How thick is your paint? Not very...

Jngrbrdman

New member
Your paint is pretty darn thin. Somewhat thinner than a Post-It note if you wanted to compare. My brother in law had a POS van where the paint was peeling right off of it. I took out my old school paint thickness gauge just to see what it would tell me. I bought mine on ebay for like $30 bucks I think, but if you google it and look around then you can find them for about $60 on the interwebs.



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The idea is to place the magnetic end on your car and pull up till it releases. Whatever it said right before it let go is how thick the paint is. Not the most precise way to measure paint, but it gives you some ballpark figures if you were ever curious. It only works on ferrous metal painted surfaces, of course, so ABS or bondo painted areas are going to remain a mystery.



Here is the baseline test on the barest of metal. It went all the way up till there were no measurements and only broke loose because the magnet isn't stronger than the spring. (It is to be noted that a 3 year old IS stronger than the spring, so don't leave this lying around or it will end up like mine did.)



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Then right next to it on a painted area and pull up. This is measuring in mils and the average is supposed to be around 7, so this is either pretty thick paint, or a slightly off measurement. I opt for thick because it was spot on with several other vehicles. The paint being so thick may account for why it is totally peeling off the vehicle. (the fact it is a Chrysler doesn't help much either)



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Just in case you didn't know, the 'mil' referred to is not 'millimeter'. This is a different unit of measure equal to .001 inch or roughly .03 millimeters. Human hair is approx 3 mils thick, so your paint is not typically as thick as three of your hairs stacked on top of each other.



And for anyone who doesn't believe that their clear coat is even thinner, take a look at this:



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I peeled that off an old '93 Integra that had serious paint problems.



So the bottom line is that your paint is pretty darn thin. You can scratch clear through it right down to the sheet metal without a whole lot of effort if the paint is soft enough. The funny thing is that my Corolla actually measures to be around 4 or 5 mils, but it is a lot harder to scratch than my Subaru which measured 6 or 7 mils. So the type of paint means almost more than the thickness sometimes.
 
[So the type of paint means almost more than the thickness sometimes.]



Scratch resistance and paint thickness are not mutual, as stated it all to do with paint type and specification
 
That's why post VOC change (2005-ish and later) cars are easier to scratch than before. The paint is just as thick, but the type of paint being used is just more fragile, for lack of a better word.
 
The van's and example of two things done by the manufacturering plant.

1. Only one coat of clear.

2. No surface primer applied. What you are seeing as the grey is e-coat, which will "powder" when UV rays get to it.

"Can't make a band-aid stick on a dusty surface" is the way I used to explain it in my classes.

If a surface primer would have been applied it would have greatly reduced the opportunity for this condition to take place, plus since it looks like a Chrysler product, a great many of them only got one pass of the atomizing bells applying the clear.

IE, more UV's got through to the E-coat.

The mechanical gauge is sort of ok, but not accurate.

An easy way to demonstrate the thickness of a modern clearcoat is to take a cellophane wrap off a pack of cigarettes, when both sides are held together, using an electronic gauge, the reading will be 1.5 to 2 mil.

Total film build, IE e-coat, surface primer, base coat and clearcoat will normally show 4.5 to 5.5 mil total.

That is unless a "powder coat primer" was used by the assembly plant, then it may show as much as 8 to 9 mil.

That is pretty much the average film build of an OEM clearcoat.

Grumpy
 
I've seen some new Infiniti cars and SUV's in the 80-90 micron range lately....:scared:
 
RaskyR1 said:
I've seen some new Infiniti cars and SUV's in the 80-90 micron range lately....:scared:



I wish my Mazda's paint was that thick. I've measured all the way into the 70s, topping out into the 90-95 range. None to pleased, but it's a DD so I'll just have to live with it.
 
I think I bought it on ebay when I got mine. Just google 'magnetic paint gauge' and you can find them for around $60 bucks on average. Like Ketch said though, they aren't really the most accurate ways to measure paint. The really accurate ones can cost you a couple hundred bucks, but for someone who was just curious (like me) the cheap magnetic one did the trick. It may be inaccurate, but at least it is consistent. I can measure the paint around a car and see when a spot is thinner than the rest. I may not know exactly how thick the paint is, but the variances can still be tracked with this tool.
 
7 mil of coating isnt crazy, roughly 175mics. Figure the spring is slightly fatigued and say 150 mics or ~6mil



I think since it was exposed alot its probably a bit "swollen" from oxidizing.



