What to do when the car paint degrades
What is paint?
Vehicle paint is consisted of two layers of coat- the base coat and protective clearcoat. These two layers combined to create a highly aesthetically pleasing, very durable, and relatively easy to maintain surface.
The color coat of vehicle paint is not near as thick as it was when single stage paints were the norm. Then, you had 4 to 6 mils of paint to safely work with when buffing or sanding a paint imperfection. (One mil equals 1/1000 of an inch or 25 microns. By comparison a dime is over 50 mils thick.) Yet, that’s all the pigmented color that lies beneath the clearcoat of most cars today. (I’ve even heard from one insider that on some lines the color is only .8 mil.) The protective clearcoat is only 1.25 to 2 mils thick. Further, manufacturers can void the warranty if over .3 -.5 mil of clearcoat is removed by buffing or sanding. When the clearcoat is breached, it very quickly is GAME OVER for the pigmented paint below.
Why does paint fade, oxidize, discolor or chalk?
To understand the answer it is useful to explain what goes into a paint or coating since the same factors figure into the loss of color and gloss on any paint system.
All pigmented paints have four basic ingredient categories. Within each category there may be more than one ingredient. The four are: binder, solvent, pigment and additive.
The binder is the resin or blend of resins which give the paint most of its thermal, mechanical and weathering properties. The binder is the backbone of the paint, the foundation upon which every other component is built. Typically, binders are polymeric and are chosen by the formulator to give the optimum combination of cost, quality and performance profile. The solvent or solvents are referred to as carriers because they make the paint flow and “carry” the coating to the surface to be painted. When they are completely evaporated the paint is “cured.” Solvents, which can be oil based, water based or both, as when a water based paint needs a co-solvent that is miscible or compatible with water or dihydrogen monoxide, the chemical name for H2O. They can also have an effect on adhesion by what their degree of surface tension efficiency is.
The pigments are mostly nothing more than extremely finely ground mineral mined from the earth and dispersed into the paint. To be blunt, they’re really just colored dirt. Think of them that way and it’s easy to understand that when left exposed to the elements, without protection from the binder, they become the proverbial “dust in the wind.” There are two types of pigments. The prime pigments give the paint its color and the extender pigments (or fillers) impact hiding, color retention, fungal and algae resistance, and durability. They both provide color opacity to an otherwise clear or translucent binder, weather resistance (elements such as titanium dioxide in either regular grade or micro-fine particles) and corrosion resistance to a paint. They are incredibly small. For instance, a particle of TiO2 is about 200 nanometers in size. You could fit 500 such particles in the width of a human hair. And, they are almost perfectly spherical when new. As paint ages, they lose that perfect sphere shape. What was once a marble becomes a golf ball and eventually a deflated furry tennis ball.
Additives are any modifiers that provide all kinds of special effects to paints, from rheology agents that make a coating flow out better, to ultraviolet absorbers and stabilizers that give it increased resistance to sun fading. They do some wonderful things; but, unfortunately, not for long. Way before a paint loses its integrity and starts to crack, peel or flake, additives are like Elvis, they’ve left the building. This is because the additive migrates to the surface and is dissipated over time rather than developing bond links to the polymer core for longer term stability. Obviously, the only difference between a clearcoat and base coat is the pigmentation. Now that we know the players, we can get to the heart of the answer.
What to do when it does degrade?
For most cars and trucks, compounds and waxes are fine as a temporary “quick fix” that doesn’t cost much. And, we all know, cost is a big factor. But, look at the problem from a different perspective, one more long term. We know the base coat has color but no color intensity or gloss on its own. It relies entirely on the clearcoat to give it a deep luster. Every non-clearcoated paint or fiberglass gelcoat has the same profile when it fades, dull color with diminished or no shine. So, whether clearcoated or not, the real solution is to put on a new layer of clearcoat.
I know you’re thinking, it’s not practical. For cars and trucks…maybe it’s not. But, that doesn’t change the fact that what you want to do for a badly faded surface is restore the original sphericality to the pigment(s) and replace their moisture content. That restores like new color. The clearcoat also gives the paint gloss or shine. If you want to test this notion, take something badly faded and apply an ounce of Mazola corn oil to it. It looks pretty good, doesn’t it? Of course, it won’t last more than a day, which just emphasizes the importance of choosing a clearcoat for long-term durability.
Think about offering your customers, and people who aren’t now your customers, something new. Be their clearcoat detailer. Check supplier training, on-going support, and reputation. Use your wash bay at night when it is not making you any money. Maybe start a mobile business. Bottom line, you can make a great deal of money doing something really needed, restoring the original color and gloss to almost every dull, faded, oxidized surface.
To illustrate, I’ve included a before and after photo I’m sure you can relate to. It shows the hood of a 1992 Jeep that recently came into our shop in Atlanta. The clearcoating was peeling badly. We washed it thoroughly, and then wet sanded the surface until all the loose clearcoating was removed. When we sprayed it with our clearcoating, all the paint was restored. Not a perfect job, I’ll admit; but, an adequate one with a very pleased customer.
Hopefully, I’ve given you a better understanding of the paint weathering process.