Paint Thickness Gauges

[Tony1]

No trouble at all. You are having trouble (clearly) grasping the fact that if you gauge off a panel and it reads LOW that you SHOULDN'T BE USING ANY HEAVY POLISH ON THAT PANEL.



Clearcoat thickness (only) would be nice, but the purpose of a PTG is to let you know the overall thickness of the paint at the spot you took the reading at. Then WITH EXPERIENCE you can determine whether or not you want to attempt to polish that panel.



It's not supposed to be a catch all for paint problems. It's not the silver bullet of paint correction.

I clearly get that. I also never said not to use the gauge. Just don't put too much faith into it and assume it's safe to cut when it might not be. I have seen good readings and the clear was very thin and damage was done because the person thought it was safe to cut. There was lots of paint according to the gauge but the clear was very thin because he went through very easily. The gauge could not determine the clear coat thickness which is what mattered.



Also in my experience repaints are almost always thicker than original paint so that gives a false sense of safety when measuring the thickness.

 

[Tony1]

Just because you get a low reading does not mean the clear is thin. Just because you get a high reading does not mean the clear is thick.

Which is why the value of using the gauge is low. You seem to get what I'm saying. You need to determine the actual thickness of the clear coat and these run of the mill gauges don't do that. In fact I could argue they are dangerous. They give people a false sense of safety. They get a thick reading and assume there is lots of clear and that is not the case.

 

[Tony1]

That's where experience comes in handy. :rofl

Well Mindflux I'm glad you have xray eyes and can look at the paint and determine it's thickness and break it down and determine the thickness of the clear coat to. You are truly extraordinary.

 

[MarcHarris]

Unless you get the gauges that can actually measure the different layers of material than the gauge is a waste of money and time IMO. The typical gauge measures all the material between it and the metal. How much of that is clear cote? How much is base coat? Unless you know it's pointless.

Yet more misconceptions of ultrasonic thickness gauges...

NO I won't be writing more on this - I've done it about half a dozen times on autopia so if someone wants the information they can find it.

well in an ideal world the base coat, color coat and clear coat are all the same thickness, so the clear would be 1/3 of your total reading on the PTG for that spot.

:

Negative. Base coat is only sprayed to give a solid color. Not only is it very thin / runny compared to the clear coat (why clear usually has the overwhelming majority of orange peel), it offers no protection. Its simply there to give color so is usually sprayed in two light coats - maybe three at most for fanning over metallics / pearls.

Clear coat is thick and is often times "hammered" on as it gives the gloss, protection, UV ray protection, etc, etc. In an ideal world - you'd still spray a lot more clear than base coat

 

[Tony1]

Yet more misconceptions of ultrasonic thickness gauges...

NO I won't be writing more on this - I've done it about half a dozen times on autopia so if someone wants the information they can find it.

OK than is there a truly accurate way to measure actual clear coat? I know I sure won't trust a standard gauge. It really doesn't tell me what I need to know.



Truth is every time you cut the paint you really don't know how thick the clear is.

 

[Dan]

It's not the base thickness that's important it's the clear coat and I agree with you 100%. The problem is if the gauge doesn't determine the two what good is it? Most gauges just measure the total material. How do you determine the clear coat thickness than?

You make an educated guess. A PTG is a tool that requires interpretation, however if you are willing to work with that, you will be rewarded with an extra margin of safety.

 

[Tony1]

You make an educated guess. A PTG is a tool that requires interpretation, however if you are willing to work with that, you will be rewarded with an extra margin of safety.

It's still a guess. I think you will find most people using the cheap gauges think they are safe if they get a thick reading.

 

[Mindflux]

Well Mindflux I'm glad you have xray eyes and can look at the paint and determine it's thickness and break it down and determine the thickness of the clear coat to. You are truly extraordinary.

How does experience=xray eyes.



It's called judgement, you use it based on the criteria at hand. Overall thickness reading via PTG, condition of the paint, location of the spot to be polished/sanded/whatever etc.



You're a riot.

 

[imported_Ivan Rajic]

HighlineII will do everything you need it to do for 225.00, Its a smart investment at times like this. It will give you and you clients a good sense of well being!

Agreed. Have had one for about a year now and comes in very handy. To those who can always spot a repaint by eye, I think you need better body shops in the area haha.



As for the cc vs base thickness argument... a very good way to tell is by measuring underside of panels like the hood, trunk or even door jambs sometimes, because they're rarely ever clearcoated. The measure the paint on top of the panels and with a little simple math you get a pretty good sense of what cc thickness is left over. Usually I'm seeing 1.5-2.0 mils primer+base and 3.5-6.5 mils total thickness, so 2.0-5.0 mils of cc. Anything reading 3.5-4.0 mils total should be corrected carefully and not hammered with wool & M105 or the like.



I do agree the better, more expensive gauges reading in layers are much better for obvious reasons, but the Highline meter is a huge help because I personally can't eyeball a 3.5mil vs 5.5 mil total thickness...

 

[Tony1]

How does experience=xray eyes.



It's called judgement, you use it based on the criteria at hand. Overall thickness reading via PTG, condition of the paint, location of the spot to be polished/sanded/whatever etc.



