Detailing Questions (Fibreglass & Glass protection coating)

[Adrianw]

Hi,

I have a TVR which a detailing specialist has offered to undertake the following work

Full paint correction
Glass sealant coating

I have two questions

1) Full paint correction usually requires measuring the paint depth via an electrical current , how difficult is this to manage on a fibre glass body ?

2) Does anyone have any experience of the glass sealant coating process and this worth the extra cost ? or it have any disadvantages ?

Many Thanks

[domster]

1. There are sonic paint thickness gauges for plastic panelled vehicles, but all PTG readings need to be interpreted and the devices are not infallible. They have a use but are relied upon too much and over-hyped IMO compared to real world value and real world detailing (you could never use a PTG and be absolutely fine applying common sense).

2. Good glass sealants have a tangible performance advantage to traditional products, because they are often based on covalent silane technology and can bond to the glass effectively using molecular bonds (glass is a relatively reactive substrate). Make sure it a decent 'nano' style product though.

[waxaholic]

This ^^^

[mike9009]

domster said:

1. There are sonic paint thickness gauges for plastic panelled vehicles, but all PTG readings need to be interpreted and the devices are not infallible. They have a use but are relied upon too much and over-hyped IMO compared to real world value and real world detailing (you could never use a PTG and be absolutely fine applying common sense).

Surely PTGs are simply ultrasonic depth gauges and results should not need to be 'interpretted'. It is a simple calculation of the speed of sound through the material (paint) and the time taken to travel through the paint to an interface. (admittably variables such as paint density, external temperature etc do have an impact on the speed of sound through the material

TBH I have never used the PTGs used within this industry - but have done a fair amount of work completing Gage R&Rs on ultrasonic equipment used to measure the wall thickness of injected wax patterns to ceramic cores for turbine blades (some less than 0.6mm) and achieving 5% Study variance GRR results on some pretty tight tolerances. So I wouldn't call the technology poor as nearly all cored turbine blades in aerospace technologies are checked using a similar methodology.

Only commenting because I was surprised by your comments about paint depth measurement based on my own experience within a different industry.....

As usual I have gone way off topic......

Mike

[Adrianw]

Many thanks for all your advice , one last question the glass coat is "22PLE VX1 Pro Signature"
is this any good or should I go for something better ?

[waxaholic]

Adrianw said:

Many thanks for all your advice , one last question the glass coat is "22PLE VX1 Pro Signature"
is this any good or should I go for something better ?

It is one of the latest coatings on the market, i have not used it myself but
imagine that it performs as good gtech or carpro coatings.

[kds keltec]

mike9009 said:

Surely PTGs are simply ultrasonic depth gauges and results should not need to be 'interpretted'. It is a simple calculation of the speed of sound through the material (paint) and the time taken to travel through the paint to an interface. (admittably variables such as paint density, external temperature etc do have an impact on the speed of sound through the material

TBH I have never used the PTGs used within this industry - but have done a fair amount of work completing Gage R&Rs on ultrasonic equipment used to measure the wall thickness of injected wax patterns to ceramic cores for turbine blades (some less than 0.6mm) and achieving 5% Study variance GRR results on some pretty tight tolerances. So I wouldn't call the technology poor as nearly all cored turbine blades in aerospace technologies are checked using a similar methodology.

Only commenting because I was surprised by your comments about paint depth measurement based on my own experience within a different industry.....

As usual I have gone way off topic......

Mike

mike you are quoting a figure thats nearly 10 times thicker than whats on a car and calling it low figure.

I can add to this as it would of been me and Dom talking about PDG on training days , and Dom famously asking "do you have to have a PDG to detail as a hobby?" and "do you need one of its your full time job"

A few considerations to think of

1) I trained over 100 pupils last year (2012) and many had a cheap PDG these all apart from one read 15% higher than an expensive accurate PDG that’s been calibrated.
2) These gauges only read total paint depth NOT individual layers and using magnetic and eddy current to obtain paint depth
3) These gauges only work on metal ferrous and non-ferrous
4) The average paint depth of factory standard car is 100-120 microns total depth some as low as 70 mircons , or the thickness of a piece of high quality A4 paper or another way 0.07mm to 0.12mm
5) Paint depth gauges that read in multiple layers are very expensive
6) Paint depth gauges that read multiple layers use ultrasound to obtain paint depth
7) The ultrasound gauges are best used on no metal surfaces for absolute accuracy but will work ok on metal surfaces
8) Ultrasound depth gauges work better on large paint thicknesses with strong joining boundary’s between paint layers
9) The ultrasound gauge has a scale called “gates” that have to be zoomed out to get complete picture of total amount then zoom in on many more readings in exact same area to obtain the “real” top layer paint depth

So the above means any carbon / plastic / fibre glass panel can ONLY be measured using ultrasound gauge which has to be interpreted each time a reading is taken or recorded.

Reason for this is car panels have underlying structures that can interfere with the readings.
The paint depth layers the gauge it trying to separate can be as low as 5-20 microns

The paint depth layers won’t show if a good key between coats (i.e. becomes one layer) or the paint system used was wet on wet again all the layers become one layer.

With this is mind you have to use body shop and paint back ground knowledge and some common sense and plenty of time to take CORRECT reading around entire car.

I have spoken to a lot of detailers that have gave up using the ultrasound gauge as they want a point and squirt gauge one that works first time every time.

Its just too much faffing around for many people who detail in one day to use such a machine

I have seen many posts of such a gauge showing a value when i can clearly see it not set correctly to give such a reading , its a scientific gauge thats requires setting / zeroing being used by guys that come from valeting trade, sometimes it wont always go perfectly.

so whats more dangerous a gauge being used incorrectly showing plenty of paint when in fact theres not going full guns at the paint or a person thats not got a gauge being very careful while machine polishing?

i think this is Doms take on the PDG subject

Seen a few of these gauges being sold on the sales section of DW through lack of use.

I use mine a lot thou

kelly

Edited by kds keltec on Friday 4th January 11:53

Edited by kds keltec on Friday 4th January 12:03

[kds keltec]

As for the coating you will be fine ,jsut as good as many other similar coatings on the market

but does need time to cure and should not get it wet before curing the best bond and results.

Of course the look and finish comes from the prep work not the coating but i think you know this and why you have chosen a detailer to undertake the work

kelly

[domster]

Hi Mike
The machines can be accurate, but what the user takes away from the result can be misleading. That is really what I meant to say. They can do more harm than good due to the large number of variables and also (often) spurious results. You can see a broad range of accurate paint readings over the same panel, for example, where the paint is sprayed thickly or thinly. Say the variation is 140-150 microns, which is very plausible (the variation may be far higher!). If Joe Detailer takes a high reading and leaves it at that he may think there is 150 microns everywhere he could wet sand himself into trouble if actually it is 140 in places - strike through tends to be just at one point.
It's really a 'rough gauge' in use, and I always like getting an overall picture from taking dozens of readings. Same when we use our Sheen Glossmeter. Only a fool takes one reading. We take dozens or even hundreds, then average. When you do the averaged multiple readings again after having made your changes, then a result can be extrapolated.

[mike9009]

Thanks for the feedback gents. The accuracy of measurement I generally got was in the region of +/-0.005mm in a production environment.

But I think the other points about taking single readings and using one reading to judge the amount of paint removal sounds more valid...... always good to learn something new - some stage I may even detail (machine polish) my hand-roller painted campervan. It looks good from a few paces away but up close it is like the surface of the moon. I presume a roller painted van (completed by previous owner) would have a fair thickness of paint on it compared to a factory sprayed car - but maybe I need a PTG??

Mike