“When is my paint past the point of no return; necessitating a vehicle repaint”

Polishing alleviates a myriad of paint surface problems. But use abrasive polishes wisely to maintain paint condition and to resolve surface damage problems. But know when to seek alternative methods of damage control and avoid over polishing with harsh, abrasive polishes.

Modern clear coat paint finishes are so good today that they lull people into thinking that vehicle paint has protection and shine when in reality there is not really much there, other than the clear coat that has a thickness of ~25.4 µ. As a point of reference a sheet of copy paper is 89 µ. 

The clear coat provides gloss plus physical protection from the elements, including ultraviolet (UV) radiation, which is in the upper level of a cured clear coat. Most car manufacturers will only allow ~ 25% of the clear-coat thickness to be removed without voiding the paint warranty and long-term durability problems becoming an issue. That means that if you started off with 50µ of clear coat (this will vary by vehicle mfg.) you would only be able to remove 12µ without voiding the paint warranty and possibly having a re-paint (Note: this may vary by vehicle mfg.).

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 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

·         200µ (micron) + 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 mils, very thin paint

These numbers are offered as a guide only, as there are too many variables to provide any more than an approximation.

Ultra violet protection (UV) a clear coat paint (isocyanate polyurethane) provides the colour and base coats with protection, and usually has ultra violet (UV) protection added in the final coating; this tends to migrate towards the upper level of the clear coat (this is why it’s important to check how much of the paint surface you are removing with an abrasive polish)

Removing more than 0.5 mil (12µ) of clear coat will cause premature paint film failure UV protection is a sacrificial / renewable component; this is due to the UV protection layer being degraded by exposure to the elements (sun, sand, road or sea salt, and etc.) it is also water miscible, so it is imperative that you renew it and needs to be re-applied on a regular basis (dependent upon location climatic condition)

Alternatives to abrasive machine polishing

Swissvax Cleaner Fluid Professional Finish - its cut and gloss characteristics make it ideal for removing wash marring and faint swirl marks on all paint types, and its filler-free formula also makes it a great choice for refining out machine holograms after heavy compounding. Add to the equation the fact that it's easy to use, generates no dust and laughs in the face of sticky paint, and it's easy to see why it is a must-have product for minor enhancement duties on all modern Porsches and Range Rovers.

Swissvax Cleaner Fluid Regular - advanced chemical cleaning agents strip away any residual grime and old protective layers, while kaolin clay particles and heavy glazing oils visually reduce the extent of wash marring and minor swirl marks by filling such defects and robbing sunlight of sharp edges off of which to reflect. In short, Swissvax Cleaner Fluid Regular is a great product that effortlessly cleans and transforms the appearance of well-maintained paint in no time at all, which makes it ideal for enthusiasts and professionals alike.

Other Relevant Articles

1.      Clear Coat and UV Protection Removal- http://togwt1980.blogspot.co.uk/2015/05/clear-coat-and-uv-protection-removal.html

2.      The Physics of Polishing - http://togwt1980.blogspot.co.uk/2015/05/the-physics-of-polishing.html

3.      Basics of abrasive polishing - http://togwt1980.blogspot.co.uk/2015/08/basics-of-abrasive-polishing.html

4.      How to determine the least aggressive polishing method? - http://togwt1980.blogspot.co.uk/2015/08/how-to-determine-least-aggressive.html

I would like to think that these articles become an asset to anyone who is new to detailing and to professional’s alike, as well as industry experts who seek to advance their knowledge.

I hope the above article was informative. By having some understanding of the ‘What’ and ‘Why’ as well as the ‘How’ along with a little science to help you understand how the chemicals we use react, you can achieve the results you desire.

I would appreciate it if you would share this article as it helps other detailers further their knowledge.

Questions and/ or constructive comments are always appreciated.

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