TOGWT

Clear Coat:
[Two stage paint; base (colour) coat and clear coat was adopted as an automotive industry standard in 1982] The statement that “a sealant has no benefit to the paint ‘because’ there is a clear coat, is baffling, as clear coat is a polyethylene paint but without colour pigmentation, its applied to provide the colour coat (base coat) with shine, if a clear coat did not need a protection applied, there would be no such thing as clear coat failure due to oxidation or any of a myriad of clear coat problems. To provide further improvements in appearance and durability the basecoat / clear coat systems were developed and introduced in the late 70’s. The base coat is comprised primarily of pigments held in place by a polymeric resin film (binder).

Solvent-based paints are categorized by the ratio of solids (resins, pigments, binders, etc.) to liquids (solvents) In the US manufacturers are required to use high solids paints, with a ratio of about 60% solids to 40% solvent. In order to produce a better flow rate a higher percentage of solvents is required, however due to recent volatile organic compound (VOC) limit restrictions; the 60/40 percentage cannot be exceeded. These restrictions stem from the Environmental Protection Agency (EPA) limits on volatile organic compound (VOC), which are in almost all solvents. In other countries, these restrictions either don't exist or are more lenient, allowing manufacturers to use low solids paints (as low as 30% solids to 70% solvent), which tend to have a smoother appearance. To combat these restrictions paint companies are developing new technologies.

High or low solid, is a ratio of paint to solvents - High is 60/40) that leaves more material (coverage) once paint has cured. Low is (30/70, which means the paint contains more solvents, once they have out-gassed (evaporated) leaves a thinner coat (paint thickness)

Waterborne paints, for example, are essentially low solids paints (up to 60% solvent), but they are legal because de-ionized water is used as the solvent, as opposed to volatile organic compounds (VOC). In addition to the low solids aspect, waterborne paints have many other neat properties that help improve the performance and appearance.

Clear Coats are two part systems (either a Urethane, or a good quality non-yellowing Polyurethane and an Epoxy) a solvent based urethane (a water-based clear coat is not yet available) is applied in two layers; it also contains UVR inhibitors Clear coat is not armour plating but by adding UV blockers it provides a level of protection for the colour pigmentation of the base (colour) coat, but it must be protected, and the most durable protection is a polymer sealant.

Durability is really a very real concern for car owners today. With the increase in airborne pollution and other environmental factors, a car's finish is subject to serious damage. Acid rain; jet fuel fallout; industrial fallout; hard water, not to mention high acidic bird droppings; insect residue; tree sap all are very dangerous to a paint finish if not removed immediately. By adding UV blockers to the clear coat you have a new level of protection for the pigments (colour) in the base coat.

Be careful what you use on a paint surface; a polyurethane paint (high solid / low solvent) clear coat can absorb moisture; as water molecules are smaller than a cross-linked clear coats molecule. So be careful of the contents in car wash concentrates, sealant and waxes (i.e. low pH acids, high pH alkaline, Dimethylsilicone (DMS) or solvents that contain butyl, heptanes, and xylene or hydrocarbon Aliphatic solvents.
(See also MSDS, Potential of Hydrogen (pH)

The clear coat finish can become ‘dull’ by using harsh (abrasive) or if a high alkaline car washing solution as used in ‘touch less’ car washing systems, or from industrial airborne pollutants compromising the clear coat allowing the suns heat to dry out and oxidize the paint .

Bear in mind that a clear coat has a thickness of 1.5 – 2.0 Mils, removing more that 0.4 mil (0.0004") of clear coat will cause premature paint film failure. As a point of reference two sheets of Saran wrap placed on top of each other measure 1.5Mil (0.0015") a surface scratch that will `catch' your fingernail is approximately 0.004" deep and will usually require wet sanding and refinishing. There comes a point when you must judge wither removing a scratch will compromise the clear coat and if so you’ll have to ‘live’ with the imperfection

The clear coat is the final original equipment manufacturers coating applied to a vehicle to protect the (base) colour coat while providing both depth and a durable, glossy appearance, originally designed to protect metallic paints, but is now applied to all colours. Any product applied on top of the clear coat needs to be transparent otherwise both the paint colour and its depth of shine will be muted.

If you look at the vehicles on the road today that have a clear coat, they look great for a while, but scratches in the surface will cause white marks to appear, and dents smudge the finish, reducing the clarity of the top coat, which in turn affects both the depth of shine and paint colour showing through. It doesn’t take long before the finish looks dull and lifeless because the clear coat isn’t reflecting light as it once did. A better finish can have a dramatic impact on the residual value of vehicles, and it certainly doesn’t hurt customer satisfaction.
(See also Paint Problems (Orange Peel) Colour Sanding / Polishing, and Polish)

No wax/sealant fluorine-type clear coat finish -
The newest technological advancement in clear coat finishes is a fluorine-type clear coat that needs little or no waxing. Currently available on Nissan Motor Corporation's Infiniti luxury automobile, "no-wax" clear-coats are likely to be available on other cars and from other manufacturers in the future.

