Clear Coat and UV Protection Removal

[togwt]

Clear Coat and UV Protection Removal



There are two considerations; how much clear coat and how much ultra violet protection can be removed, they are not interchangeable. The following are the maximum allowable clear coat reductions the major USA car manufacturers will allow before the paint warranty becomes void; Chrysler- 0.5 Mil (12µ) Ford – 0.3 Mil (7.5 µ) GM – 0.5 Mil (12µ) (Source - Automotive International)



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 manufacturer) 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 as the paint of cross-links along with the thinner solvents and particulates, 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 e 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 ultra violet inhibitors).



Be cognizant that ultra violet protection 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 ultra violet protection, its long-term durability and / or the paint warranty



Paint Removed by Polish or Compound



Using a medium abrasive polish and a rotary polisher will remove approximately 2.5 - 3µ (0. 1 Mil) from the paint surface, which is typically four passes at 1500-1800 RPM; however many variables such as polish/compound and speed / pressure used and etc that may affect the amount of paint and ultra violet protection removed



If you have reservations about the amount of paint surface removed or the amount of paint remaining the use of a paint thickness gauge (PTG) is arbitrary. There comes a point when you must judge wither removing a scratch will compromise the clear coat and / or UV protection, if so you’ll have to ‘live’ with the imperfection

.

Paint thickness will often depend upon the OEM paint specification, which can vary by vehicle assembly plant. It’s interesting to note that painters must now demonstrate proficiency with an electronic paint thickness gauge in order to become certified to perform paint refinish warranty work for General Motors Corp. (GM) vehicles



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



Notes:

1. The elongation (elasticity) of paint enables it to move in tandem with the metal as it expands and contracts due to environmental temperature fluctuations; for this reason note the paint temperature when taking readings as they can vary in accordance to the surface temperature.

2. Measure your paint thickness in a very cold environment, then measure it when the paint surface is hot to the touch, you may find it varies by as much as a 2µ(microns)



Paint Insurance



The newer coatings available like synthetic polymers are a cross-linking thermoplastic, its cross-linking process attaches the polymer with covalent bond that becomes part of the surface of the material it is attached to, which in effect becomes a secondary protection for the clear coat, in fact a relatively inexpensive (when compared to repainting) renewable sacrificial coating.



Silica (AQuartz) or reactive resin hydrophobic coatings (OPT Opti-Coatâ„¢); think paint sealant that has greater durability and scratch resistance (9H) something that also provides a self-cleaning protection, with a durability on a timescale measured in years rather than months, these coatings add a measurable protection of 2-3 µ microns to the clear coat.



Opti-Coatâ„¢ is not a nano particle; it is rather a pre-polymer that cross links and forms a continuous film on the surfaces it is applied to, similar to a single component isocyanate that forms a clear coat finish. It is very resistant to alkaline car wash concentrates as used by car wash spas and tunnel wash companies



The coating is very low maintenance and requires cleaning less often than conventional paint protection products. Provided the surface is kept free of abrasive grime, bird excrement or other acids, the coating should last for around two years. Coating longevity will be improved if the paint surface is cleaned on a regular basis, and only with either normal pH car care concentrate shampoo or a citrus degreaser.



After Care



To enable a vehicle to maintain its value original paint that is in good condition is an asset. People are keeping their vehicles an average of nearly nine years. Making you client aware of how to wash and dry a paint surface while inflicting the least amount of damage will help to avoid the need to overly polish the clear coat to remove scratches and the subsequent loss of both clear coat and ultra violet paint protection. Providing this kind of value added-value services will enhance your reputation and enable you to become the source for both ethical service and high quality work. As with the successful sale of any product, educating the customer is the key.

[wascallyrabbit]

nice article. you`ve now made me smater.

[Lotuseffect]

Great info. I always thought the UV protection and inhibitors were sprayed on separately at the plant after the initial clear spraying. It makes sense for them to be able to migrate to the surface as well, since that is where they are needed.



I wonder if we have a chemist familiar with the actual process on the forum who can sshed some light on how much clear they believe is safely removable before we are actually endangering our customers.

[lostdaytomorrow]

Good article and well-written but lacks and source citing. Do you have any source for those figures you give or is that anecdotal?

[togwt]

Good article and well-written but lacks and source citing. Do you have any source for those figures you give or is that anecdotal?

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



Research - always keep an open mind and I would also strongly suggest that you verify any information that I or anyone else shares with you. Be pro-active and research others opinions and products, test them and then make an objective decision based upon the factual information gained from research. Don’t regard any source as something you can entirely rely on

[Darkstar752]

Thanks for the info TOWGT!