Clearcoats are thin by Mike Phillips

[Mike Phillips]

Clearcoats are thin by Mike Phillips


The majority of cars being manufactured today and starting since the 1980's use what's called a basecoat/clearcoat paint system. With this system, a clear layer of paint is sprayed over the top of the basecoat which is also the color coat or the layer of paint that has pigment in it. If the car has a metallic finish, then the metallic flakes are also in the basecoat.

The basecoat doesn't offer any gloss or shine and in fact it's dull or matte looking after it's sprayed. The basecoat gets it's gloss, shine, depth and reflectivity by the spraying of the clearcoat layer of paint over the top of it. This is why if a person removes too much clearcoat when buffing and they expose the basecoat it will appear to be a dull round or oval spot on a body panel. The part of the paint system that adds beauty has been removed revealing the dull or matte basecoat layer of paint.



Just how thin is the clear layer of paint on a factory paint job?

The factory clearcoat on a new or modern car measures approximately 2 mils thin.


The average Post-it Note is around 3 mils thin or 80 microns.

What does this mean?

This means the factory clearcoat on a new or modern car is thinner than a Post-it Note. The next time you have a Post-it Note in front of you, feel a single Post-it Note between your fingers. Like this...

This experience will drive home the point as to just how thin the clear layer of paint is on modern car with a factory paint job. It should also drive home the importance of using the least aggressive pad, product and even tools to get the job done.

When I say, get the job done, the context of this usually means someone is buffing out a car to remove paint defects like swirls, scratches, water spots and oxidation to make the paint and thus the car look better.

By using the least aggressive products you "get the job done" while leaving the most paint on the car to it will last over the mechanical service life of the car.

And always remember,

1. Sanding removes paint.
2. Compounding removes paint.
3. Polishing removes a little paint.

The last thing you want to see when buffing out your sanding marks is the color of the basecoat on the face of your buffing pad. This is a very bad sign. I have a saying that goes like this,


Words cannot describe the heart-sinking feeling that overcomes you when you discover you've burned or buffed through the clearcoat of some other dude's car -Mike Phillips


If you're working on your own cars and you're reading this, you're already ahead of the game by reading this article on my discussion forum and if you're a member so you can ask questions and get more help.

If you're working on customer's cars take a professional approach as a service to your customers. Start by EDUCATING the customer that the factory clearcoat paint on their car is thinner than a Post-It Note. Then hand them a Post-It Note because it's very easy for the average person to feel a Post-It Note and wrap their brain around just how thin the paint on their car is from the factory.

Be very careful my friends when sanding factory clearcoats.


Mike

 

[Mike Phillips]

Continued....

I started using a Paint Thickness Gauge back in the early 2000s, back then, the PTG I was using displayed measurements in MILS - not microns. So I got use to understanding paint thickness using this unit of measurement.


Which is the best unit of measurement microns or mills?
When measuring film builds that are extremely thin, using a gauge that offers the ability to measure paint thickness in increments of microns is a lot more accurate than using a paint thickness gauge that measures in mils. Most quality paint thickness gauges will give you the option to choose either microns or mils in the settings.

The reason microns are more accurate than mils is because 1 unit of um is equal to one millionth of a meter. On the other hand, the unit of mils are equal to one-thousandth of an inch. The scale difference between measuring to one millionth of a meter as compared to one-thousandth of an inch is huge, at least in the context of measuring thin car paint. And the more accurately you can measure the total film-build, the better the understanding you’ll have of the thickness or thinness of the paint on the car in front of you.

For Reference

Um: Um is also referred to as micrometer or micron. 1 unit of um is equal to one millionth of a meter.
Mil: 1 unit of mm is equal to one-thousandth of an inch.
Mm: mm is also referred to as millimeter. 1 unit of mm is equal to one-thousandth of a meter.


What is a good paint thickness measurement?
Generally speaking, when measuring both factory paint or repaint, more is better. Cars with the factory paint will tend to measure in a low range of 75 microns or 3 mils and a high range of up to 200 microns or 8 mils.

The downside to a paint thickness gauge is that most only measure TOTAL film build. This means the paint thickness gauge measures all layers of material on top of the metal substrate. For factory paint, this includes the e-coat, primer, basecoat and clearcoat. For repaint, this includes primer, basecoat and clearcoat.


How thin is too thin to safely do paint correction?
The thinner the readings the less aggressive you want to be when doing any paint correction.

Factory Paint
Even thin factory paints can be polished, but caution should be taken if considering any heavy paint correction like using an aggressive compound. For the most part, there are no auto manufacturers that I know of that are putting more or extra or thicker paints while the car is being built on the assembly line. That said, you don’t know until you measure.

Repaint or Custom Paint
If a car is being repainted, either as a part of collision repair or if the car is a custom build or restoration, then the painter will tend to spray more paint than what comes from the factory. For this reason, repaints or custom paint jobs have more paint film build and this enables you to use more aggressive products, pad, and tools to remove deeper defects or wet sanding to remove orange peel, which is a common procedure in the custom car world.


The Big Picture - Go or Don’t Go Decision Maker
Back in the year 2016, I wrote an article on using paint thickness gauges and in the article, I coined the term Big Picture Indictor. And as the words state, a paint thickness gauge is basically going to tell you if you’re working on really thin paint, or super thick paint, or somewhere in the middle of these ranges.

For me, measuring the paint thickness on a car I’m going to detail helps me to make the Go or No Go decision. This means, if the paint is measuring more on the thick side, then I’m GO for doing aggressive paint correction using a compound or even doing sanding. If the paint is measuring thin and/or super thin, then I’m NO GO for doing anything aggressive to the paint and will tend to only use fine cut or medium cut polishes, (no compounds) and definitely no sanding.


Let the pictures do the talking
Here's a RHOTPOINT Coating Thickness Gauge - out of the 3 PTG gauges I own, this is the most accurate. In the picture below, I'm measuring the surface of a Calibration Plate and because it purposefully completely flat the RHOPOINT PTG reads 0.000

Here I'm measuring a Post-It Note - the reading is 2.988 mils - close enough to 3 mils to prove my point.

Next I'll switch the RHOPOINT Coating Thickness Gauge over to MICRONS and then I'll remeasure the same Post-It Note.

The reading for the same Post-It Note are now 75.9 microns - for ease of understanding and general use, let's just call it 80 microns.

Due to the much smaller units of measurement, once you get the hang of it, using microns instead of mils will provide you with a much more accurate idea of how thick or how thin the paint is you're working on and help you to make any Go or No Go decisions as to how aggressive or how NON-aggressive to be when dialing in your paint correction and/or sanding process.


I don't sell these Rhopoint Coating Thickness Gauges, but my long-time friend, professional detailer and incredible detailing instructor, Todd Cooperider does offer these on his website.


Rhopoint Thickness Gauge - $169.00



Mike

 

[Mike Phillips]

When the clear layer of paint become too (from improper detailing) or if it's not properly and regularly washed and waxed one result can be clearcoat failure.

Clearcoat failure is where the paint flakes and peels off. Your car will look like it has a rash. Like this,

My friend Paul owns a body shop. He only does professional quality repaints. I asked him if someone brought him a car, for example an average sized passenger car and it needed ZERO body work. It only needs new paint. How much on average would he charge?


He said about $3000.00


Now this is for a high quality paint job to a mundane passenger car that needs no body work. Of course you can get a less costly paint job but instead,

Learn to take proper care of your car's paint while its still in great shape.

Only hire qualified detailers to do the work for you but - do hire them and have your car washed and waxed on a regular schedule.


Mike