The fluorine-type clear coat finish requires special detailing, especially to correct damage to the clear coat, and should be treated exactly per the manufacturer's instructions in the owner's manual. Polishing and waxing in the usual detailing sense are not appropriate for these high-tech finishes. Because no-wax/minimum-wax finishes are so different from conventional finishes and from most other clear-coat finishes that have been available to date, it is likely that each manufacturer that produces such a finish in the future will also include very specific product and procedure recommendations for its individual formulation of no-wax clear coat.

Almost all original equipment manufacturers' (OEM's) automotive paint systems manufactured from 1990 on (with the exception of single stage paint systems) used today have a pigmented base coat protected by a thin layer of clear coat, that contains polymeric resin or binder, UV inhibitors, and generally one or more silicone additives. The base coat is comprised primarily of pigments or colorants held in place by a polymeric resin film (binder). Detailer’s should know, understand and be able to identify a two-stage paint finish. To check, take a cleaner type wax and in an inconspicuous place like a door jam rub the surface using a medium to heavy pressure and wipe off. If there is no paint colour (this is somewhat difficult to see with silver paint) on the cloth it has a clear coat finish.

There are three major paint suppliers to the automotive industry PPG Industries, DuPont Chemicals, and BASF Aktiengesellschaft, they have all have focused on creating super-hard clear coats. These "rigid" clears are more resistant to chemical etching which makes them less susceptible to acid rain spots and owner induced swirls from washing and drying improperly. The disadvantage of rigid clears is their susceptibility to chip when struck by stones or road debris; they also require a more abrasive polish to enable paint repairs. It should be noted that some car manufacturers use a harder clear coat then others, regardless of the cars paint colour (GM Corvette, VW, and Audi etc)

More resilient clear coat-a newer technology (2004) clear coat (CeramiClear) used by Mercedes-Benz and Chrysler, which provides an outstanding premium gloss, distinctness of image and long-lasting colour retention and a hard protective layer, some of the German (Audi, BMW, Porsche, etc) and European vehicle manufacturers have been using a BASF clear coat for some time.

When polishing a clear coat ‘spot’ surface temperature should be limited to 100oF (138oC) as urethane starts to soften at 115oF, just like any other plastic material, polishing at this or elevated temperatures will cause scratches to be driven deeper into the surface due to urethane expansion and foam / wool pad friction on the softened paint surface. Information resource: Heat Vs Urethane Coatings, The Society of Automotive Engineers (SAE) article
(See also Oxidation)

Reference source - Automotive Detailing; Inside & Out, A Knowledge Base for the Perfectionist – by Jon Miller aka TOGWT

TOGWT Copyright © 2002-2007. Jon Miller, all rights reserved

cdodkin

TOGWT - Thanks for the write-up

so when applying a 'layer' of sealant over the clear coat, how much thickness are we actually talking about for that sealant?

And when we add layers, which is a really popular concept - do we really build thickness in the sealant, or are we just polishing the same surface more?

And how can varying the last step product effect the perceived depth of color, if the layer that we're applying that product to is of course already a clear coat?

TOGWT

Q1: So when applying a 'layer' of sealant over the clear coat, how much thickness are we actually talking about for that sealant?
A1: less than 0.000001" thick.

Q2. And when we add layers, which is a really popular concept - do we really build thickness in the sealant, or are we just polishing the same surface more?
A2: Layering:
I prefer the word ‘film’ as opposed to ‘layer’, a film more accurately describes a thinly applied sealant or wax, were as a layer tends to describe a thicker covering. Some specialty paint protection systems can have subsequent film added to increase protection and paint appearance, systems must cure or cross-link prior to application of subsequent coats. Depending on the product type, cure times vary from a few hours to days.

By applying another low-solvent product (Victoria Concours Wax - http://www.victoriawax.com/) on top of one that has already cross-linked you can increase its density (up to a point) two to four cross-linked (cured) applications are usually considered optimum One thing that will negate the applied product density is lack of clarity, the base coat (that contains the vehicle’s colour) is covered / protected by a clear coat of urethane paint, which as well as providing protection is clear to enable the paint colour to show through and provide the colour with depth. Any product applied on top of the clear coat needs to be optically clear (transparent) otherwise both the paint colour and its depth of shine will be muted. One of the problems with ‘layering’ some polymers is that they tend to occlude (become less opaque) as the thickness increases

The viscosity of the previous layer requires more solvent to significantly melt away than the next applied wax layer can contain The carrier system allows the product to fill and level the paint film surface to produce a flat surface (this flat level surface is more pronounced with polymers due to their molecular alignment characteristics). This level surface optimizes the paint film surface's desired optical properties (i.e. surface reflectance, clarity, gloss, and depth of shine)

