a lot and you may be able to find some
previous sanding marks or edges that are burned through. If it's 200 microns, perhaps it's been repainted and you can find some evidence of tape lines or blending. Or you very well may find that your vehicle is an exception to my gross generalization.
 
Jmbrown415 said:
Sorry another dumb question. I

just ordered a new paint gauge. Which measures in um ( micrometres )

as as a rule of thumb how much clear coat generally do you have to work with?

for example I have a 2015 solid black Audi, has had a bit of correction, so some cutting.

also do paint gauges just measure the clear coat or everything including primer etc??

thanks
justin
Click to expand...

To answer your question OP, the gauge will measure the total thickness of the three paint types on your car.

Not sure exact thickness of each type but if the clear is 2 mil and your reading is 7.0 then the primer and colour coats are likely 2.5 mil each.

I have used a gauge to measure a repaint while doing my B-Pillars.

Filler primer 2 coats was 2.5 mil.

Colour 2 coats was 1.5mil

Clear 3 coats was 3.5 mil.

Total 7.5 mil.

Also did my daughters Yaris hood.

Before reading was 5.0-6.0 (you always want to take a few readings per section to get an average).

Rest of the Yaris was 6.5 to 7.5 except driver'rear door which was 9.7 (must have been repaired so some original paint was affecting the reading).

The after painted reading was 8.0.

The point is on new cars the 2 mil clear is probably close enough.

On an older car (mine is 16 years old) you have to measure to be sure you are not working on original clear coat, you want to know if it is thin or not.

Another good idea is the form that Mike has with a picture of the car and you can map out your readings.
 
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