You're a riot.

Why don't you walk me through the process. You get a car to detail. You measure the paint thickness with the gauge. How does your experience tell you how much clear is there? You have no way of knowing because you never messured the clear. It's a guess at best. You claim to be able to tell so it must be xray eyes.

 

[Tony1]

I do agree the better, more expensive gauges reading in layers are much better for obvious reasons, but the Highline meter is a huge help because I personally can't eyeball a 3.5mil vs 5.5 mil total thickness...

That's because your not Mindflux. He can tell because he is EXPERIENCED :rofl

 

[Mindflux]

Why don't you walk me through the process. You get a car to detail. You measure the paint thickness with the gauge. How does your experience tell you how much clear is there? You have no way of knowing because you never messured the clear. It's a guess at best. You claim to be able to tell so it must be xray eyes.

Clear is - well clear. No Xray needed. Is there orange peel? No? Good chance it's been sanded or has a lead base paint on it (determine age of vehicle)



otherwise you take an educated guess on condition of JUST te clear. Or one could call it calculated risk. But bottom line, if you aren't sanding or doing HEAVY compounding I think you are over worrying.



There's a thread about how much m105 removed with a wool pad on another forum. .01 mil - If you are that thin on clear it should be evident via clearcoat failure signs.

 

[Mindflux]

That's because your not Mindflux. He can tell because he is EXPERIENCED :rofl

Don't mind the troll.

 

[Accumulator]

Some random thoughts from somebody who got by for decades without an ETG but still finds it handy now that he has one:



-It's easy enough to extrapolate useful *relative* info from total-thickness readings. BTDT, had it save me from making some mistakes (and I'm no newcomer likely to make dumb assumptions). Some info is better than *no* info, just gotta watch you don't make incorrect assumptions in the vein where "a little knowledge is a dangerous thing" [insert generic critical-thinking lecture here].



E.g.#1- If nothing else, you can keep track of how much clear you're removing when it's a repeat-correction/customer situation and/or you can spot places that deserve extra consideration on a newcomer ("gee, I wonder why the paint on this half of the hood is so much thinner than on the other half even though they look the same!?!").



E.g.#2- When inspecting a car that oughta have 4.5 mils of total thickness, any area that significantly differs deserves consideration. No, you *can't* always eyeball it, even after thirty-some years of experience



-Consider what materials you'll be working with; fiberglass, aluminum, etc. and get a gauge that'll read off that material.



-Don't buy a PhaseII if you can find something else; I find mine *VERY* userunfriendly compared to other ETGs I've used.

 

[Tony1]

Don't mind the troll.

I think you need to learn what a troll is. I have participated in many threads here and have never just tried to cause trouble. Just because I'm not in agreement with you doesn't make me a troll.



I found some of your comments snarky especially the one when you mentioned experience implying I didn't have any. If you had the experience you think you have you would have seen situations when the thickness was good according to the gauge but the clear was thin.

 

[Tony1]

I'm not saying the gauges have no purpose. There are some situations I find them useful. If I'm working on a car I can take the measurement and it gives me a reading. You start cutting than you can take another reading and see how much you have removed. It still doesn't tell how much of the reading is clear though.

 

[Mindflux]

I think you need to learn what a troll is. I have participated in many threads here and have never just tried to cause trouble. Just because I'm not in agreement with you doesn't make me a troll.



I found some of your comments snarky especially the one when you mentioned experience implying I didn't have any. If you had the experience you think you have you would have seen situations when the thickness was good according to the gauge but the clear was thin.

No, what makes you a troll is the accusations you are making against other members (myself included). You are trolling whether you see it that way or not.



If I were to have experience with 'good' readings on a PTG but finding the clear thin you'd see me posting about burning through clearcoat. Do you see me posting things like that? Nope.

 

[imported_Ivan Rajic]

I'm not saying the gauges have no purpose. There are some situations I find them useful. If I'm working on a car I can take the measurement and it gives me a reading. You start cutting than you can take another reading and see how much you have removed. It still doesn't tell how much of the reading is clear though.

Measure a panel that's not clear coated and you'll get a good estimate of how much cc is on there.

 

[Dan]

Why don't you walk me through the process. You get a car to detail. You measure the paint thickness with the gauge. How does your experience tell you how much clear is there? You have no way of knowing because you never messured the clear. It's a guess at best. You claim to be able to tell so it must be xray eyes.

I go right to the emblems and measure there. If the emblem has an opening it makes it absolute cake. You can also take off body trim, etc. Use that number to find what the original paint thickness was. Then measure the other panels. If the numbers are significantly different, its time to be really careful.



I also use the PTG before doing scratch removal. I measure, set the amount of paint I'm comfortable with removing. Polish, measure, repeat.

 

[Tony1]

No, what makes you a troll is the accusations you are making against other members (myself included). You are trolling whether you see it that way or not.



If I were to have experience with 'good' readings on a PTG but finding the clear thin you'd see me posting about burning through clearcoat. Do you see me posting things like that? Nope.

What accusations have I made? You just made one you can't back up so that makes you a troll. you obviously have an issue with me and are looking for trouble.



I don't believe you would post that you went though the clear.