You could also try this ‘layering’ technique- apply a liquid Carnauba wax (liquid wax usually contains polymer and solvents) and allow to set-up (usually 1-2 hours, do a smear test to endure that its dry and then a apply to a paste Carnauba wax; allow the solvents to evaporate for 2-4 hours, and finally buff surface with a 100% cotton towel (http//: www.DFTowel.com ) to produce jetting (a ‘wet-look’ shine)

Wax- two coats to ensure even coverage (maximum is four) a wax cures (hardens when the solvents have evaporated ) usually 25-45 minuets then you can apply the second coat (ensure that there are no solvents left by doing a smear test otherwise the solvents in the second coat will remove the first) (See also Spit Shine)

Paste wax – use a low-solvent wax (Victoria Concours Wax, Souverän or P21S) is just a thicker form of liquid wax, just a different consistency, not necessarily more or less solvents. Some wax products use an emulsion to keep more liquid without adding solvents which, in high concentrations could remove the underlying wax too rapidly to allow the "melting" together of the wax" strata.

Polymers- some contain a mineral or silicone oil, or solvent based carrier system (these may also be in the form of an oil / water emulsion) and by the nature of this product they need to vaporise / dissipate and then its needs to cross-link (this is time dependant (unless a catalyst is added) and is quite separate from the drying process To my knowledge, all polymer sealants are based on an emulsion system containing petroleum distillates. As a result, even the mildest petroleum distillates remove polymer sealants. Zaino Show Car Polish is the only polymer sealant that I'm aware of that is not based on the element silicone and can therefore be successfully layered (a new application of Zaino Show Car Polish does not remove previous applications).

Solvents / oils provide a lubricant and aid the adherence process by working their way into the microscopic gaps and valleys of the previous `layer' softening it, providing each subsequent applications carrying agent (solvent, oils silicones or emulsion) are not so concentrated that they degrade or remove (as in the case of a cleaner wax) what has been previously applied.

Also be aware that the both the product and the foam pad may be non-abrasive, but application pressure if not kept to an absolute minimum and using use a very light and even pressure, may re-introduce surface marring and/or removal of the previously applied product by friction.
(See also Spit Shining, Wax (Hand applied)

Q3. And how can varying the last step product effect the perceived depth of color, if the layer that we're applying that product to is of course already a clear coat?
A3. Any product applied on top of the clear coat needs to be optically clear (transparent) otherwise both the paint colour and its depth of shine will be muted. One of the problems with ‘layering’ some products (polymer/wax) is that they tend to occlude (become less opaque) as the thickness increases

cdodkin

Mmmmmmm, so that has me wondering.

There are a whole range of sealant products that talk about enhancing the depth of shine by layering applications of the same product 2, 3, 4 20, 40 times, for extra shine.

Klasse SG is a typical example.

Either it's BS, or a psychological benefit, or we are somehow 'adding' shine to the finish with all of these 'coats'?

My personal experience is that 2 coats look and feel better than 1, but after that, ?????????

I have layered polymer sealant with carnauba paste wax over the top, and on certain colors, like Guards Red, this really produces a great wet-look deep color.

But that had me wondering - where the 'wetness' in the look came from, if the original sealant was already optically clear?

Or did the carnauba solvents just dissolve the polymer layer any way?

TOGWT

Q: But that had me wondering - where the 'wetness' in the look came from, if the original sealant was already optically clear?

A wax or sealant can only reflect what is underneath it, so a clean, level well-prepared surface is the most important consideration (85% of a surfaces reflectivity is its preparation) along with applied product clarity.

If you apply a product over a surface that is dirty or one that has surface imperfections a wax or sealant will not disguise it, only highlight them.

The wax can be thought of as semi-solid until the solvent carrier components evaporate, these wax molecules form an egg-grate type mesh over the smaller molecules of the paint film surface, which gives it an optical depth Due to this shape the reflected light becomes somewhat distorted, this produces jetting (the so called ‘wet-look’) sometimes described as liquidity.. Carnauba wax is inherently hydroscopic when exposed to water; wax swells and closes its pores, which along with surface tension, causes `water beading'. (See also Wax, Durability, and Melting Point)

Q; Or did the carnauba solvents just dissolve the polymer layer any way?
Once a product has cross-linked the solvent in a wax (unless it has a very high solvent content) will have only a marginal effect. The products you cited Klasse SG and Pinnacle wax, Klasse SG is an acrylic resin, which cross-links and forms a hard ‘shell’, Pinnacle is a very low solvent product (basically formulated for layering, it's formulation was based on an 'expensive' Zymol product as a cheaper (cost) alternative)

When I entered Concours d’élégance events I used Klasse AIO / Klasee SG x3 and a coat of Zymol Concorse

Hope this helps

cdodkin

Thank you sir!

As always, informative and educational