My Evolution IX is around 90-105 polished 1 time in 5 years.
 
When the mechanical gauges came out, about 20 years ago, they were around $25.

If I recall, Bud at Detail Plus is still selling them for around that price or a little bit more.

Hey, they are better than a WAG!

Grumpy
 
Buddy of mine has a newer 2011 white Ram 2500. He showed me a few stone chips on various body parts. A couple on the hood, on the door and rear fenders. Normally the thickness of these chips would show primer but were done to bare metal. I could not believe how thin this paint is.
 
RaskyR1 said:
I've seen some new Infiniti cars and SUV's in the 80-90 micron range lately....:scared:



Dang.... used to be when you saw those kind of numbers it was time to get real nervous!
 
There is ultra violet (UV) protection all the way through the paint, but the majority of it migrates to the top of cross-linked clear coat ( this is dependent on the UV stabilizer being used) along with the thinner solvents and particles, the paint is also less dense (softer) below this level. Therefore removing clear coat ultra violet protection is not a linear process; by removing a small percentage of the clear coat paint tends to remove a larger percentage of the ultra violet (UV) inhibitors.



With a clear coat thickness of ~49µ and knowing that most of the ultra violet protection is in the top 50% (~24.5µ); therefore, limiting UV protection removal to ~25 % means that approximately 6.125µ< can be removed before the ultra violet protection is compromised. Once you remove too much clear coat you'll have no paint UV protection other than what you apply with a LSP (providing it contains UV protection.



Be cognizant that clear coat removal is not a liner process; and the first paint renovation will remove the most UV protection, therefore the above are probably conservative estimates. Two variables need to be established; how much clear coat is available and how much clear coat can be removed without compromising the paint systems long-term durability / paint warranty



A paint thickness reading of > 4 Mil ( 100 µ (Microns) is reasonably safe for polishing. 3 – 3.5 Mil ( 80-90 µ) I wouldn't use anything stronger than > 2000 grit polish, 2.75 – 3.0 Mil (70-80 µ) > 2500 grit polish and under 2.75 Mil (70 µ) use a glaze. The readings tend to vary from panel to panel and are thinner towards the panel edge.



• 200µ + can be expected on older cars that have been hand painted or a re-painted vehicle

• 100 – 200µ 4 – 8 mil - normal paint thickness

• 80 – 100 µ - 3 – 4 mils, thin paint

• 80 µ < - less than 3 mil, very thin paint



See also article "Clear Coat Thickness and UV Protection Removed by Polishing" - http://www.autopia.org/forum/guid...ness-paint-removal-polishing.html#post1448231
 
Shiny Lil Detlr said:
Dang.... used to be when you saw those kind of numbers it was time to get real nervous!



Maybe time to revise my 'safe' numbers
 
mikenap said:
I wish my Mazda's paint was that thick. I've measured all the way into the 70s, topping out into the 90-95 range. None to pleased, but it's a DD so I'll just have to live with it.



That's about how my '01 MPV was. Good incentive to get my wash regimen sorted out ;)



And that was one of those vehicles where the areas that don't show weren't cleared, just a light fogging of basecoat that 3M PI-III MG (of all things!) would cut right through.
 
Accumulator said:
That's about how my '01 MPV was. Good incentive to get my wash regimen sorted out ;)



And that was one of those vehicles where the areas that don't show weren't cleared, just a light fogging of basecoat that 3M PI-III MG (of all things!) would cut right through.



Lol, forum member WeekendWarrior's in-laws have an MPV too, and he told me it's right there in the same range as your old Mazda and mine. At least it's not butter soft like other Japanese cars.
 
mikenap said:
Lol, forum member WeekendWarrior's in-laws have an MPV too...



Ah, yeah, I'd forgotten that! Hope theirs isn't rusting out (inside-out) the way ours did, or having similar (unfixable) drivability issues. That ended up being maybe the worst POS new-car I've ever owned, and that's saying something.
 
They ended up buying a lot of those back.

It was a pretty neat vehicle for it's time, just too many mechanical/brake issues.

Grumpy
 
TOGWT said:
Maybe time to revise my 'safe' numbers



Would be helpful if someone who owns a DeFelsko 6000 or 200/Adv. could take some measurements on those "super-thin" Infinitis and other newer models and show us exactly what we're working with. Considering the number of changes to paint systems and application methods at the OEM level lately there's no telling how the layer-by-layer makeup of the film build actually looks.
 
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